# kb

id: yau-s-conjecture-on-the-first-eigenvalue-20260505-0
file: data/en.wikipedia.org/wiki/Yau's_conjecture_on_the_first_eigenvalue-0.md
category: reference
title: Yau's conjecture on the first eigenvalue
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Yau's_conjecture_on_the_first_eigenvalue
date_saved: 2026-05-05T11:04:06.733095+00:00
instance: kb-cron
parent: yau-s-conjecture-on-the-first-eigenvalue-20260505-0
summary:
In mathematics, Yau's conjecture on the first eigenvalue is, as of 2018, an unsolved conjecture proposed by Shing-Tung Yau in 1982. It asks: Is it true that the first eigenvalue for the Laplace–Beltrami operator on an embedded closed minimal hypersurface of S n + 1 {\displaystyle S^{n+1}} is n {\displaystyle n} ? If true, it will imply that the area of embedded minimal hypersurfaces in S 3 {\displaystyle S^{3}} will have an upper bound depending only on the genus. The Yau's conjecture is verified for several special cases, but still open in general. Shiing-Shen Chern conjectured that a closed, minimally immersed hypersurface in S n + 1 {\displaystyle S^{n+1}} (1), whose second fundamental form has constant length, is isoparametric. If true, it would have established the Yau's conjecture for the minimal hypersurface whose second fundamental form has constant length. A possible generalization of the Yau's conjecture: Let M d {\displaystyle M^{d}} be a closed minimal submanifold in the unit sphere S N + 1 {\displaystyle S^{N+1}} (1) with dimension d {\displaystyle d} of M d {\displaystyle M^{d}} satisfying d ≥ 2 n / 3 + 1 {\displaystyle d\geq 2n/3+1} . Is it true that the first eigenvalue of M d


id: list-of-unsolved-problems-in-neuroscience-20260505-0
file: data/en.wikipedia.org/wiki/List_of_unsolved_problems_in_neuroscience-0.md
category: reference
title: List of unsolved problems in neuroscience
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/List_of_unsolved_problems_in_neuroscience
date_saved: 2026-05-05T11:04:08.315856+00:00
instance: kb-cron
parent: list-of-unsolved-problems-in-neuroscience-20260505-0
summary:
The following is a list of notable unsolved problems in neuroscience. A problem is considered unsolved if no answer is known or if there is significant disagreement among experts about a proposed solution. == Consciousness == Consciousness: How can consciousness be defined? What is the neural basis of subjective experience, cognition, wakefulness, alertness, arousal, and attention? Binding problem: How exactly is it that objects, background, and abstract or emotional features are combined into a single experience? What is the neural basis of self? Quantum mind: Do quantum mechanical phenomena, such as entanglement and superposition, play an important part in the brain's function and can it explain critical aspects of consciousness? Is there a "hard problem of consciousness"? If so, how is it solved? Vertiginous question: Why is it that a specific subject of experience is "live" from a given perspective? What, if anything, is the function of consciousness? Problem of mental causation: How exactly do mental states cause intentional actions to happen? What is the nature and mechanism behind near-death experiences? How can death be defined? Can consciousness exist after death? If consciousness is generated by brain activity, then how do some patients with physically deteriorated brains suddenly gain a


id: activation-synthesis-hypothesis-20260505-0
file: data/en.wikipedia.org/wiki/Activation-synthesis_hypothesis-0.md
category: reference
title: Activation-synthesis hypothesis
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Activation-synthesis_hypothesis
date_saved: 2026-05-05T11:04:09.469790+00:00
instance: kb-cron
parent: activation-synthesis-hypothesis-20260505-0
summary:
The activation-synthesis hypothesis, proposed by Harvard University psychiatrists John Allan Hobson and Robert McCarley, is a neurobiological theory of dreams first published in the American Journal of Psychiatry in December 1977. The differences in neuronal activity of the brainstem during waking and REM sleep were observed, and the hypothesis proposes that dreams result from brain activation during REM sleep. Since then, the hypothesis has undergone an evolution as technology and experimental equipment has become more precise. Currently, a three-dimensional model called AIM Model, described below, is used to determine the different states of the brain over the course of the day and night. The AIM Model introduces a new hypothesis that primary consciousness is an important building block on which secondary consciousness is constructed. == Background == With the advancement of brain imaging technology, the sleep-waking cycle can be studied as never before. The brain can be objectively quantified and identified as being in either one of three states: awake, REM sleep, and NREM sleep due to these advanced methods of measurement. It has been shown that global deactivation of the brain from waking state to NREM sleep occurs, and a subsequent reactivation during REM sleep, to a degree greater


id: activation-synthesis-hypothesis-20260505-1
file: data/en.wikipedia.org/wiki/Activation-synthesis_hypothesis-1.md
category: reference
title: Activation-synthesis hypothesis
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Activation-synthesis_hypothesis
date_saved: 2026-05-05T11:04:09.469790+00:00
instance: kb-cron
parent: activation-synthesis-hypothesis-20260505-0
summary:
=== REM === REM sleep may be a more evolutionarily recent sleep state, and is prominent in most birds and mammals, although may exist in reptiles and other vertebrates to varying degrees. REM stands for rapid eye movement. It is generally a later sleep state following non-REM (NREM) sleep. It is regulated in part by the pontine brainstem. Infants spend most of their time in REM sleep, and rather than enter stage 1 sleep they may go directly to REM sleep. Most REM sleep occurs just above stage I of sleep, and experiences different mental abilities than during NREM sleep. The thought process is sometimes non-logical or even bizarre, sensation and perception is vivid but created internally by the brain, and the body's movements are inhibited. Most REM stages last 10–15 minutes, and the average human will go through 4–6 of these stages during sleep each night. Subsequent REM stages increase in duration, so the last REM stage before awakening is the longest and thus may have the most vivid dream imagery. It has been proposed that REM sleep is necessary for preparation of many integrative functions, of which one is consciousness. It supports the idea that sleep, and dreaming,


id: activation-synthesis-hypothesis-20260505-2
file: data/en.wikipedia.org/wiki/Activation-synthesis_hypothesis-2.md
category: reference
title: Activation-synthesis hypothesis
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Activation-synthesis_hypothesis
date_saved: 2026-05-05T11:04:09.469790+00:00
instance: kb-cron
parent: activation-synthesis-hypothesis-20260505-0
summary:
==== Activation (A) ==== Large parts of the brain that are activated and sending signals during waking are inactive during NREM sleep and become reactivated during REM sleep. It is based on the fact that the brain and its neural circuitry is plastic and self-regulating, especially in its own activation and inactivation. This was observed by two experiments: development of sleepiness after dopamine neuron destruction in substantia nigra in the midbrain, and discovery of the reticular activating system, which are visual cues received through our eyes and to our brain that begin the waking process, that waking consciousness depends sleep. Following these studies, it became clear that activity levels and quality of consciousness were functions of brain activation and deactivation. ==== Input-output gating (I) ==== It has been shown that the internal activation of the brain is associated with the inhibition of both external sensory input and motor output. This implies that the brain is actively kept offline during REM, and the brainstem guarantees the coordination of factors I and A via the input-output gate control within the brainstem. PGO waves play a part in the ability of the brain to remain asleep while constituting the building blocks for perception


id: als-20260505-0
file: data/en.wikipedia.org/wiki/ALS-0.md
category: reference
title: ALS
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/ALS
date_saved: 2026-05-05T11:04:10.701513+00:00
instance: kb-cron
parent: als-20260505-0
summary:
Amyotrophic lateral sclerosis (ALS), also known as motor neuron disease (MND) or Lou Gehrig's disease, is a rare terminal neurodegenerative disease defined by the progressive loss of both upper and lower motor neurons that normally control voluntary muscle contraction. ALS is the most common of the motor neuron diseases. ALS often presents with gradual muscle stiffness, twitches, weakness, and wasting. Motor neuron loss typically continues until the ability to eat, speak, move, and breathe without mechanical support is lost. At least 50% of people with ALS experience significant changes in thinking and behavior, with 15% of individuals going on to develop frontotemporal dementia. An ALS diagnosis is made based on a person's signs and symptoms, with additional testing conducted to rule out other potential causes. Depending on which areas of the body are affected first, ALS may be classified as limb-onset (beginning with weakness in the arms or legs) or bulbar-onset (beginning with difficulty in speaking or swallowing). Respiratory onset occurs in approximately 1–3% of cases. Most cases of ALS (about 90–95%) have no known cause and are known as sporadic ALS. Genetic, autoimmune, and environmental factors are believed to be involved in the onset of ALS. Approximately 5–10% of


id: als-20260505-1
file: data/en.wikipedia.org/wiki/ALS-1.md
category: reference
title: ALS
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/ALS
date_saved: 2026-05-05T11:04:10.701513+00:00
instance: kb-cron
parent: als-20260505-0
summary:
Classical ALS accounts for about 70% of all cases of ALS and can be subdivided into cases where symptoms first appear, as these are usually focused on one region of the body at initial presentation before later spread. Limb-onset ALS (also known as spinal-onset) and bulbar-onset ALS. Limb-onset ALS begins with weakness in the hands, arms, feet, and/or legs and accounts for about two-thirds of all classical ALS cases. Bulbar-onset ALS begins with weakness in the muscles of speech, chewing, and swallowing and accounts for about 25% of classical ALS cases. A rarer type of classical ALS affecting about 3% of patients is respiratory-onset, in which the initial symptoms are difficulty breathing (dyspnea) upon exertion, at rest, or while lying flat (orthopnea). Primary lateral sclerosis (PLS) accounts for about 5% of all ALS cases and only affects the upper motor neurons in the arms, legs, and bulbar region. However, more than 75% of people with apparent PLS go on to later develop lower motor neuron signs within four years of symptom onset, meaning that a definitive diagnosis of PLS cannot be made until several years have passed. PLS has a better prognosis than classical ALS, as it progresses more slowly,


id: als-20260505-2
file: data/en.wikipedia.org/wiki/ALS-2.md
category: reference
title: ALS
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/ALS
date_saved: 2026-05-05T11:04:10.701513+00:00
instance: kb-cron
parent: als-20260505-0
summary:
=== Progression === Although the initial site of symptoms and subsequent rate of disability progression vary from person to person, the initially affected body region is usually the most affected over time, and symptoms usually spread to a neighbouring body region. For example, symptoms starting in one arm usually spread to either the opposite arm or to the leg on the same side. Bulbar-onset patients most typically experience their next symptoms in their arms rather than legs, arm-onset patients typically spread to the legs before the bulbar region, and leg-onset patients typically spread to the arms rather than the bulbar region. Over time, regardless of where symptoms began, most people eventually lose the ability to walk or use their hands and arms independently. They may also lose the ability to speak and to swallow food. It is the eventual development of weakness of the respiratory muscles, with the loss of ability to cough and to breathe without mechanical support, that is ultimately life-shortening in ALS. The rate of progression can be measured using the ALS Functional Rating Scale - Revised (ALSFRS-R), a 12-item instrument survey administered as a clinical interview or self-reported questionnaire that produces a score between 48 (normal


id: als-20260505-3
file: data/en.wikipedia.org/wiki/ALS-3.md
category: reference
title: ALS
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/ALS
date_saved: 2026-05-05T11:04:10.701513+00:00
instance: kb-cron
parent: als-20260505-0
summary:
=== Cognitive, emotional, and behavioral symptoms === Cognitive impairment or behavioral dysfunction is present in 30–50% of individuals with ALS, and can appear more frequently in later stages of the disease. Language dysfunction, executive dysfunction, and troubles with social cognition and verbal memory are the most commonly reported cognitive symptoms in ALS. Cognitive impairment is found more frequently in patients with C9orf72 gene repeat expansions, bulbar onset, bulbar symptoms, family history of ALS and/or a predominantly upper motor neuron phenotype. Pseudobulbar affect and emotional lability are a type of symptom in which patients cry, smile, yawn, or laugh, either in the absence of emotional stimuli, or when they are feeling the opposite emotion to that being expressed. Approximately half of ALS patients experience this; it is more common in those with bulbar-onset ALS. While more or less benign relative to other symptoms, it can cause increased stigma and social isolation as people around the patient struggle to react appropriately to what can be frequent and inappropriate outbursts in public. In addition to mild changes in cognition that may only emerge during neuropsychological testing, around 10–15% of individuals have signs of frontotemporal dementia (FTD). Repeating phrases or gestures, apathy, and loss


id: als-20260505-4
file: data/en.wikipedia.org/wiki/ALS-4.md
category: reference
title: ALS
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/ALS
date_saved: 2026-05-05T11:04:10.701513+00:00
instance: kb-cron
parent: als-20260505-0
summary:
=== Environmental and other factors === The multi-step hypothesis suggests the disease is caused by some interaction between an individual's genetic risk factors and their cumulative lifetime of exposures to environmental factors, termed their exposome. The most consistent lifetime exposures associated with developing ALS (other than genetic mutations) include heavy metals (e.g. lead and mercury), chemicals (e.g. pesticides and solvents), electric shock, physical injury (including head injury), and smoking (in men more than women). Generally, the effect of each exposure is relatively small. For instance, an individual's lifetime risk of developing ALS might increase from "1 in 400" without exposure to between "1 in 300" and "1 in 200" if they were exposed to heavy metals. Some industries are heavily dependent upon the use or exposure to these environmental factors, which may increase employees' susceptibility. For example, agricultural tasks may involve as many as 5 such risk factors excluding workers' smoking habits. A range of other factors have weaker evidence supporting them and include participation in professional sports, having a lower body mass index, lower educational attainment, manual occupations, military service, exposure to beta-Methylamino-L-alanine (BMAA), and viral infections. Although some personality traits, such as openness, agreeableness and conscientiousness appear remarkably


id: als-20260505-5
file: data/en.wikipedia.org/wiki/ALS-5.md
category: reference
title: ALS
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/ALS
date_saved: 2026-05-05T11:04:10.701513+00:00
instance: kb-cron
parent: als-20260505-0
summary:
Neurodegeneration in ALS is thought to involve many different cellular and molecular processes. The genes known to be involved in ALS can be grouped into three general categories based on their normal function: protein degradation, the cytoskeleton, and RNA processing. Mutant SOD1 protein forms intracellular aggregations that inhibit protein degradation. Cytoplasmic aggregations of wild-type (normal) SOD1 protein are common in sporadic ALS. It is thought that misfolded mutant SOD1 can cause misfolding and aggregation of wild-type SOD1 in neighboring neurons in a prion-like manner. Other protein degradation genes that can cause ALS when mutated include VCP, OPTN, TBK1, and SQSTM1. Three genes implicated in ALS that are important for cytoskeletal maintenance and axonal transport include DCTN1, PFN1, and TUBA4A. Several ALS genes encode RNA-binding proteins. The first to be discovered was TDP-43 protein, a nuclear protein that aggregates in the cytoplasm of motor neurons in almost all cases of ALS; however, mutations in TARDBP, the gene that codes for TDP-43, are a rare cause of ALS. FUS codes for FUS, another RNA-binding protein with a similar function to TDP-43, which can cause ALS when mutated. It is thought that mutations in TARDBP and FUS increase the binding affinity of the


id: als-20260505-6
file: data/en.wikipedia.org/wiki/ALS-6.md
category: reference
title: ALS
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/ALS
date_saved: 2026-05-05T11:04:10.701513+00:00
instance: kb-cron
parent: als-20260505-0
summary:
=== Differential diagnosis === Because symptoms of ALS can be similar to those of a wide variety of other diseases or disorders, appropriate tests must be conducted to exclude the possibility of other conditions. One of these tests is electromyography (EMG), a special recording technique that detects electrical activity in muscles. Certain EMG findings can support the diagnosis of ALS. Another common test measures nerve conduction velocity (NCV). Specific abnormalities in the NCV results may suggest, for example, that the person has a form of peripheral neuropathy (damage to peripheral nerves) or myopathy (muscle disease) rather than ALS. While a magnetic resonance imaging (MRI) is often normal in people with early-stage ALS, it can reveal evidence of other problems that may be causing the symptoms, such as a spinal cord tumor, multiple sclerosis, a herniated disc in the neck, syringomyelia, or cervical spondylosis. Based on the person's symptoms and findings from these tests, the physician may order tests on blood and urine samples to eliminate the possibility of other diseases, as well as routine laboratory tests. In some cases, for example, if a physician suspects the person may have a myopathy rather than ALS, a muscle biopsy may be performed.


id: als-20260505-7
file: data/en.wikipedia.org/wiki/ALS-7.md
category: reference
title: ALS
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/ALS
date_saved: 2026-05-05T11:04:10.701513+00:00
instance: kb-cron
parent: als-20260505-0
summary:
Riluzole has been found to modestly prolong survival by about 2–3 months. It may have a greater survival benefit for those with bulbar-onset ALS. It may work by decreasing release of the excitatory neurotransmitter glutamate from pre-synaptic neurons. The most common side effects are nausea and a lack of energy (asthenia). People with ALS should begin treatment with riluzole as soon as possible following their diagnosis. Riluzole is available as a tablet, liquid, or dissolvable oral film. Edaravone has been shown to modestly slow the decline in function in a small group of people with early-stage ALS. It may work by protecting motor neurons from oxidative stress. The most common side effects are bruising and gait disturbance. Edaravone is available as an intravenous infusion or as an oral suspension. Tofersen (Qalsody) is an antisense oligonucleotide that was approved for medical use in the United States in April 2023 for the treatment of SOD1-associated ALS. In a study of 108 patients with SOD1-associated ALS there was a non-significant trend towards a slowing of progression, as well as a significant reduction in neurofilament light chain, a putative ALS biomarker thought to indicate neuronal damage. A follow-up study and open-label extension suggested that


id: als-20260505-8
file: data/en.wikipedia.org/wiki/ALS-8.md
category: reference
title: ALS
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/ALS
date_saved: 2026-05-05T11:04:10.701513+00:00
instance: kb-cron
parent: als-20260505-0
summary:
==== Invasive ventilation ==== Invasive ventilation bypasses the nose and mouth (the upper airways) by making a cut in the trachea (tracheostomy) and inserting a tube connected to a ventilator. It is an option for people with advanced ALS whose respiratory symptoms are poorly managed despite continuous NIV use. While invasive ventilation prolongs survival, especially for those younger than 60, it does not treat the underlying neurodegenerative process. The person with ALS will continue to lose motor function, making communication increasingly difficult and sometimes leading to locked-in syndrome, in which they are completely paralyzed except for their eye muscles. About half of the people with ALS who choose to undergo invasive ventilation report a decrease in their quality of life, but most still consider it to be satisfactory. However, invasive ventilation imposes a heavy burden on caregivers and may decrease their quality of life. Attitudes toward invasive ventilation vary from country to country; about 30% of people with ALS in Japan choose invasive ventilation, versus less than 5% in North America and Europe. === Therapy === Physical therapy plays a large role in rehabilitation for individuals with ALS. Specifically, physical, occupational, and speech therapists can set goals and promote benefits


id: als-20260505-9
file: data/en.wikipedia.org/wiki/ALS-9.md
category: reference
title: ALS
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/ALS
date_saved: 2026-05-05T11:04:10.701513+00:00
instance: kb-cron
parent: als-20260505-0
summary:
=== End-of-life care === Palliative care, which relieves symptoms and improves the quality of life without treating the underlying disease, should begin shortly after someone is diagnosed with ALS. Early discussion of end-of-life issues gives people with ALS time to reflect on their preferences for end-of-life care and can help avoid unwanted interventions or procedures. Once they have been fully informed about all aspects of various life-prolonging measures, they can fill out advance directives indicating their attitude toward noninvasive ventilation, invasive ventilation, and feeding tubes. Late in the disease course, difficulty speaking due to muscle weakness (dysarthria) and cognitive dysfunction may impair their ability to communicate their wishes regarding care. Continued failure to solicit the preferences of the person with ALS may lead to unplanned and potentially unwanted emergency interventions, such as invasive ventilation. If people with ALS or their family members are reluctant to discuss end-of-life issues, it may be useful to use the introduction of gastrostomy or noninvasive ventilation as an opportunity to bring up the subject. Hospice care, or palliative care at the end of life, is especially important in ALS because it helps to optimize the management of symptoms and increases the likelihood of a peaceful


id: als-20260505-10
file: data/en.wikipedia.org/wiki/ALS-10.md
category: reference
title: ALS
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/ALS
date_saved: 2026-05-05T11:04:10.701513+00:00
instance: kb-cron
parent: als-20260505-0
summary:
Descriptions of the disease date back to at least 1824 by Charles Bell. In 1850, François-Amilcar Aran was the first to describe a disorder he named "progressive muscular atrophy", a form of ALS in which only the lower motor neurons are affected. In 1869, the connection between the symptoms and the underlying neurological problems was first described by Jean-Martin Charcot, who initially introduced the term amyotrophic lateral sclerosis in his 1874 paper. Flail arm syndrome, a regional variant of ALS, was first described by Alfred Vulpian in 1886. Flail leg syndrome, another regional variant of ALS, was first described by Pierre Marie and his student Patrikios in 1918. === Diagnostic criteria === In the 1950s, electrodiagnostic testing (EMG) and nerve conduction velocity (NCV) testing began to be used to evaluate clinically suspected ALS. In 1969, Edward H. Lambert published the first EMG/NCS diagnostic criteria for ALS, consisting of four findings he considered to strongly support the diagnosis. Since then, several diagnostic criteria have been developed, which are mostly in use for research purposes for inclusion/exclusion criteria, and to stratify patients for analysis in trials. Research diagnostic criteria for ALS include the "El Escorial" in 1994, revised in 1998. In 2006,


id: alzheimer-s-disease-20260505-0
file: data/en.wikipedia.org/wiki/Alzheimer's_disease-0.md
category: reference
title: Alzheimer's disease
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Alzheimer's_disease
date_saved: 2026-05-05T11:04:11.975566+00:00
instance: kb-cron
parent: alzheimer-s-disease-20260505-0
summary:
Alzheimer's disease (AD) is a neurodegenerative disease and is the most common form of dementia, accounting for around 60–70% of cases. The most common early symptom is difficulty in remembering recent events. As the disease advances, symptoms can include problems with language, disorientation (including easily getting lost), mood swings, loss of motivation, self-neglect, and behavioral issues. As a person's condition declines, they often withdraw from family and society. Gradually, bodily functions are lost, ultimately leading to death. Although the speed of progression can vary, the average life expectancy following diagnosis is three to twelve years. The causes of Alzheimer's disease remain poorly understood. There are many environmental and genetic risk factors associated with its development. The strongest genetic risk factor is from an allele of apolipoprotein E, a protein involved in the metabolism of fats in mammals. Other risk factors include a history of head injury, clinical depression, and high blood pressure. The progression of the disease is largely characterised by the accumulation of malformed protein deposits in the cerebral cortex, called amyloid plaques and neurofibrillary tangles. These misfolded protein aggregates interfere with normal cell function, and over time lead to irreversible degeneration of neurons and loss of synaptic connections


id: alzheimer-s-disease-20260505-1
file: data/en.wikipedia.org/wiki/Alzheimer's_disease-1.md
category: reference
title: Alzheimer's disease
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Alzheimer's_disease
date_saved: 2026-05-05T11:04:11.975566+00:00
instance: kb-cron
parent: alzheimer-s-disease-20260505-0
summary:
=== Early stage === In people with Alzheimer's disease, the increasing impairment of learning and memory eventually leads to a definitive diagnosis. In a small percentage, difficulties with language, executive functions, perception (agnosia), or execution of movements (apraxia) are more prominent than memory problems. Alzheimer's disease does not affect all memory capacities equally. Older memories of the person's life (episodic memory), facts learned (semantic memory), and implicit memory (the memory of the body on how to do things, such as using a fork to eat or how to drink from a glass) are affected to a lesser degree than new facts or memories. Language problems are mainly characterised by a shrinking vocabulary and decreased word fluency, leading to a general impoverishment of oral and written language. In this stage, the person with Alzheimer's is usually capable of communicating basic ideas adequately. While performing fine motor tasks such as writing, drawing, or dressing, certain movement coordination and planning difficulties (apraxia) may be present; however, they are commonly unnoticed. As the disease progresses, people with Alzheimer's disease can often continue to perform many tasks independently; however, they may need assistance or supervision with the most cognitively demanding activities. === Middle stage ===


id: alzheimer-s-disease-20260505-2
file: data/en.wikipedia.org/wiki/Alzheimer's_disease-2.md
category: reference
title: Alzheimer's disease
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Alzheimer's_disease
date_saved: 2026-05-05T11:04:11.975566+00:00
instance: kb-cron
parent: alzheimer-s-disease-20260505-0
summary:
Only 1–2% of Alzheimer's cases are inherited due to autosomal dominant mutations, as Alzheimer's disease is substantially polygenic. When autosomal dominant variants cause the disease, it is known as early-onset familial Alzheimer's disease, which is rarer and tends to progress more rapidly. Less than 5% of sporadic Alzheimer's disease have an earlier onset, and early-onset Alzheimer's is about 90% heritable. Familial Alzheimer's disease usually implies two or more persons affected in one or more generations. Early onset familial Alzheimer's disease can be attributed to mutations in one of three genes: those encoding amyloid-beta precursor protein (APP) and presenilins PSEN1 and PSEN2. Most mutations in the APP and presenilin genes increase the production of a small protein called amyloid beta (Aβ)42, which is the main component of amyloid plaques. Some of the mutations merely alter the ratio between Aβ42 and the other major forms—particularly Aβ40—without increasing Aβ42 levels in the brain. Two other genes associated with autosomal dominant Alzheimer's disease are ABCA7 and SORL1. Alleles in the TREM2 gene have been associated with a three to five times higher risk of developing Alzheimer's disease. A Japanese pedigree of familial Alzheimer's disease was found to be associated with a deletion mutation of


id: alzheimer-s-disease-20260505-3
file: data/en.wikipedia.org/wiki/Alzheimer's_disease-3.md
category: reference
title: Alzheimer's disease
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Alzheimer's_disease
date_saved: 2026-05-05T11:04:11.975566+00:00
instance: kb-cron
parent: alzheimer-s-disease-20260505-0
summary:
==== Infection ==== The possibility that infectious agents cause Alzheimer's disease has been considered since the early 20th century, when Oskar Fischer likened amyloid plaques to small masses (called 'Drusen') of a microbe called actinomyces. Since then, at least 15 different agents, including bacteria, viruses, fungi and protozoa, have been proposed to cause Alzheimer's disease. No definitive evidence has been presented that a specific infectious agent is necessary and sufficient to cause Alzheimer's disease. However, it is possible that microbial infections might act as risk factors for the disease. For example, human herpes viruses such as HSV-1, HHV-6, and HHV-7 have been linked to the risk of Alzheimer's disease. In addition, some pathogens have been reported to seed Aβ deposition in the brain, and aggregated Aβ has antimicrobial properties, suggesting that Aβ plaques might form when brain cells generate Aβ to fight infection. Researchers caution that brain infections can cause dementia by mechanisms unrelated to Alzheimer's disease. ==== DNA damage ==== DNA damage accumulates in affected brains; reactive oxygen species may be the major source of this DNA damage. ==== Cholinergic ==== The cholinergic hypothesis proposes that the loss of neurons in the basal forebrain, which produce the neurotransmitter acetylcholine,


id: alzheimer-s-disease-20260505-4
file: data/en.wikipedia.org/wiki/Alzheimer's_disease-4.md
category: reference
title: Alzheimer's disease
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Alzheimer's_disease
date_saved: 2026-05-05T11:04:11.975566+00:00
instance: kb-cron
parent: alzheimer-s-disease-20260505-0
summary:
The gross (macroscopic) appearance of the brain in Alzheimer's disease is variable. In many cases the cortical sulci are widened and the gyri are shrunken, but the degree of cortical atrophy varies. It can sometimes be difficult to discern, particularly in the very elderly. The areas most affected by atrophy are the medial temporal lobe including the hippocampal formation, the amygdala, the frontal lobe and the parietal lobe; the occipital lobe is relatively unaffected by atrophy. The volume of the ventricles increases in parallel with cortical shrinkage. Studies using MRI and PET have documented reductions in the size of specific brain regions in people with Alzheimer's disease as they progress from mild cognitive impairment to Alzheimer's disease, and in comparison with similar images from healthy older adults. These macroscopic changes in the brain are not specific to Alzheimer's and can occur in other disorders and to some extent in normal aging. At the microscopic level, the defining histopathologic characteristics of Alzheimer's disease are abundant amyloid plaques and neurofibrillary tangles in certain brain regions. Both of these abnormalities are clearly visible by microscopy, and amyloid imaging. In the early stages of disease, tangles are present mainly in the medial temporal lobe


id: alzheimer-s-disease-20260505-5
file: data/en.wikipedia.org/wiki/Alzheimer's_disease-5.md
category: reference
title: Alzheimer's disease
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Alzheimer's_disease
date_saved: 2026-05-05T11:04:11.975566+00:00
instance: kb-cron
parent: alzheimer-s-disease-20260505-0
summary:
=== Disease mechanism === Exactly how disturbances of production and aggregation of the Aβ peptide give rise to the pathology of Alzheimer's disease is not known. The amyloid hypothesis (also known as the 'amyloid cascade hypothesis') posits that the accumulation of abnormally shaped Aβ peptides is the central event triggering the sequence of changes that eventually lead to neurodegeneration and dementia. Misfolded Aβ accumulates in the brain because it causes normal Aβ molecules to similarly misfold by a prion-like 'seeding' mechanism. The aggregated Aβ takes the form of small oligomers (which are particularly toxic to neurons) and amyloid fibrils, the long polymers that are the main components of Aβ plaques. Some researchers have argued that the amyloid fibrils bind up smaller oligomers and thus protect brain cells from the injurious effects of the oligomers. However, the plaques are not benign inasmuch as they are associated with abnormal neuronal processes and local inflammation. Whatever the relative influence of Aβ oligomers and fibrils, the presence of aggregated Aβ is associated with the disruption of neuronal metabolism and various other changes such as inflammation. Aβ also selectively builds up in mitochondria in the cells of Alzheimer's-affected brains, and it inhibits certain enzyme functions


id: alzheimer-s-disease-20260505-6
file: data/en.wikipedia.org/wiki/Alzheimer's_disease-6.md
category: reference
title: Alzheimer's disease
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Alzheimer's_disease
date_saved: 2026-05-05T11:04:11.975566+00:00
instance: kb-cron
parent: alzheimer-s-disease-20260505-0
summary:
Alzheimer's disease (AD) can only be definitively diagnosed with autopsy findings; in the absence of autopsy, clinical diagnoses of AD are "possible" or "probable", based on other findings. Up to 23% of those clinically diagnosed with AD may be misdiagnosed and may have pathology suggestive of another condition with symptoms that mimic those of AD. AD is usually clinically diagnosed based on a person's medical history, observations from friends or relatives, and behavioral changes. The presence of characteristic neuropsychological changes with impairments in at least two cognitive domains that are severe enough to affect a person's functional abilities is required for the diagnosis. Domains that may be impaired include memory (most commonly impaired), language, executive function, visuospatial functioning, or other areas of cognition. The neurocognitive changes must be a decline from a prior level of function, and the diagnosis requires ruling out other common causes of neurocognitive decline. Advanced medical imaging with computed tomography (CT) or magnetic resonance imaging (MRI), and with single-photon emission computed tomography (SPECT) or positron emission tomography (PET), can be used to help exclude other cerebral pathology or subtypes of dementia. On MRI or CT, Alzheimer's disease usually shows a generalised or focal cortical atrophy, which


id: alzheimer-s-disease-20260505-7
file: data/en.wikipedia.org/wiki/Alzheimer's_disease-7.md
category: reference
title: Alzheimer's disease
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Alzheimer's_disease
date_saved: 2026-05-05T11:04:11.975566+00:00
instance: kb-cron
parent: alzheimer-s-disease-20260505-0
summary:
Neuropsychological tests including cognitive tests such as the mini–mental state examination (MMSE), the Montreal Cognitive Assessment (MoCA) and the Mini-Cog are widely used to aid in diagnosis of the cognitive impairments in AD. These tests may not always be accurate, as they lack sensitivity to mild cognitive impairment, and can be biased by language or attention problems; more comprehensive test arrays are necessary for high reliability of results, particularly in the earliest stages of the disease. Further neurological examinations are crucial in the differential diagnosis of Alzheimer's disease and other diseases. Interviews with family members are used in assessment, and caregivers can supply important information on daily living abilities and on the decrease in the person's mental function. A caregiver's viewpoint is particularly important, since a person with Alzheimer's disease is commonly unaware of their deficits. Many times, families have difficulties in the detection of initial dementia symptoms and may not communicate accurate information to a physician. Supplemental testing can rule out other potentially treatable diagnoses and help avoid misdiagnoses. Common supplemental tests include blood tests, thyroid function tests, as well as tests to assess vitamin B12 levels, rule out neurosyphilis and rule out metabolic problems (including tests for kidney


id: alzheimer-s-disease-20260505-8
file: data/en.wikipedia.org/wiki/Alzheimer's_disease-8.md
category: reference
title: Alzheimer's disease
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Alzheimer's_disease
date_saved: 2026-05-05T11:04:11.975566+00:00
instance: kb-cron
parent: alzheimer-s-disease-20260505-0
summary:
Certain lifestyle activities, such as physical and cognitive exercises, higher education and occupational attainment, cigarette smoking, stress, sleep, and the management of other comorbidities, including diabetes and hypertension, may affect the risk of developing AD. Physical exercise is associated with a decreased rate of dementia, and is effective in reducing symptom severity in those with AD. Memory and cognitive functions can be improved with aerobic exercises including brisk walking three times weekly for forty minutes. It may also induce neuroplasticity of the brain. Participating in mental exercises, such as reading, crossword puzzles, and chess have reported potential to be preventive. Meeting the WHO recommendations for physical activity is associated with a lower risk of AD. Higher education and occupational attainment, and participation in leisure activities, contribute to a reduced risk of developing AD, or of delaying the onset of symptoms. This is compatible with the cognitive reserve theory, which states that some life experiences result in more efficient neural functioning, providing the individual with a cognitive reserve that delays the onset of dementia. Education delays the onset of Alzheimer's disease syndrome without changing the duration of the disease. Cessation in smoking may reduce the risk of developing AD, specifically in


id: alzheimer-s-disease-20260505-9
file: data/en.wikipedia.org/wiki/Alzheimer's_disease-9.md
category: reference
title: Alzheimer's disease
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Alzheimer's_disease
date_saved: 2026-05-05T11:04:11.975566+00:00
instance: kb-cron
parent: alzheimer-s-disease-20260505-0
summary:
=== Psychosocial === Psychosocial interventions are used as an adjunct to pharmaceutical treatment and can be classified within behavior-, emotion-, cognition- or stimulation-oriented approaches. Behavioral interventions attempt to identify and reduce the antecedents and consequences of problem behaviors. This approach has not reported success in improving overall functioning, but can help to reduce some specific problem behaviors, such as incontinence. There is a lack of high quality data on the effectiveness of these techniques in other behavior problems such as wandering. Music therapy is effective in reducing behavioral and psychological symptoms. Emotion-oriented interventions include reminiscence therapy, validation therapy, supportive psychotherapy, sensory integration, also called snoezelen, and simulated presence therapy. A Cochrane review has found no evidence that this is effective. Reminiscence therapy (RT) involves the discussion of past experiences, individually or in groups, many times with the aid of photographs, household items, music and sound recordings, or other familiar items from the past. A 2018 review of the effectiveness of RT found that effects were inconsistent, small in size, and of doubtful clinical significance, and varied by setting. Simulated presence therapy (SPT) is based on attachment theories and involves playing a recording with the voices of the closest relatives of


id: alzheimer-s-disease-20260505-10
file: data/en.wikipedia.org/wiki/Alzheimer's_disease-10.md
category: reference
title: Alzheimer's disease
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Alzheimer's_disease
date_saved: 2026-05-05T11:04:11.975566+00:00
instance: kb-cron
parent: alzheimer-s-disease-20260505-0
summary:
Regarding incidence, where a disease-free population is followed over the years have shown rates between 10 and 15 per thousand person-years for all dementias and 5–8 for AD in Spain and Italy, which means that half of new dementia cases each year are Alzheimer's disease. Advancing age is a primary risk factor for the disease, and incidence rates are not equal for all ages: every 5 years after the age of 65, the risk of acquiring the disease approximately doubles, increasing from 3 to as much as 69 per thousand person-years. The prevalence of AD in populations is dependent upon factors including incidence and survival. Since the incidence of AD increases with age, prevalence depends on the mean age of the population for which prevalence is given. In the United States in 2020, AD dementia prevalence was estimated to be 5.3% for those in the 60–74 age group, with the rate increasing to 13.8% in the 74–84 group and to 34.6% in those greater than 85. Prevalence rates in some less developed regions around the globe are lower. Both the prevalence and incidence rates of AD are steadily increasing, and the prevalence rate is estimated to triple by 2050 reaching


id: alzheimer-s-disease-20260505-11
file: data/en.wikipedia.org/wiki/Alzheimer's_disease-11.md
category: reference
title: Alzheimer's disease
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Alzheimer's_disease
date_saved: 2026-05-05T11:04:11.975566+00:00
instance: kb-cron
parent: alzheimer-s-disease-20260505-0
summary:
=== Social costs === Dementia, and specifically Alzheimer's disease, may be among the most costly diseases for societies worldwide. As populations age, these costs will probably increase and become an important social problem and economic burden. Costs associated with AD include direct and indirect medical costs, which vary between countries depending on social care for a person with AD. Direct costs include doctor visits, hospital care, medical treatments, nursing home care, specialised equipment, and household expenses. Indirect costs include the cost of informal care and the loss in productivity of informal caregivers. In the United States as of 2019, informal (family) care is estimated to constitute nearly three-fourths of caregiving for people with AD at a cost of US$234 billion per year and approximately 18.5 billion hours of care. The cost to society worldwide to care for individuals with AD is projected to increase nearly ten-fold, and reach about US$9.1 trillion by 2050. Costs for those with more severe dementia or behavioral disturbances are higher and are related to the additional caregiving time to provide physical care. === Caregiving burden === Individuals with Alzheimer's will require assistance in their lifetime, and care will most likely come in the form of


id: attention-20260505-0
file: data/en.wikipedia.org/wiki/Attention-0.md
category: reference
title: Attention
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Attention
date_saved: 2026-05-05T11:04:13.138266+00:00
instance: kb-cron
parent: attention-20260505-0
summary:
Attention is the concentration of awareness directed at some task or phenomenon while mostly excluding others. Across disciplines, the nature of this directedness is conceptualized in different ways. In cognitive psychology, attention is often described as the allocation of limited cognitive processing resources to a subset of information, thoughts, or tasks. In neuropsychology, attention is understood as a set of mechanisms by which sensory cues and internal goals modulate neuronal tuning and orient behavioral and cognitive processes. Attention is not a unitary phenomenon but an umbrella term for multiple related processes, including selective attention (prioritizing some stimuli over others), sustained attention (maintaining focus), divided attention (sharing resources across tasks), and orienting (shifting focus in space or time). These processes are supported by distributed neural networks in frontal, parietal, and subcortical regions and are closely linked to working memory, executive functions, and consciousness. Patterns of attention also vary across cultures, especially in how individuals attend to context versus focal objects and how children are guided to manage attention in everyday activities. == History == === 16th century === John B. Watson called Juan Luis Vives the father of modern psychology. In his book De Anima et Vita, Vives argued that the


id: attention-20260505-1
file: data/en.wikipedia.org/wiki/Attention-1.md
category: reference
title: Attention
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Attention
date_saved: 2026-05-05T11:04:13.138266+00:00
instance: kb-cron
parent: attention-20260505-0
summary:
Modern experimental work began with investigations of the "cocktail party problem" by Colin Cherry in 1953. Cherry asked how people at a noisy party can attend to one conversation while ignoring others. He studied this through dichotic listening tasks, in which participants heard two simultaneous streams of speech through headphones and were asked to shadow (repeat) one stream while ignoring the other. These paradigms were extended by Donald Broadbent and others. By the 1990s, psychologists increasingly used positron emission tomography (PET) and functional magnetic resonance imaging (fMRI) to study attention in the brain. Because this equipment was typically housed in hospitals, psychologists collaborated with neurologists. Psychologist Michael Posner and neurologist Marcus Raichle pioneered imaging studies of selective attention. The adoption of neuroimaging, alongside long-standing techniques such as electroencephalography (EEG), led to extensive research on the neural basis of attention. A growing body of work identified a frontoparietal attention network implicated in the control of attention. == Components == Attention is constrained by both the number of elements that can be processed and the duration of exposure. Experimental studies of attention began with Wundt’s findings. He suggested the scope of attention limited to about 3–6 items. Decades of research on subitizing


id: attention-20260505-2
file: data/en.wikipedia.org/wiki/Attention-2.md
category: reference
title: Attention
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Attention
date_saved: 2026-05-05T11:04:13.138266+00:00
instance: kb-cron
parent: attention-20260505-0
summary:
=== Load === Some individuals can perform certain overlearned tasks with minimal conscious attention. For example, highly trained Morse code operators have been shown to copy messages accurately while engaging in a concurrent conversation. This reflects the development of automaticity through extensive practice: once a skill is overlearned beyond 100% accuracy, its execution can become largely autonomous and require fewer attentional resources. Perceptual load theory proposes that attentional resources are limited and must be fully used. Under high perceptual load, fewer resources remain available for processing irrelevant stimuli, reducing distraction; under low load, more resources “spill over”, increasing susceptibility to distraction. In applied settings, such as education, measurement often emphasizes accuracy and reaction time (RT), which can obscure finer-grained distributions of temporal and spatial attention. === Neural correlates === Eric Knudsen identified four fundamental components of attention: (a) working memory, (b) competitive selection, (c) top-down sensitivity control, and (d) salience filters. At different hierarchical levels, spatial maps enhance or inhibit activity in sensory areas and guide orienting behaviors such as eye movements: At higher levels, the frontal eye fields (FEF) and dorsolateral prefrontal cortex contain retinocentric spatial maps. Microstimulation in the FEF can induce saccades to specific locations, and subthreshold


id: attention-20260505-3
file: data/en.wikipedia.org/wiki/Attention-3.md
category: reference
title: Attention
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Attention
date_saved: 2026-05-05T11:04:13.138266+00:00
instance: kb-cron
parent: attention-20260505-0
summary:
Divided attention refers to attempts to allocate attention to multiple sources of information or tasks at the same time. In everyday language, this is often called multitasking. Research consistently shows that people make more errors and perform tasks more slowly when multitasking than when focusing on one task at a time. Early research examined limits on learning and perception when people performed simultaneous tasks, such as reading while listening and writing something else, or listening to two different messages through each ear (dichotic listening). Later work examined divided attention in applied settings such as driving while tuning a radio or driving while talking on a phone. Most contemporary research on multitasking investigates dual-task performance, often combining driving with secondary tasks such as texting, eating, or conversing. These studies show that driving performance deteriorates under dual-task conditions: drivers are more error-prone, brake harder and later, drift across lanes, and show reduced awareness of their surroundings. There is little difference between speaking on hands-free versus hand-held phones, suggesting that the primary limitation is cognitive rather than motor. In contrast, passengers in the car can adapt their conversation to the demands of driving (e.g., pausing when traffic becomes complex), reducing interference. Daniel Kahneman


id: attention-20260505-4
file: data/en.wikipedia.org/wiki/Attention-4.md
category: reference
title: Attention
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Attention
date_saved: 2026-05-05T11:04:13.138266+00:00
instance: kb-cron
parent: attention-20260505-0
summary:
=== Filter === Broadbent's Filter Model of Attention proposed that sensory information is briefly held in a pre-attentive store, and a filter selects input based on simple physical characteristics (e.g., location, pitch). Selected information passes into a limited capacity processing system, while unattended inputs are blocked and not semantically processed. This implies that information in the unattended channel does not reach meaning-level analysis, and that shifting the filter between channels requires time. Experiments by Gray and Wedderburn and subsequent work by Anne Treisman challenged this strict early filter model, leading to refinements. In Treisman’s attenuation model, unattended inputs are not completely blocked; instead, they are attenuated and can be processed to some extent, especially if they are highly salient (e.g., a person’s own name). Deutsch and Deutsch later proposed a late selection model in which all inputs are processed semantically, and selection occurs at the point of response or conscious access. In this view, the ‘‘attentional bottleneck’’ occurs late, after semantic analysis. === Selection === Debates between early-selection and late-selection models centered on whether unattended information is processed semantically. Early-selection models (e.g., Broadbent, Treisman) posit that attention acts before full semantic analysis, whereas late-selection models (e.g., Deutsch & Deutsch) posit


id: autosomal-dominant-nocturnal-frontal-lobe-epilepsy-20260505-0
file: data/en.wikipedia.org/wiki/Autosomal_dominant_nocturnal_frontal_lobe_epilepsy-0.md
category: reference
title: Autosomal dominant nocturnal frontal lobe epilepsy
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Autosomal_dominant_nocturnal_frontal_lobe_epilepsy
date_saved: 2026-05-05T11:04:14.343019+00:00
instance: kb-cron
parent: autosomal-dominant-nocturnal-frontal-lobe-epilepsy-20260505-0
summary:
Autosomal dominant nocturnal frontal lobe epilepsy (ADNFLE) is an epileptic disorder that causes frequent violent seizures during sleep. These seizures often involve complex motor movements, such as hand clenching, arm raising/lowering, and knee bending. Vocalizations such as shouting, moaning, or crying are also common. ADNFLE is often misdiagnosed as nightmares. Attacks often occur in clusters and typically first manifest in childhood. There are four known loci for ADNFLE, three with known causative genes. These genes, CHRNA4, CHRNB2, and CHRNA2, encode various nicotinic acetylcholine receptor α and β subunits. == Signs and symptoms == == Causes == While not well understood, it is believed that malfunction in thalamocortical loops plays a vital role in ADNFLE. The reasons for this belief are threefold. Firstly, thalamocortical loops are important in sleep and the frontal cortex is the origin of ADNFLE seizures. Secondly, both the thalamus and cortex receive cholinergic inputs and acetylcholine receptor subunits comprise the three known causative genes for ADNFLE. Thirdly, K-complex are almost invariably present at the start of seizures. == Mechanism == === CHRNA4 === The first mutation associated with ADNFLE is a serine to phenylalanine transition at position 248 (S248F), located in the second transmembrane spanning region of


id: awareness-20260505-0
file: data/en.wikipedia.org/wiki/Awareness-0.md
category: reference
title: Awareness
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Awareness
date_saved: 2026-05-05T11:04:15.557513+00:00
instance: kb-cron
parent: awareness-20260505-0
summary:
In psychology and philosophy, awareness is the perception or knowledge of something. The concept is often synonymous with consciousness; however, one can be aware of something without being explicitly conscious of it (e.g., blindsight). The states of awareness are also associated with the states of experience, so that the structure represented in awareness is mirrored in the structure of experience. == Concept == Awareness is a relative concept. It may refer to an internal state, such as a visceral feeling, or on external events by way of sensory perception. It is analogous to sensing something, a process distinguished from observing and perceiving (which involves a basic process of acquainting with the items we perceive). Awareness can be described as something that occurs when the brain is activated in certain ways, such as when the color red is seen once the retina is stimulated by light waves. This conceptualization is posited due to the difficulty in developing an analytic definition of awareness or sensory awareness. Awareness is also associated with consciousness in the sense that it denotes a fundamental experience such as a feeling or intuition that accompanies the experience of phenomena. Specifically, this is referred to as awareness of experience.


id: awareness-20260505-1
file: data/en.wikipedia.org/wiki/Awareness-1.md
category: reference
title: Awareness
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Awareness
date_saved: 2026-05-05T11:04:15.557513+00:00
instance: kb-cron
parent: awareness-20260505-0
summary:
Living systems are cognitive systems, and living as a process is a process of cognition. This statement is valid for all organisms, with or without a nervous system. This theory contributes a perspective that cognition is a process present at organic levels that people do not usually consider to be aware. Given the possible relationship between awareness and cognition, and consciousness, this theory contributes an interesting perspective in the philosophical and scientific dialogue of awareness and living systems theory. == Communications and information systems == In cooperative settings, awareness is a term used to denote "knowledge created through the interaction of an agent and its environment — in simple terms 'knowing what is going on'". In this setting, awareness is meant to convey how individuals monitor and perceive the information surrounding their colleagues and the environment they are in. This information is incredibly useful and critical to the performance and success of collaborations. Awareness can be further defined by breaking it down into a set of characteristics: Knowledge about the state of some environment Environments are continually changing, therefore awareness knowledge must be constantly maintained Individuals interact with the environment, and maintenance of awareness is accomplished through this interaction. Generally


id: binding-problem-20260505-0
file: data/en.wikipedia.org/wiki/Binding_problem-0.md
category: reference
title: Binding problem
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Binding_problem
date_saved: 2026-05-05T11:04:16.760782+00:00
instance: kb-cron
parent: binding-problem-20260505-0
summary:
The unity of consciousness and (cognitive) binding problem is the problem of how objects, background, and abstract or emotional features are combined into a single experience. The binding problem refers to the overall encoding of our brain circuits for the combination of decisions, actions, and perception. It is considered a "problem" because no complete model exists. The binding problem can be subdivided into the four areas of perception, neuroscience, cognitive science, and the philosophy of mind. It includes general considerations on coordination, the subjective unity of perception, and variable binding. == General considerations on coordination == === Summary of problem === Attention is crucial in determining which phenomena appear to be bound together, noticed, and remembered. This specific binding problem is generally referred to as temporal synchrony. At the most basic level, all neural firing and its adaptation depends on specific consideration to timing (Feldman, 2010). At a much larger level, frequent patterns in large scale neural activity are a major diagnostic and scientific tool. === Synchronization theory and research === A popular hypothesis mentioned by neuroscientist Peter Milner, in his 1974 article A Model for Visual Shape Recognition, has been that features of individual objects are bound/segregated via synchronization


id: binding-problem-20260505-1
file: data/en.wikipedia.org/wiki/Binding_problem-1.md
category: reference
title: Binding problem
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Binding_problem
date_saved: 2026-05-05T11:04:16.760782+00:00
instance: kb-cron
parent: binding-problem-20260505-0
summary:
=== Summary of problem === The visual feature binding problem refers to the question of why we do not confuse a red circle and a blue square with a blue circle and a red square. The understanding of the circuits in the brain stimulated for visual feature binding is increasing. A binding process is required for us to accurately encode various visual features in separate cortical areas. In her feature integration theory, Treisman suggested that one of the first stages of binding between features is mediated by the features' links to a common location. The second stage is combining individual features of an object that requires attention, and selecting that object occurs within a "master map" of locations. Psychophysical demonstrations of binding failures under conditions of full attention provide support for the idea that binding is accomplished through common location tags. An implication of these approaches is that sensory data such as color or motion may not normally exist in "unallocated" form. For Merker: "The 'red' of a red ball does not float disembodied in an abstract color space in V4." If color information allocated to a point in the visual field is converted directly, via the instantiation of some


id: binding-problem-20260505-2
file: data/en.wikipedia.org/wiki/Binding_problem-2.md
category: reference
title: Binding problem
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Binding_problem
date_saved: 2026-05-05T11:04:16.760782+00:00
instance: kb-cron
parent: binding-problem-20260505-0
summary:
=== Summary of problem === Smythies defines the combination problem, also known as the subjective unity of perception, as "How do the brain mechanisms actually construct the phenomenal object?". Revonsuo equates this to "consciousness-related binding", emphasizing the entailment of a phenomenal aspect. As Revonsuo explores in 2006, there are nuances of difference beyond the basic BP1:BP2 division. Smythies speaks of constructing a phenomenal object ("local unity" for Revonsuo) but philosophers such as René Descartes, Gottfried Wilhelm Leibniz, Immanuel Kant, and James (see Brook and Raymont) have typically been concerned with the broader unity of a phenomenal experience ("global unity" for Revonsuo) – which, as Bayne illustrates may involve features as diverse as seeing a book, hearing a tune and feeling an emotion. Further discussion will focus on this more general problem of how sensory data that may have been segregated into, for instance, "blue square" and "yellow circle" are to be re-combined into a single phenomenal experience of a blue square next to a yellow circle, plus all other features of their context. There is a wide range of views on just how real this "unity" is, but the existence of medical conditions in which it appears to be subjectively


id: binding-problem-20260505-3
file: data/en.wikipedia.org/wiki/Binding_problem-3.md
category: reference
title: Binding problem
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Binding_problem
date_saved: 2026-05-05T11:04:16.760782+00:00
instance: kb-cron
parent: binding-problem-20260505-0
summary:
==== fMRI work ==== Stoll and colleagues conducted an fMRI experiment to see whether participants would view a dynamic bistable stimulus globally or locally. Responses in lower visual cortical regions were suppressed when participants viewed the stimulus globally. However, if global perception was without shape grouping, higher cortical regions were suppressed. This experiment shows that higher order cortex is important in perceptual grouping. Grassi and colleagues used three different motion stimuli to investigate scene segmentation or how meaningful entities are grouped together and separated from other entities in a scene. Across all stimuli, scene segmentation was associated with increased activity in the posterior parietal cortex and decreased activity in lower visual areas. This suggests that the posterior parietal cortex is important for viewing an integrated whole. ==== EEG work ==== Mersad and colleagues used an EEG frequency tagging technique to differentiate between brain activity for the integrated whole object and brain activity for parts of the object. The results showed that the visual system binds two humans in close proximity as part of an integrated whole. These results are consistent with evolutionary theories that face-to-face bodies are one of the earliest representations of social interaction. It also supports other experimental


id: binding-problem-20260505-4
file: data/en.wikipedia.org/wiki/Binding_problem-4.md
category: reference
title: Binding problem
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Binding_problem
date_saved: 2026-05-05T11:04:16.760782+00:00
instance: kb-cron
parent: binding-problem-20260505-0
summary:
=== Modern theories === Daniel Dennett has proposed that we, as humans, sensing our experiences as individual single events is illusory and that, instead, at any one time there are "multiple drafts" of sensory patterns at multiple sites. Each would only cover a fragment of what we think we experience. Arguably, Dennett is claiming that consciousness is not unified and there is no phenomenal binding problem. Most philosophers have difficulty with this position (see Bayne), but some physiologists agree with it. In particular, the demonstration of perceptual asynchrony in psychophysical experiments by Moutoussis and Zeki, where color is perceived before orientation of lines and before motion by 40 and 80 ms respectively, constitutes an argument that, over these very short time periods, different attributes are consciously perceived at different times, leading to the view that at least over these brief periods of time after visual stimulation, different events are not bound to each other, leading to the view of a disunity of consciousness, at least over these brief time intervals. Dennett's view might be in keeping with evidence from recall experiments and change blindness purporting to show that our experiences are much less rich than we sense them to be


id: binding-problem-20260505-5
file: data/en.wikipedia.org/wiki/Binding_problem-5.md
category: reference
title: Binding problem
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Binding_problem
date_saved: 2026-05-05T11:04:16.760782+00:00
instance: kb-cron
parent: binding-problem-20260505-0
summary:
== Shared intentionality and binding == According to bioengineer Igor Val Danilov, the mother–fetus neurocognitive model—knowledge about neurophysiological processes during shared intentionality—can reveal insights into the binding problem and even the perception of object development since intentionality succeeds before organisms confront the binding problem. Indeed, at the beginning of life, the environment is the cacophony of stimuli: electromagnetic waves, chemical interactions, and pressure fluctuations. Because the environment is uncategorised for the organisms at this beginning stage of development, the sensation is too limited by the noise to solve the cue problem—the relevant stimulus cannot overcome the noise magnitude if it passes through the senses. While very young organisms need to combine objects, background and abstract or emotional features into a single experience for building the representation of the surrounded reality, they cannot distinguish relevant sensory stimuli independently to integrate them into object representations. Even the embodied dynamical system approach cannot get around the cue to noise problem. The application of embodied information requires an already categorised environment onto objects—holistic representation of reality—which occurs through (and only after the emergence of) perception and intentionality. In short, properties of the mother's heart—the electromagnetic and acoustic oscillations—converge the neuronal activity of both nervous


id: biochemistry-of-alzheimer-s-disease-20260505-0
file: data/en.wikipedia.org/wiki/Biochemistry_of_Alzheimer's_disease-0.md
category: reference
title: Biochemistry of Alzheimer's disease
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Biochemistry_of_Alzheimer's_disease
date_saved: 2026-05-05T11:04:17.929946+00:00
instance: kb-cron
parent: biochemistry-of-alzheimer-s-disease-20260505-0
summary:
The biochemistry of Alzheimer's disease, the most common cause of dementia, is not yet very well understood. Alzheimer's disease (AD) has been identified as a proteopathy: a protein misfolding disease due to the accumulation of abnormally folded amyloid beta (Aβ) protein in the brain. Amyloid beta is a short peptide that is an abnormal proteolytic byproduct of the transmembrane protein amyloid-beta precursor protein (APP), whose function is unclear but thought to be involved in neuronal development. The presenilins are components of proteolytic complex involved in APP processing and degradation. Amyloid beta monomers are soluble and contain short regions of beta sheet and polyproline II helix secondary structures in solution, though they are largely alpha helical in membranes; however, at sufficiently high concentration, they undergo a dramatic conformational change to form a beta sheet-rich tertiary structure that aggregates to form amyloid fibrils. These fibrils and oligomeric forms of Aβ deposit outside neurons in formations known as senile plaques. There are different types of plaques, including the diffuse, compact, cored or neuritic plaque types, as well as Aβ deposits in the walls of small blood vessel walls in the brain called cerebral amyloid angiopathy. AD is also considered a tauopathy due to


id: biochemistry-of-alzheimer-s-disease-20260505-1
file: data/en.wikipedia.org/wiki/Biochemistry_of_Alzheimer's_disease-1.md
category: reference
title: Biochemistry of Alzheimer's disease
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Biochemistry_of_Alzheimer's_disease
date_saved: 2026-05-05T11:04:17.929946+00:00
instance: kb-cron
parent: biochemistry-of-alzheimer-s-disease-20260505-0
summary:
== Disease mechanisms == While the gross histological features of AD in the brain have been well characterized, several different hypotheses have been advanced regarding the primary cause. Among the oldest hypotheses is the cholinergic hypothesis, which suggests that deficiency in cholinergic signaling initiates the progression of the disease. Current theories establish that both misfolding tau protein inside the cell and aggregation of amyloid beta outside the cell initiates the cascade leading to AD pathology. Newer potential hypotheses propose metabolic factors, vascular disturbance, lipid invasion and chronically elevated inflammation in the brain as contributing factors to AD. The amyloid beta hypothesis of molecular initiation have become dominant among many researchers to date. The amyloid and tau hypothesis are the most widely accepted. === Tau hypothesis === The hypothesis that tau is the primary causative factor has long been grounded in the observation that deposition of amyloid plaques does not correlate well with neuron loss. A mechanism for neurotoxicity has been proposed based on the loss of microtubule-stabilizing tau protein that leads to the degradation of the cytoskeleton. However, consensus has not been reached on whether tau hyperphosphorylation precedes or is caused by the formation of the abnormal helical filament aggregates.


id: biochemistry-of-alzheimer-s-disease-20260505-2
file: data/en.wikipedia.org/wiki/Biochemistry_of_Alzheimer's_disease-2.md
category: reference
title: Biochemistry of Alzheimer's disease
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Biochemistry_of_Alzheimer's_disease
date_saved: 2026-05-05T11:04:17.929946+00:00
instance: kb-cron
parent: biochemistry-of-alzheimer-s-disease-20260505-0
summary:
=== Historical cholinergic hypothesis === The cholinergic hypothesis of AD development was first proposed in 1976 by Peter Davies and A.J.F Maloney. It claimed that Alzheimer's begins as a deficiency in the production of acetylcholine, a vital neurotransmitter. Much early therapeutic research was based on this hypothesis, including restoration of the "cholinergic nuclei". The possibility of cell-replacement therapy was investigated on the basis of this hypothesis. All of the first-generation anti-Alzheimer's medications are based on this hypothesis and work to preserve acetylcholine by inhibiting acetylcholinesterases (enzymes that break down acetylcholine). These medications, though sometimes beneficial, have not led to a cure. In all cases, they have served to only treat symptoms of the disease and have neither halted nor reversed it. These results and other research have led to the conclusion that acetylcholine deficiencies may not be directly causal, but are a result of widespread brain tissue damage, damage so widespread that cell-replacement therapies are likely to be impractical. More recent findings center on the effects of the misfolded and aggregated proteins, amyloid beta and tau: tau protein abnormalities may initiate the disease cascade, then beta amyloid deposits progress the disease. === Glucose consumption === The human brain is one


id: biochemistry-of-alzheimer-s-disease-20260505-3
file: data/en.wikipedia.org/wiki/Biochemistry_of_Alzheimer's_disease-3.md
category: reference
title: Biochemistry of Alzheimer's disease
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Biochemistry_of_Alzheimer's_disease
date_saved: 2026-05-05T11:04:17.929946+00:00
instance: kb-cron
parent: biochemistry-of-alzheimer-s-disease-20260505-0
summary:
=== Oxidative stress === Oxidative stress is emerging as a key factor in the pathogenesis of AD. Reactive oxygen species (ROS) over-production is thought to play a critical role in the accumulation and deposition of amyloid beta in AD. Brains of AD patients have elevated levels of oxidative DNA damage in both nuclear and mitochondrial DNA, but the mitochondrial DNA has approximately 10-fold higher levels than nuclear DNA. Aged mitochondria may be the critical factor in the origin of neurodegeneration in AD. Even individuals with mild cognitive impairment, the phase between normal aging and early dementia, have increased oxidative damage in their nuclear and mitochondrial brain DNA (see Aging brain). Naturally occurring DNA double-strand breaks (DSBs) arise in human cells largely from single-strand breaks induced by various processes including the activity of reactive oxygen species, topoisomerases, and hydrolysis due to thermal fluctuations. In neurons DSBs are induced by a type II topoisomerase as part of the physiologic process of memory formation. DSBs are present in both neurons and astrocytes in the postmortem human hippocampus of AD patients at a higher level than in non-AD individuals. AD is associated with an accumulation of DSBs in neurons and astrocytes in the hippocampus


id: biochemistry-of-alzheimer-s-disease-20260505-4
file: data/en.wikipedia.org/wiki/Biochemistry_of_Alzheimer's_disease-4.md
category: reference
title: Biochemistry of Alzheimer's disease
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Biochemistry_of_Alzheimer's_disease
date_saved: 2026-05-05T11:04:17.929946+00:00
instance: kb-cron
parent: biochemistry-of-alzheimer-s-disease-20260505-0
summary:
=== Reelin hypothesis === A 1994 study showed that the isoprenoid changes in Alzheimer's disease differ from those occurring during normal aging and that this disease cannot, therefore, be regarded as a result of premature aging. During aging the human brain shows a progressive increase in levels of dolichol, a reduction in levels of ubiquinone, but relatively unchanged concentrations of cholesterol and dolichyl phosphate. In Alzheimer's disease, the situation is reversed with decreased levels of dolichol and increased levels of ubiquinone. The concentrations of dolichyl phosphate are also increased, while cholesterol remains unchanged. The increase in the sugar carrier dolichyl phosphate may reflect an increased rate of glycosylation in the diseased brain and the increase in the endogenous anti-oxidant ubiquinone an attempt to protect the brain from oxidative stress, for instance induced by lipid peroxidation. Ropren, identified previously in Russia, is neuroprotective in a rat model of Alzheimer's disease. A relatively recent hypothesis based mainly on rodent experiments links the onset of Alzheimer's disease to the hypofunction of the large extracellular protein reelin. A decrease of reelin in the human entorhinal cortex where the disease typically initiates is evident while compensatory increase of reelin levels in other brain structures of


id: catecholaldehyde-hypothesis-20260505-0
file: data/en.wikipedia.org/wiki/Catecholaldehyde_hypothesis-0.md
category: reference
title: Catecholaldehyde hypothesis
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Catecholaldehyde_hypothesis
date_saved: 2026-05-05T11:04:19.139868+00:00
instance: kb-cron
parent: catecholaldehyde-hypothesis-20260505-0
summary:
The catecholaldehyde hypothesis is a scientific theory positing that neurotoxic aldehyde metabolites of the catecholamine neurotransmitters dopamine and norepinephrine are responsible for neurodegenerative diseases involving loss of catecholaminergic neurons, for instance Parkinson's disease. The specific metabolites thought to be involved include 3,4-dihydroxyphenylacetaldehyde (DOPAL) and 3,4-dihydroxyphenylglycolaldehyde (DOPEGAL), which are formed from dopamine and norepinephrine by monoamine oxidase, respectively. These metabolites are subsequently inactivated and detoxified by aldehyde dehydrogenase (ALDH). DOPAL and DOPEGAL are monoaminergic neurotoxins in preclinical models and inhibition of and polymorphisms in ALDH are associated with Parkinson's disease. The catecholaldehyde hypothesis additionally posits that DOPAL oligomerizes with α-synuclein resulting in accumulation of oligomerized α-synuclein (i.e., synucleinopathy) and that this contributes to cytotoxicity. == See also == Amyloid hypothesis == References ==


id: cerebral-polyopia-20260505-0
file: data/en.wikipedia.org/wiki/Cerebral_polyopia-0.md
category: reference
title: Cerebral polyopia
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Cerebral_polyopia
date_saved: 2026-05-05T11:04:20.324237+00:00
instance: kb-cron
parent: cerebral-polyopia-20260505-0
summary:
Cerebral diplopia or polyopia describes seeing two or more images arranged in ordered rows, columns, or diagonals after fixation on a stimulus. The polyopic images occur monocular bilaterally (one eye open on both sides) and binocularly (both eyes open), differentiating it from ocular diplopia or polyopia. The number of duplicated images can range from one to hundreds. Some patients report difficulty in distinguishing the replicated images from the real images, while others report that the false images differ in size, intensity, or color. Cerebral polyopia is sometimes confused with palinopsia (visual trailing), in which multiple images appear while watching an object. However, in cerebral polyopia, the duplicated images are of a stationary object which are perceived even after the object is removed from the visual field. Movement of the original object causes all of the duplicated images to move, or the polyopic images disappear during motion. In palinoptic polyopia, movement causes each polyopic image to leave an image in its wake, creating hundreds of persistent images (entomopia). Infarctions, tumors, multiple sclerosis, trauma, encephalitis, migraines, and seizures have been reported to cause cerebral polyopia. Cerebral polyopia has been reported in extrastriate visual cortex lesions, which is important for detecting motion, orientation,


id: cerebral-polyopia-20260505-1
file: data/en.wikipedia.org/wiki/Cerebral_polyopia-1.md
category: reference
title: Cerebral polyopia
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Cerebral_polyopia
date_saved: 2026-05-05T11:04:20.324237+00:00
instance: kb-cron
parent: cerebral-polyopia-20260505-0
summary:
== Theories of cerebral polyopia == The preliminary theory of cerebral polyopia proposed by Bender postulated that polyopia occurs as a result of instability of fixation due to occipital lobe disease. Under this explanation, small, involuntary eye movements that accompanied normal fixation were the cause of polyopic images. These involuntary eye movements lead to the development of new retinal and corresponding cortical regions that code for central vision called false maculae. Thus, polyopic images resulted from the stimulation of both the original and acquired maculae. However, Bender's theory does not account for recent studies in which fixation did not change and no eye movements were produced while polyopia was experienced, therefore polyopic images were not a result of involuntary eye movements. Instead, Cornblath offers a possible pathophysiological mechanism in which polyopia results from the recoding of visual receptive fields in primary visual cortex (Area V1). The report of polyopic images of complex objects at fixation suggests that the disorder is not limited to lower-order visual areas in occipital cortex (in which simple features such as borders and angles are encoded), but rather it involves the interaction between lower-order visual areas in the occipital lobe and higher-order visual areas in the


id: cortisol-awakening-response-20260505-0
file: data/en.wikipedia.org/wiki/Cortisol_awakening_response-0.md
category: reference
title: Cortisol awakening response
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Cortisol_awakening_response
date_saved: 2026-05-05T11:04:21.561040+00:00
instance: kb-cron
parent: cortisol-awakening-response-20260505-0
summary:
The cortisol awakening response (CAR) is an increase between 38% and 75% in cortisol levels peaking 30–45 minutes after awakening in the morning in some people. This rise is superimposed upon the late-night rise in cortisol which occurs before awakening. While its purpose is uncertain, it may be linked to the hippocampus' preparation of the hypothalamic-pituitary-adrenal axis (HPA) in order to face anticipated stress. Other research has challenged the idea that this elevation in morning cortisol is specifically linked to the onset of waking. == Description == Shortly after awakening, a sharp 38–75% (average 50%) increase occurs in the blood level of cortisol in about 77% of healthy people of all ages. The average level of salivary cortisol upon waking is roughly 15 nmol/L; 30 minutes later it may be 23 nmol/L, though there are wide variations. The cortisol awakening response reaches a maximum approximately 30 minutes after awakening though it may still be heightened by 34% an hour after waking. The pattern of this response to waking is relatively stable for any individual. Twin studies show its pattern is largely genetically determined since there is a heritability of 0.40 for the mean cortisol increase after awakening and 0.48 for


id: decision-making-20260505-0
file: data/en.wikipedia.org/wiki/Decision-making-0.md
category: reference
title: Decision-making
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Decision-making
date_saved: 2026-05-05T11:04:22.741043+00:00
instance: kb-cron
parent: decision-making-20260505-0
summary:
In psychology, decision-making (also spelled decision making and decisionmaking) is regarded as the cognitive process resulting in the selection of a belief or a course of action among several possible alternative options. It could be either rational or irrational. The decision-making process is a reasoning process based on assumptions of values, preferences and beliefs of the decision-maker. Every decision-making process produces a final choice, which may or may not prompt action. Research about decision-making is also published under the label problem solving, particularly in European psychological research. == Overview == Decision-making can be regarded as a problem-solving activity yielding a solution deemed to be optimal, or at least satisfactory. It is therefore a process which can be more or less rational or irrational and can be based on explicit or tacit knowledge and beliefs. Tacit knowledge is often used to fill the gaps in complex decision-making processes. Usually, both of these types of knowledge, tacit and explicit, are used together in the decision-making process. Human performance has been the subject of active research from several perspectives: Psychological: examining individual decisions in the context of a set of needs, preferences and values the individual has or seeks. Cognitive: the decision-making process


id: decision-making-20260505-1
file: data/en.wikipedia.org/wiki/Decision-making-1.md
category: reference
title: Decision-making
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Decision-making
date_saved: 2026-05-05T11:04:22.741043+00:00
instance: kb-cron
parent: decision-making-20260505-0
summary:
The first is analysis process paralysis. This type of paralysis is often spoken of as a cyclical process. One is unable to make a decision because they get stuck going over the information again and again for fear of making the wrong decision. The second is decision precision paralysis. This paralysis is cyclical, just like the first one, but instead of going over the same information, the decision-maker will find new questions and information from their analysis and that will lead them to explore into further possibilities rather than making a decision. The third is risk uncertainty paralysis. This paralysis occurs when the decision-maker wants to eliminate any uncertainty but the examination of provided information is unable to get rid of all uncertainty. === Extinction by instinct === On the opposite side of analysis paralysis is the phenomenon called extinction by instinct. Extinction by instinct is the state that a person is in when they make careless decisions without detailed planning or thorough systematic processes. Extinction by instinct can possibly be fixed by implementing a structural system, like checks and balances into a group or one's life. Analysis paralysis is the exact opposite where a group's schedule could be saturated


id: decision-making-20260505-2
file: data/en.wikipedia.org/wiki/Decision-making-2.md
category: reference
title: Decision-making
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Decision-making
date_saved: 2026-05-05T11:04:22.741043+00:00
instance: kb-cron
parent: decision-making-20260505-0
summary:
=== Group === Consensus decision-making tries to avoid "winners" and "losers". Consensus requires that a majority approve a given course of action, but that the minority agree to go along with the course of action. In other words, if the minority opposes the course of action, consensus requires that the course of action be modified to remove objectionable features. Voting-based methods: Majority requires support from more than 50% of the members of the group. Thus, the bar for action is lower than with consensus. See also Condorcet method. Plurality, where the largest faction in a group decides, even if it falls short of a majority. Score voting (or range voting) lets each member score one or more of the available options, specifying both preference and intensity of preference information. The option with the highest total or average is chosen. This method has experimentally been shown to produce the lowest Bayesian regret among common voting methods, even when voters are strategic. It addresses issues of voting paradox and majority rule. See also approval voting. Quadratic voting allows participants to cast their preference and intensity of preference for each decision (as opposed to a simple for or against decision). As in score


id: decision-making-20260505-3
file: data/en.wikipedia.org/wiki/Decision-making-3.md
category: reference
title: Decision-making
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Decision-making
date_saved: 2026-05-05T11:04:22.741043+00:00
instance: kb-cron
parent: decision-making-20260505-0
summary:
Orientation. Members meet for the first time and start to get to know each other. Conflict. Once group members become familiar with each other, disputes, little fights and arguments occur. Group members eventually work it out. Emergence. The group begins to clear up vague opinions by talking about them. Reinforcement. Members finally make a decision and provide justification for it. It is said that establishing critical norms in a group improves the quality of decisions, while the majority of opinions (called consensus norms) do not. Conflicts in socialization are divided in to functional and dysfunctional types. Functional conflicts are mostly the questioning the managers assumptions in their decision making and dysfunctional conflicts are like personal attacks and every action which decrease team effectiveness. Functional conflicts are the better ones to gain higher quality decision-making caused by the increased team knowledge and shared understanding. == Rational and irrational == In economics, it is thought that if humans are rational and free to make their own decisions, then they would behave according to rational choice theory. Rational choice theory says that a person consistently makes choices that lead to the best situation for themselves, taking into account all available considerations including costs


id: decision-making-20260505-4
file: data/en.wikipedia.org/wiki/Decision-making-4.md
category: reference
title: Decision-making
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Decision-making
date_saved: 2026-05-05T11:04:22.741043+00:00
instance: kb-cron
parent: decision-making-20260505-0
summary:
=== Adults === Adults are generally better able to control their risk-taking because their cognitive-control system has matured enough to the point where it can control the socioemotional network, even in the context of high arousal or when psychosocial capacities are present. Also, adults are less likely to find themselves in situations that push them to do risky things. For example, teens are more likely to be around peers who peer pressure them into doing things, while adults are not as exposed to this sort of social setting. == Cognitive and personal biases == Biases usually affects decision-making processes. They appear more when decision task has time pressure, is done under high stress and/or are highly complex. Here is a list of commonly debated biases in judgment and decision-making: Selective search for evidence (also known as confirmation bias): People tend to be willing to gather facts that support certain conclusions but disregard other facts that support different conclusions. Individuals who are highly defensive in this manner show significantly greater left prefrontal cortex activity as measured by EEG than do less defensive individuals. Premature termination of search for evidence: People tend to accept the first alternative that looks like it might


id: decision-making-20260505-5
file: data/en.wikipedia.org/wiki/Decision-making-5.md
category: reference
title: Decision-making
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Decision-making
date_saved: 2026-05-05T11:04:22.741043+00:00
instance: kb-cron
parent: decision-making-20260505-0
summary:
The psychologist Daniel Kahneman, adopting terms originally proposed by the psychologists Keith Stanovich and Richard West, has theorized that a person's decision-making is the result of an interplay between two kinds of cognitive processes: an automatic intuitive system (called "System 1") and an effortful rational system (called "System 2"). System 1 is a bottom-up, fast, and implicit system of decision-making, while system 2 is a top-down, slow, and explicit system of decision-making. System 1 includes simple heuristics in judgment and decision-making such as the affect heuristic, the availability heuristic, the familiarity heuristic, and the representativeness heuristic. === Combinatorial vs. positional === Styles and methods of decision-making were elaborated by Aron Katsenelinboigen, the founder of predispositioning theory. In his analysis of styles and methods, Katsenelinboigen referred to the game of chess, saying that "chess does disclose various methods of operation, notably the creation of predisposition methods which may be applicable to other, more complex systems." Katsenelinboigen states that apart from the methods (reactive and selective) and sub-methods randomization, predispositions, programming), there are two major styles: positional and combinational. Both styles are utilized in the game of chess. The two styles reflect two basic approaches to uncertainty: deterministic (combinational style) and indeterministic


id: emotion-and-memory-20260505-0
file: data/en.wikipedia.org/wiki/Emotion_and_memory-0.md
category: reference
title: Emotion and memory
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Emotion_and_memory
date_saved: 2026-05-05T11:04:24.054436+00:00
instance: kb-cron
parent: emotion-and-memory-20260505-0
summary:
Emotion can have a powerful effect on humans and animals. Numerous studies have shown that the most vivid autobiographical memories tend to be of emotional events, which are likely to be recalled more often and with more clarity and detail than neutral events. The activity of emotionally enhanced memory retention can be linked to human evolution; during early development, responsive behavior to environmental events would have progressed as a process of trial and error. Survival depended on behavioral patterns that were repeated or reinforced through life and death situations. Through evolution, this process of learning became genetically embedded in humans and all animal species in what is known as flight or fight instinct. Artificially inducing this instinct through traumatic physical or emotional stimuli essentially creates the same physiological condition that heightens memory retention by exciting neuro-chemical activity affecting areas of the brain responsible for encoding and recalling memory. This memory-enhancing effect of emotion has been demonstrated in many laboratory studies, using stimuli ranging from words to pictures to narrated slide shows, as well as autobiographical memory studies. However, as described below, emotion does not always enhance memory. == Arousal and valence in memory == One of the most common frameworks


id: emotion-and-memory-20260505-1
file: data/en.wikipedia.org/wiki/Emotion_and_memory-1.md
category: reference
title: Emotion and memory
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Emotion_and_memory
date_saved: 2026-05-05T11:04:24.054436+00:00
instance: kb-cron
parent: emotion-and-memory-20260505-0
summary:
==== Prioritized processing ==== Emotional items also appear more likely to be processed when attention is limited, suggesting a facilitated or prioritized processing of emotional information. This effect was demonstrated using the attentional blink paradigm in which 2 target items are presented in close temporal proximity within a stream of rapidly presented stimuli. The typical finding is that participants often miss the second target item, as if there were a "blink" of attention following the first target's presentation, reducing the likelihood that the second target stimulus is attended. However, when the second target stimulus elicits emotional arousal (a "taboo" word), participants are less likely to miss the target's presentation, which suggests that under conditions of limited attention, arousing items are more likely to be processed than neutral items. Additional support for the prioritized processing hypothesis was provided by studies investigating the visual extinction deficit. People suffering from this deficit can perceive a single stimulus in either side visual field if it is presented alone but are unaware of the same stimulus in the visual field opposed to the lesional side, if another stimulus is presented simultaneously on the lesional side. Emotion has been found to modulate the magnitude of the


id: emotion-and-memory-20260505-2
file: data/en.wikipedia.org/wiki/Emotion_and_memory-2.md
category: reference
title: Emotion and memory
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Emotion_and_memory
date_saved: 2026-05-05T11:04:24.054436+00:00
instance: kb-cron
parent: emotion-and-memory-20260505-0
summary:
==== Contextual effects of emotion on memory ==== Contextual effects occur as a result of the degree of similarity between the encoding context and the retrieval context of an emotional dimension. The main findings are that the current mood we are in affects what is attended, encoded and ultimately retrieved, as reflected in two similar but subtly different effects: the mood congruence effect and mood-state dependent retrieval. Positive encoding contexts have been connected to activity in the right fusiform gyrus. Negative encoding contexts have been correlated to activity in the right amygdala (Lewis & Critchley, 2003). However, Lewis and Critchley (2003) claim that it is not clear whether involvement of the emotional system in encoding memory differs for positive or negative emotions, or whether moods at recall lead to activity in the corresponding positive or negative neural networks. ===== Mood congruence effect ===== The mood congruence effect refers to the tendency of individuals to retrieve information more easily when it has the same emotional content as their current emotional state. For instance, being in a depressed mood increases the tendency to remember negative events (Drace, 2013). This effect has been demonstrated for explicit retrieval as well as implicit retrieval. =====


id: emotion-and-memory-20260505-3
file: data/en.wikipedia.org/wiki/Emotion_and_memory-3.md
category: reference
title: Emotion and memory
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Emotion_and_memory
date_saved: 2026-05-05T11:04:24.054436+00:00
instance: kb-cron
parent: emotion-and-memory-20260505-0
summary:
== Neurobiological mechanisms of emotional memory enhancement == The neural mechanism underlying emotional memory enhancement involves the interaction between the amygdala and the hippocampus, as well as several other factors that prioritize the encoding of emotional experiences. When an emotional experience occurs, the amygdala becomes highly active, signaling the hippocampus to strengthen the encoding and consolidation of these memories. This process is facilitated by the release of stress hormones and neurotransmitters, which modulate synaptic plasticity and enhance neural connectivity. Multiple mechanisms have been proposed to explain this prioritized encoding, including the neuromodulatory effects on plasticity and the dynamic interplay between the amygdala and the hippocampus. Intracranial EEG studies have shown that the amygdala triggers pronounced hippocampal sharp-wave ripples after encoding emotional experiences, further reinforcing the consolidation of these memories during both awake and sleep. This coordinated activity between the amygdala and hippocampus ensures that emotionally significant events are prioritized in long-term memory storage, leveraging both immediate neurochemical changes and enduring structural adaptations in neural circuits. == Memory of felt emotion == Many researchers use self-report measures of felt emotion as a manipulation check. This raises an interesting question and a possible methodological weakness: are people always accurate when they recall


id: emotion-and-memory-20260505-4
file: data/en.wikipedia.org/wiki/Emotion_and_memory-4.md
category: reference
title: Emotion and memory
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Emotion_and_memory
date_saved: 2026-05-05T11:04:24.054436+00:00
instance: kb-cron
parent: emotion-and-memory-20260505-0
summary:
== Emotion regulation effects on memory == An interesting issue in the study of the emotion-memory relationship is whether our emotions are influenced by our behavioral reaction to them, and whether this reaction—in the form of expression or suppression of the emotion—might affect what we remember about an event. Researchers have begun to examine whether concealing feelings influences our ability to perform common cognitive tasks, such as forming memories, and found that the emotion regulation efforts do have cognitive consequences. In the seminal work on negative affect arousal and white noise, Seidner found support for the existence of a negative affect arousal mechanism through observations regarding the devaluation of speakers from other ethnic origins." In a study of Richards and Gross (1999) and Tiwari (2013), participants viewed slides of injured men that produced increases in negative emotions, while information concerning each man was presented orally with his slide. The participants were assigned to either an expressive suppression group (where they were asked to refrain from showing emotion while watching the slides) or to a control group (where they were not given regulatory instructions at all). As predicted by the researchers, suppressors showed significantly worse performance on a memory test for


id: encephalitis-lethargica-20260505-0
file: data/en.wikipedia.org/wiki/Encephalitis_lethargica-0.md
category: reference
title: Encephalitis lethargica
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Encephalitis_lethargica
date_saved: 2026-05-05T11:04:25.215156+00:00
instance: kb-cron
parent: encephalitis-lethargica-20260505-0
summary:
Encephalitis lethargica (EL) is an atypical form of encephalitis. Also known as "von Economo Encephalitis", "sleeping sickness" or "sleepy sickness" (distinct from tsetse fly–transmitted sleeping sickness), it was first described in 1917 by neurologist Constantin von Economo and pathologist Jean-René Cruchet. The disease attacks the brain, leaving some victims in a statue-like condition, speechless and motionless. Between 1915 and 1926, an epidemic of encephalitis lethargica spread around the world. The exact number of people infected is unknown, but it is estimated that more than one million people contracted the disease during the epidemic, which directly caused more than 500,000 deaths. Most of those who survived never recovered their pre-morbid vigor. == Signs and symptoms == Encephalitis lethargica is characterized by high fever, sore throat, headache, lethargy, double vision, delayed physical and mental response, sleep inversion and catatonia. In severe cases, patients may enter a coma-like state (akinetic mutism). Patients may also experience abnormal eye movements ("oculogyric crises"), Parkinsonism, upper body weakness, muscular pains, tremors, neck rigidity, and behavioral changes including psychosis. Klazomania, a vocal tic involving compulsive screaming, is sometimes present. Approximately a third of the affected children experienced change of behavior, with many of them becoming "delinquents". Boys between


id: encephalitis-lethargica-20260505-1
file: data/en.wikipedia.org/wiki/Encephalitis_lethargica-1.md
category: reference
title: Encephalitis lethargica
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Encephalitis_lethargica
date_saved: 2026-05-05T11:04:25.215156+00:00
instance: kb-cron
parent: encephalitis-lethargica-20260505-0
summary:
In 1580, Europe was swept by a serious febrile and lethargic illness that led to Parkinsonism and other neurological sequelae. From 1673 to 1675, a similar serious epidemic occurred in London, which Thomas Sydenham described as "febris comatosa". In 1695, a 20-year-old woman in Germany experienced oculogyric crises, Parkinsonism, diplopia, strabismus, and other symptoms following an attack of somnolent brain fever, as described by Albrecht of Hildesheim. In 1712–1713, a severe epidemic of Schlafkrankheit ('sleep sickness') occurred in Tübingen, Germany, followed in many cases by persistent slowness of movement and lack of initiative (aboulia). Between 1750 and 1800, France and Germany experienced minor epidemics of "coma somnolentum" with features of Parkinsonism, including hyperkinetic hiccup, myoclonus, chorea, and tics. Between 1848 and 1882, Paris-based neurologist Jean-Martin Charcot documented many isolated cases of juvenile Parkinsonism, associated with diplopia, oculogyria, tachypnoea, retropulsion, and obsessional disorders, which were almost certainly post-encephalitic in origin. In 1890 in Italy, following the influenza epidemic of 1889–1890, a severe epidemic of somnolent illnesses (nicknamed the "Nona") appeared. For the few survivors of the Nona, Parkinsonism and other sequelae developed in almost all cases. Between 1915 and 1927, a world-wide encephalitis lethargica pandemic occurred, impacting nearly 5 million people


id: facial-onset-sensory-and-motor-neuronopathy-20260505-0
file: data/en.wikipedia.org/wiki/Facial_onset_sensory_and_motor_neuronopathy-0.md
category: reference
title: Facial onset sensory and motor neuronopathy
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Facial_onset_sensory_and_motor_neuronopathy
date_saved: 2026-05-05T11:04:26.390586+00:00
instance: kb-cron
parent: facial-onset-sensory-and-motor-neuronopathy-20260505-0
summary:
Facial onset sensory and motor neuronopathy, often abbreviated FOSMN, is a rare disorder of the nervous system in which sensory and motor nerves of the face and limbs progressively degenerate over a period of months to years. This degenerative process, the cause of which is unknown, eventually results in sensory and motor symptoms — the former consisting mainly of paresthesia followed by numbness, and the latter in muscle weakness, atrophy, and eventual paralysis. FOSM is characterized by sensory and motor loss beginning in the face and spreading to involve an increasingly larger area including the scalp, upper arms and trunk. The muscles or respiration and swallowing are commonly affected. In many ways, it is reminiscent of the much better known condition amyotrophic lateral sclerosis, with which it is closely related. There is no cure; treatment is supportive. Life expectancy may be shortened by respiratory complications arising from weakness of the muscles that aid breathing and swallowing. It was first described in four patients by Vucic and colleagues working at the Massachusetts General Hospital in the United States; subsequent reports from the United Kingdom, Europe and Asia point to a global incidence of the disease. It is thought to be exceptionally


id: fatal-insomnia-20260505-0
file: data/en.wikipedia.org/wiki/Fatal_insomnia-0.md
category: reference
title: Fatal insomnia
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Fatal_insomnia
date_saved: 2026-05-05T11:04:27.568044+00:00
instance: kb-cron
parent: fatal-insomnia-20260505-0
summary:
Fatal insomnia is a neurodegenerative disease that results in trouble sleeping as its hallmark symptom. The majority of cases are familial (fatal familial insomnia [FFI]), stemming from a mutation in the PRNP gene, with the remainder of cases occurring sporadically (sporadic fatal insomnia [sFI]). The problems with sleeping typically start out gradually and worsen over time. Eventually, the patient will succumb to total insomnia (agrypnia excitata), most often leading to other symptoms such as speech problems, coordination problems, and dementia. It results in death within a few months to a few years, and there is no known disease-modifying treatment. == Signs and symptoms == The disease has four stages: Characterized by worsening insomnia, resulting in panic attacks, paranoia, and phobias. This stage lasts for about four months. Hallucinations and panic attacks become noticeable, continuing for about five months. Complete inability to sleep followed by rapid loss of weight. This lasts for about three months. Dementia, during which the person becomes unresponsive or mute over the course of six months, is the final stage of the disease, followed by death. Clinically, Fatal insomnia manifests with a disordered sleep-wake cycle, dysautonomia, motor disturbances, and neuropsychiatric disorders. Other symptoms include profuse sweating, miosis


id: fatal-insomnia-20260505-1
file: data/en.wikipedia.org/wiki/Fatal_insomnia-1.md
category: reference
title: Fatal insomnia
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Fatal_insomnia
date_saved: 2026-05-05T11:04:27.568044+00:00
instance: kb-cron
parent: fatal-insomnia-20260505-0
summary:
=== Differential diagnosis === Other diseases involving the mammalian prion protein are known. Some are transmissible (TSEs, including FFI) such as kuru, bovine spongiform encephalopathy (BSE, also known as mad cow disease) in cattle and chronic wasting disease in American deer and American elk in some areas of the United States and Canada, as well as Creutzfeldt–Jakob disease (CJD). == Treatments == Treatment involves palliative care. There is conflicting evidence over the use of sleeping pills, including barbiturates, as a treatment for the disease. Symptoms of fatal familial insomnia may be treated with medications. Clonazepam may be prescribed to treat muscle spasms, and eszopiclone or zolpidem may be prescribed to help treat insomnia. However, these drugs do not work in the long term. == Prognosis == Like all prion diseases, FFI is invariably fatal. Life expectancy ranges from seven months to six years, with an average of 18 months. == Epidemiology and history == Fatal insomnia was first described by Elio Lugaresi et al. in 1986. In 1998, 40 families were known to carry the gene for FFI globally: eight German, five Italian, four American, two French, two Australian, two British, one Japanese and one Austrian. In the Basque Country


id: form-perception-20260505-0
file: data/en.wikipedia.org/wiki/Form_perception-0.md
category: reference
title: Form perception
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Form_perception
date_saved: 2026-05-05T11:04:28.772828+00:00
instance: kb-cron
parent: form-perception-20260505-0
summary:
Form perception is the recognition of visual elements of objects, specifically those to do with shapes, patterns and previously identified important characteristics. An object is perceived by the retina as a two-dimensional image, but the image can vary for the same object in terms of the context with which it is viewed, the apparent size of the object, the angle from which it is viewed, how illuminated it is, as well as where it resides in the field of vision. Despite the fact that each instance of observing an object leads to a unique retinal response pattern, the visual processing in the brain is capable of recognizing these experiences as analogous, allowing invariant object recognition. Visual processing occurs in a hierarchy with the lowest levels recognizing lines and contours, and slightly higher levels performing tasks such as completing boundaries and recognizing contour combinations. The highest levels integrate the perceived information to recognize an entire object. Essentially object recognition is the ability to assign labels to objects in order to categorize and identify them, thus distinguishing one object from another. During visual processing information is not created, but rather reformatted in a way that draws out the most detailed information of


id: form-perception-20260505-1
file: data/en.wikipedia.org/wiki/Form_perception-1.md
category: reference
title: Form perception
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Form_perception
date_saved: 2026-05-05T11:04:28.772828+00:00
instance: kb-cron
parent: form-perception-20260505-0
summary:
=== Injury and illness === Potential injuries to the brain include but are not limited to stroke, oxygen deprivation, blunt force trauma, and surgical injuries. When patients have lesions on their brain that develop as a result of injury or illness, such as multiple sclerosis or epilepsy, it is possible that they may have impaired object recognition which can manifest in the form of many different agnosias. Similar deficits have also been observed adults that have suffered blunt force trauma, strokes, severe carbon monoxide poisoning as well as in adults that have surgical damage following removal of tumors. Deficits have also been observed in children with types of epilepsy that do not lead to the formation of lesions. It is believed that in these cases the seizures cause a functional disruption that is capable of interfering with the processing of objects. Regions that specifically lead to deficits in object recognition when a lesion is present include the right lateral fusiform gyrus and the ventrolateral or ventromedial occipito-temporal cortex. These structures have all been identified as being crucial to the processing of shape and contour information, which is the basis for object recognition. Although people with damage to these structures are


id: memory-consolidation-20260505-0
file: data/en.wikipedia.org/wiki/Memory_consolidation-0.md
category: reference
title: Memory consolidation
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Memory_consolidation
date_saved: 2026-05-05T11:04:29.928717+00:00
instance: kb-cron
parent: memory-consolidation-20260505-0
summary:
Memory consolidation is a process in the brain that stabilizes newly learned information, allowing the memory to be stored long-term. A memory trace is the biological change in neural circuits that occurs during learning. Memory consolidation is essential for learning as it allows experiences to be transformed into stable long-term memories that can guide future behavior. Consolidation is divided into two main processes, synaptic consolidation and systems consolidation. Synaptic consolidation occurs rapidly on a small scale in the individual synapses within the first few hours of learning. Systems consolidation occurs on a larger scale and involves gradual reorganization and reduced reliance on the hippocampus and increased involvement of cortical networks over a period of weeks to years. These processes involve molecular and cellular changes that stabilize neural representations, referred to as a neural ensemble (engram). A third process, reconsolidation, has been proposed, in which previously consolidated memories can become unstable again after retrieval and may need to be updated before being re-stabilized. == History == Memory consolidation was first referred to in the writings of the renowned Roman teacher of rhetoric Quintillian, who noted that memory improves over time. In the late 19th century, German researchers Müller and Alfons Pilzecker


id: memory-consolidation-20260505-1
file: data/en.wikipedia.org/wiki/Memory_consolidation-1.md
category: reference
title: Memory consolidation
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Memory_consolidation
date_saved: 2026-05-05T11:04:29.928717+00:00
instance: kb-cron
parent: memory-consolidation-20260505-0
summary:
=== Protein synthesis === Protein synthesis has shown to play an important role in the formation of new memories. Studies have shown that protein synthesis inhibitors administered after learning weaken memory, suggesting that protein synthesis is required for memory consolidation. Additionally, reports have suggested that the effects of protein synthesis inhibitors also inhibit LTP. However, other results have shown that protein synthesis may not in fact be necessary for memory consolidation, as it has been found that the formation of memories can withstand vast amounts of protein synthesis inhibition, suggesting that its role may not be absolute. == Systems consolidation == Systems consolidation is the later phase of memory consolidation in which memories are reorganized across brain regions over time. Newly formed memories are first encoded in the hippocampus and then are gradually reorganized across cortical networks in a more permanent form of storage. Systems consolidation is a slow dynamic process which occurs over days to years as a gradual shift from hippocampus-dependent to hippocampus-independent memory storage. Systems consolidation is proposed to be involved in repeated reactivation of memory traces especially during sleep. The reactivations help strengthen the connections between cortical regions thereby gradually reducing reliance on the hippocampus. Over


id: memory-inhibition-20260505-0
file: data/en.wikipedia.org/wiki/Memory_inhibition-0.md
category: reference
title: Memory inhibition
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Memory_inhibition
date_saved: 2026-05-05T11:04:31.129532+00:00
instance: kb-cron
parent: memory-inhibition-20260505-0
summary:
In psychology, memory inhibition is the ability not to remember irrelevant information. The scientific concept of memory inhibition should not be confused with everyday uses of the word "inhibition". Scientifically speaking, memory inhibition is a type of cognitive inhibition, which is the stopping or overriding of a mental process, in whole or in part, with or without intention. Memory inhibition is a critical component of an effective memory system. While some memories are retained for a lifetime, most memories are forgotten. According to evolutionary psychologists, forgetting is adaptive because it facilitates selectivity of rapid, efficient recollection. For example, a person trying to remember where they parked their car would not want to remember every place they have ever parked. In order to remember something, therefore, it is essential not only to activate the relevant information, but also to inhibit irrelevant information. There are many memory phenomena that seem to involve inhibition, although there is often debate about the distinction between interference and inhibition. == History == In the early days of psychology, the concept of inhibition was prevalent and influential (e.g., Breese, 1899; Pillsbury, 1908; Wundt, 1902). These psychologists applied the concept of inhibition (and interference) to early theories of


id: memory-inhibition-20260505-1
file: data/en.wikipedia.org/wiki/Memory_inhibition-1.md
category: reference
title: Memory inhibition
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Memory_inhibition
date_saved: 2026-05-05T11:04:31.129532+00:00
instance: kb-cron
parent: memory-inhibition-20260505-0
summary:
=== "Think/no-think" paradigm and intentional inhibition === During the recovered memory debate of the 1990s, cognitive psychologists were dubious about whether specific memories could be repressed. One stumbling block was that repression had not been demonstrated in a research study. In 2001, researchers Anderson and Green claimed to have found laboratory evidence of suppression. They trained their participants with a list of unrelated word pairs (such as ordeal-roach), so they could respond with the second member of the pair (roach) when they saw the other member (ordeal). The more frequently participants had tried to not think about a particular word, the less likely they were to retrieve it on a final memory test. This impairment even occurred when participants were given an "independent probe" test, i.e. given a similar category (insect) instead of the original cue (roach), and asked to fill in the blank on the memory test: insect-r_____. According to Anderson and Green, the fact that participants had a decreased ability to recall items they were told to forget strongly supports the existence of an inhibitory control mechanism and the idea that people have the ability to suppress unwanted memories. Though Anderson & Green's (2001) results have been replicated


id: phantom-vibration-syndrome-20260505-0
file: data/en.wikipedia.org/wiki/Phantom_vibration_syndrome-0.md
category: reference
title: Phantom vibration syndrome
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Phantom_vibration_syndrome
date_saved: 2026-05-05T11:04:32.333444+00:00
instance: kb-cron
parent: phantom-vibration-syndrome-20260505-0
summary:
Phantom vibration syndrome or phantom ringing syndrome is the perception that one's mobile phone is vibrating or ringing when it is not. Other terms for this concept include ringxiety (a portmanteau of ring and anxiety), fauxcellarm (a portmanteau of "faux" /foʊ/ meaning "fake" or "false" and "cellphone" and "alarm" pronounced similarly to "false alarm"), phonetom (a portmanteau of phone and phantom) and phantom phone signals. According to Michael Rothberg, it is not a syndrome, but is better characterised as a tactile hallucination since the brain perceives a sensation that is not actually present. WebMD published an article on phantom vibration syndrome with Rothberg as a source. Several other articles have been published in 2010s, including in NPR, Bustle, CBS News, and Psychology Today. Phantom ringing may be experienced while taking a shower, watching television, or using a noisy device. Humans are particularly sensitive to auditory tones between 1,000 and 6,000 hertz, and basic mobile phone ringtones often fall within this range. Phantom vibrations develop after carrying a cell phone set to use vibrating alerts. Researcher Michelle Drouin found that almost 9 out of 10 undergraduates at her college experienced phantom vibrations. == History == In the comic strip Dilbert, cartoonist


id: posterior-cortical-atrophy-20260505-0
file: data/en.wikipedia.org/wiki/Posterior_cortical_atrophy-0.md
category: reference
title: Posterior cortical atrophy
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Posterior_cortical_atrophy
date_saved: 2026-05-05T11:04:33.570892+00:00
instance: kb-cron
parent: posterior-cortical-atrophy-20260505-0
summary:
Posterior cortical atrophy (PCA), also called Benson's syndrome, is a rare form of dementia which is considered a visual variant or an atypical variant of Alzheimer's disease (AD). The disease causes atrophy of the posterior part of the cerebral cortex, resulting in the progressive disruption of complex visual processing. PCA was first described by D. Frank Benson in 1988. PCA usually affects people at an earlier age than typical cases of Alzheimer's disease, with initial symptoms often experienced in people in their mid-fifties or early sixties. This was the case with writer Terry Pratchett (1948–2015), who went public in 2007 about being diagnosed with PCA. In rare cases, PCA can be caused by dementia with Lewy bodies and Creutzfeldt–Jakob disease. == Symptoms == The main symptom resulting from posterior cortical atrophy is a decrease in visuospatial and visuoperceptual capabilities, since the area of atrophy involves the occipital lobe responsible for visual processing. The atrophy is progressive; early symptoms include difficulty reading, blurred vision, light sensitivity, issues with depth perception, and trouble navigating through space. Additional symptoms include apraxia, a disorder of movement planning, alexia, an impaired ability to read, and visual agnosia, an object recognition disorder. In the two-streams hypothesis,


id: postvaccinal-encephalitis-20260505-0
file: data/en.wikipedia.org/wiki/Postvaccinal_encephalitis-0.md
category: reference
title: Postvaccinal encephalitis
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Postvaccinal_encephalitis
date_saved: 2026-05-05T11:04:34.702052+00:00
instance: kb-cron
parent: postvaccinal-encephalitis-20260505-0
summary:
Postvaccinal encephalitis (PVE) is a rare complication which was associated with vaccination with vaccinia virus during the worldwide smallpox eradication campaign. With mortality ranging between 25 – 30% it is the most severe adverse event associated with this vaccination. The mechanism of how it happens is unknown. == Symptoms and signs == PVE symptoms start to appear between 8th and 14th day after vaccination. Amongst the first are fever, headache, confusion and nausea. With passing time lethargy, seizures, short and long term memory dysfunctions, localized paralysis, hemiplegia, polyneuritis and convulsions. In extreme cases PVE can lead to coma and death. == Histology == Inflammatory extra-adventitial lesions are found not only in the brain but in the spinal cord as well. Lesions might be uniform in acute phase or disseminated in subacute phase. Unlike in cases of encephalitis lethargica the main damage is found in white brain matter. Meninges are infiltrated with T cells, plasmatic cells and phagocytic cells. Polymorfonuclear cells were found only in severe lesions. Apart from cellular infiltrate in perivascular space there is a tissue rarefication in spaces close to damaged blood vessels. Accumulated small nuclei are found in places of such rarefication. Strong demyelination with rapid clearance


id: progressive-muscular-atrophy-20260505-0
file: data/en.wikipedia.org/wiki/Progressive_muscular_atrophy-0.md
category: reference
title: Progressive muscular atrophy
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Progressive_muscular_atrophy
date_saved: 2026-05-05T11:04:35.927722+00:00
instance: kb-cron
parent: progressive-muscular-atrophy-20260505-0
summary:
Progressive muscular atrophy (PMA), also called Duchenne–Aran disease and Duchenne–Aran muscular atrophy, is a disorder characterized by the degeneration of lower motor neurons, resulting in generalized, progressive loss of muscle function. PMA is classified among motor neuron diseases (MND) and it sporadically appears during adulthood. It is speculated that about 2.5%-11% of adult onset MND is PMA, making it less common than ALS. PMA affects only the lower motor neurons, in contrast to amyotrophic lateral sclerosis (ALS), the most common MND, which affects both the upper and lower motor neurons, or primary lateral sclerosis, another MND, which affects only the upper motor neurons. The history of PMA involved determining if it was a separate disease from ALS or if it was just the earlier stages of ALS. Eventually, scientists concluded that PMA was its own disease under the same category as ALS. The signs and symptoms of PMA are similar to ALS, but are located in a different region of the body. Additionally, the diagnosis can be more complex due to the nature of PMA and ALS. The prognosis of PMA can be longer than ALS because it affects less of the motor neurons. The options for treatment are small


id: progressive-muscular-atrophy-20260505-1
file: data/en.wikipedia.org/wiki/Progressive_muscular_atrophy-1.md
category: reference
title: Progressive muscular atrophy
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Progressive_muscular_atrophy
date_saved: 2026-05-05T11:04:35.927722+00:00
instance: kb-cron
parent: progressive-muscular-atrophy-20260505-0
summary:
The prognosis is a little better. A recent study found the 5-year survival rate in PMA to be 33% (vs 20% in ALS) and the 10-year survival rate to be 12% (vs 6% in ALS). Patients with PMA do not have the cognitive change identified in certain groups of patients with MND. Because PMA patients do not have UMN signs, they usually do not meet the World Federation of Neurology El Escorial Research Criteria for "Definite" or "Probable" ALS and so are ineligible to participate in the majority of clinical trials conducted in ALS. Because of its rarity (even compared to ALS) and confusion about the condition, some insurance policies or local healthcare policies may not recognize PMA as being the life-changing illness that it is. In cases where being classified as being PMA rather than ALS is likely to restrict access to services, it may be preferable to be diagnosed as "slowly progressive ALS" or "lower motor neuron predominant" ALS. An initial diagnosis of PMA could turn out to be slowly progressive ALS many years later, sometimes even decades after the initial diagnosis. The occurrence of upper motor neuron symptoms such as brisk reflexes, spasticity, or a Babinski sign


id: qualia-20260505-0
file: data/en.wikipedia.org/wiki/Qualia-0.md
category: reference
title: Qualia
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Qualia
date_saved: 2026-05-05T11:04:37.131418+00:00
instance: kb-cron
parent: qualia-20260505-0
summary:
In philosophy of mind, qualia (; singular: quale ) are defined as instances of subjective experience. The term qualia derives from the Latin neuter plural form (qualia) of the Latin adjective quālis (Latin pronunciation: [ˈkʷaːlɪs]) meaning "of what sort" or "of what kind" in relation to a specific instance, such as "what it is like to taste a specific apple — this particular apple now". Examples of qualia include the perceived sensation of pain of a headache, the taste of wine, and the redness of an evening sky. As qualitative characteristics of sensations, qualia stand in contrast to propositional attitudes, where the focus is on beliefs about experience rather than what it is directly like to be experiencing. C.S. Peirce introduced the term quale in philosophy in 1866, and in 1929 C. I. Lewis was the first to use the term "qualia" in its generally agreed-upon modern sense. Frank Jackson later defined qualia as "...certain features of the bodily sensations especially, but also of certain perceptual experiences, which no amount of purely physical information includes". Philosopher and cognitive scientist Daniel Dennett suggested that qualia was "an unfamiliar term for something that could not be more familiar to each of us:


id: qualia-20260505-1
file: data/en.wikipedia.org/wiki/Qualia-1.md
category: reference
title: Qualia
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Qualia
date_saved: 2026-05-05T11:04:37.131418+00:00
instance: kb-cron
parent: qualia-20260505-0
summary:
The inverted spectrum thought experiment, originally developed by John Locke, invites us to imagine two individuals who perceive colors differently: where one person sees red, the other sees green, and vice versa. Despite this difference in their subjective experiences, they behave and communicate as if their perceptions are the same, and no physical or behavioral test can reveal the inversion. Critics of functionalism, and of physicalism more broadly, argue that if we can imagine this happening without contradiction, it follows that we are imagining a change in a property that determines the way things look to us, but that has no physical basis. The idea that an inverted spectrum would be undetectable in practice is also open to criticism on more scientific grounds, by C. L. Hardin, among others. As Alex Byrne puts it: ...there are more perceptually distinguishable shades between red and blue than there are between green and yellow, which would make red-green inversion behaviorally detectable. And there are yet further asymmetries. Dark yellow is brown (qualitatively different from yellow), whereas dark blue is blue[...] Similarly, desaturated bluish-red is pink (qualitatively different from saturated bluish-red), whereas desaturated greenish-yellow is similar to saturated greenish-yellow. Again, red is a "warm"


id: qualia-20260505-2
file: data/en.wikipedia.org/wiki/Qualia-2.md
category: reference
title: Qualia
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Qualia
date_saved: 2026-05-05T11:04:37.131418+00:00
instance: kb-cron
parent: qualia-20260505-0
summary:
Joseph Levine's paper Conceivability, Identity, and the Explanatory Gap takes up where the criticisms of conceivability arguments (such as the inverted spectrum argument and the zombie argument) leave off. Levine agrees that conceivability is a flawed means of establishing metaphysical realities, but points out that even if we come to the metaphysical conclusion that qualia are physical, there is still an explanatory problem. While I think this materialist response is right in the end, it does not suffice to put the mind-body problem to rest. Even if conceivability considerations do not establish that the mind is in fact distinct from the body, or that mental properties are metaphysically irreducible to physical properties, still they do demonstrate that we lack an explanation of the mental in terms of the physical. However, such an epistemological or explanatory problem might indicate an underlying metaphysical issue, as even if not proven by conceivability arguments, the non-physicality of qualia is far from ruled out. In the end, we are right back where we started. The explanatory gap argument doesn't demonstrate a gap in nature, but a gap in our understanding of nature. Of course a plausible explanation for there being a gap in our understanding


id: qualia-20260505-3
file: data/en.wikipedia.org/wiki/Qualia-3.md
category: reference
title: Qualia
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Qualia
date_saved: 2026-05-05T11:04:37.131418+00:00
instance: kb-cron
parent: qualia-20260505-0
summary:
==== E. J. Lowe ==== E. J. Lowe denies that indirect realism, wherein which we have access only to sensory features internal to the brain, necessarily implies a Cartesian dualism. He agrees with Bertrand Russell that the way images are received by our retinas, our "retinal images", are connected to "patterns of neural activity in the cortex". He defends a version of the causal theory of perception in which a causal path can be traced between the external object and the perception of it. He is careful to deny that we do any inferring from the sensory field; he believes this allows us to build an access to knowledge on that causal connection. In a later work he moves closer to the non-epistemic argument in that he postulates "a wholly non-conceptual component of perceptual experience". ==== J. B. Maund ==== John Barry Maund, an Australian philosopher of perception, argues that qualia can be described on two levels, a fact that he refers to as "dual coding". Maund extended his argument with reference to color. Color he sees as a dispositional property, not an objective one. Colors are "virtual properties", which means they are as if things possessed them. Although the


id: qualia-20260505-4
file: data/en.wikipedia.org/wiki/Qualia-4.md
category: reference
title: Qualia
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Qualia
date_saved: 2026-05-05T11:04:37.131418+00:00
instance: kb-cron
parent: qualia-20260505-0
summary:
Vilayanur S. Ramachandran and William Hirstein proposed three laws of qualia (with a fourth later added), which are "functional criteria that need to be fulfilled in order for certain neural events to be associated with qualia" by philosophers of the mind: Qualia are irrevocable and indubitable. You don't say 'maybe it is red but I can visualize it as green if I want to'. An explicit neural representation of red is created that invariably and automatically 'reports' this to higher brain centres. Once the representation is created, what can be done with it is open-ended. You have the luxury of choice, e.g., if you have the percept of an apple you can use it to tempt Adam, to keep the doctor away, bake a pie, or just to eat. Even though the representation at the input level is immutable and automatic, the output is potentially infinite. This isn't true for, say, a spinal reflex arc where the output is also inevitable and automatic. Indeed, a paraplegic can even have an erection and ejaculate without an orgasm. Short-term memory. The input invariably creates a representation that persists in short-term memory – long enough to allow time for choice of output. Without


id: qualia-20260505-5
file: data/en.wikipedia.org/wiki/Qualia-5.md
category: reference
title: Qualia
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Qualia
date_saved: 2026-05-05T11:04:37.131418+00:00
instance: kb-cron
parent: qualia-20260505-0
summary:
Dennett attempts to show that we cannot satisfy (a) either through introspection or through observation, and that qualia's very definition undermines its chances of satisfying (b). Supporters of qualia point out that in order for you to notice a change in qualia, you must compare your current qualia with your memories of past qualia. Arguably, such a comparison would involve immediate assessment of your current qualia and your memories of past qualia, but not of the past qualia themselves. Furthermore, modern functional brain imaging has increasingly suggested that the memory of an experience is processed in similar ways, and in similar zones of the brain, as the original perception. This may mean that there would be asymmetric outcomes between altering the mechanism of perception of qualia and altering the memory of that qualia. If the diabolical neurosurgery altered the immediate perception of qualia, the inversion might not be noticed directly, since the brain zones which re-process the memories would invert the remembered qualia. On the other hand, alteration of the qualia memories themselves would be processed without inversion, and thus you would perceive them as an inversion. Thus, you might know immediately if memory of your qualia had been altered,


id: qualia-20260505-6
file: data/en.wikipedia.org/wiki/Qualia-6.md
category: reference
title: Qualia
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Qualia
date_saved: 2026-05-05T11:04:37.131418+00:00
instance: kb-cron
parent: qualia-20260505-0
summary:
=== Paul Churchland === According to Paul Churchland, Mary might be considered akin to a feral child who suffered extreme isolation during childhood. Technically when Mary leaves the room, she would not have the ability to see or know what the color red is, as a brain has to learn and develop how to see colors. Patterns need to form in the V4 section of the visual cortex, which occurs via exposure to wavelengths of light. This exposure needs to occur during the early stages of brain development. In Mary's case, the identifications and categorizations of color will only be in respect to representations of black and white. === Gary Drescher === In his book Good and Real, Gary Drescher compares qualia with "gensyms" (generated symbols) in Common Lisp. These are objects that Lisp treats as having no properties or components, which can only be identified as equal or not equal to other objects. Drescher explains, "we have no introspective access to whatever internal properties make the red gensym recognizably distinct from the green [...] even though we know the sensation when we experience it." Under this interpretation of qualia, Drescher responds to the Mary thought experiment by noting that


id: qualia-20260505-7
file: data/en.wikipedia.org/wiki/Qualia-7.md
category: reference
title: Qualia
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Qualia
date_saved: 2026-05-05T11:04:37.131418+00:00
instance: kb-cron
parent: qualia-20260505-0
summary:
"[T]he purportedly metaphysical "problem of consciousness" is no more and no less than the epistemological "problem of privileged access," and that once this is seen questions about dualism versus materialism lose their interest." Rorty suggests that the only answer that one can give as to why qualia are ontologically distinct from physical processes is that the lack of an appearance/reality distinction is an essential feature of their being (i.e. it is an essential feature of a quale that it be incorrigibly known), but he notes that in making this move, qualia have been hypostatized such that they can take on the property of being pure appearances. In other words, they have been turned into non-physical, property-bearing particulars, meaning they are no longer properties of the person who has them, but rather particulars that exist in addition to that person. Thus, the dualistic intuition that an explanation of, say, pain in terms of physical functions and behaviors leaves out the raw feel of pain itself is the result of hypostatizing pain into something non-physical which accompanies those physical processes: "The neo-dualist who identifies a pain with how it feels to be in pain is hypostatizing a property—painfulness—into a special sort of


id: qualia-20260505-8
file: data/en.wikipedia.org/wiki/Qualia-8.md
category: reference
title: Qualia
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Qualia
date_saved: 2026-05-05T11:04:37.131418+00:00
instance: kb-cron
parent: qualia-20260505-0
summary:
"Poised" - the phenomenal experience is always present to the understanding, whether or not the agent is able to apply a concept to it. "Abstract" - it is unclear whether you are in touch with a concrete object (for example, someone may feel a pain in an amputated limb). "Nonconceptual" - phenomenon can exist although one does not have the concept by which to recognize it. "Intentional (Content)" - it represents something, whether or not the observer is taking advantage of that fact. Tye adds that the experience is like a map in that, in most cases, it goes beyond the shapes, edges, volumes, etc. in the world – you may not be reading the a map but, as with an actual map there is a reliable match with what it is mapping. This is why Tye calls his theory representationalism, makes it plain that Tye believes that he has retained a direct contact with what produces the phenomena and is therefore not hampered by any trace of a "veil of perception". == See also == == References == === Citations === === Other references === Various authors (19 March 2007). Chalmers, David (ed.). "Online collection of papers on qualia".


id: sleep-onset-20260505-0
file: data/en.wikipedia.org/wiki/Sleep_onset-0.md
category: reference
title: Sleep onset
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Sleep_onset
date_saved: 2026-05-05T11:04:38.285135+00:00
instance: kb-cron
parent: sleep-onset-20260505-0
summary:
Sleep onset is the transition from wakefulness into sleep. Sleep onset usually transits into non-rapid eye movement sleep (NREM sleep) but under certain circumstances (e.g. narcolepsy) it is possible to transit from wakefulness directly into rapid eye movement sleep (REM sleep). == History == During the 1920s an obscure disorder that caused encephalitis and attacked the part of the brain that regulates sleep influenced Europe and North America. Although the virus that caused this disorder was never identified, the psychiatrist and neurologist Constantin von Economo decided to study this disease and identified a key component in the sleep-wake regulation. He identified the pathways that regulated wakefulness and sleep onset by studying the parts of the brain that were affected by the disease and the consequences it had on the circadian rhythm. He stated that the pathways that regulated sleep onset are located between the brain stem and the basal forebrain. His discoveries were not appreciated until the last two decades of the 20th century when the pathways of sleep were found to reside in the exact place that Constantin von Economo stated. == Neural circuit == Sleep electrophysiological measurements can be made by attaching electrodes to the scalp to measure


id: subacute-sclerosing-panencephalitis-20260505-0
file: data/en.wikipedia.org/wiki/Subacute_sclerosing_panencephalitis-0.md
category: reference
title: Subacute sclerosing panencephalitis
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Subacute_sclerosing_panencephalitis
date_saved: 2026-05-05T11:04:39.501994+00:00
instance: kb-cron
parent: subacute-sclerosing-panencephalitis-20260505-0
summary:
Subacute sclerosing panencephalitis (SSPE), also known as Dawson disease, is a rare form of progressive brain inflammation caused by a persistent infection with the measles virus. The condition primarily affects children, teens, and young adults. It has been estimated that about 2 in 10,000 people who get measles will eventually develop SSPE. However, a 2016 study estimated that the rate for unvaccinated infants under 15 months was as high as 1 in 609. No cure for SSPE exists, and the condition is almost always fatal. SSPE is sometimes confused with acute disseminated encephalomyelitis, which can also be caused by the measles virus, but has a very different timing and course. SSPE is caused by some strains of the wild-type (naturally occurring) measles virus, such as the B3 strain, but not by the strains used in measles vaccines. == Signs and symptoms == SSPE is characterized by a history of primary measles infection, followed by a normal, unremarkable recovery. Symptoms of SSPE appear later. On average, the first symptoms appear about 10 years after the initial infection, though this varies significantly, as some people have developed SSPE symptoms as soon as 1 month after infection, and others as long as 27


id: thought-20260505-0
file: data/en.wikipedia.org/wiki/Thought-0.md
category: reference
title: Thought
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Thought
date_saved: 2026-05-05T11:04:40.951647+00:00
instance: kb-cron
parent: thought-20260505-0
summary:
In their most common sense, thought and thinking refer to cognitive processes that occur independently of direct sensory stimulation. Core forms include judging, reasoning, concept formation, problem solving, and deliberation. Other processes, such as entertaining an idea, memory, or imagination, are also frequently considered types of thought. Unlike perception, these activities can occur without immediate input from the sensory organs. In a broader sense, any mental event—including perception and unconscious processes—may be described as a form of thought. The term can also denote not the process itself, but the resulting mental states or systems of ideas. A variety of theories attempt to explain the nature of thinking. Platonism holds that thought involves discerning eternal forms and their interrelations, distinguishing these pure entities from their imperfect sensory imitations. Aristotelianism interprets thinking as instantiating the universal essence of an object within the mind, derived from sense experience rather than a changeless realm. Conceptualism, closely related to Aristotelianism, identifies thinking with the mental evocation of concepts. Inner speech theories suggest that thought takes the form of silent verbal expression, sometimes in a natural language and sometimes in a specialized "mental language," or Mentalese, as proposed by the language of thought hypothesis. Associationism views


id: thought-20260505-1
file: data/en.wikipedia.org/wiki/Thought-1.md
category: reference
title: Thought
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Thought
date_saved: 2026-05-05T11:04:40.951647+00:00
instance: kb-cron
parent: thought-20260505-0
summary:
=== Aristotelianism and conceptualism === According to Aristotelianism, the mind thinks about an object by instantiating its essence. For example, when thinking about trees, the mind instantiates "tree-ness." Unlike actual trees, this instantiation does not occur in matter but in the mind, though the universal essence is the same in both cases. In contrast with Platonism, universals are not seen as timeless forms existing in a separate intelligible realm. Instead, they exist only insofar as they are instantiated. The mind comes to recognize universals through abstraction from experience, a view that avoids some objections directed against Platonism. Conceptualism is closely related. It holds that thinking consists in mentally evoking concepts. While some concepts may be innate, most are acquired through abstraction from sensory experience before they can be used in thought. Critics argue that both theories face difficulties. One problem is explaining the logical structure of thought. For instance, to think that it will either rain or snow, it is not enough to instantiate the essences of rain and snow or to evoke the relevant concepts. The disjunctive relation between them is not captured in this way. Another challenge lies in providing a clear account of how the mind acquires


id: thought-20260505-2
file: data/en.wikipedia.org/wiki/Thought-2.md
category: reference
title: Thought
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Thought
date_saved: 2026-05-05T11:04:40.951647+00:00
instance: kb-cron
parent: thought-20260505-0
summary:
=== Associationism === An important view in the empiricist tradition has been associationism, the view that thinking consists in the succession of ideas or images. This succession is seen as being governed by laws of association, which determine how the train of thought unfolds. These laws are different from logical relations between the contents of thoughts, which are found in the case of drawing inferences by moving from the thought of the premises to the thought of the conclusion. Various laws of association have been suggested. According to the laws of similarity and contrast, ideas tend to evoke other ideas that are either very similar to them or their opposite. The law of contiguity, on the other hand, states that if two ideas were frequently experienced together, then the experience of one tends to cause the experience of the other. In this sense, the history of an organism's experience determines which thoughts the organism has and how these thoughts unfold. But such an association does not guarantee that the connection is meaningful or rational. For example, because of the association between the terms "cold" and "Idaho", the thought "this coffee shop is cold" might lead to the thought "Russia should


id: thought-20260505-3
file: data/en.wikipedia.org/wiki/Thought-3.md
category: reference
title: Thought
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Thought
date_saved: 2026-05-05T11:04:40.951647+00:00
instance: kb-cron
parent: thought-20260505-0
summary:
=== Computationalism === Computationalist theories of thinking, often found in the cognitive sciences, understand thinking as a form of information processing. These views developed with the rise of computers in the second part of the 20th century, when various theorists saw thinking in analogy to computer operations. On such views, the information may be encoded differently in the brain, but in principle, the same operations take place there as well, corresponding to the storage, transmission, and processing of information. But while this analogy has some intuitive attraction, theorists have struggled to give a more explicit explanation of what computation is. A further problem consists in explaining the sense in which thinking is a form of computing. The traditionally dominant view defines computation in terms of Turing machines, though contemporary accounts often focus on neural networks for their analogies. A Turing machine is capable of executing any algorithm based on a few very basic principles, such as reading a symbol from a cell, writing a symbol to a cell, and executing instructions based on the symbols read. This way it is possible to perform deductive reasoning following the inference rules of formal logic as well as simulating many other functions of


id: thought-20260505-4
file: data/en.wikipedia.org/wiki/Thought-4.md
category: reference
title: Thought
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Thought
date_saved: 2026-05-05T11:04:40.951647+00:00
instance: kb-cron
parent: thought-20260505-0
summary:
=== Entertaining, judging, and reasoning === Thinking is often identified with the act of judging. A judgment is a mental operation in which a proposition is evoked and then either affirmed or denied. It involves deciding what to believe and aims at determining whether the judged proposition is true or false. Various theories of judgment have been proposed. The traditionally dominant approach is the combination theory. It states that judgments consist in the combination of concepts. On this view, to judge that "all men are mortal" is to combine the concepts "man" and "mortal". The same concepts can be combined in different ways, corresponding to different forms of judgment, for example, as "some men are mortal" or "no man is mortal". Other theories of judgment focus more on the relation between the judged proposition and reality. According to Franz Brentano, a judgment is either a belief or a disbelief in the existence of some entity. In this sense, there are only two fundamental forms of judgment: "A exists" and "A does not exist". When applied to the sentence "all men are mortal", the entity in question is "immortal men", of whom it is said that they do not exist. Important


id: thought-20260505-5
file: data/en.wikipedia.org/wiki/Thought-5.md
category: reference
title: Thought
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Thought
date_saved: 2026-05-05T11:04:40.951647+00:00
instance: kb-cron
parent: thought-20260505-0
summary:
=== Problem solving === In the case of problem solving, thinking aims at reaching a predefined goal by overcoming certain obstacles. This process often involves two different forms of thinking. On the one hand, divergent thinking aims at coming up with as many alternative solutions as possible. On the other hand, convergent thinking tries to narrow down the range of alternatives to the most promising candidates. Some researchers identify various steps in the process of problem solving. These steps include recognizing the problem, trying to understand its nature, identifying general criteria the solution should meet, deciding how these criteria should be prioritized, monitoring the progress, and evaluating the results. An important distinction concerns the type of problem that is faced. For well-structured problems, it is easy to determine which steps need to be taken to solve them, but executing these steps may still be difficult. For ill-structured problems, on the other hand, it is not clear what steps need to be taken, i.e. there is no clear formula that would lead to success if followed correctly. In this case, the solution may sometimes come in a flash of insight in which the problem is suddenly seen in a new light.


id: thought-20260505-6
file: data/en.wikipedia.org/wiki/Thought-6.md
category: reference
title: Thought
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Thought
date_saved: 2026-05-05T11:04:40.951647+00:00
instance: kb-cron
parent: thought-20260505-0
summary:
=== Unconscious thought === Conscious thought is the paradigmatic form of thinking and is often the focus of the corresponding research. But it has been argued that some forms of thought also happen on the unconscious level. Unconscious thought is thought that happens in the background without being experienced. It is therefore not observed directly. Instead, its existence is usually inferred by other means. For example, when someone is faced with an important decision or a difficult problem, they may not be able to solve it straight away. But then, at a later time, the solution may suddenly flash before them even though no conscious steps of thinking were taken towards this solution in the meantime. In such cases, the cognitive labor needed to arrive at a solution is often explained in terms of unconscious thoughts. The central idea is that a cognitive transition happened and we need to posit unconscious thoughts to be able to explain how it happened. It has been argued that conscious and unconscious thoughts differ not just concerning their relation to experience but also concerning their capacities. According to unconscious thought theorists, for example, conscious thought excels at simple problems with few variables but is


id: thought-20260505-7
file: data/en.wikipedia.org/wiki/Thought-7.md
category: reference
title: Thought
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Thought
date_saved: 2026-05-05T11:04:40.951647+00:00
instance: kb-cron
parent: thought-20260505-0
summary:
=== Phenomenology === Phenomenology is the science of the structure and contents of experience. The term "cognitive phenomenology" refers to the experiential character of thinking or what it feels like to think. Some theorists claim that there is no distinctive cognitive phenomenology. On such a view, the experience of thinking is just one form of sensory experience. According to one version, thinking just involves hearing a voice internally. According to another, there is no experience of thinking apart from the indirect effects thinking has on sensory experience. A weaker version of such an approach allows that thinking may have a distinct phenomenology but contends that thinking still depends on sensory experience because it cannot occur on its own. On this view, sensory contents constitute the foundation from which thinking may arise. An often-cited thought experiment in favor of the existence of a distinctive cognitive phenomenology involves two persons listening to a radio broadcast in French, one who understands French and the other who does not. The idea behind this example is that both listeners hear the same sounds and therefore have the same non-cognitive experience. In order to explain the difference, a distinctive cognitive phenomenology has to be posited: only


id: thought-20260505-8
file: data/en.wikipedia.org/wiki/Thought-8.md
category: reference
title: Thought
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Thought
date_saved: 2026-05-05T11:04:40.951647+00:00
instance: kb-cron
parent: thought-20260505-0
summary:
=== Metaphysics === The mind–body problem concerns the explanation of the relationship that exists between minds, or mental processes, and bodily states or processes. The main aim of philosophers working in this area is to determine the nature of the mind and mental states/processes, and how—or even if—minds are affected by and can affect the body. Human perceptual experiences depend on stimuli which arrive at one's various sensory organs from the external world and these stimuli cause changes in one's mental state, ultimately causing one to feel a sensation, which may be pleasant or unpleasant. Someone's desire for a slice of pizza, for example, will tend to cause that person to move his or her body in a specific manner and in a specific direction to obtain what he or she wants. The question, then, is how it can be possible for conscious experiences to arise out of a lump of gray matter endowed with nothing but electrochemical properties. A related problem is to explain how someone's propositional attitudes (e.g. beliefs and desires) can cause that individual's neurons to fire and his muscles to contract in exactly the correct manner. These comprise some of the puzzles that have confronted epistemologists


id: thought-20260505-9
file: data/en.wikipedia.org/wiki/Thought-9.md
category: reference
title: Thought
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Thought
date_saved: 2026-05-05T11:04:40.951647+00:00
instance: kb-cron
parent: thought-20260505-0
summary:
The "id", "ego" and "super-ego" are the three parts of the "psychic apparatus" defined in Sigmund Freud's structural model of the psyche; they are the three theoretical constructs in terms of whose activity and interaction mental life is described. According to this model, the uncoordinated instinctual trends are encompassed by the "id", the organized realistic part of the psyche is the "ego", and the critical, moralizing function is the "super-ego". For psychoanalysis, the unconscious does not include all that is not conscious, rather only what is actively repressed from conscious thought or what the person is averse to knowing consciously. In a sense this view places the self in relationship to their unconscious as an adversary, warring with itself to keep what is unconscious hidden. If a person feels pain, all he can think of is alleviating the pain. Any of his desires, to get rid of pain or enjoy something, command the mind what to do. For Freud, the unconscious was a repository for socially unacceptable ideas, wishes or desires, traumatic memories, and painful emotions put out of mind by the mechanism of psychological repression. However, the contents did not necessarily have to be solely negative. In the psychoanalytic


id: thought-20260505-10
file: data/en.wikipedia.org/wiki/Thought-10.md
category: reference
title: Thought
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Thought
date_saved: 2026-05-05T11:04:40.951647+00:00
instance: kb-cron
parent: thought-20260505-0
summary:
=== Counterfactual thinking === Counterfactual thinking involves mental representations of non-actual situations and events, i.e. of what is "contrary to the facts". It is usually conditional: it aims at assessing what would be the case if a certain condition had obtained. In this sense, it tries to answer "What if"-questions. For example, thinking after an accident that one would be dead if one had not used the seatbelt is a form of counterfactual thinking: it assumes, contrary to the facts, that one had not used the seatbelt and tries to assess the result of this state of affairs. In this sense, counterfactual thinking is normally counterfactual only to a small degree since just a few facts are changed, like concerning the seatbelt, while most other facts are kept in place, like that one was driving, one's gender, the laws of physics, etc. When understood in the widest sense, there are forms of counterfactual thinking that do not involve anything contrary to the facts at all. This is the case, for example, when one tries to anticipate what might happen in the future if an uncertain event occurs and this event actually occurs later and brings with it the anticipated consequences.


id: thought-20260505-11
file: data/en.wikipedia.org/wiki/Thought-11.md
category: reference
title: Thought
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Thought
date_saved: 2026-05-05T11:04:40.951647+00:00
instance: kb-cron
parent: thought-20260505-0
summary:
=== Critical thinking === Critical thinking is a form of thinking that is reasonable, reflective, and focused on determining what to believe or how to act. It holds itself to various standards, like clarity and rationality. In this sense, it involves not just cognitive processes trying to solve the issue at hand but at the same time meta-cognitive processes ensuring that it lives up to its own standards. This includes assessing both that the reasoning itself is sound and that the evidence it rests on is reliable. This means that logic plays an important role in critical thinking. It concerns not just formal logic, but also informal logic, specifically to avoid various informal fallacies due to vague or ambiguous expressions in natural language. No generally accepted standard definition of "critical thinking" exists but there is significant overlap between the proposed definitions in their characterization of critical thinking as careful and goal-directed. According to some versions, only the thinker's own observations and experiments are accepted as evidence in critical thinking. Some restrict it to the formation of judgments but exclude action as its goal. A concrete everyday example of critical thinking, due to John Dewey, involves observing foam bubbles moving in


id: time-perception-20260505-0
file: data/en.wikipedia.org/wiki/Time_perception-0.md
category: reference
title: Time perception
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Time_perception
date_saved: 2026-05-05T11:04:42.322703+00:00
instance: kb-cron
parent: time-perception-20260505-0
summary:
In psychology and neuroscience, time perception or chronoception is the subjective experience, or sense, of time, which is measured by someone's own perception of the duration of the indefinite and unfolding of events. The perceived time interval between two successive events is referred to as perceived duration. Though directly experiencing or understanding another person's perception of time is not possible, perception can be objectively studied and inferred through a number of scientific experiments. Some temporal illusions help to expose the underlying neural mechanisms of time perception. The ancient Greeks recognized the difference between chronological time (chronos) and subjective time (kairos). Pioneering work on time perception, emphasizing species-specific differences, was conducted by Karl Ernst von Baer. == Theories == Time perception is typically categorized in five distinct ranges, because different ranges of duration are processed in different areas of the brain: Sub-second timing or millisecond timing Interval timing or seconds-to-minutes timing Circadian timing Astrocyte glutamine clearance delay Mitochondrial hysteresis There are many theories and computational models for time perception mechanisms in the brain. William J. Friedman (1993) contrasted two theories of the sense of time: The strength model of time memory. This posits a memory trace that persists over time, by


id: time-perception-20260505-1
file: data/en.wikipedia.org/wiki/Time_perception-1.md
category: reference
title: Time perception
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Time_perception
date_saved: 2026-05-05T11:04:42.322703+00:00
instance: kb-cron
parent: time-perception-20260505-0
summary:
if the visual brain wants to get events correct timewise, it may have only one choice: wait for the slowest information to arrive. To accomplish this, it must wait about a tenth of a second. In the early days of television broadcasting, engineers worried about the problem of keeping audio and video signals synchronized. Then they accidentally discovered that they had around a hundred milliseconds of slop: As long as the signals arrived within this window, viewers' brains would automatically resynchronize the signals. He goes on to say, "This brief waiting period allows the visual system to discount the various delays imposed by the early stages; however, it has the disadvantage of pushing perception into the past. There is a distinct survival advantage to operating as close to the present as possible; an animal does not want to live too far in the past. Therefore, the tenth-of-a-second window may be the smallest delay that allows higher areas of the brain to account for the delays created in the first stages of the system while still operating near the border of the present. This window of delay means that awareness is retroactive, incorporating data from a window of time after an


id: time-perception-20260505-2
file: data/en.wikipedia.org/wiki/Time_perception-2.md
category: reference
title: Time perception
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Time_perception
date_saved: 2026-05-05T11:04:42.322703+00:00
instance: kb-cron
parent: time-perception-20260505-0
summary:
When returning to the hive with nectar, forager honey bees need to know the current ratio of nectar-collecting to nectar-processing rates in the colony. To do so, they estimate the time it takes them to find a food-storer bee, which will unload the forage and store it. The longer it takes them to find one, the busier the food-storer bees are, and therefore the higher the nectar-collecting rate of the colony. Forager bees also assess the quality of nectar by comparing the length of time it takes to unload the forage: a longer unloading time indicates higher quality nectar. They compare their own unloading time to the unloading time of other foragers present in the hive, and adjust their recruiting behavior accordingly. For instance, honey bees reduce the duration of their waggle dance if they judge their own yield to be inferior. Scientists have demonstrated that anesthesia disrupts the circadian clock and impairs the time perception of honey bees, as observed in humans. Experiments revealed that a six-hour-long general anesthesia significantly delayed the start of the foraging behaviour of honeybees if induced during daytime, but not if induced during nighttime. Bumble bees can be successfully trained to respond to a


id: time-perception-20260505-3
file: data/en.wikipedia.org/wiki/Time_perception-3.md
category: reference
title: Time perception
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Time_perception
date_saved: 2026-05-05T11:04:42.322703+00:00
instance: kb-cron
parent: time-perception-20260505-0
summary:
In an experiment, participants were told to stare at an "x" symbol on a computer screen whereby a moving blue doughnut-like ring repeatedly circled the fixed "x" point. Occasionally, the ring would display a white flash for a split second that physically overlapped the ring's interior. However, when asked what was perceived, participants responded that they saw the white flash lagging behind the center of the moving ring. In other words, despite the reality that the two retinal images were actually spatially aligned, the flashed object was usually observed to trail a continuously moving object in space — a phenomenon referred to as the flash-lag effect. The first proposed explanation, called the "motion extrapolation" hypothesis, is that the visual system extrapolates the position of moving objects but not flashing objects when accounting for neural delays (i.e., the lag time between the retinal image and the observer's perception of the flashing object). The second proposed explanation by David Eagleman and Sejnowski, called the "latency difference" hypothesis, is that the visual system processes moving objects at a faster rate than flashed objects. In the attempt to disprove the first hypothesis, David Eagleman conducted an experiment in which the moving ring suddenly reverses


id: time-perception-20260505-4
file: data/en.wikipedia.org/wiki/Time_perception-4.md
category: reference
title: Time perception
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Time_perception
date_saved: 2026-05-05T11:04:42.322703+00:00
instance: kb-cron
parent: time-perception-20260505-0
summary:
==== Awe ==== Research has suggested the feeling of awe has the ability to expand one's perceptions of time availability. Awe can be characterized as an experience of immense perceptual vastness that coincides with an increase in focus. Consequently, it is conceivable that one's temporal perception would slow down when experiencing awe. The perception of time can differ as people choose between savoring moments and deferring gratification. ==== Fear ==== Possibly related to the oddball effect, research suggests that time seems to slow down for a person during dangerous events (such as a car accident, a robbery, or when a person perceives a potential predator or mate), or when a person skydives or bungee jumps, where they are capable of complex thoughts in what would normally be the blink of an eye (e.g., a fight-or-flight response). This reported slowing in temporal perception may have been evolutionarily advantageous because it may have enhanced one's ability to intelligibly make quick decisions in moments that were of critical importance to survival. However, even though observers commonly report that time seems to have moved in slow motion during these events, it is unclear whether this is a function of increased time resolution during the


id: time-perception-20260505-5
file: data/en.wikipedia.org/wiki/Time_perception-5.md
category: reference
title: Time perception
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Time_perception
date_saved: 2026-05-05T11:04:42.322703+00:00
instance: kb-cron
parent: time-perception-20260505-0
summary:
When solved, S 2 − S 1 = K ( log ⁡ R 2 − log ⁡ R 1 ) = K log ⁡ ( R 2 / R 1 ) {\displaystyle S_{2}-S_{1}=K(\log {R_{2}}-\log {R_{1}})=K\log {\left({R_{2}}/{R_{1}}\right)}} . One day would be approximately 1/4,000 of the life of an 11-year-old, but approximately 1/20,000 of the life of a 55-year-old. So a year would be experienced by a 55-year-old as passing approximately five times more quickly than a year experienced by an 11-year-old. If long-term time perception is based solely on the proportionality of a person's age, then the following four periods in life would appear to be quantitatively equal: ages 5–10 (1x), ages 10–20 (2x), ages 20–40 (4x), age 40–80 (8x), as the end age is twice the start age. However, this does not work for ages 0–10, which corresponds to ages 10–∞. ==== Proportional to the subjective time ==== Lemlich posits that the passage of subjective time relative to actual time is inversely proportional to total subjective time, rather than the total real time: d S d R = K S {\displaystyle {\frac {dS}{dR}}={\frac {K}{S}}} When mathematically solved, S 2 = 2 K R + C {\displaystyle S^{2}=2KR+C} It avoids


id: time-perception-20260505-6
file: data/en.wikipedia.org/wiki/Time_perception-6.md
category: reference
title: Time perception
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Time_perception
date_saved: 2026-05-05T11:04:42.322703+00:00
instance: kb-cron
parent: time-perception-20260505-0
summary:
== Time perception and artificial intelligence == Time perception refers to the ability to represent, estimate, and use temporal information. While it is a fundamental aspect of biological cognition, recent research has increasingly sought to model temporal processing in artificial systems, especially embodied artificial systems. This line of research has been suggested to be crucial for human-robot interaction, where understanding subtle timing cues can improve coordination and collaboration. For example, timing precision also affects user satisfaction, as temporal accuracy in robotic movements often matters more than spatial precision. Computational studies of biological timing mechanisms also help generate testable hypotheses about biological time perception. Consequently, computational and robotic models have been developed to simulate various timing abilities, such as duration estimation, interval reproduction, and temporal prediction, across cognitive and emergent modelling frameworks. Many of these models use neural network dynamics, oscillatory systems, or reinforcement learning to produce clock-like timing without an explicit clock structure. == Applications in urban design == Beyond laboratory settings, time perception has also been studied in relation to the design of urban environments. In this context, Shakibamanesh and Ghorbanian (2017) developed an applied time-based evaluation checklist that enables urban designers to systematically analyze how spatial form, visual


id: unihemispheric-slow-wave-sleep-20260505-0
file: data/en.wikipedia.org/wiki/Unihemispheric_slow-wave_sleep-0.md
category: reference
title: Unihemispheric slow-wave sleep
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Unihemispheric_slow-wave_sleep
date_saved: 2026-05-05T11:04:43.626925+00:00
instance: kb-cron
parent: unihemispheric-slow-wave-sleep-20260505-0
summary:
Unihemispheric slow-wave sleep (USWS) is sleep where one half of the brain rests while the other half remains alert. This is in contrast to normal sleep where both eyes are shut and both halves of the brain show unconsciousness. In USWS, also known as asymmetric slow-wave sleep, one half of the brain is in deep sleep, a form of non-rapid eye movement sleep and the eye corresponding to this half is closed while the other eye remains open. When examined by electroencephalography (EEG), the characteristic slow-wave sleep tracings are seen from one side while the other side shows a characteristic tracing of wakefulness. The phenomenon has been observed in a number of terrestrial, aquatic and avian species. Unique physiology, including the differential release of the neurotransmitter acetylcholine, has been linked to the phenomenon. USWS offers a number of benefits, including the ability to rest in areas of high predation or during long migratory flights. The behaviour remains an important research topic because USWS is possibly the first animal behaviour which uses different regions of the brain to simultaneously control sleep and wakefulness. The greatest theoretical importance of USWS is its potential role in elucidating the function of sleep by challenging


id: unihemispheric-slow-wave-sleep-20260505-1
file: data/en.wikipedia.org/wiki/Unihemispheric_slow-wave_sleep-1.md
category: reference
title: Unihemispheric slow-wave sleep
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Unihemispheric_slow-wave_sleep
date_saved: 2026-05-05T11:04:43.626925+00:00
instance: kb-cron
parent: unihemispheric-slow-wave-sleep-20260505-0
summary:
=== Eye opening === In domestic chicks and other species of birds exhibiting USWS, one eye remained open contra-lateral (on the opposite side) to the "awake" hemisphere. The closed eye was shown to be opposite the hemisphere engaging in slow-wave sleep. Learning tasks, such as those including predator recognition, demonstrated the open eye could be preferential. This has also been shown to be the favored behavior of belugas, although inconsistencies have arisen directly relating the sleeping hemisphere and open eye. Keeping one eye open aids birds in engaging in USWS while mid-flight as well as helping them observe predators in their vicinity. Also crocodilians have been shown to sleep with one eye open. Given that USWS is preserved also in blind animals or during a lack of visual stimuli, it cannot be considered as a consequence of keeping an eye open while sleeping. Furthermore, the open eye in dolphins does not forcibly activate the contralateral hemisphere. Although unilateral vision plays a considerable role in keeping active the contralateral hemisphere, it is not the motive power of USWS. Consequently, USWS might be generated by endogenous mechanisms. === Thermoregulation === Brain temperature has been shown to drop when a sleeping EEG is


id: unihemispheric-slow-wave-sleep-20260505-2
file: data/en.wikipedia.org/wiki/Unihemispheric_slow-wave_sleep-2.md
category: reference
title: Unihemispheric slow-wave sleep
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Unihemispheric_slow-wave_sleep
date_saved: 2026-05-05T11:04:43.626925+00:00
instance: kb-cron
parent: unihemispheric-slow-wave-sleep-20260505-0
summary:
==== Regulation based on surroundings ==== Birds can sleep more efficiently with both hemispheres sleeping simultaneously (bihemispheric slow-wave sleep) when in safe conditions, but will increase the usage of USWS if they are in a potentially more dangerous environment. It is more beneficial to sleep using both hemispheres; however, the positives of unihemispheric slow-wave sleep prevail over its negatives under extreme conditions. While in unihemispheric slow-wave sleep, birds will sleep with one open eye towards the direction from which predators are more likely to approach. When birds do this in a flock, it's called the "group edge effect". The mallard is one bird that has been used experimentally to illustrate the "group edge effect". Birds positioned at the edge of the flock are most alert, scanning often for predators. These birds are more at risk than the birds in the center of the flock and are required to be on the lookout for both their own safety and the safety of the group as a whole. They have been observed spending more time in unihemispheric slow-wave sleep than the birds in the center. Since USWS allows for the one eye to be open, the cerebral hemisphere that undergoes slow-wave sleep


id: unihemispheric-slow-wave-sleep-20260505-3
file: data/en.wikipedia.org/wiki/Unihemispheric_slow-wave_sleep-3.md
category: reference
title: Unihemispheric slow-wave sleep
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Unihemispheric_slow-wave_sleep
date_saved: 2026-05-05T11:04:43.626925+00:00
instance: kb-cron
parent: unihemispheric-slow-wave-sleep-20260505-0
summary:
== Future research == Recent studies have illustrated that the white-crowned sparrow, as well as other passerines, have the capability of sleeping most significantly during the migratory season while in flight. However, the sleep patterns in this study were observed during migratory restlessness in captivity and might not be analogous to those of free-flying birds. Free-flying birds might be able to spend some time sleeping while in non-migratory flight as well when in the unobstructed sky as opposed to in controlled captive conditions. To truly determine if birds can sleep in flight, recordings of brain activity must take place during flight instead of after landing. A method of recording brain activity in pigeons during flight has recently proven promising in that it could obtain an EEG of each hemisphere but for relatively short periods of time. Coupled with simulated wind tunnels in a controlled setting, these new methods of measuring brain activity could elucidate the truth behind whether or not birds sleep during flight. Additionally, based on research elucidating the role of acetylcholine in control of USWS, additional neurotransmitters are being researched to understand their roles in the asymmetric sleep model. == See also == Sleep in animals == References


id: list-of-unsolved-problems-in-physics-20260505-0
file: data/en.wikipedia.org/wiki/List_of_unsolved_problems_in_physics-0.md
category: reference
title: List of unsolved problems in physics
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/List_of_unsolved_problems_in_physics
date_saved: 2026-05-05T11:04:45.237201+00:00
instance: kb-cron
parent: list-of-unsolved-problems-in-physics-20260505-0
summary:
The following is a list of notable unsolved problems grouped into broad areas of physics. Some of the major unsolved problems in physics are theoretical, meaning that existing theories are currently unable to explain certain observed phenomena or experimental results. Others are experimental, involving challenges in creating experiments to test proposed theories or to investigate specific phenomena in greater detail. A number of important questions remain open in the area of physics beyond the Standard Model, such as the strong CP problem, determining the absolute mass of neutrinos, understanding matter–antimatter asymmetry, and identifying the nature of dark matter and dark energy. Another significant problem lies within the mathematical framework of the Standard Model itself, which remains inconsistent with general relativity. This incompatibility causes both theories to break down under extreme conditions, such as within known spacetime gravitational singularities like those at the Big Bang and at the centers of black holes beyond their event horizons. == Historical problems and lists == Isaac Newton in his book Opticks (first edition 1704), published a list of 31 queries about light. In 1900, Lord Kelvin in a speech identified two main issues in classical physics that represented "two clouds" for the physics of


id: list-of-unsolved-problems-in-physics-20260505-1
file: data/en.wikipedia.org/wiki/List_of_unsolved_problems_in_physics-1.md
category: reference
title: List of unsolved problems in physics
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/List_of_unsolved_problems_in_physics
date_saved: 2026-05-05T11:04:45.237201+00:00
instance: kb-cron
parent: list-of-unsolved-problems-in-physics-20260505-0
summary:
== Quantum gravity == Quantum gravity: Can quantum mechanics and general relativity be realized as a fully consistent theory (perhaps as a quantum field theory)? Is spacetime fundamentally continuous or discrete? Would a consistent theory involve a force mediated by a hypothetical graviton, or be a product of a discrete structure of spacetime itself (as in loop quantum gravity)? Are there deviations from the predictions of general relativity at very small or very large scales or in other extreme circumstances that flow from a quantum gravity mechanism? Black holes, black hole information paradox, and black hole radiation: Do black holes produce thermal radiation, as expected on theoretical grounds? Does this radiation contain information about their inner structure, as suggested by gauge–gravity duality, or not, as implied by Hawking's original calculation? If not, and black holes can evaporate away, what happens to the information stored in them (since quantum mechanics does not provide for the destruction of information)? Or does the radiation stop at some point, leaving black hole remnants? Is there another way to probe their internal structure somehow, if such a structure even exists? The cosmic censorship hypothesis and the chronology protection conjecture: Can singularities not hidden behind an


id: list-of-unsolved-problems-in-physics-20260505-2
file: data/en.wikipedia.org/wiki/List_of_unsolved_problems_in_physics-2.md
category: reference
title: List of unsolved problems in physics
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/List_of_unsolved_problems_in_physics
date_saved: 2026-05-05T11:04:45.237201+00:00
instance: kb-cron
parent: list-of-unsolved-problems-in-physics-20260505-0
summary:
Dark matter: What is the identity of dark matter? Is it a particle? If so, is it a WIMP, axion, the lightest superpartner (LSP), or some other particle? Or, are the phenomena attributed to dark matter the result of an alternate theory of gravity separate from general relativity altogether? Despite extensive research, the exact composition of dark matter remains unknown. It is inferred from gravitational effects on visible matter, radiation, and the universe's large-scale structure. Understanding its properties is crucial for a comprehensive understanding of the universe. Dark energy: What is the cause of the observed accelerating expansion of the universe (the de Sitter phase)? Are the observations rightly interpreted as the accelerating expansion of the universe, or are they evidence that the cosmological principle is false? Why is the energy density of the dark energy component of the same magnitude as the density of matter at present when the two evolve quite differently over time; could it be simply that we are observing at exactly the right time? Is dark energy a pure cosmological constant or are models of quintessence such as phantom energy applicable? Dark flow: Is a non-spherically-symmetric gravitational pull from outside the observable universe responsible for


id: list-of-unsolved-problems-in-physics-20260505-3
file: data/en.wikipedia.org/wiki/List_of_unsolved_problems_in_physics-3.md
category: reference
title: List of unsolved problems in physics
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/List_of_unsolved_problems_in_physics
date_saved: 2026-05-05T11:04:45.237201+00:00
instance: kb-cron
parent: list-of-unsolved-problems-in-physics-20260505-0
summary:
The QCD vacuum: Many of the equations in non-perturbative QCD are currently unsolved. These energies are the energies sufficient for the formation and description of atomic nuclei. How thus does low energy /non-pertubative QCD give rise to the formation of complex nuclei and nuclear constituents? Generations of matter: Why are there three generations of quarks and leptons? Is there a theory that can explain the masses of particular quarks and leptons in particular generations from first principles (a theory of Yukawa couplings)? Neutrino mass: What is the absolute mass of neutrinos? Are they Dirac or Majorana fermions? Is the mass hierarchy normal or inverted? Is the CP violating phase equal to 0? Reactor antineutrino anomaly: There is an anomaly in the existing body of data regarding the antineutrino flux from nuclear reactors around the world. Measured values of this flux appears to be only 94% of the value expected from theory. It is unknown whether this is due to unknown physics (such as sterile neutrinos), experimental error in the measurements, or errors in the theoretical flux calculations. Strong CP problem and axions: Why is the strong nuclear interaction invariant to parity and charge conjugation? Is Peccei–Quinn theory the solution to


id: list-of-unsolved-problems-in-physics-20260505-4
file: data/en.wikipedia.org/wiki/List_of_unsolved_problems_in_physics-4.md
category: reference
title: List of unsolved problems in physics
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/List_of_unsolved_problems_in_physics
date_saved: 2026-05-05T11:04:45.237201+00:00
instance: kb-cron
parent: list-of-unsolved-problems-in-physics-20260505-0
summary:
Solar cycle: How does the Sun generate its periodically reversing large-scale magnetic field? How do other solar-like stars generate their magnetic fields, and what are the similarities and differences between stellar activity cycles and that of the Sun? What caused the Maunder Minimum and other grand minima, and how does the solar cycle recover from a minima state? Coronal heating problem: Why is the Sun's corona (atmosphere layer) so much hotter than the Sun's surface? Why is the magnetic reconnection effect many orders of magnitude faster than predicted by standard models? Astrophysical jet: Why do only certain accretion discs surrounding certain astronomical objects emit relativistic jets along their polar axes? Why are there quasi-periodic oscillations in many accretion discs? Why does the period of these oscillations scale as the inverse of the mass of the central object? Why are there sometimes overtones, and why do these appear at different frequency ratios in different objects? Diffuse interstellar bands: What is responsible for the numerous interstellar absorption lines detected in astronomical spectra? Are they molecular in origin, and if so which molecules are responsible for them? How do they form? Supermassive black holes: What is the origin of the M–sigma relation between


id: list-of-unsolved-problems-in-physics-20260505-5
file: data/en.wikipedia.org/wiki/List_of_unsolved_problems_in_physics-5.md
category: reference
title: List of unsolved problems in physics
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/List_of_unsolved_problems_in_physics
date_saved: 2026-05-05T11:04:45.237201+00:00
instance: kb-cron
parent: list-of-unsolved-problems-in-physics-20260505-0
summary:
Quantum chromodynamics: What are the phases of strongly interacting matter, and what roles do they play in the evolution of the cosmos? What is the detailed partonic structure of the nucleons? What does QCD predict for the properties of strongly interacting matter? What determines the key features of QCD, and what is their relation to the nature of gravity and spacetime? Does QCD truly lack CP violations? Quark–gluon plasma: Where is the onset of deconfinement: 1) as a function of temperature and chemical potentials? 2) as a function of relativistic heavy-ion collision energy and system size? What is the mechanism of energy and baryon-number stopping leading to creation of quark-gluon plasma in relativistic heavy-ion collisions? Why is sudden hadronization and the statistical-hadronization model a near-to-perfect description of hadron production from quark–gluon plasma? Is quark flavor conserved in quark–gluon plasma? Are strangeness and charm in chemical equilibrium in quark–gluon plasma? Does strangeness in quark–gluon plasma flow at the same speed as up and down quark flavours? Why does deconfined matter show ideal flow? Specific models of quark–gluon plasma formation: Do gluons saturate when their occupation number is large? Do gluons form a dense system called colour glass condensate? What are the


id: list-of-unsolved-problems-in-physics-20260505-6
file: data/en.wikipedia.org/wiki/List_of_unsolved_problems_in_physics-6.md
category: reference
title: List of unsolved problems in physics
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/List_of_unsolved_problems_in_physics
date_saved: 2026-05-05T11:04:45.237201+00:00
instance: kb-cron
parent: list-of-unsolved-problems-in-physics-20260505-0
summary:
== Plasma physics == Plasma physics and fusion power: Fusion energy may potentially provide power from an abundant resource (e.g. hydrogen) without the type of radioactive waste that fission energy currently produces. However, can ionized gases (plasma) be confined long enough and at a high enough temperature to create fusion power? What is the physical origin of H-mode? The injection problem: Fermi acceleration is thought to be the primary mechanism that accelerates astrophysical particles to high energy. However, it is unclear what mechanism causes those particles to initially have energies high enough for Fermi acceleration to work on them. Alfvénic turbulence: In the solar wind and the turbulence in solar flares, coronal mass ejections, and magnetospheric substorms are major unsolved problems in space plasma physics. Ball lightning: the exact physical nature of this mystery in atmospheric electricity. == Biophysics == Abiogenesis: can life be created from physical processes alone? Stochasticity and robustness to noise in gene expression: How do genes govern our body, withstanding different external pressures and internal stochasticity? Certain models exist for genetic processes, but we are far from understanding the whole picture, in particular in development where gene expression must be tightly regulated. Quantitative study of the


id: list-of-unsolved-problems-in-physics-20260505-7
file: data/en.wikipedia.org/wiki/List_of_unsolved_problems_in_physics-7.md
category: reference
title: List of unsolved problems in physics
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/List_of_unsolved_problems_in_physics
date_saved: 2026-05-05T11:04:45.237201+00:00
instance: kb-cron
parent: list-of-unsolved-problems-in-physics-20260505-0
summary:
=== High-energy physics/particle physics === Existence of pentaquarks (1964–2015): In July 2015, the LHCb collaboration at CERN identified pentaquarks in the Λ0b→J/ψK−p channel, which represents the decay of the bottom lambda baryon (Λ0b) into a J/ψ meson (J/ψ), a kaon (K−) and a proton (p). The results showed that sometimes, instead of decaying directly into mesons and baryons, the Λ0b decayed via intermediate pentaquark states. The two states, named P+c(4380) and P+c(4450), had individual statistical significances of 9 σ and 12 σ, respectively, and a combined significance of 15 σ—enough to claim a formal discovery. The two pentaquark states were both observed decaying strongly to J/ψp, hence must have a valence quark content of two up quarks, a down quark, a charm quark, and an anti-charm quark (uudcc), making them charmonium-pentaquarks. Existence of quark-gluon plasma, a new phase of matter was discovered and confirmed in experiments at CERN-SPS (2000), BNL-RHIC (2005) and CERN-LHC (2010). Higgs boson and electroweak symmetry breaking (1963–2012): The mechanism responsible for breaking the electroweak gauge symmetry, giving mass to the W and Z bosons, was solved with the discovery of the Higgs boson of the Standard Model, with the expected couplings to the weak bosons. No


id: accretion-disk-20260505-0
file: data/en.wikipedia.org/wiki/Accretion_disk-0.md
category: reference
title: Accretion disk
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Accretion_disk
date_saved: 2026-05-05T11:04:46.406689+00:00
instance: kb-cron
parent: accretion-disk-20260505-0
summary:
An accretion disk is a structure (often a circumstellar disk) formed by diffuse material in orbital motion around a massive central body. The central body is most frequently a star. Friction, uneven irradiance, magnetohydrodynamic effects, and other forces induce instabilities causing orbiting material in the disk to spiral inward toward the central body. Gravitational and frictional forces compress and raise the temperature of the material, causing the emission of electromagnetic radiation. The frequency range of that radiation depends on the central object's mass. Accretion disks of young stars and protostars radiate in the infrared; those around neutron stars and black holes in the X-ray part of the spectrum. The study of oscillation modes in accretion disks is referred to as diskoseismology. == Manifestations == Accretion disks are a ubiquitous phenomenon in astrophysics; active galactic nuclei, protoplanetary disks, and gamma ray bursts all involve accretion disks. These disks very often give rise to astrophysical jets coming from the vicinity of the central object. Jets are an efficient way for the star-disk system to shed angular momentum without losing too much mass. The most prominent accretion disks are those of active galactic nuclei and of quasars, which are thought to be massive


id: accretion-disk-20260505-1
file: data/en.wikipedia.org/wiki/Accretion_disk-1.md
category: reference
title: Accretion disk
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Accretion_disk
date_saved: 2026-05-05T11:04:46.406689+00:00
instance: kb-cron
parent: accretion-disk-20260505-0
summary:
=== α-Disk model === Shakura and Sunyaev (1973) proposed turbulence in the gas as the source of an increased viscosity. Assuming subsonic turbulence and the disk height as an upper limit for the size of the eddies, the disk viscosity can be estimated as ν = α c s H {\displaystyle \nu =\alpha c_{\rm {s}}H} where c s {\displaystyle c_{\rm {s}}} is the sound speed, H {\displaystyle H} is the scale height of the disk, and α {\displaystyle \alpha } is a free parameter between zero (no accretion) and approximately one. In a turbulent medium ν ≈ v t u r b l t u r b {\displaystyle \nu \approx v_{\rm {turb}}l_{\rm {turb}}} , where v t u r b {\displaystyle v_{\rm {turb}}} is the velocity of turbulent cells relative to the mean gas motion, and l t u r b {\displaystyle l_{\rm {turb}}} is the size of the largest turbulent cells, which is estimated as l t u r b ≈ H = c s / Ω {\displaystyle l_{\rm {turb}}\approx H=c_{\rm {s}}/\Omega } and v t u r b ≈ c s {\displaystyle v_{\rm {turb}}\approx c_{\rm {s}}} , where Ω = ( G M ) 1 / 2 r


id: accretion-disk-20260505-2
file: data/en.wikipedia.org/wiki/Accretion_disk-2.md
category: reference
title: Accretion disk
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Accretion_disk
date_saved: 2026-05-05T11:04:46.406689+00:00
instance: kb-cron
parent: accretion-disk-20260505-0
summary:
Most astrophysical disks do not meet this criterion and are therefore prone to this magnetorotational instability. The magnetic fields present in astrophysical objects (required for the instability to occur) are believed to be generated via dynamo action. === Magnetic fields and jets === Accretion disks are usually assumed to be threaded by the external magnetic fields present in the interstellar medium. These fields are typically weak (about few micro-Gauss), but they can get anchored to the matter in the disk, because of its high electrical conductivity, and carried inward toward the central star. This process can concentrate the magnetic flux around the centre of the disk giving rise to very strong magnetic fields. Formation of powerful astrophysical jets along the rotation axis of accretion disks requires a large scale poloidal magnetic field in the inner regions of the disk. Such magnetic fields may be advected inward from the interstellar medium or generated by a magnetic dynamo within the disk. Magnetic fields strengths at least of order 100 Gauss seem necessary for the magneto-centrifugal mechanism to launch powerful jets. There are problems, however, in carrying external magnetic flux inward toward the central star of the disk. High electric conductivity dictates that


id: accretion-disk-20260505-3
file: data/en.wikipedia.org/wiki/Accretion_disk-3.md
category: reference
title: Accretion disk
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Accretion_disk
date_saved: 2026-05-05T11:04:46.406689+00:00
instance: kb-cron
parent: accretion-disk-20260505-0
summary:
== Decretion disk == The opposite of an accretion disk is an decretion disk where instead of material accreting from a disk on to a central object, material is excreted from the center outward onto the disk. They are formed from matter ejected from a star, and are often assosicated with Be stars. == See also == == Notes == == References == == Further reading == Frank, Juhan; Andrew King; Derek Raine (2002), Accretion power in astrophysics (Third ed.), Cambridge University Press, ISBN 978-0-521-62957-7 Krolik, Julian H. (1999), Active Galactic Nuclei, Princeton University Press, ISBN 978-0-691-01151-6 Blaes, Omer (2014). "General Overview of Black Hole Accretion Theory". Space Science Reviews. 183 (1–4): 21–41. arXiv:1304.4879. Bibcode:2014SSRv..183...21B. doi:10.1007/s11214-013-9985-6. A modern review focused on models for turbulence required by alpha process. Abramowicz, M.A. (December 22, 2005). "Super-Eddington Black Hole Accretion:: Polish Doughnuts and Slim Disks". In Merloni, Andrea; Nayakshin, Sergei; Sunyaev, Rashid A. (eds.). Growing Black Holes: Accretion in a Cosmological Context. Berlin, Heidelberg: Springer Berlin Heidelberg. pp. 257–273. doi:10.1007/11403913_49. ISBN 978-3-540-25275-7. Retrieved 2026-04-13. Review with a good introduction to the topic. == External links == Professor John F. Hawley homepage, University of Virginia (archived 2015) The Dynamical Structure of Nonradiative Black Hole


id: ball-lightning-20260505-0
file: data/en.wikipedia.org/wiki/Ball_lightning-0.md
category: reference
title: Ball lightning
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Ball_lightning
date_saved: 2026-05-05T11:04:47.852283+00:00
instance: kb-cron
parent: ball-lightning-20260505-0
summary:
Ball lightning is a rare and unexplained phenomenon described as luminescent spherical objects that vary from pea-sized to several meters in diameter. Though usually associated with thunderstorms, the observed phenomenon is reported to last considerably longer than the split-second flash of a lightning bolt and is distinct from St. Elmo's fire and will-o'-the-wisp. Some 20th-century reports describe balls that eventually explode and leave behind an odor of sulfur. Descriptions of ball lightning appear in a variety of accounts over the centuries and have received attention from scientists. An optical spectrum of what appears to have been a ball lightning event was published in January 2014 and included a video at high frame rate. Nevertheless, scientific data on ball lightning remain scarce. Although laboratory experiments have produced effects that are visually similar to reports of ball lightning, how these relate to the phenomenon remains unclear. == Characteristics == Descriptions of ball lightning vary widely. It has been described as moving up and down, sideways or in unpredictable trajectories, hovering and moving with or against the wind; attracted to, unaffected by, or repelled from buildings, people, cars and other objects. Some accounts describe it as moving through solid masses of wood or


id: ball-lightning-20260505-1
file: data/en.wikipedia.org/wiki/Ball_lightning-1.md
category: reference
title: Ball lightning
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Ball_lightning
date_saved: 2026-05-05T11:04:47.852283+00:00
instance: kb-cron
parent: ball-lightning-20260505-0
summary:
=== The sloop Catherine and Mary === In December 1726, a number of British newspapers printed an extract of a letter from John Howell of the sloop Catherine and Mary: As we were coming thro' the Gulf of Florida on 29th of August, a large ball of fire fell from the Element and split our mast in Ten Thousand Pieces, if it were possible; split our Main Beam, also Three Planks of the Side, Under Water, and Three of the Deck; killed one man, another had his Hand carried of [sic], and had it not been for the violent rains, our Sails would have been of a Blast of Fire. === HMS Montague === One particularly large example was reported "on the authority of Dr. Gregory" in 1749: Admiral Chambers on board the HMS Montague, 4 November 1749, was taking an observation just before noon ... he observed a large ball of blue fire about three miles [5 km] distant from them. They immediately lowered their topsails, but it came up so fast upon them, that, before they could raise the main tack, they observed the ball rise almost perpendicularly, and not above forty or fifty yards [35 or 45


id: ball-lightning-20260505-2
file: data/en.wikipedia.org/wiki/Ball_lightning-2.md
category: reference
title: Ball lightning
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Ball_lightning
date_saved: 2026-05-05T11:04:47.852283+00:00
instance: kb-cron
parent: ball-lightning-20260505-0
summary:
Once my parents were away, and I was at the all-night vigil with my grandfather in the small church in Alexandria. During the service there was a powerful thunderstorm, streaks of lightning flashed one after the other, and it seemed as if the peals of thunder would shake even the church and the whole world to its foundations. Suddenly it became quite dark, a blast of wind from the open door blew out the flame of the candles which were lit in front of the iconostasis, there was a long clap of thunder, louder than before, and I suddenly saw a fiery ball flying from the window straight towards the head of the Emperor. The ball (it was of lightning) whirled around the floor, then passed the chandelier and flew out through the door into the park. My heart froze, I glanced at my grandfather – his face was completely calm. He crossed himself just as calmly as he had when the fiery ball had flown near us, and I felt that it was unseemly and not courageous to be frightened as I was. I felt that one had only to look at what was happening and believe in the


id: ball-lightning-20260505-3
file: data/en.wikipedia.org/wiki/Ball_lightning-3.md
category: reference
title: Ball lightning
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Ball_lightning
date_saved: 2026-05-05T11:04:47.852283+00:00
instance: kb-cron
parent: ball-lightning-20260505-0
summary:
Willy Ley discussed a sighting in Paris on 5 July 1852 "for which sworn statements were filed with the French Academy of Sciences". During a thunderstorm, a tailor living next to Church of the Val-de-Grâce saw a ball the size of a human head come out of the fireplace. It flew around the room, reentered the fireplace, and exploded in and destroyed the top of the chimney. On 30 April 1877, a ball of lightning entered the Golden Temple at Amritsar, India, and exited through a side door. Several people observed the ball, and the incident is inscribed on the front wall of Darshani Deori. On 22 November 1894, an unusually prolonged instance of natural ball lightning occurred in Golden, Colorado, which suggests it could be artificially induced from the atmosphere. The Golden Globe newspaper reported:A beautiful yet strange phenomenon was seen in this city on last Monday night. The wind was high and the air seemed to be full of electricity. In front of, above and around the new Hall of Engineering of the School of Mines, balls of fire played tag for half an hour, to the wonder and amazement of all who saw the display. In this


id: ball-lightning-20260505-4
file: data/en.wikipedia.org/wiki/Ball_lightning-4.md
category: reference
title: Ball lightning
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Ball_lightning
date_saved: 2026-05-05T11:04:47.852283+00:00
instance: kb-cron
parent: ball-lightning-20260505-0
summary:
== Direct measurements of natural ball lightning == In January 2014, scientists from Northwest Normal University in Lanzhou, China, published the results of recordings made in July 2012 of the optical spectrum of what was thought to be natural ball lightning made by chance during the study of ordinary cloud–ground lightning on the Tibetan Plateau. At a distance of 900 m (3,000 ft), a total of 1.64 seconds of digital video of the ball lightning and its spectrum was made, from the formation of the ball lightning after the ordinary lightning struck the ground, up to the optical decay of the phenomenon. Additional video was recorded by a high-speed (3000 frames/sec) camera, which captured only the last 0.78 seconds of the event, due to its limited recording capacity. Both cameras were equipped with slitless spectrographs. The researchers detected emission lines of neutral atomic silicon, calcium, iron, nitrogen, and oxygen—in contrast with mainly ionized nitrogen emission lines in the spectrum of the parent lightning. The ball lightning traveled horizontally across the video frame at an average speed equivalent of 8.6 m/s (28 ft/s). It had a diameter of 5 m (16 ft) and covered a distance of about 15 m (49


id: ball-lightning-20260505-5
file: data/en.wikipedia.org/wiki/Ball_lightning-5.md
category: reference
title: Ball lightning
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Ball_lightning
date_saved: 2026-05-05T11:04:47.852283+00:00
instance: kb-cron
parent: ball-lightning-20260505-0
summary:
=== Vaporized silicon hypothesis === This hypothesis suggests that ball lightning consists of vaporized silicon burning through oxidation. Lightning striking Earth's soil could vaporize the silica contained within it, and somehow separate the oxygen from the silicon dioxide, turning it into pure silicon vapor. As it cools, the silicon could condense into a floating aerosol, bound by its charge, glowing due to the heat of silicon recombining with oxygen. An experimental investigation of this effect, published in 2007, reported producing "luminous balls with lifetime in the order of seconds" by evaporating pure silicon with an electric arc. Videos and spectrographs of this experiment have been made available. This hypothesis got significant supportive data in 2014, when the first ever recorded spectra of natural ball lightning were published. The theorized forms of silicon storage in soil include nanoparticles of Si, SiO, and SiC. Matthew Francis has dubbed this the "dirt clod hypothesis", in which the spectrum of ball lightning shows that it shares chemistry with soil. === Electrically charged solid-core model === In this model, ball lightning is assumed to have a solid, positively charged core. According to this underlying assumption, the core is surrounded by a thin electron layer with


id: ball-lightning-20260505-6
file: data/en.wikipedia.org/wiki/Ball_lightning-6.md
category: reference
title: Ball lightning
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Ball_lightning
date_saved: 2026-05-05T11:04:47.852283+00:00
instance: kb-cron
parent: ball-lightning-20260505-0
summary:
=== Buoyant plasma hypothesis === The declassified Project Condign report concludes that buoyant charged plasma formations similar to ball lightning are formed by novel physical, electrical, and magnetic phenomena, and that these charged plasmas are capable of being transported at enormous speeds under the influence and balance of electrical charges in the atmosphere. These plasmas appear to originate due to more than one set of weather and electrically charged conditions, the scientific rationale for which is incomplete or not fully understood. One suggestion is that meteoroids breaking up in the atmosphere and forming charged plasmas as opposed to burning completely or impacting as meteorites could explain some instances of the phenomena, in addition to other unknown atmospheric events. However, according to Stenhoff, this explanation is considered insufficient to explain the ball lightning phenomenon, and would likely not withstand peer review. === Hallucinations induced by magnetic field === Cooray and Cooray (2008) stated that the features of hallucinations experienced by patients having epileptic seizures in the occipital lobe are similar to the observed features of ball lightning. The study also showed that the rapidly changing magnetic field of a close lightning flash is strong enough to excite the neurons in the


id: ball-lightning-20260505-7
file: data/en.wikipedia.org/wiki/Ball_lightning-7.md
category: reference
title: Ball lightning
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Ball_lightning
date_saved: 2026-05-05T11:04:47.852283+00:00
instance: kb-cron
parent: ball-lightning-20260505-0
summary:
Spinning electric dipole hypothesis. A 1976 article by V. G. Endean postulated that ball lightning could be described as an electric field vector spinning in the microwave frequency region. Electrostatic Leyden jar models. Stanley Singer discussed (1971) this type of hypothesis and suggested that the electrical recombination time would be too short for the ball lightning lifetimes often reported. Smirnov proposed (1987) a fractal aerogel hypothesis. M. I. Zelikin proposed (2006) an explanation (with a rigorous mathematical foundation) based on the hypothesis of plasma superconductivity (see also). A. Meessen presented a theory at the 10th International Symposium on Ball Lightning (21–27 June 2010, Kaliningrad, Russia) explaining all known properties of ball lightning in terms of collective oscillations of free electrons. The simplest case corresponds to radial oscillations in a spherical plasma membrane. These oscillations are sustained by parametric amplification, resulting from regular "inhalation" of charged particles that are present at lower densities in the ambient air. Ball lightning vanishes thus by silent extinction when the available density of charged particles is too low, while it disappears with a loud and sometimes very violent explosion when this density is too high. Electronic oscillations are also possible as stationary waves in a


id: baryogenesis-20260505-0
file: data/en.wikipedia.org/wiki/Baryogenesis-0.md
category: reference
title: Baryogenesis
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Baryogenesis
date_saved: 2026-05-05T11:04:49.171800+00:00
instance: kb-cron
parent: baryogenesis-20260505-0
summary:
In physical cosmology, baryogenesis (also known as baryosynthesis) is the physical process that is hypothesized to have taken place during the early universe to produce baryonic asymmetry, the observation that only matter (baryons) and not antimatter (antibaryons) is detected in the universe (other than in cosmic ray collisions). Since it is assumed in cosmology that the particles we see were created using the same physics we measure today, and in particle physics experiments today matter and antimatter are always symmetric, the dominance of matter over antimatter is unexplained. A number of theoretical mechanisms are proposed to account for this discrepancy, namely identifying conditions that favour symmetry breaking and the creation of normal matter (as opposed to antimatter). This imbalance has to be exceptionally small, on the order of 1 in every 1630000000 (≈2×109) particles a small fraction of a second after the Big Bang. After most of the matter and antimatter was annihilated, what remained was all the baryonic matter in the current universe, along with a much greater number of bosons. Experiments reported in 2010 at Fermilab, however, seem to show that this imbalance is much greater than previously assumed. These experiments involved a series of particle collisions and


id: baryogenesis-20260505-1
file: data/en.wikipedia.org/wiki/Baryogenesis-1.md
category: reference
title: Baryogenesis
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Baryogenesis
date_saved: 2026-05-05T11:04:49.171800+00:00
instance: kb-cron
parent: baryogenesis-20260505-0
summary:
== In the Standard Model == The Standard Model can incorporate baryogenesis, though the amount of net baryons (and leptons) thus created may not be sufficient to account for the present baryon asymmetry. There is a required one excess quark per billion quark-antiquark pairs in the early universe in order to provide all the observed matter in the universe. This insufficiency has not yet been explained, theoretically or otherwise. Baryogenesis within the Standard Model requires the electroweak symmetry breaking to be a first-order cosmological phase transition, since otherwise sphalerons wipe out any baryon asymmetry that happened up to the phase transition. Beyond this, the remaining amount of baryon non-conserving interactions is negligible. The phase transition domain wall breaks the P-symmetry spontaneously, allowing for CP-symmetry violating interactions to break C-symmetry on both its sides. Quarks tend to accumulate on the broken phase side of the domain wall, while anti-quarks tend to accumulate on its unbroken phase side. Due to CP-symmetry violating electroweak interactions, some amplitudes involving quarks are not equal to the corresponding amplitudes involving anti-quarks, but rather have opposite phase (see CKM matrix and Kaon); since time reversal takes an amplitude to its complex conjugate, CPT-symmetry is conserved in this


id: baryon-asymmetry-20260505-0
file: data/en.wikipedia.org/wiki/Baryon_asymmetry-0.md
category: reference
title: Baryon asymmetry
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Baryon_asymmetry
date_saved: 2026-05-05T11:04:50.353706+00:00
instance: kb-cron
parent: baryon-asymmetry-20260505-0
summary:
In physical cosmology, the baryon asymmetry problem, also known as the matter asymmetry problem or the matter–antimatter asymmetry problem, is the observed imbalance in baryonic matter and antibaryonic matter in the observable universe. As the two form and behave in nearly identical ways, it is expected that they would have been created in near equal portions by the Big Bang, where in reality matter makes up the vast majority of the universe (including the Earth and humanity). Neither the Standard Model of particle physics nor the theory of general relativity provides a known explanation for why this should be so, and it is a natural assumption that the universe is neutral with all conserved charges. Since this does not seem to have been the case, it is likely some physical laws must have acted differently or did not exist for matter and/or antimatter. Several competing hypotheses exist to explain the imbalance of matter and antimatter that resulted in baryogenesis. However, there is as of yet no consensus theory to explain the phenomenon, which has been described as "one of the great mysteries in physics". == Sakharov conditions == In 1967, Andrei Sakharov proposed a set of three necessary conditions that


id: baryon-asymmetry-20260505-1
file: data/en.wikipedia.org/wiki/Baryon_asymmetry-1.md
category: reference
title: Baryon asymmetry
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Baryon_asymmetry
date_saved: 2026-05-05T11:04:50.353706+00:00
instance: kb-cron
parent: baryon-asymmetry-20260505-0
summary:
=== Regions of the universe where antimatter dominates === Another possible explanation of the apparent baryon asymmetry is that matter and antimatter are essentially separated into different, widely distant regions of the universe. The formation of antimatter galaxies was originally thought to explain the baryon asymmetry, as from a distance, antimatter atoms are indistinguishable from matter atoms; both produce light (photons) in the same way. Along the boundary between matter and antimatter regions, however, annihilation (and the subsequent production of gamma radiation) would be detectable, depending on its distance and the density of matter and antimatter. Such boundaries, if they exist, would likely lie in deep intergalactic space. The density of matter in intergalactic space is reasonably well established at about one atom per cubic meter. Assuming this is a typical density near a boundary, the gamma ray luminosity of the boundary interaction zone can be calculated. No such zones have been detected, but 30 years of research have placed bounds on how far they might be. On the basis of such analyses, it is now deemed unlikely that any region within the observable universe is dominated by antimatter. === Mirror anti-universe === The state of the universe, as it


id: bgs-conjecture-20260505-0
file: data/en.wikipedia.org/wiki/BGS_conjecture-0.md
category: reference
title: BGS conjecture
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/BGS_conjecture
date_saved: 2026-05-05T11:04:51.490503+00:00
instance: kb-cron
parent: bgs-conjecture-20260505-0
summary:
The Bohigas–Giannoni–Schmit (BGS) conjecture also known as the random matrix conjecture) for simple quantum mechanical systems (ergodic with a classical limit) few degrees of freedom holds that spectra of time reversal-invariant systems whose classical analogues are K-systems show the same fluctuation properties as predicted by the GOE (Gaussian orthogonal ensembles). Alternatively, the spectral fluctuation measures of a classically chaotic quantum system coincide with those of the canonical random-matrix ensemble in the same symmetry class (unitary, orthogonal, or symplectic). That is, the Hamiltonian of a microscopic analogue of a classical chaotic system can be modeled by a random matrix from a Gaussian ensemble as the distance of a few spacings between eigenvalues of a chaotic Hamiltonian operator generically statistically correlates with the spacing laws for eigenvalues of large random matrices. A simple example of the unfolded quantum energy levels in a classically chaotic system correlating like that would be Sinai billiards: Energy levels: − ℏ 2 2 m ▽ 2 ψ + V ( x ) ψ = E i ψ {\displaystyle -{\frac {\hbar ^{2}}{2{\mathit {m}}}}\bigtriangledown ^{2}\psi +{\mathit {V}}({\mathit {x}})\psi ={{\mathit {E}}_{\mathit {i}}}\psi } Spectral density: ρ ( x ) = ∑ i δ ( x − E i ) {\displaystyle


id: color-confinement-20260505-0
file: data/en.wikipedia.org/wiki/Color_confinement-0.md
category: reference
title: Color confinement
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Color_confinement
date_saved: 2026-05-05T11:04:52.706223+00:00
instance: kb-cron
parent: color-confinement-20260505-0
summary:
In quantum chromodynamics (QCD), color confinement or infrared slavery, often simply called confinement, is the phenomenon that color-charged particles (such as quarks and gluons) cannot be isolated, and therefore cannot be directly observed in normal conditions below the Hagedorn temperature of approximately 2 terakelvin (corresponding to energies of approximately 130–140 MeV per particle). Quarks and gluons must clump together to form hadrons. The two main types of hadron are the mesons (one quark, one antiquark) and the baryons (often three quarks or antiquarks, though other exotic variants exist). In addition, colorless glueballs formed only of gluons are also consistent with confinement, though difficult to identify experimentally. Quarks and gluons cannot be separated from their parent hadron without producing new hadrons. == Origin == There is not yet an analytic proof of color confinement in any non-abelian gauge theory. The phenomenon can be understood qualitatively by noting that the force-carrying gluons of QCD have color charge, unlike the photons of quantum electrodynamics (QED). Whereas the electric field between electrically charged particles decreases rapidly as those particles are separated, the gluon field between a pair of color charges forms a narrow flux tube (or string) between them. Because of this behavior of


id: cosmic-coincidence-20260505-0
file: data/en.wikipedia.org/wiki/Cosmic_coincidence-0.md
category: reference
title: Cosmic coincidence
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Cosmic_coincidence
date_saved: 2026-05-05T11:04:53.889377+00:00
instance: kb-cron
parent: cosmic-coincidence-20260505-0
summary:
In cosmology, the cosmic coincidence is the observation that at the present epoch of the universe's evolution, the energy densities associated with dark matter and dark energy are of the same order of magnitude, leading to their comparable effects on the dynamics of the cosmos. This coincidence is puzzling because these energies have vastly different effects on the universe's expansion—dark matter tends to slow down expansion through gravitational attraction, while dark energy seems to accelerate it. The observed similarity in the magnitudes of these two components' energy densities at this particular epoch in the universe's history raises questions about whether there might be some underlying physical connection or shared origin between dark matter and dark energy. Indeed, some theories attempt to explain this coincidence by proposing that they are different manifestations of the same fundamental force or field. == References == == See also == Fine-tuned universe


id: cuspy-halo-problem-20260505-0
file: data/en.wikipedia.org/wiki/Cuspy_halo_problem-0.md
category: reference
title: Cuspy halo problem
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Cuspy_halo_problem
date_saved: 2026-05-05T11:04:55.069610+00:00
instance: kb-cron
parent: cuspy-halo-problem-20260505-0
summary:
The cuspy halo problem (also known as the core-cusp problem) is a discrepancy between the inferred dark matter density profiles of low-mass galaxies and the density profiles predicted by cosmological N-body simulations. Nearly all simulations form dark matter halos which have "cuspy" dark matter distributions, with density increasing steeply at small radii, while the rotation curves of most observed dwarf galaxies suggest that they have flat central dark matter density profiles ("cores"). Several possible solutions to the core-cusp problem have been proposed. Many recent studies have shown that including baryonic feedback (particularly feedback from supernovae and active galactic nuclei) can "flatten out" the core of a galaxy's dark matter profile, since feedback-driven gas outflows produce a time-varying gravitational potential that transfers energy to the orbits of the collisionless dark matter particles. Other works have shown that the core-cusp problem can be solved outside of the most widely accepted Lambda-Cold Dark Matter paradigm (ΛCDM): simulations with warm or self-interacting dark matter also produce dark matter cores in low-mass galaxies. It is also possible that the distribution of dark matter that minimizes the system energy has a flat central dark matter density profile. == Simulation results == According to W.J.G. de Blok


