Vijay Shankar Sharma
Textbook neuroscience, philosophy of mind, and clinical terms. Not a reinterpretation of Vijay's Law or the Consciousness Index. 148 terms. Textbook meanings only.
148 terms. Page 2 of 3.
consciousness-theories · intermediate
A view proposed by philosophers Andy Clark and David Chalmers holding that cognitive processes can extend beyond the brain and body to include external tools and objects, such as a notebook used reliably to store and retrieve information, when those tools are functionally integrated into a person's cognitive processes in the same way memory ordinarily is.
perception · intro
The sense of stimuli originating outside the body, conveyed through the traditional external senses of sight, hearing, touch, taste, and smell. It is generally contrasted with interoception, the sense of the body's internal physiological state, and proprioception, the sense of the body's own position and movement.
perception · intro
The perceptual organisation of a visual scene into a foreground object of attention, the figure, and a background against which it is perceived, the ground. Classic ambiguous images, such as the vase that can also be seen as two facing profiles, demonstrate how the same sensory input can be organised into different figure-ground interpretations, with perception typically settling on only one at a time.
sleep-and-altered-states · intermediate
A state of complete absorption in an activity, characterised by intense focus, a sense of effortless control, and a distorted sense of time, typically occurring when the challenge of a task closely matches a person's skill level. The concept was developed by psychologist Mihaly Csikszentmihalyi based on interviews with people describing peak experiences across a wide range of activities.
self-and-social-cognition · intermediate
Also called: free will
The capacity to make genuinely undetermined choices, in the sense of being able to have done otherwise given exactly the same prior circumstances, as opposed to actions being the fully determined outcome of prior physical causes. It remains a deeply contested philosophical question, engaged from angles including determinism, compatibilism, and, more recently, findings from neuroscience about the timing of decision-related brain activity.
philosophy-of-mind · intermediate
The view that mental states are defined by the functional or causal role they play, such as the inputs that produce them and the behaviour they produce, rather than by the specific physical material that realises them. On this view, a mental state like pain could in principle be realised in a biological brain, a silicon computer, or another substrate entirely, as long as the same functional role is played.
neuroscience · intermediate
Also called: gamma-aminobutyric acid
Gamma-aminobutyric acid, the primary inhibitory neurotransmitter in the mammalian central nervous system, which reduces the likelihood that a neuron will fire. It plays a key role in regulating anxiety, muscle tone, and the balance between neural excitation and inhibition. Many anti-anxiety medications and sedatives, including benzodiazepines, work by enhancing GABA's inhibitory effect.
clinical-and-disorders · intro
A medically induced state of controlled unconsciousness, produced by drugs that suppress the central nervous system, used to prevent pain and awareness during surgical procedures. Despite widespread clinical use for well over a century, the precise mechanism by which anesthetic drugs reliably suppress consciousness while leaving basic life functions intact remains an active area of neuroscience research.
perception · intermediate
A school of psychology, originating in early twentieth-century Germany, holding that the mind perceives whole patterns and configurations rather than simply assembling perception from individual sensory parts, often summarised by the phrase 'the whole is different from the sum of its parts.' It produced several enduring principles of perceptual organisation, including figure-ground segregation and grouping by proximity and similarity.
neuroscience · intro
A non-neuronal support cell in the nervous system that provides structural support, insulation, nutrients, and immune defence for neurons, and plays an active role in regulating synaptic signalling. Glial cells outnumber neurons in much of the brain and were long considered merely supportive, though research has increasingly shown they actively participate in information processing.
consciousness-theories · intermediate
Also called: GWT, global neuronal workspace
A theory of consciousness, originally proposed by psychologist Bernard Baars and later developed with neuroscientific detail by Stanislas Dehaene, holding that information becomes conscious when it is broadcast widely across many specialised brain regions via a shared 'workspace', making it available for varied cognitive processes such as memory, language, and decision-making at once. Unconscious processing, by contrast, stays confined to local, specialised circuits.
neuroscience · intermediate
The primary excitatory neurotransmitter in the mammalian central nervous system, involved in most fast synaptic signalling and central to learning and memory processes such as long-term potentiation. Excessive glutamate activity is associated with excitotoxicity, a process implicated in stroke damage and some neurodegenerative diseases.
philosophy-of-mind · intro
The question of why and how physical processes in the brain give rise to subjective experience at all, as opposed to the comparatively tractable question of explaining the brain's functions and behaviours. The term was coined by philosopher David Chalmers to distinguish this question from the 'easy problems' of explaining cognitive functions like memory or attention, which are difficult in practice but not mysterious in the same way.
cognitive-science · intro
A mental shortcut or rule of thumb that allows quick, efficient judgements or decisions without exhaustive analysis, at the cost of sometimes producing systematic errors. Psychologists Amos Tversky and Daniel Kahneman documented several influential heuristics, including the availability heuristic, in which people judge the likelihood of an event by how easily examples come to mind.
consciousness-theories · intermediate
Also called: HOT
A family of theories holding that a mental state becomes conscious when it is the object of a further, higher-order mental state representing it, such as a thought about that state. On this view, a perception becomes a conscious perception not simply by occurring, but by being represented, monitored, or noticed by a higher-order mental process directed at it.
neuroscience · intro
A seahorse-shaped brain structure in the medial temporal lobe central to forming new long-term memories, especially of facts and events, and to spatial navigation. The famous patient H.M., whose hippocampus was removed to treat epilepsy, lost the ability to form new long-term memories while retaining earlier ones, providing key evidence for its role. It is one of few brain regions where new neurons continue to form in adulthood.
sleep-and-altered-states · intermediate
The transitional state between wakefulness and sleep, often accompanied by vivid, dream-like imagery, unusual sensations, or brief hallucinations. A related state occurring during the transition from sleep back to wakefulness is termed hypnopompia. Both states have historically been associated with reports of creative insight.
sleep-and-altered-states · intermediate
A state of focused attention and heightened suggestibility, typically induced through a structured procedure, in which a person's perceptions, memories, or behaviours can be temporarily altered in response to suggestions. Contrary to popular depictions, hypnosis does not typically involve unconsciousness or loss of control, and a person generally cannot be hypnotised to act against their basic will or values.
philosophy-of-mind · intermediate
The philosophical view that reality is fundamentally mental or experiential in nature, and that the physical world as commonly understood is either constituted by, or dependent on, mind or consciousness, rather than the reverse. It stands in direct contrast to physicalism, which treats the physical as fundamental and the mental as dependent on or reducible to it.
cognitive-science · intro
Also called: procedural memory
A form of long-term memory that influences thought and behaviour without conscious, deliberate recollection, including skills, habits, and conditioned responses. A person can improve at a motor skill like riding a bicycle through implicit memory even without being able to explicitly describe what has changed.
cognitive-science · intermediate
The failure to notice a fully visible but unexpected object or event because attention is engaged elsewhere. It was famously demonstrated in the 'invisible gorilla' experiment, in which many observers focused on counting basketball passes failed to notice a person in a gorilla suit walking through the scene, illustrating that focused attention, not just open eyes, is necessary for conscious perception.
consciousness-theories · intermediate
Also called: IIT
A theory of consciousness, developed by neuroscientist Giulio Tononi, that proposes consciousness corresponds to a physical system's capacity to integrate information in a way that could not be replicated by its parts operating independently, formally quantified by a measure often denoted phi. On this view, the degree of consciousness a system has is, in principle, a mathematically computable property of its causal structure, not tied specifically to biological brains.
philosophy-of-mind · intermediate
The property of mental states, such as beliefs and desires, of being directed at or about something, whether real or imagined. A belief is always a belief about something; a fear is always a fear of something. Philosophers treat intentionality as a distinctive mark of the mental, distinguishing thoughts from purely physical events that are not, in this sense, about anything.
perception · intermediate
The sense of the internal physiological state of the body, including signals such as heartbeat, hunger, and breathing. It plays a significant role in emotional experience, since many theories of emotion hold that the felt quality of an emotion depends partly on how internal bodily signals are perceived and interpreted.
self-and-social-cognition · intro
The deliberate examination and reporting of one's own conscious mental states, such as thoughts, feelings, and perceptions. It was the primary experimental method of early psychology, but fell out of favour for much of the twentieth century due to concerns about its reliability, before being partly rehabilitated as one useful source of evidence, among others, in contemporary consciousness research.
self-and-social-cognition · intermediate
A famous 1980s experiment by neuroscientist Benjamin Libet in which participants reported the moment they consciously decided to move a finger, while brain activity called the readiness potential was recorded and found to begin measurably before that reported moment of conscious decision. It has been widely, and controversially, cited as evidence bearing on the existence and nature of free will, though its interpretation remains strongly disputed.
neuroscience · intro
A group of interconnected brain structures, including the amygdala, hippocampus, and hypothalamus, traditionally associated with emotion, motivation, and memory. While the term remains in wide use, contemporary neuroscience treats it as a useful but imprecise grouping rather than a single, sharply defined anatomical or functional system.
clinical-and-disorders · intermediate
A rare condition, typically resulting from damage to the brainstem, in which a patient is fully conscious and cognitively intact but almost completely paralysed, retaining control of only very limited voluntary movement, such as vertical eye movements or blinking, which can sometimes be used to communicate. It is distinguished from disorders of consciousness by the patient's intact awareness, despite the near-total loss of motor output.
cognitive-science · intro
The relatively permanent storage of information over extended periods, ranging from days to a lifetime, as distinguished from the brief, limited-capacity storage of working memory. It is commonly divided into explicit (consciously recollected) and implicit (unconsciously expressed) forms, and further into subtypes such as episodic, semantic, and procedural memory.
sleep-and-altered-states · intermediate
A state during REM sleep in which the dreamer becomes aware that they are dreaming, and in some cases can exert deliberate control over the content of the dream. It has been verified experimentally through pre-arranged eye-movement signals that lucid dreamers can perform on cue while their sleep stage is independently confirmed by brain monitoring.
philosophy-of-mind · intermediate
Also called: knowledge argument
A thought experiment in which Mary, a scientist who has lived her whole life in a black-and-white room, knows every physical fact about colour vision but has never seen colour. The question is whether she learns something new the moment she finally sees red for the first time. Philosopher Frank Jackson used it to argue that physical knowledge alone may not capture everything there is to know about conscious experience.
sleep-and-altered-states · intro
A family of mental practices, many originating in contemplative religious traditions, that train attention and awareness, often aimed at achieving a calm, focused, or altered state of consciousness. Neuroimaging studies of experienced meditators have documented measurable changes in brain structure and activity associated with sustained practice, particularly in regions related to attention and emotional regulation.
cognitive-science · intermediate
An internal cognitive symbol or model that stands in for an external object, situation, or concept, allowing the mind to reason about things that are not immediately present to the senses. Debates over the format of mental representations, such as whether some are picture-like and others language-like, have been central to cognitive science since its early history.
self-and-social-cognition · intermediate
The cognitive process of inferring and reasoning about the mental states, such as beliefs, intentions, and emotions, of oneself and others, closely related to theory of mind. It engages a consistent network of brain regions, sometimes referred to as the 'mentalizing network', which shows substantial overlap with the brain's default mode network.
cognitive-science · intermediate
Awareness and understanding of one's own thought processes, often described informally as thinking about thinking. It includes monitoring how well one understands or remembers something, and regulating cognitive strategies accordingly, and is closely linked to higher-order theories of consciousness that treat awareness itself as a form of monitoring directed at other mental states.
philosophy-of-mind · intro
The general philosophical question of how mental states, such as thoughts, feelings, and conscious experiences, relate to physical states of the body and brain. It is one of the oldest problems in philosophy, and essentially every position in philosophy of mind, from dualism to physicalism to panpsychism, is an attempt to answer it.
self-and-social-cognition · intermediate
A shift of attention away from a current task or the external environment toward internally generated thoughts, such as memories, plans, or fantasies, occurring spontaneously and often without full awareness that one's attention has shifted. It is strongly associated with activity in the brain's default mode network and occupies a substantial fraction of waking mental life.
sleep-and-altered-states · intro
A form of attention characterised by a non-judgemental, moment-to-moment awareness of present experience, including thoughts, bodily sensations, and the surrounding environment. It has been adapted from Buddhist contemplative traditions into secular clinical interventions, and is used in structured therapeutic programmes for conditions including chronic stress and recurrent depression.
clinical-and-disorders · intermediate
Also called: MCS
A condition of severely altered consciousness in which a patient shows minimal but definite behavioural evidence of self- or environmental awareness, such as inconsistently following simple commands or reaching for objects, distinguishing it from the persistent vegetative state, where no such evidence is present.
self-and-social-cognition · intermediate
Neurons, first identified in the premotor cortex of macaque monkeys, that fire both when an individual performs a specific action and when they observe another individual performing that same action. Their discovery generated considerable interest in a possible neural basis for empathy, imitation, and understanding others' actions, though claims about their precise role and importance in humans remain debated among researchers.
self-and-social-cognition · intermediate
A test of self-awareness, most famously the 'mirror test' developed by psychologist Gordon Gallup, in which a mark is placed on an individual's body in a location visible only via a mirror; touching or investigating the mark upon seeing the reflection is taken as evidence of recognising the reflection as oneself. Very few species, including humans past a certain age, great apes, dolphins, and some corvids, have reliably passed versions of this test.
consciousness-theories · intermediate
A model of consciousness proposed by philosopher Daniel Dennett, which rejects the idea of a single, central point in the brain where information becomes consciously experienced all at once, in favour of many parallel streams of interpretation and revision occurring across the brain simultaneously, with no single stream having privileged status as 'the' conscious experience.
perception · intermediate
The process by which the brain combines information from different sensory modalities, such as vision and hearing, into a coherent, unified perceptual experience. The McGurk effect, in which mismatched visual and auditory speech cues produce a perceived sound different from either input alone, is a well-known demonstration of how strongly the senses influence one another.
neuroscience · intro
A fatty insulating sheath, produced by glial cells, that wraps around many axons and dramatically speeds the conduction of electrical signals along them. Myelinated axons conduct impulses far faster than unmyelinated ones. The progressive loss of myelin is the hallmark of multiple sclerosis, which produces a range of neurological symptoms as signal transmission is disrupted.
self-and-social-cognition · intermediate
The sense of self constructed through an ongoing, autobiographical story a person tells about their own life, connecting past experiences, present identity, and anticipated future into a coherent personal narrative. It is distinguished by some theorists from a more minimal, moment-to-moment sense of self that does not depend on this extended, story-like structure.
clinical-and-disorders · intermediate
Also called: hemispatial neglect
A neurological condition, usually following damage to the right parietal lobe, in which a person fails to attend to or acknowledge stimuli on one side of space, typically the left, despite having no basic sensory impairment on that side. Affected patients may eat food from only one side of a plate, or fail to shave or apply makeup to one side of the face, without being aware of the omission.
consciousness-theories · intermediate
Also called: binding problem
The question of how the brain combines separately processed features of a stimulus, such as an object's colour, shape, and motion, which are handled by different specialised brain regions, into a single, unified conscious perception. Proposed solutions include the synchronisation of neural firing across regions processing different features of the same object.
neuroscience · intermediate
Also called: NCC
The minimal set of neural events and structures sufficient, on their own, to give rise to a specific conscious experience, a concept used to organise empirical research on consciousness without requiring a settled theory of what consciousness ultimately is. Researchers look for patterns of brain activity that reliably track what a person reports experiencing, distinguishing them from activity that merely enables or precedes conscious perception.
neuroscience · intro
The basic signaling cell of the nervous system, specialised to receive, process, and transmit information as electrical and chemical signals. A typical neuron has dendrites that receive input, a cell body that integrates it, and an axon that carries an output signal to other neurons. The human brain contains on the order of 86 billion neurons, each forming thousands of connections with others.
neuroscience · intro
A chemical messenger released by a neuron at a synapse that binds to receptors on a target cell, either exciting or inhibiting its activity. Well-known examples include dopamine, serotonin, glutamate, and GABA, each associated with distinct roles across mood, movement, arousal, and cognition. Many psychiatric medications work by altering neurotransmitter levels or receptor activity.