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 1 of 3.
philosophy-of-mind · intermediate
The availability of a mental state's content for use in reasoning, verbal report, and the rational control of action, as distinguished from the raw subjective feel of the state itself. A piece of information can in principle be accessible for reasoning and report without there being anything it is like to have it, which is why philosophers treat access consciousness as conceptually separate from phenomenal consciousness.
neuroscience · intro
Also called: nerve impulse, spike
A brief, all-or-nothing electrical impulse that travels along a neuron's axon, triggered when the neuron's membrane voltage crosses a threshold. It results from a rapid influx of sodium ions followed by an efflux of potassium ions, restoring the resting state within about a millisecond. Action potentials are the basic unit of long-distance signalling in the nervous system.
clinical-and-disorders · intermediate
A neurological condition in which a person loses the ability to recognise objects, faces, sounds, or other stimuli, despite intact basic sensory function, indicating a deficit in the higher-level interpretation of sensory information rather than in the senses themselves. Prosopagnosia, or face blindness, in which a person cannot recognise familiar faces despite normal vision, is a well-studied form.
sleep-and-altered-states · intro
Also called: ASC
Any mental state that differs noticeably from an individual's ordinary, alert waking consciousness in terms of perception, cognition, or sense of self, including states induced by sleep, meditation, hypnosis, or psychoactive substances. The term is used broadly across psychology and neuroscience to group together a wide range of qualitatively distinct departures from baseline waking experience.
neuroscience · intro
A small, almond-shaped structure in the temporal lobe central to processing emotion, particularly fear and threat detection, and to attaching emotional significance to memories. It receives rapid sensory input that can trigger a threat response before conscious awareness catches up, which is part of why frightening stimuli can produce a bodily reaction before a person consciously registers danger.
clinical-and-disorders · intermediate
A rare complication of general anesthesia in which a patient regains some degree of consciousness during a surgical procedure, sometimes retaining explicit or implicit memory of events despite intended unconsciousness. Study of this phenomenon, along with the reverse question of what exactly anesthesia suppresses in the brain, has become an important empirical route into understanding the neural basis of consciousness itself.
clinical-and-disorders · intermediate
A neurological condition in which a person is unaware of, or denies, a deficit caused by their own illness or injury, such as a paralysed patient insisting they can move a limb that is in fact motionless. It is most often associated with damage to the right parietal lobe following stroke, and is distinguished from ordinary psychological denial by its direct neurological basis.
clinical-and-disorders · intro
An acquired language disorder, usually resulting from brain damage such as stroke, that impairs a person's ability to produce or comprehend spoken or written language, while typically leaving general intelligence intact. Different patterns of aphasia are associated with damage to different language-related brain regions, historically mapped through the study of patients with localised brain injuries.
clinical-and-disorders · intermediate
A neurological condition in which a person loses the ability to perform purposeful, learned motor movements on command, despite having the physical capacity, muscle strength, and basic motor coordination needed to do so, indicating a disruption in the planning of movement rather than in movement execution itself.
self-and-social-cognition · intro
A general physiological and psychological state of alertness and readiness to respond to stimuli, ranging along a continuum from deep sleep to intense excitement. It is regulated largely by brainstem systems including the reticular activating system, and is treated as distinct from the specific content of consciousness, since a person can be highly aroused yet still have very limited conscious awareness, as in some seizure states.
cognitive-science · intro
The cognitive process of selectively concentrating on some information or stimuli while ignoring other, competing information. Attention is limited in capacity, which is why tasks requiring sustained focus become harder as distractions or competing demands increase. It can be directed voluntarily, as when deliberately focusing on a task, or captured involuntarily, as by a sudden loud noise.
consciousness-theories · intermediate
Also called: AST
A theory of consciousness proposed by neuroscientist Michael Graziano, which holds that the brain constructs a simplified internal model, or schema, of its own attention process, and that this model is what we experience as subjective awareness. On this view, the felt sense of consciousness is a useful but simplified internal representation the brain builds of its own attentional state, similar to how it builds a body schema of its own physical form.
consciousness-theories · intermediate
A position developed by philosopher John Searle holding that consciousness is a real, biological phenomenon caused by specific neurobiological processes in the brain, in the same way that digestion is caused by the biological processes of the digestive system, and that it is a mistake to treat consciousness as something purely abstract or computational that could be equally realised in any substrate.
perception · intermediate
A condition in which a person with damage to the primary visual cortex reports being unable to consciously see in part of their visual field, yet can still respond accurately, above chance, to visual stimuli presented there, such as correctly guessing the location or orientation of an object they report not seeing. It is used as evidence that visual information can be processed and acted upon without producing conscious visual experience.
perception · intro
A mode of perceptual processing that begins with raw sensory data and builds up toward more complex interpretations, without relying on prior knowledge or expectations to shape the initial input. It is typically contrasted with top-down processing, in which prior knowledge and expectation shape how incoming sensory data is interpreted from the outset.
clinical-and-disorders · intro
The complete and irreversible loss of all brain function, including the brainstem, resulting in the total absence of consciousness, spontaneous breathing, and brainstem reflexes. It is legally and medically recognised as equivalent to death, distinguishing it from states such as coma or the vegetative state, in which some brain function persists and recovery, though often unlikely, remains biologically possible.
neuroscience · intermediate
The stalk-like region connecting the brain to the spinal cord, comprising the midbrain, pons, and medulla, which regulates basic life-sustaining functions including heart rate, breathing, and the sleep-wake cycle. It also contains the reticular activating system, a network central to arousal and consciousness. Because it controls vital autonomic functions, brainstem damage is far more life-threatening than damage of similar size elsewhere in the brain.
neuroscience · intro
The outer, folded layer of the brain responsible for higher-order functions including perception, language, reasoning, and voluntary movement. In humans it is highly convoluted, packing a large surface area into the skull, and is organised into distinct lobes (frontal, parietal, temporal, occipital) with somewhat specialised roles. Its six-layered structure is a defining feature of mammalian brains.
cognitive-science · intermediate
The failure to detect a significant change in a visual scene, particularly when the change occurs during a brief visual disruption such as an eye movement, a flicker, or an edit in a film. It demonstrates that detailed visual representations are not automatically retained across such interruptions, contrary to the intuitive sense of a rich, continuously updated visual world.
philosophy-of-mind · intermediate
A thought experiment devised by philosopher John Searle in which a person who does not understand Chinese follows a rulebook to manipulate Chinese symbols well enough to produce convincing responses, without ever understanding the language. Searle used it to argue that a computer program manipulating symbols according to rules, however successfully, does not thereby genuinely understand or possess a mind, challenging strong claims made on behalf of artificial intelligence.
sleep-and-altered-states · intro
An internally generated, roughly 24-hour biological cycle that regulates sleep-wake timing, hormone release, body temperature, and other physiological processes, synchronised to the external day-night cycle primarily through exposure to light. Disruption of circadian rhythms, as in jet lag or shift work, is linked to a range of negative effects on health and cognitive performance.
cognitive-science · intro
A systematic pattern of deviation from rational judgement, in which people draw conclusions in a way that departs from objective, logical evaluation of available evidence. Well-documented examples include confirmation bias, the tendency to favour information that confirms existing beliefs, and anchoring bias, in which an initial piece of information disproportionately influences subsequent judgements.
cognitive-science · intermediate
The total amount of mental effort being used in working memory at a given time. When the demands of a task exceed available cognitive resources, performance and learning both suffer, which is why instructional design often aims to minimise unnecessary cognitive load so more capacity remains available for the actual material being learned.
clinical-and-disorders · intro
A prolonged state of unarousable unresponsiveness in which a person shows no purposeful response to stimulation and cannot be awakened, typically resulting from severe brain injury, illness, or intoxication. It is generally a transitional state, with patients either recovering to varying degrees of consciousness or progressing to a vegetative or minimally conscious state within a few weeks.
self-and-social-cognition · intro
The state of being aware of, and able to have subjective experience of, one's own existence, sensations, thoughts, and surroundings. Despite being one of the most immediately familiar aspects of existence to anyone who has it, consciousness remains one of the most difficult phenomena to define precisely or explain scientifically, and different disciplines and theories emphasise different aspects of it, from raw subjective feel to the functional integration of information.
neuroscience · intro
The large bundle of nerve fibres connecting the brain's left and right cerebral hemispheres, allowing them to share information. In some historical epilepsy treatments the corpus callosum was surgically severed, producing split-brain patients whose two hemispheres could no longer directly communicate, a condition that has been studied extensively for what it reveals about lateralised brain function and the unity of conscious experience.
neuroscience · intermediate
Also called: DMN
A set of interconnected brain regions, including parts of the medial prefrontal and posterior cingulate cortex, that becomes more active when a person is not focused on the external world, such as during mind-wandering, self-reflection, or recalling memories. It was identified through neuroimaging studies noting consistent brain activity during supposed rest periods, and its activity typically decreases during externally focused, effortful tasks.
clinical-and-disorders · intro
An acute, typically fluctuating disturbance of attention, awareness, and cognition that develops over a short period, often caused by an underlying medical illness, medication effect, or withdrawal. It is distinguished from dementia by its rapid onset and fluctuating course, though the two conditions can co-occur and delirium is more common in patients who already have an underlying dementia.
clinical-and-disorders · intro
A general term for a progressive, typically irreversible decline in cognitive function, including memory, reasoning, and language, severe enough to interfere with daily functioning. Alzheimer's disease is the most common underlying cause, though dementia can also result from vascular disease, Lewy body pathology, and several other conditions.
sleep-and-altered-states · intermediate
A dissociative experience characterised by a persistent or recurrent feeling of being detached from, or an outside observer of, one's own thoughts, feelings, or body, often described as feeling unreal or automated. It can occur transiently under extreme stress or fatigue, or persist as part of a diagnosable dissociative disorder.
sleep-and-altered-states · intermediate
A dissociative experience characterised by a persistent or recurrent feeling that the external world is unreal, dreamlike, or distant, even though a person can usually still recognise, on some level, that this feeling does not reflect an objective change in reality. It frequently co-occurs with depersonalization.
clinical-and-disorders · intermediate
An umbrella clinical term covering conditions of severely altered or diminished consciousness following brain injury, including coma, the vegetative state, and the minimally conscious state, distinguished from one another by the specific pattern of preserved wakefulness and awareness each involves. Accurately distinguishing between these states has real clinical stakes, since misdiagnosis affects treatment and end-of-life decisions.
sleep-and-altered-states · intermediate
A disruption in the normal integration of consciousness, memory, identity, or perception of the environment, ranging from mild, everyday experiences such as becoming absorbed in a task and losing track of time, to more severe clinical presentations involving disconnection from one's sense of self or surroundings. It can occur as a response to acute stress or trauma.
cognitive-science · intermediate
The cognitive ability to process and respond to more than one task or source of information at the same time. Performance on divided-attention tasks generally degrades as the component tasks become more similar or more demanding, which is part of the evidence behind warnings against activities like using a phone while driving.
neuroscience · intro
A neurotransmitter involved in reward, motivation, movement, and reinforcement learning. Dopamine release is associated with the anticipation of reward as much as the reward itself, which is part of why it plays a central role in theories of addiction and habit formation. The loss of dopamine-producing neurons in a specific midbrain region is the primary cause of Parkinson's disease.
cognitive-science · intermediate
A framework proposing that human thinking operates through two distinct types of processes: a fast, automatic, intuitive mode and a slower, effortful, deliberate mode. It was popularised for a general audience by psychologist Daniel Kahneman as System 1 and System 2 thinking, and is used to explain patterns of cognitive bias that arise when fast, intuitive processing overrides more careful reasoning.
philosophy-of-mind · intro
The view that mind and body, or mental and physical properties, are fundamentally distinct kinds of thing, neither reducible to the other. René Descartes' substance dualism, which held that mind and matter are two separate kinds of substance, is the most historically influential version, though it faces the longstanding challenge of explaining how two entirely distinct substances could causally interact.
sleep-and-altered-states · intermediate
A temporary loss of the ordinary subjective sense of being a distinct, bounded self, sometimes accompanied by a felt sense of unity with one's surroundings or with the world at large. It is most commonly reported during intense psychedelic experiences, deep meditative states, or certain unusual neurological and psychiatric conditions.
philosophy-of-mind · intermediate
The view that some or all of our everyday, common-sense mental concepts, such as beliefs and desires, do not correspond to anything real and should eventually be eliminated in favour of a more accurate neuroscientific vocabulary, much as folk theories about heat as an invisible fluid were eventually replaced by molecular kinetic theory. It is a minority but influential position within physicalist philosophy of mind.
consciousness-theories · intermediate
The view that cognitive processes are deeply shaped by, and dependent on, the body's physical form and its interactions with the environment, rather than occurring in an abstract mental space independent of bodily structure. On this view, concepts like understanding or reasoning cannot be fully explained by brain activity alone, without reference to the body's sensorimotor engagement with the world.
philosophy-of-mind · intermediate
The view that consciousness arises, or emerges, from complex physical systems such as brains once they reach a sufficient level of organisation or complexity, without being present in any of the system's simpler parts. It is a common alternative to both panpsychism, which posits consciousness at the most basic level, and strict reductive physicalism, which holds mental properties are nothing over and above physical ones.
self-and-social-cognition · intro
A complex psychological and physiological state involving subjective feeling, bodily changes, and characteristic expressive and behavioural responses, typically triggered by an evaluation of a situation as relevant to one's goals or wellbeing. Theories of emotion differ on how central bodily and interoceptive signals are to the felt quality of an emotional experience, versus purely cognitive appraisal.
self-and-social-cognition · intro
The capacity to understand and share the feelings of another person, often distinguished into a cognitive component (understanding what another person is feeling) and an affective component (actually feeling a resonant emotional response). Both components are studied in relation to distinct, though overlapping, neural systems.
consciousness-theories · intermediate
A theoretical approach holding that cognition arises through a dynamic interaction between an organism and its environment, through ongoing sensorimotor activity, rather than through the brain passively representing an external, pre-given world. It is closely related to embodied cognition and challenges purely computational, representation-focused models of mind.
clinical-and-disorders · intro
A sudden, abnormal burst of synchronised electrical activity in the brain, which can produce a wide range of effects depending on the brain regions involved, from brief lapses in awareness to full-body convulsions. Seizures that involve widespread cortical disruption commonly cause at least a temporary loss or alteration of consciousness.
philosophy-of-mind · intermediate
The view that mental states, including conscious experience, are caused by physical processes in the brain but have no causal influence on the physical world in return, making consciousness a byproduct that accompanies brain activity without itself doing any causal work. Critics argue this sits uneasily with the intuitive sense that thoughts and feelings do influence our actions.
cognitive-science · intro
The form of long-term, explicit memory for specific personal events and experiences, including their time and place, as distinguished from semantic memory for general facts and knowledge. Recalling a specific birthday party is episodic memory; knowing that birthdays are celebrated annually is semantic memory. The hippocampus plays a central role in forming new episodic memories.
cognitive-science · intro
A set of higher-order cognitive processes, including planning, inhibitory control, cognitive flexibility, and working memory, that allow goal-directed behaviour and the regulation of thought and action, particularly in novel or complex situations. These functions are strongly associated with the prefrontal cortex, and they continue developing into early adulthood.
philosophy-of-mind · intermediate
The apparent gap between physical descriptions of brain processes and explanations of why those processes are accompanied by subjective experience, such that even a complete physical account of the brain seems to leave the question of why there is subjective experience at all unanswered. The term was introduced by philosopher Joseph Levine to describe this persistent explanatory shortfall, independent of whether consciousness is ultimately physical.
cognitive-science · intro
Also called: declarative memory
A form of long-term memory that is deliberately and consciously recollected, including memory for facts (semantic memory) and personal experiences (episodic memory). It is distinguished from implicit memory, which influences behaviour without requiring conscious recall.