Neurobiology of Brain States: Consciousness, Neural Coding, Large-Scale Networks, and Perception

Comprehensive vocabulary flashcards covering the neurobiology of brain states, theories of consciousness, neural coding schemes, default mode and salience networks, graph theoretical neuroscience, and the cognitive mechanisms of belief.

Higher Order (Cognitivist) Theory

A neurobiological hypothesis of consciousness proposing that a first-order sensory representation becomes conscious only when the brain represents or monitors that sensory information again at a higher cognitive level.

Recurrent Activation (Noncognitivist) Theory

A neurobiological hypothesis asserting that conscious experience arises from recurrent, feedback interactions within sensory-processing systems itself, without strictly requiring a higher-order cognitive representation.

Intracranial Electrical Stimulation (iES)

An invasive experimental technique used primarily in awake neurosurgical patients undergoing epilepsy evaluation to causally perturb localized neural activity and observe reportable changes in subjective experience.

Neural Constitution of Consciousness

The specific neural activity that directly realizes, embodies, or makes up a particular conscious experience (analogous to the blocked light forming a shadow).

Global Enabling Factors of Consciousness

The physiological conditions and brain states that allow consciousness to occur, but do not directly constitute the specific subjective experience itself (analogous to the sun making a shadow possible).

Double Representation Approach

A specific higher-order framework wherein sensory information is represented at a first level and then represented again at a higher cognitive level to yield conscious awareness.

Perceptual Reality Monitoring

A higher-order cognitive process wherein higher-order mechanisms evaluate and monitor sensory representations to determine whether they represent external reality.

Dorsolateral Prefrontal Cortex (DLPFC)

A region on the upper and outer surface of the frontal lobe whose activity correlates with reporting perceived stimuli, but likely reflects postperceptual processes such as thinking, decision-making, and reporting rather than conscious perception itself.

Orbitofrontal Cortex (OFC)

A prefrontal cortex region situated on the ventral surface of the frontal lobe just above the eye sockets that contributes to emotional and specific subjective experiences.

Anterior Cingulate Cortex (ACC)

A medial frontal cortex region along the front portion of the cingulate cortex above the corpus callosum that contributes to emotional experiences, motivation, and subjective conscious feelings such as the urge to laugh.

Anterior Midcingulate Cortex (aMCC)

A specific subregion of the broader cingulate cortex where electrical stimulation can evoke an intense subjective sense of facing a challenge and feeling determined to persevere.

Rate-Based Coding

A theory of neural computation holding that neurons transmit information solely through their average firing rate over a given time interval, treating the exact timing of individual spikes as relatively unimportant.

Spike-Based Coding

A theory of neural computation holding that individual action potentials, their exact timing, and precise temporal coordination across neurons drive computational interactions.

State Dependence (Neural Variability)

An explanation for trial-to-trial spike variability stating that a neuron's response is governed by changing internal brain states, ongoing activity, attention, and prior memory rather than random noise.

Deterministic Chaos (Neural Variability)

A property of nonlinear neural systems where strict deterministic rules produce wildly divergent spike patterns across trials due to extreme sensitivity to minute differences in starting conditions.

Degeneracy (Neural Variability)

The biological capacity of a neural system to achieve identical functional results or computational outputs using different structural combinations or distinct spike patterns.

Synchrony

The temporal alignment wherein action potentials from multiple distinct neurons arrive or occur at approximately the same time.

Correlation (Neural Activity)

A statistical dependency between the activity profiles of two neurons across time, which does not require coincident firing and can be actively canceled by balanced excitation and inhibition.

Brain's Dark Energy

The substantial baseline metabolic energy consumption and ongoing intrinsic electrical activity maintained by the brain even in the absence of an explicit task.

Slow Cortical Potentials (SCPs)

Low-frequency electrical voltage shifts in the cerebral cortex occurring at fractions of a hertz ($< 1\,\text{Hz}$) that modulate population excitability and phase-couple with higher-frequency rhythms.

Cross-Frequency Coupling

The regulatory phenomenon wherein the rising phase of slow cortical potentials modulates the amplitude and strength of faster neural oscillations.

Default Mode Network (DMN)

A large-scale, interconnected brain network anchored along the midline that exhibits elevated activity during rest, internally focused thought, and self-referential processing, and decreases activity during attention-demanding external tasks.

Oxygen Extraction Fraction (OEF)

The ratio of consumed oxygen relative to local blood delivery; it is relatively uniform across the brain at rest but decreases locally during activation because blood flow increases disproportionately more than oxygen consumption.

Ventral Medial Prefrontal Cortex (vmPFC)

A primary anatomical subdivision of the default mode network associated with emotional processing, mood regulation, and social behavior.

Dorsal Medial Prefrontal Cortex (dmPFC)

An anatomical subdivision of the default mode network linked to self-referential judgments and evaluating thoughts about oneself.

Posterior DMN Subdivision

The first discovered component of the default mode network, encompassing the posterior cingulate cortex (PCC), precuneus, and lateral parietal cortex, primarily dedicated to memory retrieval and recollection.

Dorsal Attention Network (DAN)

A task-positive brain network focused on externally directed attention that typically exhibits an anticorrelated (negative) functional relationship with the default mode network during demanding tasks.

Predictive Perception

The neurobiological framework stating that the brain uses prior internal models to actively anticipate and interpret the external world, updating these models using limited sensory bandwidth rather than passively building bottom-up copies.

Graph Theory

A mathematical discipline used to analyze complex networks by modeling them as sets of discrete elements (nodes or vertices) interconnected by relationships (edges).

Nodes (Vertices)

The individual fundamental units or defined anatomical brain regions within a network graph model.

Edges

The links between nodes in a network, which represent structural pathways (such as white matter tracts) or functional statistical dependencies.

Small-World Architecture

A network organizational topology combining dense local connectivity (high clustering) with short path lengths, promoting both specialized local segregation and efficient global integration.

Clustering Coefficient

A graph theoretical metric quantifying the degree to which a node's neighboring vertices are connected to one another, indexing local network segregation.

Path Length

A graph metric defined as the average number of intermediate connection steps required to travel between two nodes, reflecting the communication efficiency of the network.

Centrality

A network measure that evaluates the structural or functional importance of a node based on its position, identifying critical communication hubs within the network.

Central Executive Network (CEN)

A large-scale frontoparietal network anchored in the dorsolateral prefrontal cortex (dlPFC) and posterior parietal cortex (PPC) dedicated to working memory, attention, planning, and goal-directed cognition.

Salience Network (SN)

A core neurocognitive network anchored in the frontoinsular cortex (FIC) and dorsal anterior cingulate cortex (dACC) that detects biologically and emotionally relevant stimuli and dynamically switches activity between the CEN and DMN.

Simplicial Complexes

Higher-order mathematical representations in network neuroscience that model multi-node group interactions (beyond pairwise dyads) to capture geometric and higher-order topological features.

Granger Causality

A directional statistical method that infers effective connectivity by testing whether past values of one neural time series contain information that improves the prediction of future values of another.

Transfer Entropy

A non-parametric information-theoretic measure that quantifies the directional flow of information between two dynamical neural processes.

Wilson-Cowan Oscillators

Theoretical mathematical models representing coupled populations of excitatory and inhibitory neurons, used to model brain dynamics and network control during neurological states like epilepsy.

Aberrant Salience

The neurocognitive process in schizophrenia wherein dysregulated striatal dopamine signaling causes neutral or irrelevant internal and external stimuli to be assigned inappropriate emotional or behavioral significance.

Positive Symptoms (Schizophrenia)

Productive symptoms of schizophrenia, such as hallucinations and delusions, which represent cognitive attempts to explain aberrant salience assigned to internal representations and external cues.

Negative Symptoms (Schizophrenia)

Deficit-related features of schizophrenia, such as blunted affect, anhedonia, poverty of speech, avolition, and social withdrawal, stemming in part from blunted reward signaling and network dysfunction.

Hypersensitive Agency-Detection Device (HADD)

An evolved perceptual mechanism that biases the brain toward detecting intentional agents and animate patterns in ambiguous sensory stimuli, minimizing costly false-negative errors at the expense of false positives.

Superior Parietal Lobules

A dorsal cortical region near the top and back of the brain responsible for maintaining the perceived boundary between the physical self and the external environment, whose deactivation induces feelings of unity and self-transcendence.

Mind-Body Dualism

An intuitive cognitive bias that arises spontaneously in early childhood, leading individuals to conceptualize minds, thoughts, and agency as distinct and separable from physical bodies.