Brainstate

Brainstate is a term used in neuroscience to describe the global configuration of brain activity across large-scale networks at a given moment. It encompasses arousal level, attentional focus, and the level of consciousness, and it can influence perceptual processing, decision making, and behavior. Brainstates are not fixed; the brain transitions among distinct patterns as the organism sleeps, wakes, or engages in different tasks.

Common brain states include wakefulness, REM sleep and various stages of non-REM sleep, anesthesia, coma, and altered states such as meditation or hypnosis. Each state has characteristic neural signatures: wakefulness shows desynchronized EEG activity with low-amplitude, mixed-frequency patterns; stage N2 and N3 show sleep spindles and slow waves, respectively; REM sleep shows low-amplitude activity with sawtooth patterns and vivid dreaming. Functional connectivity and thalamo-cortical interactions define each state; changes occur in motor and default mode networks.

Brainstate is typically assessed with electrophysiological and imaging methods such as EEG, MEG, fMRI, PET, and intracranial recordings. Analyses focus on spectral power, coherence, entropy, and network metrics to classify states and transitions. The concept is central to sleep research, anesthesia, disorders of consciousness, and psychiatric conditions, and it is studied in relation to circadian biology, development, drugs, and neuromodulation.