Practice question

Electroencephalographic frequencies correlate closely with behavioral states across sleep-wake cycle. Deep non-rapid eye movement sleep stage N3, also termed slow-wave sleep, exhibits synchronized high-amplitude slow oscillations reflecting alternating hyperpolarized down states and depolarized up states in extensive thalamocortical networks with reduced consciousness. Beta rhythm around 13-30 Hz indicates alert active cognition, alpha at 8-13 Hz marks relaxed eyes-closed wakefulness, theta at 4-8 Hz appears in drowsiness. Predominant activity during restorative deep sleep below 4 Hz is designated delta rhythm essential for memory consolidation.