AP PSYCHOLOGY

Detailed explanation-1: -The K-Complex is a waveform identified on electroencephalography (EEG), which primarily occurs during Stage 2 (N2) of NREM sleep, along with sleep spindles, which make up the two distinct features seen in this stage.

Detailed explanation-2: -Along with another wave pattern called K-complexes, sleep spindles are considered a hallmark of stage 2 NREM sleep.

Detailed explanation-3: -K complexes are large waves that stand out from the background and often occur in response to environmental stimuli such as sounds in the bedroom. Sleep spindles are brief bursts of fast activity that appear something like the shape of an “eye” as they rapidly increase in amplitude and then rapidly decay.

Detailed explanation-4: -K-complexes occur roughly every 1.0–1.7 minutes and are often followed by bursts of sleep spindles. They occur spontaneously but also occur in response to external stimuli such as sounds, touches on the skin and internal ones such as inspiratory interruptions.

Detailed explanation-5: -Sleep spindles and K-complexes emerge in stage 2 sleep. Stage 3 and stage 4 are described as slow-wave sleep that is marked by a predominance of delta waves. REM sleep involves rapid movements of the eyes, paralysis of voluntary muscles, and dreaming.