AP PSYCHOLOGY

Detailed explanation-1: -9 Stage 2 sleep is characterized by the appearance of both sleep spindles and K-complexes. Stage 3 is often referred to as deep sleep or slow-wave sleep because this stage is characterized by low frequency (less than 3 Hz), high amplitude delta waves (Figure SC.

Detailed explanation-2: -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-3: -Stage II is the predominant sleep stage during a normal night’s sleep. The distinct and principal EEG criterion to establish stage II sleep is the appearance of sleep spindles or K complexes. The presence of sleep spindles is necessary and sufficient to define stage II sleep.

Detailed explanation-4: -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.

Detailed explanation-5: -Stage N2 is the equivalent to the R and K stage II. It is characterized by the presence of sleep spindles and K complexes on a background of low-amplitude, mixed frequency EEG activity. Sleep spindles are trains of higher frequency bursts that were named according to their shapes, which tend to have tapering ends.