AP PSYCHOLOGY

Detailed explanation-1: -K-complexes are long delta waves that last for approximately one second and are known to be the longest and most distinct of all brain waves.

Detailed explanation-2: -Stage 3. Stage 3 sleep is also known as N3 or deep sleep, and it is harder to wake someone up if they are in this phase. Muscle tone, pulse, and breathing rate decrease in N3 sleep as the body relaxes even further. The brain activity during this period has an identifiable pattern of what are known as delta waves.

Detailed explanation-3: -In the deepest level of sleep, stage IV sleep, the predominant EEG activity consists of low frequency (1–4 Hz), high-amplitude fluctuations called delta waves, the characteristic slow waves for which this phase of sleep is named.

Detailed explanation-4: -EEG delta waves are high-amplitude brain waves and are associated with deep sleep stages.

Detailed explanation-5: -Stage 2 sleep is characterized by the appearance of both sleep spindles and K-complexes. Stage 3 of sleep is often referred to as deep sleep or slow-wave sleep because these stages are characterized by low frequency (less than 3 Hz), high amplitude delta waves (Figure 4).