AP PSYCHOLOGY

Detailed explanation-1: -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. The entire sequence from drowsiness to deep stage IV sleep usually takes about an hour.

Detailed explanation-2: -EEG delta waves are high-amplitude brain waves and are associated with deep sleep stages.

Detailed explanation-3: -Both delta waves and theta waves occur when you’re asleep, but delta waves are the waves that dominate when you’re in a period of deep, restorative sleep.

Detailed explanation-4: -Generally, brain waves are faster and have higher frequencies during wakefulness. Brain waves become slower when a person is drowsy and slow down further during deeper stages of sleep. However, in REM sleep. View Source, brain wave patterns resemble those of someone who is awake.