type of relatively low frequency, relatively high amplitude brain wave that becomes synchronized; characteristic of the beginning of stage 1 sleep

type of low frequency, high amplitude brain wave characteristic of stage 3 and stage 4 sleep

very high amplitude pattern of brain activity associated with stage 2 sleep that may occur in response to environmental stimuli

period of sleep outside periods of rapid eye movement (REM) sleep

period of sleep characterized by brain waves very similar to those during wakefulness and by darting movements of the eyes under closed eyelids

rapid burst of high frequency brain waves during stage 2 sleep that may be important for learning and memory

first stage of sleep; transitional phase that occurs between wakefulness and sleep; the period during which a person drifts off to sleep

second stage of sleep; the body goes into deep relaxation; characterized by the appearance of sleep spindles

third stage of sleep; deep sleep characterized by low frequency, high amplitude delta waves

type of low frequency, low amplitude brain wave characteristic of the end of stage 1 sleep

increased time spent in REM sleep after having been deprived of REM sleep

feeling drowsy and disoriented when woken up while in stage 3 of sleep

high frequency, low amplitude waves typical of brain activity during times of wakefulness and dreaming