I. electroencephalograph (EEG) is used to study sleep
1. beta waves: alert & aroused
2. alpha waves: resting quietly & stage 1 of sleep
3. theta waves: occurs in stage 1 of sleep
4. delta waves: more frequent during slow wave sleep
II. types of sleep
1. Non-Rapid Eye Movement (NREM) sleep
A. stage 1: some alpha & mostly theta
waves
B. stage 2: mixed EEG with sleep spindles
& K complexes
C. stage 3: delta waves (slow wave sleep:
reduced HR. breathing, etc.)
D. stage 4: delta waves (slow wave sleep)
deepest sleep
2. Rapid Eye Movement (REM) sleep (paradoxical sleep or dream
sleep)
A. EEG, heart rate, & breathing resemble
an awake person
B. very little muscle tone but dreaming occurs
III. Why do we sleep
1. circadian rhythm (biological cycles of about 24 hr)
A. these are often influenced by signals such
as the light of day
B. biological clock in the suprachiasmatic
nucleus (SCN) of the hypothalamus
2. sleep may have evolved because it has a survival advantages
3. NREM sleep may restore us
4. REM sleep may also be important:
A. learning appears to increase REM sleep
IV. Sleep disorders
1. insomnia: tired during the day due to sleep problems
2. narcolepsy: quickly go from awake state to REM sleep
3. sleep apnea: person stops breathing during sleep
A. Sudden Infant Death Syndrome (SIDS)
4. nightmares: bad dreams in REM sleep
5. night terrors: horrific NREM images (in stage 4)
6. sleepwalking: occurs in NREM sleep & common in children
7. REM sleep disorder: person acts out their dreams
V. Mechanisms that control sleep & waking
1. reticular formation (RF: nuclei that make up the interior
of the brain stem)
2. preoptic area (just rostral to the hypothalamus)