Updated for 1999
Lecture Notes
Chapter 9 - Sleep
STAGES OF SLEEP

Awake: alpha (awake, relaxed, drowsy, often with eyes closed, synchronized) and beta (alert, attentive, thinking, desynchronized) activity

Stage 1: alpha and theta activity, transition between sleep and wakefulness

Stage 2: theta activity, sleep spindles and K complexes (both involved in keeping person asleep by decreasing sensory awareness)

Stages 3 and 4: delta activity, "slow wave sleep" REM: theta waves, desynchrony WHY SLEEP?

1) adaptive response

2) restorative process

PURPOSE OF REM SLEEP

1) learning - more REM after learning; impaired performance after learning if sleep deprived; less REM in retarded vs. normal children; more REM during exam time in college students

2) developmental - offspring of animals born with developed brains spend less time in REM than less developed offspring (Problem with this theory?)

SLEEP DISORDERS

1) insomnia - affects 20% of population at any given time (Definition?)

Causes:

2) narcolepsy - rare neurological disorder, probably genetic 3) REM without atonia - lack of typical paralysis during sleep

4) bedwetting - bell and pad treatment; typically occurs during slow wave sleep

5) sleepwalking - not related to dreaming, occurs in slow wave sleep

6) night terrors - child acts awake and terrified, but actually in slow wave sleep

BIOLOGICAL CLOCKS

1) circadian rhythm - a daily, rhythmical change in behavior or physiological process

2) Basic rest-activity cycle (BRAC) - 90-minute period, controls occurrence of REM sleep

3) daily schedule - anticipation of lunch, for example

4) seasonal rhythms - pineal gland secretes melatonin when directed to do so by the SCN

PHYSIOLOGICAL MECHANISMS OF SLEEP AND WAKING

Controlled by substances in blood promoting sleep or wakefulness?

Arousal - controlled by brainstem

Slow-wave sleep REM sleep 1) serotonergic neurons in the raphe nuclei and noradrenergic neurons in the locus coeruleus become silent (typically inhibit ACh neurons)

2) then, acetylcholinergic neurons in pons become active

3) this results in: