Sleep and Dreaming
Sleep
Sleep observation
EEG
EOG
EMG
EEG
electroencephalogram
like recording crowd sounds at Fenway
from a microphone suspended from a
helicopter
EOG
electrooculogram
records eye movements
EMG
electromyogram
records peripheral muscle movements
A Night’s Sleep
in the sleep lab:
put on jammies
hop in bed
have electrodes pasted to skull (EEG),
chin (EMG), around eyes (EOG)
cuddle up with Teddy and lights out
Stage 1
EEG recordings change from Beta to
Alpha
Beta
13-30 Hertz (Hz)
low amplitude,
high frequency,
desynchronized (a chorus of thousands
singing different tunes)
Alpha
8-12 Hz
high amplitude
low frequency
synchronized (“Omm”)
Beta vs. Alpha waves
Beta: awake and alert
Alpha: relaxed
Stage 1
transition between sleeping and waking
eyelids slowly open and close
eyes roll up and down
Beta Alpha Theta
awake, alert drowsy
Stage 1
Theta
3.5-7.5 Hz
Stage 1
Theta
10 minutes later...
Stage 2
person sleeping soundly
if awakened, deny they were asleep
Stage 2 EEG
Theta
Sleep spindles (12-14 Hz)
K complexes
Stage 2 EEG
spindle
K complex
15 minutes later...
Stage 3
appearance of Delta waves (20-50%)
50 % Delta
REM sleep
EEG desynchronizes, looks like Stage 1
eyes dart rapidly back and forth under
lids
EMG goes silent
Loss of muscle tonus, with brief
occasional twitching of hands and feet
REM sleep
beta waves
Function of Sleep
adaptation
restoration
Adaptation
over 50% of variability in sleep time
accounted for by size, vulnerability
Restoration
physical
mental
Restoration
sleep deprivation should produce signs
of physical, mental deterioration
Peter Tripp vs. Randy Gardner
Tripp in late 30’s; Gardner a teenager
Human Sleep Deprivation studies
no real effects when physical activity
minimized
sleepiness greates at night; peaks at 48
hours and doesn’t increase further
Animal deprivation studies
rats dunked in water died of massive
internal damage:
ulcers
massive internal hemorrhage
STRESS?
Stage 4 sleep deprivation
(in humans)
rebound
muscle pains, irritability, etc.
in Stage 3: secretion of growth hormone
and synthesis of new proteins
REM deprivation (humans)
rebound
may have effects on mental health
Depression studies
depressed patients spend more time in
REM
anti-depressants inhibit REM
sleep loss may lift depression
REM and consolidation
early 70’s: REM deprivation interfers
with memory of emotionally loaded
words
REM and emotional procesing
Circumcision in S. Pacific Islanders:film
produces anxiety which drops on
subsequent viewings
REM deprivation interfers with drop in
anxiety
dream content between showings
reflects film content
REM and depression
normal people unrealistic about
negative events
depressed people too realistic
interrupting processing of negative
events by alleviate depression