Transcript Theories of sleep - psychlotron.org.uk

Theories of sleep
• Oswald (1980) – REM for brain; SWS for
body
• Horne (1988) – core sleep (REM & SWS)
vs. optional sleep
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• Restoration (Oswald; Horne)
• The function of sleep is to allow body to
be repaired and restored
Restoration theory
• Deficits in functioning during sleep
deprivation
• Rebound following deprivation
• Increase in REM during brain growth,
reorganisation & repair
• Increase in SWS during illness, recovery
from injury
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• Main predictions:
Effects of sleep deprivation
• Prolonged sleep deprivation causes
immune failure & death
• Studies of humans produce less clear-cut
results
• Confounding effects of stress etc.
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• Animal studies tend to support
restoration
Rebound
• Generally, people catch up on sleep
following deprivation
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• Not all lost sleep is reclaimed
• About 70% of lost SWS and about 50% of
lost REM typically recovered
• Only some sleep is necessary
24 hour period
5yrs
REM
NREM
Age
• Reduction in
sleep over
lifespan
• Highest in
infants;
highest REM
in early years
• Some
changes in
adolescence
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Growth & reorganisation
Illness & injury
• Total sleep time increases during illness
• REM increases during recovery from brain
injury, ECT & drug withdrawal
• SWS deprivation can cause physical
symptoms
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• Sleep does increase during illness and
recovery from injury
Evaluation
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• Much evidence is consistent with the
restoration view
• Main problem comes from apparent lack
of serious biological malfunction during
sleep deprivation in humans