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The primary function of REM sleep
Andrew E. Bernhard
In this paper, the physiological features associated with the different stages of REM sleep and with what
information processing researchers have called “effort” and “arousal” are compared. It is suggested that
tonic REM sleep and effort involve an increase in the metabolism of cerebral glycogen, and phasic REM
sleep and arousal involve the transfer of glucose from the body to the brain. Both stages of REM sleep
seem to elevate cerebral glucose levels and likely result in increased ATP generation in some part(s) of the
brain. It is noted that the functioning of the hippocampus depends heavily on ATP, and that this part of the
brain becomes especially active during REM sleep. From this, although many details remain to be
clarified, it seems clear that the primary function of REM sleep is to re-energize the brain.
1. Introduction
Although many different theories have been suggested to explain the function of
sleep, none has been widely accepted (Zepelin, Siegel, & Tobler, 2005). Common sense
suggests that a person is somehow re-energized during sleep, and many scientists and
members of the general public share this view. However, it has proved extremely difficult
to determine what sort of energy reserve is replenished during sleep, where this reserve is
located, when it is replenished, and how the process occurs (Rechtschaffen, 1998). Sleep
has long remained “one of the major unanswered questions in biology” and “one of
nature’s greatest mysteries” (Bennington & Heller, 1995, p. 347; Frank, 2006, p. 47).
I propose that depleted ATP reserves in the hippocampus and associated brain
structures are replenished during rapid eye movement (REM) sleep. A comparison of the
physiological features associated with REM sleep and what information-processing
preliminary draft (9/24/2006)