Page 181 - Mind Games The Aging Brain and How to Keep it Healthy

Regain an Agile Brain • 165

5. On a scale of 1 to 5, with 1 being excellent and 5 being ex-
tremely poor, how would you rate your sleep habits?
__________

Sleep deprivation results in fatigue (no surprise there),
irritability, decreased attention span, slower response time,
memory gaps, and impaired judgment. Sleep is essential to
maintain memory functions. There are two primary types of
sleep: rapid eye movement (REM) sleep, during which you
dream, and non-REM, or slow-wave sleep. The sleep cycle
can be divided into stages that you cycle through approxi-
mately every 90 minutes (an ultradian rhythm). Non-REM
sleep accounts for 75 percent of your sleep and has four
stages. As you progress through the stages, sleep becomes
deeper and brain waves become larger. After you reach the
deepest level of sleep in stage four, sleep begins to lighten
until you reach REM sleep. It appears that different types of
learning may be facilitated within the different types of
sleep, (See Figure 6-2).
During REM sleep, activity in the brain begins in the
pons and other midbrain areas. The pons communicates
with the cerebral cortex and the thalamus. The pons also
“turns off” motor neurons in the spinal cord, preventing
movement.
REM sleep is important to procedural memory formation
of tasks such as typing and playing the piano. People who
learned a repetitive task were found to be more efficient at
the task after sleeping and experiencing REM sleep. In one
study, subjects were trained on a task in the evening. During
the night, some of the subjects were awakened each time
they entered REM sleep, and the rest were awakened each
time they entered non-REM sleep. Those who were awak-
ened during REM sleep were just as efficient as they were the
evening before. However, those who were awakened during
non-REM sleep demonstrated significant improvement in
performance over the performance levels of the evening be-
fore. Another type of memory, called declarative, in which
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