FoundationalConceptsNeuroscience

brainstem. New medications that are antagonists at orexin receptors
are currently entering the pharmaceutical marketplace as treatments
for insomnia. This represents a new pharmacologic approach to pro-
moting sleep, very different from the GABA-modulating drugs (ben-
zodiazepines and zolpidem-like compounds) that have dominated the
market for decades.
REM behavior disorder is an impairment of motor inhibition in
REM-stage sleep, resulting in sleepers acting out their dreams. The
body may flail around and even jump out of bed, at which point awak-
ening likely occurs.
With sleep paralysis, one partially awakens while in REM-stage
sleep. The person becomes aware but is unable to move the body be-
cause the neural activity of REM continues to inhibit motor output
from the brain. In addition, because of the robust cortical activity of
REM, the person is likely to have vivid sensory experiences. Some-
times people report the perception that a being is entering the room,
an experience that is generally accompanied by a feeling of significant
distress or terror.
Sleepwalking, or somnambulism, occurs when a person, while still
asleep, rises from bed and walks about, sometimes engaging in such
activities as bathing, housecleaning, eating, and occasionally even
dangerous things like cooking or driving. Sleepwalking tends to hap-
pen while the person is in the deep stages of slow-wave sleep, stages
3 and 4 of NREM. A sleepwalking person who is awakened generally
registers complete surprise and will usually not be able to recall any
dream at the time.
Perhaps the most widely occurring sleep-related problem in the
modern world is chronic sleep deprivation. Although eight hours is
commonly quoted as the “normal” human sleep time, individuals
vary widely in how much sleep they get and how much they appear