REM sleep

Clinic

• Rapid eye movement sleep, also known as paradoxical sleep because of physiological similarities to waking states including rapid, low-voltage desynchronized brain waves.
• It represents a smaller portion of total sleep time.
• It is the main occasion for dreams (or nightmares)
• It is associated with desynchronized and fast brain waves, eye movements, loss of muscle tone, and suspension of homeostasis.
• REM is a unique phase of sleep in mammals and birds.
• Electrical and chemical activity regulating this phase seems to originate in the brain stem, and is characterized most notably by an abundance of the neurotransmitter acetylcholine, combined with a nearly complete absence of monoamine neurotransmitters histamine, serotonin and norepinephrine.
• Experiences of REM sleep are not transferred to permanent memory due to absence of norepinephrine.
• Absence of visual and auditory stimulation (sensory deprivation) during REM sleep can cause hallucinations.
• The transition to REM sleep begins with electrical bursts called "ponto-geniculo-occipital waves" (PGO waves) originating in brain stem.
• REM sleep occurs 4 times in a 7 hour sleep.
• Organisms in REM sleep suspend central homeostasis, allowing large fluctuations in respiration, thermoregulation and circulation which do not occur in any other modes of sleeping or waking.
• Body abruptly loses muscle tone, a state known as REM atonia.