Overview

REM atonia


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An inhibition of skeletal muscles (but not extra-ocular muscles) during REM sleep, manifested as complete atonia, that is governed by a small inhibitory centre in the pons called the subcoerulear nucleus and by the magnocellular nucleus in the medulla oblongata to which it is connected, and that prevents spinal nerves from activating skeletal muscles and thereby stops dreams from being acted out by the sleeper. The only observable bodily movements in a person in REM sleep, apart from breathing and rapid eye movements, are occasional twitches of the extremities, except in people with REM behaviour disorder. The French physiologist Michel Jouvet (born 1925) discovered the mechanism in 1965 by performing experiments on cats in which he used a heated wire to destroy a small volume of the subcoerulear nucleus or of the magnocellular nucleus to which it is linked. This caused the cats to move about during REM sleep, stand up, twitch their whiskers, hiss, paw the air, and make movements typical of stalking and attacking prey—a phenomenon called REM sleep without atonia. See also narcolepsy, sleep paralysis. [From rapid eye movement + atonia, from Greek a- without + tonos tension or tone + -ia indicating a condition or quality]

Subjects: psychology.


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