Muscle Paralysis During Sleep
Narcolepsy (excessive daytime sleepiness), cataplexy (sudden loss of muscle tone), and rapid eye movement (REM) sleep behavior disorder are serious sleep-related disorders. The researchers have found neurons in the brain that link all three disorders and could provide a target for treatments.
The research led by Professor Takeshi Sakurai at the University of Tsukuba is published in the
Journal of Neuroscience.
Most of the dreams occur during REM sleep in which the eyes move back and forth, but our bodies remain still. This
near-paralysis of muscles while dreaming is called REM-atonia. In patients with REM sleep behavior disorder, REM-atonia is absent due to which the muscles move around often leading to stand up and jump, yell, or punch. Researchers have found neurons in the brain that normally prevent this type of behavior during REM sleep.
Researchers from the University of Tsukuba have discovered a group of neurons in the mouse brainstem that control muscle tone. Inhibiting these neuronal cells caused mice to move during REM sleep, reminiscent of REM sleep behavior disorders. These neurons were also responsible for episodes of cataplexy in a mouse model of narcolepsy; inhibiting them reduced the number of cataplexic bouts. These circuits could thus be a new target for treating these sleep disorders.