Phasic loss of intercostal muscle activity occurring with rapid eye movements during REM sleep.

We tried to estimate the phasic motor inhibition occurring with rapid eye movements (REMs) during REM sleep in children by means of polysomnography. Phasic inhibition of intercostal muscle activity with REMs has been proved by averaging the integrated surface electromyograms in three children. The average latency from the onset of REMs to this inhibition was 38.0 ms, their average duration being 237.0 ms. We discussed the possibility that the REM-related phasic inhibition obtained here was involved in the brainstem-spinal cord inhibitory system functioning during REM sleep.