Sustained facial muscle activity during REM sleep

Abstract

Few studies have been undertaken to explore whether REM EMG suppression is exhibited in facial muscles other than the mentalis. The present study is an investigation of facial muscle activity during REM sleep in ten vivid dreamers. Sustained facial muscle activity (FMA) was observed during paradoxical sleep in six of the ten subjects. The FMAs observed ranged from a minimum criterion of 6 seconds to sustained FMA "bouts" of up to 59.5 seconds in duration. The FMAs observed had voltages which ranged from a minimum criterion of 4.0 v to maximum bursts of 78 v. Across the 6 subjects who exhibited FMAs, there was a total of 19 events. EMG activity was usually observed in the corrugator, although it was sometimes observed in the zygomatic, frontalis, and masseter. The potential relevance of sustained facial muscle activity to emotion experienced during REM is discussed.