1993 年 56 巻 6 号 p. 539-540
The disappearance of tonic discharge has been observed immediately preceding rapid voluntary movements. This phenomenon, referred to as the premotion silent period, is thought to be a learned, rather than automatic, motor response. Seven healthy male subjects who were maintaining steady, slight voluntary contractions of the masseter were asked to respond to an acoustic stimulus by maximum voluntary clenching as rapidly as possible. The premotion silent period was observed in the masseter muscle in 5 of the 7 subjects.