Premovement facilitation of corticospinal excitability before simple and sequential movement.

The purpose of this study was to investigate whether premovement facilitation of corticospinal excitability before sequential movement was different from that before simple movement. Each of 7 participants who performed choice reaction tasks with the right hand pressed a force transducer with the index finger in response to a start cue or pressed the transducers sequentially with the index finger, little finger, thumb, little finger, and index finger. Transcranial magnetic stimulation was delivered to the left motor cortex before the electromyographic burst in the first dorsal interosseous muscle and motor evoked potentials were recorded from the first dorsal interosseous muscle. The amplitude of the motor-evoked potential increased as its onset got closer to the onset of the electromyographic burst. The increase before the sequential movement was larger and began earlier than that before the simple movement. These findings indicate that premovement facilitation of corticospinal excitability is different in magnitude and timing between sequential and simple movements.