抄録
Postural adjustments and voluntary movement appear to be parts of thesame motor program. Anticipatory postural movements should result from muscular functionalsynergies selected from a pre-evaluation of the perturbative aspects of the forthcoming movement. The present study was designed to investigate the relationship between anticipatory postural activities of the sternocleidomastoid muscle (SCM) and peripheral processes associated with execution of the voluntary movement. When subjects executed wide jaw opening as rapidly as possible at the acoustic signal, the following results were obtained:
1. Relations between firing latencies of the SCM and reaction time (RT) were highly signifi-cant. However, firing latencies of the SCM had no relation with motor time (MT).
2. Anticipatory postural period of SCM's activities which preceded the burst of Da had no correlation with opening distance, opening velocity, and MT. These results suggested that anticipatory postural activities of SCM were not associated with peripheral processes of voluntary rapid jaw opening.
