CORTICAL REPRESENTATION OF SELF-PACED FINGER MOVEMENT

WE compared the cortical fields activated by simple, self-paced index- finger flexions with those activated during visually triggered movemen t and rest using PET. Of 12 fields detected during self-paced movement compared to rest, three were located in the classically defined motor areas: primary motor area (M1), premotor cortex (PM) and supplementar y motor area (SMA). The latter extended into the cingulate motor area (CMA). Four corresponding clusters were also found when triggered move ment was subtracted from self-paced movement. The change in regional c erebral blood flow (rCBF) was greater in SMA than in PM during self-pa ced movement compared with either control. We conclude that repetitive , self-paced index-finger flexions can activate SMA, PM and CMA, and t hat this movement activates SMA more strongly than PM.