Distribution of readiness potential, pre-motion positivity, and motor potential of the human cerebral cortex preceding voluntary finger movements

Summary

Potentials recorded from the scalp of human subjects preceding voluntary finger movements may be devided into 3 components:

• 1. a slowly increasing surface negative readiness potential which starts about 850 msec before movement and is bilaterally symmetrical over the pre- and post-central region with a maximum at the vertex;

• 2. a pre-motion positivity which is also bilaterally symmetrical and starts about 86 msec before the onset of EMG;

• 3. a surface negative motor potential which starts about 56 msec before the onset of movement in the EMG and has its maximum over the contralateral precentral hand area.