Abstract
The purpose of this study was to investigate the location of equivalent current dipoles estimated by the scalp-skull-brain/dipole tracing (S SB/DT) method during complex and simple tasks. The complex task involved self paced right hand grasping followed by elbow flexion, whereas the simple task involved right middle finger flexion. The movement-related cortical potential was recorded with scalp electroencephalogram surface electrodes (international 10/20 system) . The negative slope, one of the components of the movement-related cortical potential, was recorded from -40 ms to the onset of electromyogram activity of finger flexion muscles during simple tasks. The negative slope was also recorded during complex and sequential tasks from -120 ms to the onset of electromyogram activity. During the simple task dipoles were recorded in both the contralateral primary motor area and the contralateral somatosensory area. For complex and sequential tasks dipoles were recorded in the bilateral supplementary motor area, contralateral primary motor cortex and the contralateral somatosensory area. These results suggest that dipoles in the bilateral supplementary motor cortex, contralateral primary motor cortex and contralateral somatosensory cortex may be activated simultaneously and produce movement-related cortical potential in humans. These results also indicate that the somatosensory cortex may receive inputs from the motor cortex directly before the onset of movement.
