ELECTRICAL SOURCE LOCALIZATION OF HUMAN MOVEMENT-RELATED CORTICAL POTENTIALS

Movement-related cortical potentials (MRCP) of healthy humans were ana lyzed with a brain electrical source analysis program for modelling eq uivalent electrical dipoles in order to suggest the generators of the MRCP. Both right and left voluntary self-paced index finger movements were performed by 14 subjects and MRCP were recorded on the scalp with 29 electrodes. A spatiotemporal three-dipole model was developed and it explained 94.1% of the right-hand data and 96.4% of the left-hand d ata. The models for right- and left-hand data were almost similar exce pt for the different hemispheres. A midline dipole was most active dur ing the preparatory period before the onset of voluntary movement and two contralaterally locating dipoles were most active during and immed iately after the motor act. The present model did not support recently suggested bilateral activation of primary motor cortices preceding th e voluntary movement. The locations, orientations and the time course of activation of the dipoles suggest the involvement of the supplement ary motor area in preparation of the movement and the contralateral pr imary motor cortex during the execution of the movement and the contra lateral primary sensory cortex following the movement.