Electrophysiological correlates preceding and following the movement onset in man

The cortical potential changes associated with unilateral voluntary self-paced hand movements were detected over the surface of the scalp by the summation method of EEG activity in 20 young subjects. A typical complex wave form of average movement potential (AMP): N1, P1, N2, P2, were discerned in all subjects in our records. This paper presents the results of the topographical distribution of the second potential of the AMP (Premotion Positivity, P1) and the last potential of the AMP (Positive Postmovement onset Potential, P2). Our results indicate a bilateral symmetrical presence of both positive components precentrally and parietally. They also indicate that both these potentials are bilaterally large posterior to the rolandic fissure, and laterality effects in amplitudes occurred only in the second positive wave parietally during right-hand responses in right handers.