Mental movement simulation affects the N30 frontal component of the somatosensory evoked potential.

It is known that somatosensory evoked potentials can be influenced by several centripetal and centrifugal factors which modify their amplitude. The present study shows for the first time that the frontal waves N30 and to a lesser extent N23 are specifically attenuated during mental movement simulation (MMS) activity. This gating phenomenon, tested on 16 normal subjects, occurred when repeated fast finger movements on the stimulated side are mentally simulated. In contrast, no significant modification appeared when the subject performed the MMS activity with the hand contralateral to that receiving electrical stimuli or when the subject performed a mental operation unrelated to the MMS. The MMS was shown by Roland et al. (1980) to increase the regional blood flow exclusively in the supplementary motor area (SMA). Our experimental data therefore indicate that the SMA could play an important role in the generation of the frontal N30.