Shortening of the cortical silent period following transcranial magnetic brain stimulation during an experimental paradigm for generating contingent negative variation (CNV)

Objectives: We investigated changes in the cortical silent period (CSP) fol lowing transcranial magnetic cortical stimulation (TCMS) during a standard paradigm which was designed to evoke contingent negative variation (CNV) in ten normal subjects. Methods: We recorded the motor evoked potentials (MEP) and CSP during the i nter-stimulus interval (ISI) of a CNV paradigm in ten normal subjects. The CNV paradigm consisted of a visual warning stimulus (S1) followed by a visu al response stimulus (S2). The CSP following TCMS on the hand motor area wa s recorded from mildly contracted first dorsal interosseous muscles. Results: The CSP was significantly shortened during the ISI (P < 0.01, t te st) with a highly significant correlation with the TCMS timing during the I SI (P < 0.02, Spearman's correlation coefficient), while the MEP amplitude and latency were unchanged. Conclusions: The results suggested that shortening of the CSP was associate d with neural processes related to preparation for voluntary movement durin g the paradigm. (C) 1999 Elsevier Science Ireland Ltd. All rights reserved.