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Updated: Sep 25, 2026

Somatosensory Event-related Potentials from Orofacial Skin Stretch Stimulation
Published on: December 18, 2015
The human supplementary motor area-proper does not receive direct somatosensory inputs from the periphery: data from
C Barba1, M Valeriani, D Restuccia
1Department of Neurology, Catholic University, Rome, Italy. carmen.barba@tiscali.it
Abstract:
Somatosensory evoked potentials to median nerve (MN) stimulation were recorded by stereotactically implanted electrodes in the frontal lobe of two epileptic patients in order to evaluate whether short-latency cortical responses could be generated in the supplementary motor area (SMA)-proper. In both patients two potentials, called P20 and N30 responses, showed a decreasing amplitude from the most superficial to the deepest contacts and were recorded in the white as well in the grey matter of the frontal lobe. Furthermore, no phase reversal of both P20 and N30 potentials was identifiable along electrode trajectories. Our results suggest that short-latency somatosensory evoked responses recorded in the SMA-proper contralateral to MN stimulation are volume conducted from remote cortical generators.
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