Different generators in human temporal-parasylvian cortex account for subdural laser-evoked potentials, auditory-evoked potentials, and event-relatedpotentials

In order to localize cortical areas mediating pain we now report subdural c ortical potentials evoked by auditory stimulation (auditory-evoked potentia ls - AEPs) and by cutaneous stimulation with a laser (laser-evoked potentia ls LEPs). Stimulation with the laser evokes a pure pain sensation by select ive activation of nociceptors. LEPs were maximal over the inferior aspect o f the central sulcus and had the same polarity on either side of the sylvia n fissure. AEPs were maximal posterior to the LEP maximum and had opposite polarity on opposite sides of the sylvian fissure, consistent with the loca tion of a known generator in the temporal operculum. Auditory P3 (event-rel ated) potentials were maximal over the temporal base. These findings demons trate that the LEP generator is not in secondary somatosensory cortex on th e parietal operculum and is different from the P3 generator. (C) 2000 Elsev ier Science Ireland Ltd. All rights reserved.