Recording of event-related potentials (P300) from human cortex.

Auditory event-related potentials were recorded simultaneously from chronically implanted subdural electrodes and from scalp electrodes in three patients who were being evaluated for surgical treatment of epilepsy. These three cases showed clearly defined scalp-P300 and scalp-N300. A cortex-P300 was recorded from the midtemporal area, and a cortex-N300 was recorded from the inferior frontal area with some reflection at the basal temporal region. There were no potentials from an interhemispheric region. We could not observe any component from the cortex studied corresponding to scalp-recorded N200. Therefore, while the activity generated from the mesial temporal lobe may only make minor contributions to scalp-P300, that generated from the midtemporal area might make a major contribution to the scalp-P300. Additionally, generators of N200, P300, and N300 are different from each other. These findings, together with previous reports regarding the generator source of P300, also suggest that P300 is a complex arising from multifactorial generator sources, including the midtemporal and inferior frontal area.