A Parietooccipital Generator for P300: Evidence from Human Intracranial Recordings

Auditory event-related potentials (ERPs) were recorded simultaneously from the scalp and from bilateral intracranial sites within the frontal and temporal lobes, as well as from intracortical sites in the parieto-occipital region in a subject undergoing evaluation for surgical treatment of medically intractable epilepsy. Scalp ERP morphology was entirely normal. Large amplitude ERPs could be recorded from all intracranial sites. Furthermore, polarity inversions of ERP components with latencies similar to that of the scalp P300 were recorded in both temporal lobes and from the parieto-occipital region. These findings are consistent with suggestions that multiple intracranial generators, including extratemporal ones, give rise to the scalp-recorded P300. These data also provide a basis for a conceptual link between hypotheses concerning the neural substrate of attention and the psychological correlates of the P300.