Altered P300 topography in schizophrenia.

The spatiotemporal evolution of the P300 waveform was topographically mapped in a group of ten male chronic schizophrenics, using the technique of brain electrical activity mapping. Group-average P300 waveforms were constructed for the schizophrenic group and a group of matched controls. The control group's P300 showed a concentric development about a maximum in the centroparietal area, slightly displaced toward the left. In contrast, the schizophrenic group's P300 maximum was more anterior and to the right, with a deficiency in left temporal activity. Using the technique of significance probability mapping, it was demonstrated that the maximum between-group difference was localized to the left-middle and posterior temporal regions, where the schizophrenic group was deficient in activity.