HIGH-DENSITY RECORDING AND TOPOGRAPHIC ANALYSIS OF THE AUDITORY ODDBALL EVENT-RELATED POTENTIAL IN PATIENTS WITH SCHIZOPHRENIA

Background: Prior research has shown reductions of the N1, N2, and P30 0 auditory event-related potential (ERP) components in schizophrenic p atients. Most studies have shown a greater P300 reduction in left vers us right temporal leads in schizophrenic patients, These studies were done with sparse electrode arrays, covering restricted areas of the he ad, thus providing an incomplete representation of the topographic fie ld distribution. Methods: We used a 64-channel montage to acquire audi tory oddball ERPs from 24 schizophrenic patients and 24 controls subje cts. The N1, P2, N2, P300, and N2 difference (N2d) amplitudes and late ncies were tested for group and laterality differences. Component topo graphies were mapped onto a three-dimensional head model to display th e group differences. Results: The schizophrenic group showed reduction of the N1 component, perhaps reflecting reduced arousal or vigilance, but no NI topographic difference. An N2d was not apparent in the schi zophrenic patients, perhaps reflecting severe disruption in neural sys tems of stimulus categorization In the patients, the P300 was smaller over the left temporal lobe sites than the right. Conclusions: The inc reased ERP spatial sampling allowed a more complete representation of the dipolar nature of the P300, which showed field contours consistent with neural sources in the posterior superior temporal plane. (C) 199 8 Society of Biological Psychiatry.