title: High-density recording and topographic analysis of the auditory oddball event-related potential in patients with schizophrenia.
abstract: BACKGROUND
  Prior research has shown reductions of the N1, N2, and P300 auditory event-related potential (ERP) components in schizophrenic patients. Most studies have shown a greater P300 reduction in left versus right temporal leads in schizophrenic patients. These studies were done with sparse electrode arrays, covering restricted areas of the head, thus providing an incomplete representation of the topographic field distribution.
  
  
  METHODS
  We used a 64-channel montage to acquire auditory oddball ERPs from 24 schizophrenic patients and 24 controls subjects. The N1, P2, N2, P300, and N2 difference (N2d) amplitudes and latencies were tested for group and laterality differences. Component topographies were mapped onto a three-dimensional head model to display the group differences.
  
  
  RESULTS
  The schizophrenic group showed reduction of the N1 component, perhaps reflecting reduced arousal or vigilance, but no N1 topographic difference. An N2d was not apparent in the schizophrenic patients, perhaps reflecting severe disruption in neural systems of stimulus categorization. In the patients, the P300 was smaller over the left temporal lobe sites than the right.
  
  
  CONCLUSIONS
  The increased 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.
authors.affiliation: Department of Psychiatry, Harvard Medical School, Boston, Massachusetts, USA.
authors.forename: G F
authors.initials: GF
authors.lastname: Potts
authors.forename: Y
authors.initials: Y
authors.lastname: Hirayasu
authors.forename: B F
authors.initials: BF
authors.lastname: O'Donnell
authors.forename: M E
authors.initials: ME
authors.lastname: Shenton
authors.forename: R W
authors.initials: RW
authors.lastname: McCarley
mesh_terms: D000328:Adult; D001921:Brain / Q000503:physiopathology; D001931:Brain Mapping; D004569:Electroencephalography; D018913:Event-Related Potentials, P300 / Q000502:physiology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D010812:Physical Stimulation; D011569:Psychiatric Status Rating Scales; D012559:Schizophrenia / Q000503:physiopathology*