N1 Component Derived from the Temporal Region during an Auditory Passive Event-Related Potential Paradigm in Schizophrenics

Event-related potentials (ERPs) were recorded at the Cz, W1 (Wernicke's area), and W2 (contralateral to Wernicke's) regions in 27 schizophrenics during an auditory passive sequence paradigm similar to that employed by Polich. N1 component for frequent tones was analyzed. In schizophrenics, the difference between the ERP waveforms at W1 and W2 was larger than that in controls, and N1 latency at W1 was significantly shorter than that at W2. To examine the similarity between interhemispheric waveforms, Person product-moment correlation coefficient (Interhemispheric Correlation Coefficient, IHCC) was calculated, time point by time point, between the ERP waveforms at W1 and at W2. The mean IHCC for schizophrenics was significantly lower than that for controls. In schizophrenics, the low IHCC group had more severe psychopathology and a longer duration of illness. These results suggest that the hemispheric imbalance of the temporal lobe is characteristic of schizophrenia.