IMPAIRMENT OF INHIBITION OF UNATTENDED STIMULI IN SCHIZOPHRENIC-PATIENTS - EVENT-RELATED POTENTIAL CORRELATES DURING SELECTIVE ATTENTION

Auditory event-related potentials (ERPs) were recorded during a dichot ic listening task in 18 remitted schizophrenic patients and in 18 age- matched controls. The subjects were instructed to press a button in re sponse to the target tones applied to one designated ear. In schizophr enic patients, P300 amplitude for attended target was significantly sm aller than in controls. Schizophrenic patients also exhibited reduced positive potentials between 200 and 400 ms in ERPs for unattended nont arget. These results suggested that schizophrenic patients lack the ab ility to inhibit unattended or irrelevant stimuli, in addition to impa irment of 'context closure' in the information processing.