Misattribution of sensory input reflected in dysfunctional target: non-target ERPs in schizophrenia

Background. While numerous studies have found disturbances in the Event-Rel ated Potentials (ERPs) of patients with schizophrenia linked to task releva nt target stimuli (most notably a reduction in P300 amplitude), few have ex amined ERPs to task irrelevant non-targets. We hypothesize, from current mo dels of dysfunction in information processing in schizophrenia, that there will be less difference between ERPs to targets and non-targets in patients with schizophrenia than in controls. Methods. EEGs were recorded for 40 subjects with schizophrenia and 40 age a nd sex matched controls during an auditory oddball reaction time task. ERPs to the targets and non-targets immediately preceding the targets were aver aged separately. Results. There was a disturbance in ERPs to targets but also to non-targets (reduced N100 amplitude and earlier P200 latency) and the difference betwe en target and non-target ERP components (N100 and P200 amplitude and P200 l atency), was significantly reduced in the schizophrenic group compared with controls. Conclusions, These findings suggest a disturbance in processing task releva nt and irrelevant stimuli, consistent with Gray's (1998) hypothesis of misa ttributions in the 'match:mismatch' of novel (target) and familiar (non-tar get) sensory input compared with stored information.