The N400 event-related brain potential response: A window on deficits in predicting meaning in schizophrenia

Schizophrenia is characterized by impairments in using past experience to predict what will happen next, at multiple levels of cognitive processing. The N400 event-related brain potential (ERP) waveform indexes our ability to use contextual information in combination with world knowledge to predict upcoming meaningful or semantic stimuli. N400 studies have provided evidence that patients with schizophrenia have deficits in such prediction. Some studies of schizophrenia patients have found these N400 semantic priming deficits to correlate with delusions, which frequently involve misinterpretations of meaningful relationships between objects or events, and to improve with antipsychotic treatment. Thus, these semantic priming deficits may reflect a neurocognitive mechanism of delusions, paralleling other cognitive domains in which prediction deficits are a proposed cause of schizophrenia symptoms.