Impaired neural response to internal but not external feedback in schizophrenia.

BACKGROUND Accurate monitoring and integration of both internal and external feedback is crucial for guiding current and future behavior. These aspects of performance monitoring are commonly indexed by two event-related potential (ERP) components: error-related negativity (ERN) and feedback negativity (FN). The ERN indexes internal response monitoring and is sensitive to the commission of erroneous versus correct responses, and the FN indexes external feedback monitoring of positive versus negative outcomes. Although individuals with schizophrenia consistently demonstrate a diminished ERN, the integrity of the FN has received minimal consideration. METHOD The current research sought to clarify the scope of feedback processing impairments in schizophrenia in two studies: study 1 examined the ERN elicited in a flanker task in 16 out-patients and 14 healthy controls; study 2 examined the FN on a simple monetary gambling task in expanded samples of 35 out-patients and 33 healthy controls. RESULTS Study 1 replicated prior reports of an impaired ERN in schizophrenia. By contrast, patients and controls demonstrated comparable FN differentiation between reward and non-reward feedback in study 2. CONCLUSIONS The differential pattern across tasks suggests that basic sensitivity to external feedback indicating reward versus non-reward is intact in schizophrenia, at least under the relatively simple task conditions used in this study. Further efforts to specify intact and impaired reward-processing subcomponents in schizophrenia may help to shed light on the diminished motivation and goal-seeking behavior that are commonly seen in this disorder.