Error processing network dynamics in schizophrenia

Current theories of cognitive dysfunction in schizophrenia emphasize an impairment in the ability of individuals suffering from this disorder to monitor their own performance, and adjust their behavior to changing demands. Detecting an error in performance is a critical component of evaluative functions that allow the flexible adjustment of behavior to optimize outcomes. The dorsal anterior cingulate cortex (dACC) has been repeatedly implicated in error-detection and implementation of error-based behavioral adjustments. However, accurate error-detection and subsequent behavioral adjustments are unlikely to rely on a single brain region. Recent research demonstrates that regions in the anterior insula, inferior parietal lobule, anterior prefrontal cortex, thalamus, and cerebellum also show robust error-related activity, and integrate into a functional network. Despite the relevance of examining brain activity related to the processing of error information and supporting behavioral adjustments in terms of a distributed network, the contribution of regions outside the dACC to error processing remains poorly understood. To address this question, we used functional magnetic resonance imaging to examine error-related responses in 37 individuals with schizophrenia and 32 healthy controls in regions identified in the basic science literature as being involved in error processing, and determined whether their activity was related to behavioral adjustments. Our imaging results support previous findings showing that regions outside the dACC are sensitive to error commission, and demonstrated that abnormalities in brain responses to errors among individuals with schizophrenia extend beyond the dACC to almost all of the regions involved in error-related processing in controls. However, error related responses in the dACC were most predictive of behavioral adjustments in both groups. Moreover, the integration of this network of regions differed between groups, with the cerebellar regions and the dACC less connected to the network in individuals with schizophrenia compared to controls. Our findings demonstrate a blunted response to error commission in the dACC that is associated with reduced error-related behavioral adjustments in individuals with schizophrenia. This result supports the hypothesis that a failure to respond appropriately to errors in individuals with schizophrenia is linked to alterations in dACC function leading to a compromise in the implementation of cognitive control. Our findings highlight the importance of examining brain activity related to the processing of error information and supporting error-related behavioral adjustments in terms of a distributed network. (C) 2010 Elsevier Inc. All rights reserved.