Subprocesses of performance monitoring: A dissociation of error processingand response competition revealed by event-related fMRI and ERPs

Performance monitoring can be implemented in the brain by two possible syst ems, one monitoring for response competition or one detecting errors. Two c urrent models of performance monitoring have different views on these monit oring subsystems. While the error detection model proposes a specific error detection system, the response competition model denies the necessity of a specific error detector and favors a more general unitary system evaluatin g response conflict. Both models suggest that the frontomedian wall in the vicinity of the anterior cingulate sulcus plays an important role in perfor mance monitoring. The present study investigates the hemodynamic and electr ophysiological correlates of response competition and error processing. Twe lve young healthy participants performed a speeded, modified flanker task, while fMRI signals and ERPs were measured in separate sessions. The event-r elated fMRI shows that networks involving the frontomedian wall are activat ed during both response competition and error processing. However, an anato mical dissociation was found: while error processing preferentially activat es the human homologue of the cingulate motor area (CHA, BA 24c') in the de pth of the anterior cingulate sulcus, response competition is accompanied b y activation of the pre-SMA and mesial BA 8. The ERP waveforms for erroneou s trials exhibit a large error-related negativity, which is most likely gen erated in the CMA. These results suggest that the CMA plays a major role in error processing. Further fMRI activations in the lateral prefrontal and p rimary motor cortex are discussed with respect to performance monitoring an d its influence on task set reconfiguration. (C) 2001 Academic Press.