The impact of cognitive deficits on conflict monitoring. Predictable dissociations between the error-related negativity and N2.

Monitoring of ongoing processing plays a critical role in regulating cognitive function. Two event-related potential components, the error-related negativity (ERN) and N2, have been proposed to reflect this monitoring function. Specifically, it has been suggested that both components reflect the role of anterior cingulate cortex (ACC) in monitoring for the occurrence of response conflict. This view appears to be challenged by findings that alcohol consumption and lesions in ACC have dissociable effects on the ERN and N2. Using a computational model, the present research demonstrates that the conflict-monitoring theory can account for these dissociations in terms of the dissociable effects of alcohol and ACC lesions on processing of relevant stimulus information (which determines ERN amplitude) and processing of irrelevant, distracting information (which determines N2 amplitude). The simulation results suggest new interpretations of the cognitive deficits caused by alcohol consumption (impaired stimulus processing) and ACC lesions (impaired attentional control).