Wednesday, February 27, 2008

Conflict Monitoring and the ACC

Botvinick, M.M., Cohen, J.D., & Carter, C.S. (December 2004). Conflict monitoring and anterior cingulate cortex: An update. Trends in Cognitive Sciences, Vol. 8, No. 12, 539-546.

Activity in the dorsal anterior cingulate cortex (ACC) shows up in a variety of tasks. For example, a transient potential (known as the error-related negativity, or ERN) is elicited from the posterior ACC in response to error commission. And a similar evoked potential, the feedback-related negativity (FRN), occurs in response to error feedback and may derive from the same portion of the cingulate that generates the ERN. These activity patterns during commission of errors led researchers to suggest an 'error detection' function for the ACC.

However, tasks which require overriding of habitual responses and tasks which require selecting among a set of equally permissible responses also yield ACC activation. This led researchers to put forth a 'conflict detection' theory of ACC function, with the structure being especially responsible for selecting between competing motor responses.

However, recent studies have proposed other unifying theories to explain the role of the ACC beyond just error detection and conflict monitoring. Some suggest the ACC serves to evaluate action outcomes, performing cost-benefit analyses on possible outcomes and using reward-related information to guide action selection. This 'action-outcome evaluation' view is particularly consonant with other research connecting the mesencephalic dopamine system with the ACC in reinforcement learning.

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