Rapid Processing of Both Reward Probability and Reward Uncertainty in the Human Anterior Cingulate Cortex

Reward probability and uncertainty are two fundamental parameters of decision making. Whereas reward probability indicates the prospect of winning, reward uncertainty, measured as the variance of probability, indicates the degree of risk. Several lines of evidence have suggested that the anterior cingulate cortex (ACC) plays an important role in reward processing. What is lacking is a quantitative analysis of the encoding of reward probability and uncertainty in the human ACC. In this study, we addressed this issue by analyzing the feedback-related negativity (FRN), an event-related potential (ERP) component that reflects the ACC activity, in a simple gambling task in which reward probability and uncertainty were parametrically manipulated through predicting cues. Results showed that at the outcome evaluation phase, while both win and loss-related FRN amplitudes increased as the probability of win or loss decreased, only the win-related FRN was modulated by reward uncertainty. This study demonstrates the rapid encoding of reward probability and uncertainty in the human ACC and offers new insights into the functions of the ACC

Internal and external information in error processing

<p>Abstract</p> <p>Background</p> <p>The use of self-generated and externally provided information in performance monitoring is reflected by the appearance of error-related and feedback-related negativities (ERN and FRN), respectively. Several authors proposed that ERN and FRN are supported by similar neural mechanisms residing in the anterior cingulate cortex (ACC) and the mesolimbic dopaminergic system. The present study is aimed to test the functional relationship between ERN and FRN. Using an Eriksen-Flanker task with a moving response deadline we tested 17 young healthy subjects. Subjects received feedback with respect to their response accuracy and response speed. To fulfill both requirements of the task, they had to press the correct button and had to respond in time to give a valid response.</p> <p>Results</p> <p>When performance monitoring based on self-generated information was sufficient to detect a criterion violation an ERN was released, while the subsequent feedback became redundant and therefore failed to trigger an FRN. In contrast, an FRN was released if the feedback contained information which was not available before and action monitoring processes based on self-generated information failed to detect an error.</p> <p>Conclusion</p> <p>The described pattern of results indicates a functional interrelationship of response and feedback related negativities in performance monitoring.</p

Electrophysiological evidence of enhanced performance monitoring in recently abstinent alcoholic men

RATIONALE: Chronic alcoholism is associated with mild to moderate cognitive impairment. Under certain conditions, impairment can be ameliorated by invoking compensatory processes. OBJECTIVE: To identify electrophysiological mechanisms of such compensation that would be required to resolve response conflict. METHODS: 14 abstinent alcoholic men and 14 similarly aged control men performed a variation of the Eriksen flanker task during an electroencephalography (EEG) recording to examine whether alcoholics could achieve and maintain control-level performance and whether EEG markers could identify evidence for the action of compensatory processes in the alcoholics. Monitoring processes engaged following a response were indexed by the correct related negativity (CRN) and error related negativity (ERN), two medial-frontal negative event-related potentials. RESULTS: The alcoholics were able to perform at control levels on accuracy and reaction time (RT). Alcoholics generated larger ERN amplitudes following incorrect responses and larger CRNs following correct responses than controls. Both groups showed evidence of post-error slowing. Larger CRN amplitudes in the alcoholics were related to longer RTs. Also observed in the alcoholics was an association between smaller CRN amplitudes and length of sobriety, suggesting a normalization of monitoring activity with extended abstinence. CONCLUSIONS: To the extent that greater amplitude of these electrophysiological markers of performance monitoring indexes greater resource allocation and performance compensation, the larger amplitudes observed in the alcoholic than control group support the view that elevated performance monitoring enables abstinent alcoholics to overcome response conflict, as was evident in their control-level performance