Processing of expected and unexpected monetary performance outcomes in healthy older subjects

The feedback-related negativity (FRN), an event-related potential (ERP) component reflecting feedback processing in the anterior cingulate cortex (ACC), has consistently been found to be reduced in healthy aging, whereas behavioral findings regarding age-related changes in decision making and feedback-based learning are inconsistent. This study aimed to elucidate similarities and differences between healthy younger and older subjects in the processing of monetary performance feedback focusing on effects of reward expectancy. Eighteen younger and 20 older subjects completed a feedback learning task, in which a rule could be learned to predict the reward probabilities associated with particular stimuli. Older subjects showed evidence of slower learning than younger subjects. In both younger and older subjects, the amplitude difference between nonreward and reward in the FRN time window was larger for unexpected than expected outcomes, driven by modulations of negative feedback ERPs. Consistent with previous findings, the amplitude difference tended to be generally reduced in older subjects. P300 amplitude was larger for reward than nonreward in both groups, and interactions between valence and probability indicated that only the P300 for reward was modulated by expectancy. Despite general changes of outcome-related ERPs in healthy aging, older subjects show evidence of preserved effects of expectancy on the processing of monetary feedback.