Performance monitoring in conflict processing: age-related and individual differences in the response-locked ERP

In ERP studies on conflict processing, performance monitoring and error processing have been studied with two response-locked components, error-related negativity (ERN) and error positivity (Pe). However, their correct-related counterparts—the correct-related negativity (CRN) and correct positivity (Pc)—have not received similar attention. In particular, the extent to which these components are modulated by normal aging and individual differences is unknown. The present study addressed this issue using a modified flanker task, in which response and flanker compatibility were manipulated orthogonally. Building upon our previous work that included 66 cognitively normal older adults, additional data were collected from 8 older and 32 younger cognitively normal adults. Behaviorally, the effect of response compatibility was larger for older than younger adults on both RT (65.5 vs. 45.8 ms, p = .011) and accuracy (5.82 vs. 3.29%, p = .043). Linear mixed-effects analysis showed that the CRN and Pc were differentially modulated by age group. While the effect of flanker compatibility was larger for young than older adults on CRN amplitude (1.17 vs. -0.08 microvolts, p = .042), the effect of response compatibility was larger for older than younger adults on Pc amplitude (1.01 vs. -0.50 microvolts, p = .006). In addition, the Pc amplitude was positively associated with inhibition function measured using the Stroop Color-Word Test, but only for older adults. Taken together, our results suggest that older and younger adults tend to monitor for different types of conflict post-response, with such performance monitoring especially associated with inhibition function in older adults.