Other features of the task may also account for discrepancies between our results and the existing literature. Many of the studies that report minimal changes in conflict monitoring with ACC disruption employ choice-based paradigms where subjects must adapt their behavior based on changes in the reward probabilities associated with different actions (26, 28, 29). On these choice-based tasks, errors stem from subjects’ inability to correctly detect and/or represent changes in reward value. In our task both GO and STOP trials are equally rewarded, and errors in performance stem from a failure to follow cues, rather than from a miscalculation of the likelihood of reward. While both forms of error could be argued to represent a failure in conflict monitoring, the latter would appear to rely more heavily on the subject’s perception of reward value, which may impact the “type” or severity of conflict that arises, thus potentially impacting the degree of ACC involvement.
