Electrophysiological evidence for flexible adjustments in cognitive control depending on feedback's contingency.

Cognitive control is a fundamental ability that enables to detect and resolve conflict. However, this ability is not encapsulated but liable to learning and motivational factors. Among them, previous studies have shown that the contingency created between conflict and performance by means of feedback, as well as its actual motivational value, influenced the behavioral manifestations of cognitive control. In this EEG study, we sought to shed light on the brain mechanisms underlying this modulation. To this end, fifty-eight participants performed the confound-minimized Stroop task wherein either congruent (i.e., no-conflict) or incongruent trials (i.e., conflict) were selectively reinforced by a performance feedback at the block level. Moreover, this feedback was either negative or neutral. At the behavioral results, we replicated previous results showing that conflict adaptation slightly improved when congruent trials were reinforced, while the reinforcement of incongruent trials led to a reduction of the congruency effect instead. Interestingly, at the EEG level, we found that this dissociation was captured by different event-related potentials (ERPs, as well as frontal alpha), but not mid-frontal theta (MFT), which was increased by conflict and performance feedback throughout. When incongruent trials were reinforced by the feedback, mostly the stimulus-locked N450 and the preceding occipital P1 component changed. In comparison, when congruent trials were selectively reinforced, the feedback-locked P3 component was altered. These findings suggest that depending on the specific contingency created between conflict and performance feedback, either stimulus or feedback-locked brain processes guide the implementation of cognitive control.