Distinct Brain Mechanisms for Conflict Adaptation Within and Across Conflict Types

Cognitive conflict, like other cognitive processes, shows the characteristic of adaptation, i.e., conflict effects are attenuated when immediately following a conflicting event, a phenomenon known as the conflict adaptation effect (CAE). One important aspect of CAE is its sensitivity to the intertrial coherence of conflict type, i.e., behavioral CAE occurs only if consecutive trials are of the same conflict type. Although reliably observed behaviorally, the neural mechanisms underlying such a phenomenon remains elusive. With a paradigm combining the classic Simon task and Stroop task, this fMRI study examined neural correlates of conflict adaptation both within and across conflict types. The results revealed that when the conflict type repeated (but not when it alternated), the CAE-like neural activations were observed in dorsal anterior cingulate cortex, inferior frontal gyrus, superior parietal lobe, etc. (i.e., regions within typical task-positive networks). In contrast, when the conflict type alternated (but not when it repeated), we found CAE-like neural deactivations in a range of regions including bilateral superior and medial frontal gyri, bilateral angular cortex, bilateral temporal cortices, etc. (i.e., regions within the typical task-negative network). Moreover, this CAE-like neural deactivation predicts behavior performance. Network analyses suggested that these regions (for CAE-like neural activities within and across conflict type[s] respectively) can be clustered into two antagonistic networks. This evidence suggests that our adaptation to cognitive conflicts within a conflict type and across different types may rely on these two distinct neural mechanisms.