Do tasks matter in task switching? Dissociating domain-general from context-specific brain activity

Throughout the past decade, the task-switching paradigm has been used extensively as a tool to delineate the neural mechanisms underlying flexible and goal-directed action control. Yet, given a large number of experimental procedures, the task-switching literature has yielded considerable inconsistencies calling for a systematic evaluation of the impact of methodological parameters. In the present study, we examine a fundamental and implicit assumption that has guided previous research on task switching. Does switch-related brain activation (i.e., the contrast between preparatory activity on switch versus repetition trials) reflect abstract cognitive control processes that are independent of specific task demands, and thus equivalent across different types of tasks? To answer this question, we compared the data of two fMRI studies that examined updating of task goals and/or stimulus-response mappings under almost identical protocols, but using entirely different tasks. In line with an abstract control process view, our results show that the vast majority of switch-related brain activity is insensitive to the context in which it occurs. The only region that exhibited a reliable contextual modulation was the anterior cingulate cortex, indicating that its contribution to preparatory adjustments might be linked to specific task demands. (C) 2014 Elsevier Inc. All rights reserved.