Dissociable neural circuits underlie the resolution of three discrete sources of competition during task-switching.

Abstract

Humans perform sub-optimally when juggling more than one task, but are nonetheless required to multitask during many daily activities. Rapidly and effectively switching attentional focus between tasks is fundamental to navigating complex environments. Task-switching paradigms in conjunction with neuroimaging have identified brain networks underpinning flexible reallocation of cognitive resources and a core network of neural regions is repeatedly implicated (i.e., posterior parietal, inferior frontal, anterior cingulate, and middle frontal cortex). Performance costs such as reduced accuracy and slowed responses accompany the first execution of a task following a task-switch. These costs stem from three main sources of competition: 1) the need to reconfigure task-rules, 2) the immediate history of motor responding, and 3) whether inputs to be acted upon provide congruent or incongruent information regarding the appropriate motor response, relative to the recently \"switched-away-from\" task. Here, we asked whether both common (domain-general) and non-overlapping (dissociable) neural circuits were involved in resolving these three distinct sources of competition under high-demand task-switching conditions. Dissociable neural circuits were active in resolving each of the three sources of competition. No domain-general regions were implicated in all three. Rather, two regions were common across rule-switching and stimulus incongruence, and five regions to incongruence and response-switching. Each source of conflict elicited activation from many regions including the posterior cingulate, thalamus, and cerebellum, regions not commonly implicated in the task-switching literature. These results suggest that dissociable neural networks are principally responsible for resolving different sources of competition, but with partial interaction of some overlapping domain-general circuitry.