Investigating the Cognitive Components of Direct and Indirect Pathway Activity in Dorsomedial Striatum during Decision Making

Abstract

Decision making is a skill needed by all animals. Although the basal ganglia has been implicated in decision making, it is not clear how specific pathways contribute. We investigated the roles of the direct and indirect pathways in the decision making process using optogenetic inhibition during a thoughtfully designed behavioral paradigm. Mice participated in three versions of a virtual reality T-maze decision making task, in which they relied on various permutations of the following three processes: evidence accumulation, memory retention, and execution of motor outputs—with and without laser inhibition of direct and indirect pathways in dorsomedial striatum (DMS). We found that direct and indirect pathway inhibition during tasks that did not require evidence accumulation did not induce any performance bias. For the memory guided task, which did require the process of evidence accumulation for successful completion, however, unilateral direct and indirect pathway inhibition produced significant lateralized biases. Our results support the finding that the direct and indirect pathways in DMS produce contralateral and ipsilateral biases during decision making, respectively, and play a principal role in the cognitive process of evidence accumulation.