Motivation modulates motor-related feedback activity in the human basal ganglia

SummaryIt is axiomatic that motivation improves learning, a principle repeatedly stressed both in the classroom and on the sports field. Motivation's influence over learning can be considered twofold: a general arousing or energising effect, and a more goal-specific component [1]. Recent developments in reward theory suggest that the latter may be achieved through the increased weighting of ‘teaching signals’ computed from feedback related to the success of a given course of action, so that the respective action may be re-inforced. This view has received experimental support in the context of explicit choices between actions [2], but whether it is relevant to the trial-to-trial learning of a single action, such as a tennis return, remains unclear. We previously showed the existence of an evoked activity in the basal ganglia that correlates with accuracy of performance in a simple task and is associated with reiteration of successful motor parameters in subsequent movements [3]. Here we establish that motivation increases the amplitude of this evoked activity for a given trial accuracy, thus promoting trial-to-trial learning