Abstract
Goal-directed actions are initiated to bring about desired effects. Bidirectional associations exist between actions and their movement-contingent perceptual events. Action-effect (A-E) associations may be used by actors to facilitate the production of related goal-directed actions. Specifically, evidence suggests that the presentation of an effect prior to the execution of an action will decrease the reaction time (RT) and increase the frequency that the actor executes the response associated with that effect. The current experiment investigated whether a single TMS pulse (over right primary motor cortex (M1)) following the presentation of an A-E would influence the expression of that A-E relationship. Participants completed pre/post-acquisition test blocks where they were instructed to choose one of two key presses, each of which was associated with a specific auditory stimulus. Test blocks were separated by a 200 trial (no TMS) acquisition block designed to establish two A-E associations. If the increased level of M1 excitation induced by TMS elevated the expression of an A-E association, a greater preference for compatible responses and shorter RTs could be expected in the stimulated hand compared to the non-stimulated hand in the post-test task. These effects were not observed - there were no between-hand differences in RT or response frequency in compatible trials. The finding that the TMS pulse had no effect on A-E expression suggests that these bindings may be coded upstream from M1.Acknowledgments: This research was supported by Discovery Grants from the Natural Sciences and Engineering Research Council of Canada (to T.N.W.) and an Early Researcher Award from the Ontario Ministry of Research and Innovation (to T.N.W.).