Poster E32, Monday, March 26, 2:30-4:30 pm, Exhibit Hall C
Effect of reward prospect on corticospinal excitability during task preparation is dependent on task and action requirements.
Carsten Bundt1, Marcel Brass1, Wim Notebaert1; 1Ghent University
Action preparation is associated with corticospinal excitability (CSE) changes that vary depending on individuals’ motivation, but it is unknown whether such motivational effect is contingent upon task and action requirements. In three different experiments, we investigated the effect of task and action requirements on reward-related CSE. In each experiment, a (non-) reward cue was presented, indicating whether accurate performance on the current trial would lead to reward (+1) or not (+0). After a delay period, a Simon (Exp. 1) or Stroop (Exp. 2) stimulus followed, requiring individuals to provide a left or right index finger response. During the delay period, we applied transcranial magnetic stimulation over the left primary motor cortex and concurrently recorded electromyography from the right first dorsal interosseous to measure CSE. Results showed that reward yielded an early increase and a subsequent transient decrease of CSE compared to non-reward in the Simon task (Exp. 1), but not in the Stroop task (Exp. 2), suggesting that the effect of reward on CSE depends on the task at hand. In Exp. 3, prior to the presentation of a (non-) reward cue, individuals were additionally informed whether (Go) or not (NoGo) an actual response had to be performed upon target presentation. We observed that reward modulated CSE for Go trials but not for NoGo trials, suggesting that the effect of reward on CSE is contingent upon the preparation of an actual response. These findings suggest that motivational effects on CSE depend on a complex interplay of task and action requirements.
Topic Area: EXECUTIVE PROCESSES: Monitoring & inhibitory control