Zachary Westrick L&S Sciences
Parietal TMS with stop signal task to dissociate models of inhibition during action selection
My experiment examines two possible models of how the brain determines which arm to use during reaching movements. Under the non-competitive model, the motor areas in each hemisphere formulate a plan and race until one has reached some threshold level of activation for movement, while the competitive model has the two hemispheres race while sending inhibitory signals to each other. I’ll be giving subjects a simple reaching task in which they must respond to cues on a screen, but occasionally withhold their movement in response to a later stop cue. While this is ongoing, I will be intermittently applying TMS, or Transcranial Magnetic Stimulation, to a region on the parietal lobe. TMS at the frequencies I will be using induces a temporary disruption of local functions, resulting in a virtual lesion of the affected area. The two models make different predictions about how these virtual lesions should affect one’s ability to inhibit movements after the stop cue, so hopefully this experiment will shed light on what is going on during these sorts of movement.