Driving oscillatory activity in the human response inhibition network to reveal the critical role of the brain areas contributing to motor inhibition

The ability to inhibit responses is an essential and fundamental component of cognitive control over action. The pre-supplementary motor area (preSMA), right inferior frontal cortex (rIFC) and subthalamic nucleus (STN) have been identified as the key nodes in the brain network supporting response inhibition, but their relative position within the network and functional role in stopping are still unclear. Furthermore, not much is known about the communication within this network. Intracranial recordings in humans revealed increased beta oscillations (15-30 Hz) in preSMA, rIFC and STN during successful stopping. To investigate the causal role of these regions in response inhibition and their temporal dynamics we propose two innovative studies. In the first phase we will use transcranial alternating current stimulation (tACS) to entrain beta frequency oscillations in preSMA and rIFC during a stop signal task. If one region is more crucial for stopping than the other, beta band stimulation of that region during stop signal trials is expected to have a larger beneficial effect on behavior, than stimulation of the other. In the second phase we will record local field potential activity from the STN of Parkinson’s disease patients with implanted deep brain stimulation electrodes during cortical beta band frequency tACS. With this design we want to gain insight into cortico-subcortical interactions during stopping and how cortical stimulation modulates these interactions.