This research examines the neural mechanisms underlying action inhibition, which is the cancellation of an initiated motor response. Healthy adults exhibit flexible motor behavior whereas adults with Parkinson’s disease (PD) experience difficulty inhibiting action. In particular, PD patients demonstrate a specific deficit turning off muscle activity. The goal of this grant is to develop a clear understanding about how brain activity, brain connectivity, and cognitive function are related to the cancellation of an initiated motor response in health and PD. Such knowledge facilitates the development of surgical and pharmaceutical interventions that target specific cortical and subcortical areas related to stopping motor output. The outcomes of this research will motivate the next phase of Dr. Neely’s research program, which is to understand how antiparkinson treatments such as deep brain stimulation and dopamine agonists alter the neural mechanisms underlying action inhibition.