Project Summary – Clinical Core (Core C) The proposed Clinical Core (Core C) will support project 4 of the Emory Udall Center in its studies of the inter- actions between the prefrontal cortex and the subthalamic nucleus (STN) in response inhibition functions in patients with Parkinson’s disease (PD) who undergo deep brain stimulation (DBS) lead implantation procedures targeting the STN. The prefrontal cortex plays a central role in PD-associated cognitive and behavioral changes, particularly in executive functions, such as response inhibition. The Core will provide coordinator services for the project 4 studies. In addition to research activity, documentation of completed assessments, and coordinat- ing the completion of detailed cognitive assessments, the Core focuses on patient recruitment and retention strategies. The Core will leverage the active DBS program at Emory to recruit well-characterized PD patients who are undertaking the DBS selection process (Aim 1), with the goal of recruiting 40 such patients for pre- operative assessments, including detailed neuropsychological testing and motor evaluations in addition to the testing during response inhibition tasks that will be done under project 4. Recruitment activities will include various advertising strategies through flyers distributed in the clinic, web and social media advertising, as well as public presentations. Of the recruited PD patients, 15 will also be tested in the OR during DBS lead implan- tation, and 20 will have a repeat outpatient assessment 6-12 months post-surgery. In addition, the Core will recruit 40 well-characterized age- and sex-matched healthy controls through a collaboration with various existing sources, including the Clinical Core of the Emory Alzheimer’s Disease Research Center (ADRC), and the Emory Healthy Brain Study (Aim 2). These individuals will undergo the same series of tests as the PD cohort at visit 1. To ensure continuity, all neuropsychological assessments will be overseen by one of the Udall Center’s Co-Is who also functions as co-leader of the ADRC clinical core. The Core will communicate the results of individual and group test results to all study participants. Finally, the Core will develop and maintain a REDCap database of data collected in project 4 (Aim 3).