Project Summary/Abstract This COBRE project aims to delineate and modulate the response inhibition network in young adults with a range of inhibitory control (IC). Inhibitory control is impaired in a va riety of clinical disorders, including substance abuse, OCD, and ADHD. Def icits in response inhibition are likely related to development of certain clinical disorders, poor treatment response, and relapse to a symptomatic state. T he goals of the proposed study are to 1) characterize the neurocircuitry of the IC network (right inferior frontal gyrus (IFG), pre-supplementary motor area (pSMA), subthalamic nucleus (STN)) in healthy young adults with a range of scores on a widely-used clinical measure of inhibitory control (BRIEF-A Inhibit subscale) using task-based (stop signal task) functional neuroimaging, 2) modulate the IC network through 2.0 mA anodal HD-tDCS to the right IFG, and 3) test the hypothesis that the functional state of the IFG and the related IC network is related to SST performance. Using a symptom-targeted approach as detailed in this proposal will lay the groundwork for personalization of treatment. In this case, there are a variety of disorders in which inhibitory failure is common, and there is tentative evidence that these disorders may share underlying pathophysiology in relevant neurocircuits. Ultimately, greater understanding of this neurocircuitry may lead to new and improved more individualized neurocircuit-based treatments based on common phenotypic presentations rather than on our relatively unspecific diagnostic categorizations.