Project Summary Alcohol abstinence is a key feature of the drinking experience, and relapse – by definition – is shifting from an abstained state to consumption. Many questions remain unanswered in the literature regarding the physiological mechanisms and neural signatures of abstinence, and understanding these substrates will be essential for developing prevention and treatment studies for Alcohol Use Disorders (AUD). The focus of the F99/K00 proposal is an investigation of central and autonomic nervous system effects associated with alcohol abstinence – in essence, how the brain responds to a period of imposed abstinence and how autonomic function impacts those responses. Before we can understand how neural processes associated with abstinence contribute to relapse in AUD patients, we need to understand what comprises a typical response, and the range of potential responses in otherwise healthy drinkers. Typically, physiological research examining alcohol drinkers focuses solely on brain function, discounting the interplay between central and peripheral nervous system measures. This study examining autonomic nervous system function, through the peripheral metric Heart Rate Variability (HRV), in addition to examine differences in functional brain network organization in everyday drinkers during a period of typical alcohol consumption and a period of abstinence. By examining the relationship between these central and peripheral measures, this study aims to capture a more complete understanding of the neurobiology associated with alcohol abstinence. At the time of this submission, the applicant, under the guidance of the sponsor, has completed all research design and data collection relevant to the study. Still remaining are analyses investigating the relationship between HRV and functional brain network connectivity during alcohol cue exposure following abstinence (F99 Phase), which will require hands‐on and didactic training analyzing HRV and brain network data. Following the completion of the F99 portion of this proposed project, the study will be expanded during a postdoctoral following to include more advanced analyses of brain network and HRV dynamics (K00 Phase).