PROJECT ABSTRACT Binge drinking during adolescence has been identified as a potential risk factor for alcohol use disorder (AUD) in adulthood. Despite this, the precise neuronal populations which are altered by adolescent drinking, and which may contribute to changes in adulthood drinking, have not been fully characterized. Somatostatin (SST)- expressing neurons in the prelimbic (PL) cortex are altered by adult binge drinking in animals models, and manipulating the activity of these neurons can reduce binge drinking. The goal of this proposal is to determine the role of SST neurons following adolescent binge drinking, as well as during escalated adulthood alcohol consumption following adolescent exposure. The first set of experiments will use whole-cell patch-clamp electrophysiology and fiber photometry to understand how adolescent alcohol use affects SST neurons in the PL cortex. The second set of experiments will use behavioral and chemogenetic manipulations to identify a causal role for SST neurons in changes in adulthood alcohol consumption after adolescent binge drinking.