Alcohol abstinence precipitates alcohol seeking and aversion-resistant intake in association with increased BNST activity.

Alcohol Use Disorder (AUD) is defined by a common diagnostic framework, yet individuals show diverse drinking patterns and relapse vulnerabilities during abstinence, reflecting neurobiological heterogeneity. The bed nucleus of the stria terminalis (BNST) is well positioned to contribute to this variability. To understand how BNST activity co-segregates with individual alcohol behavior trajectories, we used the Structured Tracking of Alcohol Reinforcement (STAR) operant task to phenotype C57BL/6J mice as high, low, or aversion-resistant ethanol drinkers. During initial self-administration, dBNST cFos+ counts correlated with intake, linking dBNST activation to operant drinking. Using in vivo fiber photometry, we found that aversion-resistant drinkers displayed elevated dBNST calcium transients during drinking bouts despite similar intake across groups, consistent with heightened dBNST recruitment. Forced abstinence uncovered prominent phenotype-specific adaptations, where ethanol seeking during protracted, but not early, abstinence predicted aversion-resistant intake. High and low drinkers reduced seeking behavior across abstinence, whereas aversion-resistant drinkers persisted. Consistently, dBNST calcium transients increased during protracted abstinence seeking only in aversion-resistant drinkers, highlighting phenotype-specific plasticity. Comparing mice exposed to abstinence versus only operant training showed that abstinence itself potentiates aversion-resistant intake. Finally, these dBNST dynamics were ethanol-specific, as saccharin drinking more closely reflected activity for high drinkers. Together, these findings reveal that ethanol abstinence precipitates ethanol seeking and aversion-resistant intake, associated with phenotypic dBNST calcium dynamics. Because causality was not established, future studies are needed to define mechanistic contributions of dBNST activity to phenotypic behaviors. By uncovering how dBNST activity adapts in aversion-resistant drinkers, this work offers insight into AUD heterogeneity.