eLife Assessment
This study presents valuable evidence of sex differences in oxycodone relapse-related behavior in rats and provides insight into associated synaptic plasticity in the paraventricular thalamus to the nucleus accumbens shell (PVT-NAcSh) circuit. The report reveals that females show heightened cue-induced oxycodone seeking compared to males after 14 days – but not 1 day – of abstinence; however, an increase in synaptic strength from the PVT inputs to the NAcSh was observed in both males and females at 14 days of abstinence. Therefore, whereas the behavioral data and much of the electrophysiology data are solid, the link between them is incomplete. Further investigation of the functional role of the PVT-NAcSh pathway in the observed sex differences in oxycodone relapse and examination of input and cell-type specificity of synaptic alterations would greatly strengthen this study.