Fig. 1: Timeline of the experiments.

Two independent experiments were carried out in the present study that involved forty-eight male Sprague Dawley rats each. After 1 week of habituation to the animal facility, rats involved in the first experiment received intra-accumbens shell (NacS) infusion of a retrograde CAV2-GFP virus under stereotaxic surgery and were left undisturbed for at least one week. Rats from both experiments were progressively food restricted to 80% of their theoretical free-feeding body weight. Then, following two sessions of habituation to the SIP context during which their regulatory water intake was measured, rats were trained under a Fixed time (FT) 60s Scheduled-Induced polydipsia (SIP) procedure for 21 1 h daily sessions. High drinkers (HD) and Low drinkers (LD) rats were selected in the upper and lower quartile of the population, respectively, based on their average water intake during the last 3 sessions. Ninety minutes after the last SIP session, rats from experiment 1 underwent a blood collection prior to being perfused transcardiacally in order for their brains to be processed for immunofluorescence. In contrast, rats from experiment 2 were sacrificed forty-five minutes after a 60 min challenge session with or without the opportunity to express their adjunctive behaviour, and their fresh brains were harvested and properly stored subsequently to be used for RNAscope assays. Exp. experiment. Cort. corticosterone.