Figure 1. Experiment design schematics.

Experiment schedule (A). Male and female Brown Norway (BN) Rats’ PRLT & PRBT performance was first assessed at baseline with no injections. Cohorts were counter-balanced into 4 groups to receive vehicle or OT (0.04, 0.2, or 1 mg/kg). Rats were then tested following acute and chronic (21 day) administration of OT. No injections were administered during the acute and chronic withdrawal phases of the study (D22-D28). Injections were administered 30 minutes prior to testing on each day of the study. On non-PRLT/PRBT days, rats were tested in the FR1 training module. Performance was compared with that of male and female Long Evans rats, which received vehicle injections throughout. Schematic of PRLT (B). At the beginning of each trial, rats nose poked in one of two lit apertures and were either rewarded with strawberry milkshake (~40 μL) delivered into the magazine or punished with a 4 second timeout and house light illumination. Rates of reward/punishment differed between the two stimuli, whereby target stimulus responses resulted in an 80% chance of reward and 20% chance of punishment, while the inverse was true for responses to the non-target stimulus. Following 8 consecutive target responses, the reward ratios of the two stimuli switched. Schematic of PRBT (C). Rats were rewarded after making a number of responses to a single stimulus. The number of responses required for a reward increased as a function of trial number. PRLT: Probabilistic Reversal Learning Task; PRBT: Progressive Ratio Breakpoint Task; FR1: FR1 training module; OT: Oxytocin