Figure 1

Experimental timeline. Female Sprague–Dawley rats received ethanol administration across the adolescent period, from postnatal day (P) 25 to P54 on a 2-days-on / 2-days-off schedule. After this period no additional ethanol was administered. Starting around P70, a total of 20 Pavlovian condition approach (PCA) training sessions were performed. Each PCA session consisted of 15 trials where a 30-s (s) conditioned stimulus (CS, cue light/lever extension) was presented, followed by the US presentation (0.1 ml of a 20% sucrose solution) immediately after the CS offset. After the training phase, a stereotaxic surgery procedure was performed for electrode array implantation in the OFC and NAc, followed by 7 days of recovery. At least 5 additional PCA sessions occurred after the surgery recovery in order to habituate the animals to the electrophysiological recording procedure. Next, to evaluate possible AIE-induced effects on neuronal activity, single-unit recordings in OFC and NAc were performed during a regular PCA session (baseline) followed by a reward omission session. During the reward omission session, all 15 trials were performed similarly to the baseline session, with one important exception: after the 30-s CS, no reward solution was delivered in the reward receptacle. In the figure, the colored drop illustrates the US presentation during PCA session and the gray dotted drop represents the reward omission session. For more details, see methods.