Experimental design
BL/6 mice (n=45) were infused bilaterally in NAc with the retrograde neuronal tracer, recombinant cholera toxin subunit β conjugated with Alexa FluorTM 555 (CTB-555, Invitrogen); 300 nL of 1 mg/mL were injected per NAc. At 14 days post-surgery, mice were single-caged and, after a further 3-4 days, assigned at random to the following stimulus groups: social reward (SR, n=12), social aversion (SA, n=12), aversive odour (AO, n=7), and no stimulus (No S, n=14). Directly after completion of the 90-min stimulus test, mice were deeply anaesthetized and transcardially perfused-fixed. The brains were further processed for c-Fos immunohistochemistry and quantification of CTB+, c-Fos+ and CTB+/c-Fos+ neurons across the AP and ML extents of the BA.