ZENK immunoreactivity across the brain regions investigated in the three groups of females (paired females exposed to novel males or their partner, and unpaired females exposed to novel males). A main effect of region was detected; the density of calls was highest in the Ac and BST. A main effect of group and interaction between group and region were not detected. Abbreviations: caudomedial nidopallium (NCM), caudomedial mesopallium (CMM), preoptic area (POA), ventromedial hypothalamus (VMH), nucleus accumbens (Ac), nucleus taeniae (TnA), bed nucleus of the stria terminalis (BST), ventral tegmental area (VTA).