Neuronal Nuclei That Are Activated After an Offensive Encounter in Female Djungarian Hamster (Phodopus campbelli)

Abstract

Neural bases of aggression have been analysed mainly in rodent males, finding that the medial preoptic area (mPOA), bed nucleus of the stria terminalis (BNST) ventromedial hypothalamus (VMH), anterior hypothalamus (AHN), and medial amygdala (MeA) integrate the core aggression circuit. The neural regulation of territorial aggression in females has been little explored, despite the fact they can be as territorial as males. In this study using the c-Fos protein as a marker of neural activity, we analysed whether mPOA, BNST, AHN, VMH, and MeA are activated after an aggressive encounter in the female Djungarian hamster (Phodopus campbelli). Twenty females and 20 males were paired for 15 days. Mating was used as a factor in induced territoriality. The couples were organized into two groups with 10 couples each; in 10 of these pairs, females were subjected to resident intruder tests, while in the other 10 pairs, the females were not confronted. Before mating the males of both groups were vasectomized to prevent that their partners from becoming pregnant. This was done to separate territorial aggression from maternal aggression. All females Djungarian hamster subjected to resident intruder tests displayed territorial aggression. The results of this study showed that mPOA, BNST, VMH, AHN, and MeA were activated in confronted females of Djungarian hamster. In male rodents, these neuronal nuclei are also activated after confrontation, supporting the hypothesis that there is a homology at the neural level in the regulation of aggressive behavior between males and females.