Synaptic correlation with social behavioral changes in male mice

Abstract

Aggressive behavior is motivated by conflicts such as territory, food, and mate. However, males need be adaptive for the reproduction of their own pups. It is previously reported that the central part of the medial preoptic area (cMPOA) and the rhomboid nucleus of the bed nucleus of the stria terminalis (BSTrh) are involved in paternal and infanticidal behaviors, respectively. In this study, we demonstrate that this behavioral shift is mediated by synaptoplastic changes induced by social experience with a female partner and pups. The cMPOA was involved in the synaptic inhibition in the BSTrh, which was enhanced by parental experiences. In contrast, the excitatory–inhibitory balance of synaptic inputs from the medial amygdala (Me) to the cMPOA was shifted toward the excitation ahead of pup delivery. The optogenetic manipulation of the Me−cMPOA synapses promoted affiliative behavior toward pups. These findings provide possible neurocellular mechanisms for the inhibition of infanticide and the emergence of paternal behavior in mice.