Single photon fluorescence calcium imaging of prefrontal cortex in freely behaving mouse during social interaction

Abstract

Social interaction is a complex behavior essential for survival of many species. Pioneering research has uncovered evidence for certain brain regions involving the prefrontal cortex (PFC) in mediating sexual and aggressive behaviors, but relatively few studies have explored the brain circuitry underlying same-sex, nonaggressive interaction. Furthermore, due to the inherent complexity of social behavior itself and the interconnected nature of the underlying brain regions, it is yet unclear how and if different subpopulations of PFC neurons contribute differently to driving or inhibiting social behaviors. Therefore, we designed an experiment to dissect the neural circuitry modulating social behavior using single-photon fluorescence calcium imaging of PFC in freely behaving male mice during interaction with another male conspecific. Specifically, we imaged a subpopulation of PFC projecting to the ventral tegmental area (VTA), the area which has been broadly implicated to participate in mediating social behavior. By analyzing spatial receptive fields of the VTA-projecting PFC neurons, we identified a subset of neurons with significant social and spatial responses that resembles a previously discovered social-spatial association learning in a different subpopulation of PFC projecting to the nucleus accumbens (NAc). Interestingly, however, differences between the two subpopulations were observed; VTA-projecting PFC neurons were revealed to have weaker social responses but a trend towards stronger modulation of velocity compared to the NAc-projecting PFC neurons. These results stronlgy support distinct roles within PFC in driving social behavior.