The role of neural excitability and coupling in the formation of social bonds

Social behavior is an important aspect of life for humans and many other animals. Yet, our understanding of the biological mechanisms giving rise to it is limited. Although extensive research has been done on the neural basis of social impairment, few studies have attempted to explain the formation of positive behaviors. Here, we report results on the mechanisms responsible for a positive social behavior, pair bonding in prarie voles (Microtus ochrogaster). Key brain areas in this process are the medial prefrontal cortex (mPFC) and the nucleus accumbens (NAcc). It was shown that the phase-amplitude-coupling (PAC) between mPFC drive to NAcc is pivotal for the formation of a bond in a voles pair. Experimental measurements from NAcc suggest non-trivial relations between the input to the network and the resulting PAC features. Using simulations and analytical methods we study the emerging coupling in networks of model neurons driven by oscillatory input. Our results show that changes in the input to the network and in the excitability of the neurons play an important role in the bond formation process. Furthermore, our results suggest the role of oxytocin, a neurotransmitter often associated with social behavior, in pair bonding is to modulate the excitability of certain neurons.