Modelling the Dynamics of Phase-Amplitude-Coupling During Prairie Vole Social Bond Formation*

Forming and maintaining social interactions is key to many species' survival and fitness. An extreme example of social behavior is pair bonding in prairie voles (M. ochrogaster), where male and a female voles form a strong social attachment after mating. Recent experiments showed the importance of coupling between regions of the brain’s reward system in the formation of pair bonding, finding that the amplitude of the high frequency activity is modulated by the phase of low frequency inputs – known as phase-amplitude coupling (PAC). In cases where the input decreased with time, the voles tended to form stronger bonds, suggesting habit formation. To shed light on these findings we developed a model of the relevant circuit as an inhibitory network of leaky integrate-and-fire neurons driven by oscillatory input. We calculate the non-linear response of the network within a self-consistent mean-field theory. Our results confirm that the network exhibits PAC between the input and higher frequency activity, showing how the network can compensate for a reduction in the oscillatory input by increasing both the DC input component and the inhibition level. Finally, we predict how changing the physiological variables of the network may alter the behavior of the animal.