Nucleus Accumbens Dopamine Release Reflects the Selective Nature of Pair Bonds

In monogamous species, prosocial behaviors directed towards partners are dramatically different from those directed towards unknown individuals and potential threats. Dopamine release in the nucleus accumbens plays an important role in guiding social behavior, however, its role in real time social decision making in a monogamous species remains largely unknown. We used monogamous prairie voles to investigate how dopamine release differs in voles when seeking and interacting with a pair bonded partner or a novel vole. Employing the sub-second temporal resolution of the fluorescent biosensor, GRABDA, during a social operant task, we found that partner seeking, anticipation, and interaction resulted in more dopamine release than the same events directed towards a novel vole. Furthermore, partner-elicited dopamine release decreases after prolonged partner separation. Thus, differences in partner- and novel-elicited dopamine release reflect the selective nature of pair bonds and may drive the social behaviors that reinforce and cement bonds over time, eroding after partner loss to facilitate new bond formation.