Dopamine and the Ontogeny of Sociosexual Behavior in Pair-living Marmosets

Résumé du livre

Social support is critical for health and well-being. Social dysfunction is associated with a host of physical and mental health deficits. Elucidating the neurobiological and environmental factors that influence the development and maintenance of enduring social bonds provides an important basis from which to assess dysregulation. Circuits using the neurotransmitter dopamine (DA) and its receptors have an established role in regulating relationships between mates in socially monogamous rodents. This dissertation examines the degree to which the neural reward system mediated by DA functions alone and in conjunction with the neuropeptide oxytocin to facilitate the development of social bonds between mates in marmoset monkeys. Marmosets display traits associated with social monogamy including high rates of affiliation, distress upon separation, and selective social preferences. Several of these behavioral patterns change throughout the development of relationships. We investigated the role of DA and length of cohabitation on social behavior in several social contexts (e.g., home environment, partner preference test, reunion) to assess if DA regulation of mate behavior is sensitive to social environment. Overall, we found that behavior between mates shifts over time -decrease in sexual behavior, with peaks of non-sexual affiliation occurring at 3-4 months of cohabitation. There is mixed evidence as to whether the effects of experimental manipulation of DA receptors remains constant across length of pairing. Manipulation of D2 receptors across different lengths of cohabitation revealed that they play a role in regulating social interest, as measured in a partner preference test. Distinct effects of D1 and D2 receptors were observed in reunion behavior of newly formed vs well-established pairs of marmosets, suggesting that both social context and cohabitation length interact in the way in which the DA system regulates behavior. Marmoset behavior was unaffected by manipulation of the oxytocin system across social environments. Overall, this series of studies provides evidence for the role of DA in regulating marmoset relationships and serves as foundational work for future studies to identify potential therapeutic DA-related targets for treating social dysfunction.