Prairie voles (Microtus ochrogaster) exhibit a constellation of traits associated with a monogamous social organization including the formation of pair bonds between males and females. Among characteristics of pair bonding are preferences for a familiar partner, usually of the opposite sex. Preliminary data indicate that in male prairie voles corticosterone treatment produces a dose-dependent increase in the preference for a familiar female partner; in contrast in females it appears that treatment with corticosterone inhibits partner preference formation. Conversely adrenalectomy, which eliminates corticosterone secretion, reduces pair bonding in males and facilitates pair bond formation in females. In the proposed research, this investigator will: (1) examine the behavioral and endocrine parameters associated with the behavioral effects of corticosterone. These studies will document the amount of stimulation necessary to form a clear partner preference in males versus females. Concurrently, she will (2) examine the time course of changes in endogenous corticosterone titers following exposure to a member of the opposite sex. In addition, she will (3) continue her studies of the behavioral effects of corticosterone to determine dose response curves for the above behavioral changes. Finally, she will (4) compare the behavioral effects of exogenous corticosterone to those of a stress-induced release of corticosterone. The results of this research will contribute to our understanding of the physiology of social attachment and social organization. The existence of social bonds is widely accepted, but we know relatively little - especially in adults - about the factors that regulate the formation of social attachments.
