The interaction of Social Experience and Hormone Changes in Modifying Aggression

University Of Texas At Austin, Austin TX

Investigators

Abstract

This project investigates how social experiences involving aggressive interactions interact with stress to change how aggressively an individual responds in future social interactions. The project will first document how aggressive tendencies and stress responses change over repeated bouts of social aggression over several days. Changes in hormonal state during this period will also be documented. Experiments will then follow to test whether two hormones are important in regulating the changes in aggressive behavior that follow this experience. These hormones are the androgen sex steroid hormones (testosterone and dihydrotestosterone), and the stress steroid hormone corticosterone. The project will also use a neuroanatomical functional imaging technique, cytochrome oxidase histochemistry, to identify brain areas that change their metabolic, or functional, properties as a result of aggressive interactions and as a result of chronic changes in hormone levels. These neuroanatomical data will be correlated with the behavioral data to identify key brain changes that underlie the shift from less to more aggression and that differentiate dominant from subordinate status. The results from all parts of the project will ultimately be used to model the interrelationships of behavioral experience, hormone level, and brain metabolic profiles using a statistical technique called "structural equation modeling" in order to test hypotheses about causal interactions among all three classes of variables. The results of the project will provide new information about the factors leading to individual differences in aggression and other responses to social challenges.