Physiological Bases for Long Term Effects of Winning

University Of Wisconsin-Madison, Madison WI

Investigators

Abstract

. LAY ABSTRACT Understanding how past experience shapes future behavior is one of the fundamental challenges for modern animal behavior and neurobiology. Meeting this challenge will require characterization of physiological changes triggered by experiences known to influence specific behaviors, such as aggression during male-male encounters. Two factors have been shown to critically influence the intensity of aggression expressed in an encounter: 1) the outcomes of previous encounters, whether won or lost, and 2) the location of the encounter, whether familiar or unfamiliar. It is the goal of the proposed work to examine the physiological components that contribute to the effect winning has on future encounters (winner effect), as well as those components that contribute to aggression associated with familiarity with the encounter location. Specifically, the function of observed changes in testosterone after competitive interactions will be evaluated. In addition, neurochemical changes that occur in response to transient changes in testosterone will be documented. To begin examining the role of site familiarity in the intensity of aggression, comparisons will be made between resident-intruder aggression (site-specific aggression) and neutral aggression (aggression in a neutral arena). It is predicted that the neurochemical vasopressin will be more closely associated with resident-intruder aggression than neutral aggression. The monogamous, highly parental Peromyscus californicus (California mouse), and the promiscuous, less parental P. leucopus (white-footed mouse) will be developed as model systems for this analysis of interactions between experience and intensity of aggression. Information obtained in these studies may provide insight into some of the physiological mechanisms underlying plasticity in the intensity of aggression in mammals.