Dopamine and the positively reinforcing properties of aggression

Abstract

DOPAMINE AND THE POSITIVELY REINFORCING PROPERTIES OF AGGRESSION

MARIA H. COUPPIS

Dissertation under the direction of Professor Craig H. Kennedy Aggression is a necessary behavioral response aimed at securing survival. However, when aggressive topographies exceed species typical norms, they become pathological and problematic to society. It has been hypothesized that aggression may be positively reinforcing and that these positively reinforcing characteristics are modulated by mesocorticolimbic dopamine systems. In order to gain a more comprehensive understanding of the rewarding properties of aggression and their biological substrates, a series of experiments were conducted to address the questions: 1) Is aggression positively reinforcing? If so, what part of the aggressive encounter serves as the positively reinforcing event? 2) Do DA1/5 and/or DA2/3 receptors in the NAC mediate access to aggression as positive reinforcement in mice? and 3) Are there any endogenous differences between aggressive and non-aggressive individuals? It was concluded from these experiments that physical aggression can be positively reinforcing, that these positively reinforcing properties are modulated by mesocorticolimbic dopamine and that there are endogenous differences in mesocorticolimbic dopamine systems between aggressive and non-aggressive individuals.