Director of the Neuroscience Institute
Office: 884 Petit Science Center
Phone: (404) 413-6307
Postdoctoral Training: Cornell University
Joint Appointment with the Psychology Department
Research in my laboratory is in the area of neuroethology, the study of the neural basis of natural behavior. We focus on the neural and endocrine systems underlying animal communication and the role of communication signals in aggressive interactions and reproductive behavior. Research in my lab is multidisciplinary, using combinations of neuroanatomical, neuroendocrinological, neurophysiological, or behavioral techniques to gain a more complete understanding of the neural mechanisms underlying social behavior and its evolution.
The acoustic communication system of frogs and toads is a model for investigating the neural and hormonal mechanisms of animal communication. As in many other systems, the vocal exchanges between frogs are part of the seasonal social behavior associated with breeding and have mate attraction and aggressive functions. We are engaged in studying the reciprocal interactions between communication behavior and hormonal systems mediated through hypothalamic centers of the brain. This entails understanding two interacting aspects of the system: How are features of the communication behavior (vocal production, behavioral responses to the calls) controlled by hormones; and, how does the reception of communication signals modify hormonal state? Furthermore, what are the neural systems that control, and are in turn modified by, these behavioral and hormonal processes? For this project, studies in the lab are aimed at identifying the anatomy and physiology of central nervous system pathways that link the auditory system with the limbic areas controlling endocrine release and in assessing the plasticity in those systems. These studies complement behavioral work focused on the seasonal and hormonal regulation of female mate choice behavior and male vocalization.
Individuals vary greatly in their aggressiveness. This is due to a variety of interacting factors, including hormonal state and past experience. We are investigating these interacting factors in order to better understand how experience and hormonal state mutually influence each other, and how both contribute to influencing the limbic centers of the brain as these centers control aggression and other types of social behavior. The green anole lizard (Anolis carolinensis) is the model animal for this project. On the behavioral side, research focuses on the plasticity in aggression displayed by males as they interact with familiar and unfamiliar challengers. Endocrinological assessments have shown that both androgens and stress hormones change during successive aggressive interactions along with the behavioral modification. Current work investigates the possibility that the hormonal changes triggered by the aggressive interactions are important for the behavioral changes that occur with aggressive experience. Research in this area also targets possible sites of neural plasticity that might underlie the behavioral plasticity that aggressive social interactions cause. For example, we have used histochemical staining for the enzyme cytochrome oxidase as an anatomical marker of functional differences in limbic system brain regions as a result of social status (dominant or subordinate) or as a result of repeated aggression interactions with another individual.