This project will investigate the mechanisms that create behavioral differences in responsiveness to testosterone. These differences exist at multiple levels even in a single species, including behavioral function, the size of muscles, and parts of the nervous system that generate the behaviors. For example, in green anole lizards, this hormone facilitates reproductive behaviors in males more so than in females, and within males to a greater degree in the breeding than during the non-breeding season. Testosterone also increases the sizes of some reproductive structures, but not others, and among those it affects, the response is greatest during the breeding season. Experiments are designed to test the ideas that these differences in anatomy and behavior are due to one or more specific factors, including the availability of a priming hormone, estradiol, in the brain, and the expression of one or more of four specific genes. Thus, behavioral, anatomical, hormonal and molecular approaches are used to enhance the understanding of what determines whether and to what degree a hormone will act. This work will provide novel information on this basic biological phenomenon, which is not yet sufficiently understood, in part because the lizards to be used provide a uniquely large set of structures and functions across which the information can be carefully integrated. Since very little work of this kind is conducted in reptiles, it will also provide a new comparative, evolutionary perspective. The research is conducted by students at multiple career stages: undergraduates, graduate students and postdoctoral students, under direct mentorship of the Principal Investigator. At present, all of these individuals are women, thus impacting future generations of scientists and these woman, in turn, will be role models for other women in the neurosciences.
