In order to learn how hormones act in the brain to modify brain function and behavior and how the social environment can influences these processes, we study the cellular and neuroanatomical mechanisms of ovarian steroid hormone action on reproductive behavior and the interactions between the environment, neurotransmitters and steroid hormone receptors.
Although much of our work has focused on the neural mechanisms by which the ovarian hormones, estradiol and progesterone, influence the expression of reproductive behaviors, a new interest of our group is the study of the long-term effects of exposure to particular stressors or immune challenges around the time of puberty on behavioral response to the hormones in adulthood. We have discovered that exposure to particular stressors, but not others, or immune challenge, only during the pubertal period causes enduring changes in behavioral response to ovarian steroid hormones in adulthood months later. In an effort to determine how wide-spread this phenomenon is, we have determined that, besides reproductive behavior, the effects of ovarian hormones on anxiety-like, depression-like and cognitive behaviors in adulthood are either blocked, or in some cases reversed, by stressor exposure during the pubertal period. We have observed long-term changes in levels of steroid hormone receptors in particular neuroanatomical areas in adulthood in response to these pubertal treatments, suggesting that this altered regulation of the receptors is part of the mechanism by which the stressors cause changes in behavioral response to the hormones. Our current work focuses on the mechanisms by which some stressors during a well-delineated developmental stage cause enduring changes in ovarian hormone receptors and consequently in an animal's response to the hormones.