This project will investigate the role of androgenic steroid hormones, including testosterone, on the structure and function of the brain region known as the medial amygdala. This nucleus, which is part of the limbic system, is known to play a role in reproductive behaviors and chemical senses such as olfaction and detection of pheromones. The central question is how androgens affect the number of neurons, the size of neurons and the synaptic connections between neurons in the medial amygdala in both normal male rodents and genetically male rodents with a dysfunctional gene for the androgen receptor. The project will employ neuroanatomical and behavioral testing methodologies to probe the relationship between changes in the brain and changes in behavior. Many of these changes may be crucial for important transitions during puberty, when the brain must be reorganized to mediate the onset of adult behavior. In recent years it has become increasingly clear that this pubertal transition is a crucial period of intense brain plasticity. Thus these studies are designed to enhance our understanding of mammalian behavioral and endocrinological development and adult function. The project will also provide outstanding training for undergraduate and graduate students embarking on careers in the life sciences. In addition to learning specific techniques, the students will also gain background knowledge of basic endocrine mechanisms and training in the experimental logic of hypothesis testing.
