Our primary mission is to study stress neurobiology and circadian regulation of brain function. We are especially interested in understanding the neurobiological basis of psychological stress, stress adaptation, and their impact on the dynamic circadian regulation of optimal brain function. A central component of our research is study of one of the body’s principal stress-response systems, the hypothalamic-pituitary-adrenal (HPA) axis. This neuroendocrine system controls the secretion of the glucocorticoid stress hormones (cortisol in humans, and corticosterone in rats). There is considerable clinical interest in the observation that disregulation of the HPA axis is often a feature of certain psychological disorders marked by stress sensitivity and circadian dysregulation, including depression and post-traumatic stress disorder (PTSD). Disregulation of this neuroendocrine system may reflect some of the underlying neural abnormalities associated with those disorders, moreover, altered glucocorticoid hormone secretion levels may contribute to the expression and progression of those disorders.