<qa>  What is the effect of hydrocortisone on the hemodynamic response?The present study investigates the influence of glucocorticoids on the hemodynamic response that occurs while processing emotionally-valenced visual stimuli known to activate the amygdala and anatomically-related areas of the prefrontal cortex PFC in healthy humans. Functional magnetic resonance images will be acquired during the performance of tasks that involve viewing emotionally expressive faces both before and following either hydrocortisone synthetic cortisol 0.15 mgkg or 0.45 mgkg bolus or placebo administration. The change in the BOLD signal in structures of interest will be compared across high dose cortisol, low dose cortisol and placebo conditions. In addition, the effects of hydrocortisone on relative blood flow in the amygdala and PFC will be assessed using an arterial spin labeling ASL technique to measure perfusion. The findings of this study will guide future research into the effects of glucocorticoids on emotional perception in subjects with mood disorders. 