<qa>  What is the name of the study that participants will undergo?Participants in this study will be screened with a medical history, physical examination, blood tests, and an interview about their mood, degree of nervousness, and behavior. On Visit 1, participants will undergo screening and neuropsychological testing. For 3 days prior to Visit 2, participants will collect their saliva. During Visit 2, participants will undergo MRI scans of the brain after infusion with either a high or low dose of hydrocortisone or placebo. Participants will also undergo functional MRI fMRI. Blood samples will be collected every 15 minutes during the scan. Following the MRI, participants will take attention and memory tests. 