MRI Studies of Emotion in Depression

The purpose of this study is to research the effects of ketamine on brain function in patients with Major Depressive Disorder (MDD). This study is an ancillary MRI neuroimaging study being conducted in patients with MDD who are enrolled in a separate clinical trial. Healthy control volunteers are also enrolled. No drug or other intervention is given as part of this protocol per se. To study brain activity related to emotion, the study team will use a technology called functional MRI (fMRI), which is a method for evaluating the flow of blood in the brain using a powerful magnet. fMRI does not involve exposure to radiation. Patients will be shown a sample of images on a computer screen designed to bring about an emotional reaction. The MRI machine will then take a number of pictures of your head. By computer analysis, this machine is able to create a picture of your brain's activity. There are several tasks during scanning that involve looking at various images that represent different emotions, and the study team will be monitoring brain activity during these tasks. Patients will be scanned before and 24 hours after receiving ketamine (as part of a separate study) to analyze treatments effects. These scans are compared to depressed patients who did not receive ketamine, as well as to healthy controls.