fMRI Studies of Emotional Circuitry in Major Depression

Major depressive disorder can be a recurrent problem for many people, interfering with their ability to function normally in day-to-day life. Although research shows that activation in certain brain areas corresponds to certain emotional functions, it is not well known which specific changes in brain functioning are related to or caused by depression. A proposed theory holds that depression is related to abnormal regulation of emotions and thoughts. This study will focus particularly on a brain circuit involved in emotional regulation, which includes the amygdala, the affective division of the anterior cingulate (ACad), and dorsolateral prefrontal cortex (DLPFC). The amygdala detects critical emotional information, especially threats; the ACad judges relevance of motivational cues, detects conflict, and regulates emotional responses; and the DLPFC has a critical role in supporting a wide range of cognitive control functions. This study will compare brain scans from people with and without depression to attempt to clarify which changes in brain functioning are related to depression.

Participation in this study will last 8 weeks. All participants will undergo initial screening in a telephone interview, then a diagnostic interview and brief physical examination. After passing through screening, participants will schedule a functional magnetic resonance imaging (fMRI) scan. The fMRI scan, lasting approximately 2 hours, will take pictures of both brain structure and brain functioning during different tasks. Also at this visit but outside the fMRI scanner, participants will be asked to complete an additional 2 hours of tasks on a computer. Depressed participants will then be given Lexapro, an approved drug for the treatment of depression. Participants taking Lexapro will go to scheduled doctor's visits after 2, 4, and 6 weeks of treatment to assess health, effectiveness of the drug, and side effects. On the eighth week, all participants will again undergo fMRI scanning and computer testing. At both the initial and follow-up fMRI study visits, images of brain function and anatomy will be recorded, heart rate will be monitored, and anxiety and arousal will be measured in the computer tests.