Depression shows altered brain activity

People in the throes of depression tend to repeatedly dwell on negative thoughts or memories, showing different patterns of brain activity as compared to healthy individuals. Some individuals have a tendency to recall broader categories of events instead of specific events. This is termed overgeneral memory. These individuals also have a higher risk of developing depression. These negative activities engage a network of brain regions called the default mode network or DMN. Prior studies using imaging techniques have already shown that the DMN activates abnormally in depressed individuals, but the link between DMN activity and depressive ruminations was not clear, the journal Biological Psychiatry reports. In this new report, Shuqiao Yao of Central South University in Hunan, China and colleagues evaluated DMN functional connectivity in untreated young adults experiencing their first episode of major depression and healthy volunteers. Each participant underwent a brain scan and completed tests to measure their levels of rumination and overgeneral memory, according to a Central South University statement. "As we dig deeper in brain imaging studies, we are becoming increasingly interested in the activity of brain circuits rather than single brain regions," said John Krystal, editor of Biological Psychiatry. "Although it is a more complicated process, studying brain circuits may provide greater insight into symptoms, such as depressive ruminations," added Krystal.