An international research team says they have identified the physical source of depression in the brain in a new study. Investigators traced depression, one of the most common mental ailments in the world, to the lateral orbitofrontal cortex, the part of the brain responsible for a non-reward mechanism. According to the research team, this is likely the reason people living with depression often feel a sense of loss, disappointment, and low self-esteem. Read the rest of the News.