The New Science of Mind - NYTimes.com: " . . . Consider the biology of depression. We are beginning to discern the outlines of a complex neural circuit that becomes disordered in depressive illnesses. Helen Mayberg, at Emory University, and other scientists used brain-scanning techniques to identify several components of this circuit, two of which are particularly important.
One is Area 25 (the subcallosal cingulate region), which mediates our unconscious and motor responses to emotional stress; the other is the right anterior insula, a region where self-awareness and interpersonal experience come together. . . ." (read more at link above)