Brain structure that tracks negative events backfires in depression

A region of the brain that responds to bad experiences has the opposite reaction to expectations of aversive events in people with depression compared to healthy adults, finds a new UCL study funded by the Medical Research Council. The study, published in Molecular Psychiatry, found that the habenula, a pea-sized region of the brain, functions abnormally in depression. The same team previously showed that the habenula was activated in healthy volunteers when they expected to receive an electric shock. "A prominent theory has suggested that a hyperactive habenula drives symptoms in people with depression: we set out to test that hypothesis" says senior author Professor Jonathan Roiser (UCL Institute of Cognitive Neuroscience). "Surprisingly, we saw the exact opposite of what we predicted. In people with depression, habenula activity actually decreased when they thought they would get a shock. This shows that in depressed people the habenula reacts in a fundamentally different way.