The bit of your brain that signals how bad things could be

An evolutionarily ancient and tiny part of the brain tracks expectations about nasty events, finds new UCL research funded by the Medical Research Council. The study, published in Proceedings of the National Academy of Sciences , demonstrates for the first time that the human habenula, half the size of a pea, tracks predictions about negative events, like painful electric shocks, suggesting a role in learning from bad experiences. Brain scans from 23 healthy volunteers showed that the habenula activates in response to pictures associated with painful electric shocks, with the opposite occurring for pictures that predicted winning money. Previous studies in animals have found that habenula activity leads to avoidance as it suppresses dopamine, a brain chemical that drives motivation. In animals, habenula cells have been found to fire when bad things happen or are anticipated. "The habenula tracks our experiences, responding more the worse something is expected to be," says senior author Dr Jonathan Roiser of the UCL Institute of Cognitive Neuroscience. "For example, the habenula responds much more strongly when an electric shock is almost certain than when it is unlikely.