Ever wondered how your brain is able to alert us to the consequences of our actions? According to a recent study the human habenula, half the size of a pea, helps us predict the outcome of negative events like electric shocks and thereby saves us a great deal of grief. That is, we learn from bad experiences.
The habenula becomes active when exposed to pictures associated with electric shocks, the brain scans of 23 healthy volunteers showed. The opposite occurs when it is shown pictures that predict winning money. In other words, the prospect of negative events activates the habenula. Such activity results in avoidance as it suppresses dopamine, a brain chemical that drives motivation. For the experiment, the brains of healthy volunteers were studied using a functional magnetic resonance imaging (fMRI) scanner. Habenula activation tracked the changing expectation of bad and good events.
Says lead author Dr Rebecca Lawson, also at the UCL Institute of Cognitive Neuroscience, “the slower people responded, the more reliably their habenula tracked the associations with shock proving that there is a key link between the habenula and motivated behaviour. This may be the result of dopamine suppression.”
People with a hyperactive habenula may make disproportionately negative predictions. “Other work shows that ketamine, a potent anti-depressant medicine, dampens habenula activity,” says Dr Roiser. “The understanding of the habenula could help us develop better treatments for treatment-resistant depression.”