Scientists have just imaged a tiny region of the brain that exerts a big influence. It’s called the habenula, and it activates when we experience negative or foreboding thoughts. It’s so small that neurologists had to devise a special technique to find it.
To find the habenula, researchers placed 23 volunteers in MRI scanners and showed them abstract images, linking those pictures just seconds later to either an electric shock, money, or neutral responses. In subsequent trials, the researchers didn’t always administer a shock or give out money as expected, making it difficult for some participants to anticipate was going to happen. The result was that the habenula lit up to varying degrees based on how certain each person was that a painful shock was imminent.
Smitha Mundasad, reporting for BBC News, talked with lead author Jonathan Roiser:
“Everything that moves needs a system like this – to tell us not to stroke the tiger or go down a dark alley.
“It is likely the habenula is a key neural hub allowing us to anticipate such events.”
This area of the brain has been seen to be overactive in animal experiments on depression.
This study, though, is the first to demonstrate these processes in humans, raising the hope that follow-up studies could help us better understand depression. Further research could illuminate why people suffering from depression amplify the affect of punishments, Catherine Harmer of the University of Oxford told the BBC, or why they don’t respond as well to rewards. Understanding the nuances of how people react in situations like that could lead to new treatments for depression.