Researchers discover area of brain used for decision making

Having a hard time making decisions? A small area of the brain may be to blame.

Researchers from the University of British Columbia (UBC) have revealed that the lateral habenula – one of the smallest parts of the brain – may play a crucial role in making cost-benefit decisions. Previous research has linked this brain region to depression and avoidance behaviors.

“These findings clarify the brain processes involved in the important decisions that we make on a daily basis, from choosing between job offers to deciding which house or car to buy,” Stan Floresco, of UBC’s Dept. of Psychology and Brain Research Centre (BRC), said in a press release. “It also suggests that the scientific community has misunderstood the true functioning of this mysterious, but important, region of the brain.”

For the study, Floresco and his team prompted lab rats to choose between a small reward – one food pellet - and a potentially larger reward of four food pellets. The small reward appeared much more consistently while the large reward appeared more sporadically.

The researchers found that rats chose the larger reward when they didn’t have to wait as long to receive the food. This meant the rats made decisions like humans typically do – choosing larger rewards when “costs” are low and choosing smaller rewards when the risks are higher.

The scientists then studied the rats after inactivating their lateral habenula – which ultimately caused the rodents to choose either option at random. According to Floresco, these findings could lead to major changes in the way doctors treat depression.

“Deep brain stimulation – which is thought to inactivate the lateral habenula — has been reported to improve depressive symptoms in humans,” Floresco said. “But our findings suggest these improvements may not be because patients feel happier. They may simply no longer care as much about what is making them feel depressed.”