Scientists Identify Brain Region Central to Decision-Making

Lisa Franchi November 27, 2013

A very small part of the brain, one of the smallest in fact, plays a vital role in helping us make important decisions on a daily basis, from choosing between job offers to deciding which house or car to buy – according to a new study.

Researchers from the University of British Columbia found that the lateral habenula – a small region in the brain linked to depression and avoidance behaviours, plays a crucial role in decision-making. They said it has been largely misunderstood and may be integral in cost-benefit decisions.

In the study, scientists trained lab mice to choose between a small yet consistent rewards (one food pallet) and a potentially larger reward (four food pellets) that was only given sporadically. Similar with human behaviours, mice tended to choose larger rewards when costs (in this case – the amount of time they had to wait before receiving the food reward) were low and preferred smaller rewards when the risks were higher.

Contrary to previous findings, turning off the lateral habenula didn’t cause rats to choose the larger, riskier reward. Instead, the subjects selected either option at random, no longer showing the ability to choose the best option for them.

Important implications for depression treatment

According to the researchers, led by Professor Stan Floresco of the Psychology and Brain Research Centre (BRC) Department, their findings have important implications for depression treatment. "Deep brain stimulation – which is thought to inactivate the lateral habenula—has been reported to improve depressive symptoms in humans," he 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."

Floresco pointed out that more research is needed to understand the complete brain functions involved in cost-benefit decision processes and related behaviour. There’s a great need to delve deeper into the science of decision-making processes, because many psychiatric disorders like schizophrenia, substance abuse and depression are associated with impairment in such processes, the researchers note.

Source of this article:

What’s better for me? Fundamental role for lateral habenula in promoting subjective decision biases