Science/Tech

How Does The Brain Make Decisions? Mysterious Brain Region May Control Risk, Outcome Assessment

decision making
The lateral habenula appears to control strategic and cost-benefit decision making. Photo Courtesy of Shutterstock

The bulk of human decision making may occur in one of the smallest parts of the brain, according to a new study. Researchers from the University of British Columbia have discovered that the tiny lateral habenula plays a crucial role in calculated, cost-benefit decisions. The findings, published in Nature Neuroscience, shed additional light on the neurological processes whereby we make up our mind. 

According to co-author Stan Floresco, the findings broaden the prevailing scientific understanding of one of our most misunderstood brain regions. "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," he told reporters. "It also suggests that the scientific community has misunderstood the true functioning of this mysterious, but important, region of the brain."

To investigate the relationship between the lateral habenula and important decision making, the researchers designed an experiment with mice. Subjects were trained to choose between small award administered consistently or a large award administered sporadially. In this case, the awards were either one or four food pellets. According to the researchers, normal mice faced with this task generally display a systemic preference based on observed award distribution. In other words, when large awards are few and far between, they will favor small, “low-risk” awards. As the wait — or “risk” — diminishes, the likelihood of the mice choosing large awards increases. 

The team found that deactivating the lateral habenula did indeed influence the subjects’ decision-making profile. The deficiency did not merely restrict their ability to assess risks and outcomes. Instead, it made the test subjects lose their decision making abilities altogether. Rather than displaying a preference for either of the two options, subjects began to select awards at random. 

According to the researchers, a broader understanding of this brain region may lead to new breakthroughs in psychiatric care and diagnosis. It also offers an explanation as to why blocking lateral habenula activity appears to alleviate major depressive disorder. "Deep brain stimulation — which is thought to inactivate the lateral habenula — has been reported to improve depressive symptoms in humans," Floresco told reporters. "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."

Source: Stopper CM, Floresco Sb. What's better for me? Fundamental role for lateral habenula in promoting subjective decision biases. Nature Neuroscience. 2013.

Loading...