Risk-taking decisions of game monkeys influenced by the region of the prefrontal cortex: injections

Experiments with two monkeys revealed a small area of ​​the brain that plays an important role in risk decisions.

When researchers inactivated this region in the prefrontal cortex, Rhesus monkeys became less inclined to choose a long shot on a safe thing, the team reported Thursday in the newspaper. Current Biology.

"They no longer liked betting," says student writer Veit Stuphorn and associate professor at Johns Hopkins University.

The discovery among our fellow primates adds to the evidence that human brains are able to constantly adjust our willingness to take risks, depending on factors such as what is at stake.

"For a long time, people thought it was like a personality trait, that some people take risks and others do not," says Stuphorn. But recent research has shown that the same person who is very careful about personal investments can be an avid elite jumper.

This study involved two monkeys who learned to play a computer game that gave them drops when they won. The monkeys played voluntarily because they liked to play, says Stuphorn.

The game offered two options. The first was a guaranteed juice reward, but usually small. The second was a bet: it could bring a lot of juice, or none.

The monkeys moved their eyes to indicate their choice at each turn.

"They are always tempted to go," says Stuphorn. "They go for the big win every time", even if safe bets would have earned them more juice.

The Stuphorn team suspected that this preference for long injections was related to activity in a small area of ​​the brain of the prefrontal cortex involved in eye movements. When a monkey won big, the brain cells in that area became really active.

But this jump alone did not prove that these cells affected the behavior of the monkey. The researchers therefore had another experiment that temporarily inactivated the brain zone by cooling it.

And once the area was inactivated, the game's monkeys played the security. Monkeys were more likely to choose the guaranteed juice option, says Stuphorn

According to Alireza Soltani, who studies decision-making at Dartmouth College and did not participate in the study, the discovery shows at least that the brain can change the willingness to take risks. And change probably depends on many factors, including what is at stake.

"The monkeys are playing for a drop of juice and this is not serious," Soltani said. They take big risks to keep the game interesting.

Other studies have shown that monkeys and people are more likely to cover themselves when the stakes are higher. And scientists think that brain circuits are probably similar.

The idea that the brain constantly adjusts our vision of risk has great implications for society, says Soltani.

"If you consider risk preference as something that is not fixed," he says, "then we can really think about what we can do to help people change their preferences."

The brain area identified in the monkey study is involved in the movement of the eyes. Michael Platt, professor of neuroscience, marketing and psychology at the University of Pennsylvania at the University of Pennsylvania, says Michael Platt, a professor at James S. Riepe University.

He suspects that different areas of the brain with a similar function may influence other risky behaviors, "whether it is to reach out to a slot machine or to go to the casino in the first place".

According to Mr. Platt, understanding the circuits that influence risk-taking may have important practical applications.

"We could help people who have decision-making problems, be it problem gambling or addiction, or other things like that," he says. "We could therefore develop more effective therapies."

Understanding why our brains sometimes tell us to do something risky could also help us make better decisions.