Why are we sometimes more prone to taking risks than at other times? Researchers are looking for an answer in resting brain activity fluctuations.

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Natural fluctuations in our brain activity could change the way we make decisions.

To some extent, risk taking is a part of our daily lives. On a daily basis, we make decisions that require us to weigh up possible outcomes.

However, although we may prefer to play it safe on some occasions, on others, we may feel brave enough to take a gamble.

Why do these changes in risk taking behaviors occur? That is what researchers from University College London in the United Kingdom recently tried to find out.

"Experts have long struggled to explain why people are so erratic, making one decision one day and the opposite decision another day. We know that the brain is constantly active, even when we aren't doing anything, so we wondered if this background activity affects our decision making," explains co-lead study author Tobias Hauser, Ph.D.

In their study, Hauser and team wondered if natural fluctuations in brain activity when the brain is in a state of rest may have something to do with our risk taking inclinations.

Their findings — which now appear in the journal PNAS — indicate that this may be the case, with higher resting brain activity being associated with higher dopamine levels and a higher chance of taking risks.

"It appears that our inconsistent behavior is partly explained by what our brain is doing when we are doing nothing," says Hauser.

Another reason not to make hasty choices

For this study, the researchers initially recruited 49 healthy young adults, of whom 43 fulfilled all the requirements to take part in the research.

As part of the research, the investigators focused on resting brain activity. When a person is awake but idle, their brain is not occupied with anything in particular, but it remains alert and active.

They studied activity in a brain region called the dopaminergic midbrain, which contains the highest amount of dopaminergic neurons. These are the brain cells that release dopamine, a chemical messenger that helps regulate self-motivation-related behaviors.

The researchers took MRI scans of the participants' brains while they took part in an experimental gambling activity. They had to choose between a safe option that would gain them a small amount of money and a risky option that could bring them either a larger amount of money or no money at all.

However, the researchers only asked the participants to make a choice when, at rest, their brains showed either a spike in activity in the dopaminergic midbrain or when activity in that area was at a low.

When there was little activity in this brain region prior to the participants' decision making, they were more likely to opt for the safest choice. However, when activity in this brain area was high during a state of rest, the participants were likelier to gamble.

Hauser and team note that these natural fluctuations in resting brain activity appear to have similar effects to other factors that influence risk taking decisions.

These other factors include taking drugs that influence the release of dopamine and the effect of aging on the brain; older people are less likely to take risks than younger people.

"Our brains may have evolved to have spontaneous fluctuations in a key brain area for decision making because it makes us more unpredictable and better able to cope with a changing world," says senior study author Robb Rutledge, Ph.D.

Going forward, the investigators want to better understand how natural fluctuations in resting brain activity influence our decisions on a daily basis. They also want to find out if they could use such findings to devise better treatments for conditions such as gambling addiction.

For now, they emphasize that their recent observations show, once more, just how crucial it is not to rush into any decisions.

"Our findings underscore the importance of taking time when making important decisions, as you might make a different decision if you just wait a few minutes."

Co-lead study author Benjamin Chew