Never in many decades has mankind been faced with a period of more uncertainty and the need to be cautious – with one’s heath, family, behavior and financial management. We are all being forced to do our best to survive the COVID-19 pandemic and its fallout.

How does the brain react to conditions of uncertainty? Is it predisposed to being overcautious or to underestimating risks? A new Tel Aviv University (TAU) study elucidates the survival mechanism activated by the brain in conditions of uncertainty after its researchers examined the brain’s reactions in conditions of uncertainty and stressful conflict in an environment of risks and opportunities. The researchers identified the areas of the brain responsible for the delicate balance between desiring gain and avoiding potential loss along the way.

Led by Prof. Talma Hendler, Prof. Itzhak Fried, Dr. Tomer Gazit and Dr. Tal Gonen from TAU’s Sackler Faculty of Medicine, the School of Psychological Sciences and the Sagol School of Neuroscience, along with researchers from the the Tel Aviv Sourasky Medical Center and the University of California at Los Angeles School of Medicine, the study has just been published in the prestigious journal Nature Communications.

Research shows that in conditions of uncertainty and conflict over which course of action to take, the human brain is affected more by a prior experience of failure or punishment than a positive experience of success and reward, something that encourages future avoidance of risk.

These findings are relevant to an understanding of the neural mechanisms involved in mental disorders that create increased or reduced avoidance such as post-traumatic stress disorder and addiction.

Hendler explained that to detect reactions in the depths of the brain, the study was performed among a unique population of epilepsy patients who had electrodes inserted into their brains for testing prior to surgery to remove the area of the brain causing epileptic seizures. Patients were asked to play a computer game that included risks and opportunities. The electrodes allowed the researchers to record neural activity in different areas of the brain connected to decision-making, emotion and memory with a high level of accuracy.

Throughout the game, the researchers recorded the electrical activity in the subjects’ nerve cells immediately after they won or lost money. The subjects were asked to try to collect coins while taking the risk of losing money from their pool. It was found that the neurons in the area of ​​the inner prefrontal cortex responded much more to loss (punishment) than to the gaining (reward) of coins.

In addition, the researchers found that the avoidance of risk-taking in the players’ next move was affected not only by post-loss activity in the area of the hippocampus, which involves learning and memory, but also with anxiety. This finding demonstrates the close connection between memory processes and decision-making when risk is present (stressful situations). That is, the loss is encoded in the hippocampus (the region of the brain associated with ​​memory), and the participant operating in a high-risk stressful situation preferred to be cautious and avoid winning the coins (surrendering the gain).

The experience of winning, however, was not encoded in the memory in a way that influenced the choice of future behavior in conditions of uncertainty. An interesting point is that this phenomenon was found only when the subject was the once influencing the result of the game and only in the presence of a high risk in the next move, which indicates a possible connection to anxiety,” she said.

“Our research shows for the first time how the human brain is affected by the experience of failure or loss when it is our responsibility, and how this inclination produces avoidance behavior under particularly stressful uncertainty. An understanding of the neural mechanism involved may guide future neuropsychiatric therapies for disorders featuring excessive avoidance, such as depression.”

Throughout life, “we ​​learn to balance the fear of risking loss with the pursuit of profit, and we learn what is a reasonable risk to take in relation to the gain based on previous experiences,” concluded Hendler. “The balance between these two tendencies is a personality trait but is also affected by stress, like the current pandemic. A disorder in this trait increase sensitivity to stress and can cause non-adaptive behavior such as a high propensity for risk-taking or excessive avoidance.