Identify two brain regions that interact to evaluate whether taking a risk is worth it: their activity predicts how we will behave.
Ask her out and maybe get rejected, or wait for her to take the first step? Send your CV for that position, or keep your boring (and safe) job? Risk assessment is a part of life, but now a group of scientists has managed to precisely locate the two regions of the brain that negotiate these types of decisions.
The result of this push and pull between prudence and propensity for risk can be read in the brain half a second before we take an action: the electrical activity of the brain predicts whether or not we will take a risk a moment before we act. The results of the study were published on Nature Neuroscience.
A tug of war with a clear winner
Scientists from the Universities of California, Berkeley and San Francisco have identified the orbitofrontal cortex as the site of this tug-of-war between the desire to take a risk and greater prudence.
This region located above the eyes and involved in decision making had already been linked to the ability to formulate plans, control emotions and motivation, but by working with epileptic patients who had electrodes placed in this area, researchers were able to measure its electrical activity in real time.
They thus discovered two distinct and adjacent areas of the orbitofrontal cortex that, like the little devil and the little angel in the heads of cartoon characters, send signals in opposite directions on the millisecond time scale: one pushes for risk taking, the other for avoidance. The negotiation process between these two areas is very similar to a tug of war: a kind of contest takes place between one pole and the other, until a clear winner emerges who brings the advantage entirely to his side.
“Most models of decision making assume that the brain gradually increases the amount of evidence until it exceeds a threshold, like a slowly turning knob,” explains Robert Knight, professor of Psychology and Neuroscience at the University of California at Berkeley and co-author of the study. “What we observed instead was more like a switch flipping back and forth, oscillating between two extremes until one stabilizes.”
A mined corridor
The researchers designed an immersive video game in which participants had to navigate a maze of bomb-strewn corridors to reach chests full of treasure. Deciding to walk down a bomb-strewn corridor was the risk you had to take to get the reward, and each corridor contained a different number of explosive threats (but also different amounts of treasure).
The scientists monitored the brain activity of six people with electrodes inserted into the orbitofrontal cortex who participated in the experiment. The orbitomedial sulcus, the area between the two located further in the center of the eyebrow, increased its activity shortly before the participants decided to take a risk; an area located about two centimeters to the side of the eyebrow, however, increased its activity shortly before a prudent decision.
When the decision was simple (for example, to avoid the risk of being blown up in a corridor with few rewards) the “tug-of-war” did not last long and the pro-risk signal immediately prevailed. In the case of more difficult choices, however, there were more rebounds before one of the two factions prevailed. In any case, just by observing the electrical activity of the brain, the researchers were able to predict what the volunteers would choose, even before they acted.
Risk as a pathological condition
The research will be relevant above all to deal with the relationship with risk in psychiatric conditions in which it is avoided (as in those suffering from depression, anxiety or obsessive-compulsive disorder) or on the contrary pursued in a pathological way (as in gambling or addictions). Knowing more precisely which areas influence these behaviors will help in more targeted and precise, and therefore more effective, brain stimulation and treatments.
