Much human behaviour is conditioned by mechanisms of reward and punishment, even though everyone acts differently to these stimuli. In fact, there are people who are more likely to seek rewards or pleasures whereas others show stronger tendencies to avoid losses and negative life events.  

The reason for these individual differences lies in the connections of a specific area of the brain, according to a study recently published in The Journal of Neuroscience. This work has involved researchers from the Institute for Biomedical Research (IDIBELL) and the Department of Basic Psychology at the University of Barcelona, Estela Camara (now at the Institute of Cognitive Neuroscience, UCL, London) and Antoni Rodríguez Fornells (ICREA). The results of this research provide new evidence on individual differences observed in how people can be more or less likely to seek rewards or pleasures or avoid unpleasant or negative situations.

The researchers studied the brain activity of a group of 35 healthy volunteers whereas they were playing and gambling with money. While the volunteers were playing, the researchers assessed their brain activity using MR. The study shows that the intensity of reward and punishment stimuli coming to the brain’s subcortical area responsible for processing them, called nucleus accumbens (in the ventral striatum), is conditioned by the structural properties of the surrounding tissues.  

Just as the size and capacity of the road determine the amount of cars that can go from one city to another, the properties of white matter connecting the various regions of the brain determine the amount of information flowing between these regions. 

The authors have shown that people with greater sensitivity to anxiety and reward mechanisms differ in the brain connections of white matter that surround the nucleus accumbens.

This new evidence is important because it provides new ideas about the strong relation between brain structure, cognition and the attitudes observed in potential situations that may lead to developing addictive behaviours such as pathological gambling or narcotic drug abuse.