Changes in the levels of the brain chemical known as serotonin, which usually occur when someone has not eaten or suffers stress, affect those brain areas that are responsible for regulating anger, according to a study conducted by the Cambridge University (United Kingdom), which has published Biological Psychiatry.
The research, which has involved healthy people, has revealed that, with low levels of serotonin, it can be more complicated for the brain to control the emotional reaction to anger.
Low levels of serotonin had already been linked to aggressive behaviors, but this study demonstrates for the first time how this substance contributes to regulate behavior in the brain, and helps to clarify the reason why certain people have a more pronounced tendency to Attack others
During the investigation, the scientists altered the serotonin levels of the participants by manipulating their diet. To reduce serotonin, they were given a combination of amino acids that did not contain tryptophan, a necessary element for the formation of serotonin. When it was their turn placebo, on the contrary, they were administered the same combination, adding tryptophan.
Next, they used the functional magnetic resonance imaging (fMRI) technique to scan the brains of the volunteers while they saw faces that showed expressions of sadness, anger, and neutrality, to evaluate the reaction and the way of communicating with each other. different areas of the brain, depending on the type of face they were contemplating at that moment.
The authors of the study proved that when serotonin levels are low, communication between certain areas of the brain located in the emotional limbic system (amygdala) and the frontal lobes is weakened. They also used a questionnaire to analyze the personality of the volunteers and determine who had a natural predisposition to adopt aggressive behaviors, and could observe that, in these individuals, when the level of serotonin decreased, the communication between the prefrontal cortex and the amygdala was still weaker compared to the rest.
Luca Passamonti, one of the collaborators in the study, believes that although the people who participated in the research were healthy, the results obtained are relevant to better understand a wide variety of psychiatric disorders. In this regard, he points out that the conclusions of the research could help to develop new therapies that alleviate the symptoms of certain diseases, such as intermittent explosive disorder, which is characterized because patients suffer intense attacks of violence that they can not control and that can be triggered, for example, when contemplating a face with an angry expression.