Every day in the media there are scandalous cases of crimes, aggressions and excessive violence . Today we know that the environment in which a person grows and evolves and the same systems that shape it directly condition their development, but, and if we ask ourselves what happens at a neurological level so that a person develops more aggressive behaviour than another person raised and educated in the same environment? In this article we answer this question

An aggressive person shows activity in certain areas of the brain

The hypothalamus, testosterone and serotonin have been the main research routes in relation to aggression for years, but nowadays different works have shown how the stimulation exerted on the amygdala activates aggressive emotional reactions in the subject , as well as inhibiting them when acting on the prefrontal cortex.

At an ontological level, the maturation of the prefrontal cortex is later than that of the amygdala, which means that the individual acquires the necessary skills for abstract reasoning, to make changes in the focus of attention or even to develop the ability to inhibit inappropriate responses, such as the control of aggression, among others.

The greater the volume of the prefrontal cortex, the less aggressive the behavior

Already in the late 1990s it was suggested that increased activity in the amygdala led to increased negative behaviors, including increased aggression, whereas decreased activity in the prefrontal cortex offered less ability to exert control over one’s emotions.

It was a study conducted by Whittle et al. (2008) in adolescents, which finally concluded that the greater the volume of the prefrontal cortex the less aggressive behaviour was perceived in boys and conversely in the case of the amygdala, a greater volume responded to offering more aggressive and reckless behaviour at the same time.

When Anthony Hopkins plays the character of Hannibal Lecter in , he shows an unusual temperament for a murderer, far from transmitting an impulsive and emotional personality, he stands out for having a profile, calculating, cold and extremely rational, which escapes the explanation we are offering.

The white substance in the prefrontal cortex and its relationship to aggression

So far we have seen how an increase in the activity of the amygdala and a decrease on the prefrontal cortex is ideal to describe a more impulsive personality, little reflective and even with little capacity in the own emotional management but how can we explain the typical characteristics of Hannibal?

In 2005, Yang et al. found that a decrease in the white substance of the prefrontal cortex responded to a decrease in one’s cognitive resources , both in persuading or manipulating others, and in making decisions at specific times. Keeping the white substance intact would explain why Hannibal and other killers with the same characteristics are able to control their behavior so masterfully, to make appropriate decisions in complex situations, always to their own benefit and to the point of circumventing authority.

Serotonin is key to understanding aggressive behavior

As we said at the beginning, serotonin also has a fundamental role in this subject, specifically, a decrease in its activity is directly related to aggression and to the initiation of risky behaviour. In 2004, New et al. showed that treatment with SSRIs (selective serotonin reuptake inhibitors) increased the activity of the prefrontal cortex, and at the end of the year the aggressive behaviours of individuals were considerably reduced.

In summary, we can point out how an increase in serotonergic activity would increase the activity of the prefrontal cortex, which would cause the inhibition of the activity of the amygdala and consequently the aggressive behaviors.

We are not slaves to our biology

Even though we know that the brain is not a determining factor in the modulation of aggression and of these behaviours by itself, it is thanks to the advances and the numerous studies carried out that we can explain its mechanism as far as the neurological process is concerned. Guido Frank, a scientist and physicist from the University of California, points out that biology and behaviour are susceptible to change and that, by combining a good therapy process and adequate individualised control, the progress of each individual can be modified.

Ultimately, as neurologist Craig Ferris, of Northeastern University in Boston in the United States, points out, we must keep in mind that “we are not completely slaves to our biology.