Brain reward system: what is it and how does it work?

The functioning of the human brain can seem chaotic due to its complexityBut the truth is that everything that happens there follows a logic: the need for survival.

Of course, such an important issue has not been overlooked by natural selection, which is why our nervous system includes many mechanisms that allow us to stay alive: regulating body temperature, integrating information visuals, breathing control, etc. All these processes are automatic and we cannot intervene on them voluntarily.

But … what happens when what brings us closer or younger to death has to do with actions learned through experience? In these cases, which are not foreseen by evolution, it acts as a component known as the brain’s reward system.

What is the reward system?

The reward system is a set of mechanisms implemented by our brain that allows us to associate certain situations with a feeling of pleasure. In this way, from these learnings we will tend to try that in the future the situations which generated this experience recur.

In a way, the reward system is what allows us to put goals in a very primary sense. As humans are exposed to a wide variety of situations that biological evolution has not prepared us for, these mechanisms reward certain actions above others, making us learn on the fly what is good for us and what is not. is not.

So the reward system is very much related to basic needs: it will make us feel very rewarded to find a place that has water in when we take too long without drinking, and it will make us feel good when we bond. to someone friendly.

Its function is to ensure that no matter what we do, and no matter how diverse our actions and behavioral options may be, we always have as a benchmark a compass that consistently points to certain sources of motivation, rather than just anyone. or.

Where is the rewards circuit going?

Although everything that goes on in our brain happens very quickly and receives feedback from many other areas of the nervous system, to better understand how the reward system works, it often simplifies how it works by describing it as a circuit with a principle. and a clear end: the mesolimbic pathway, characterized among other things by the importance of a neurotransmitter called dopamine.

The start of this chain of information transmission is located in an area of ​​the brainstem called the ventral tegmental area. This region is linked to the basic mechanisms of survival that are automated with the lower part of the brain, and from there rise to the limbic system, a collection of structures known to be responsible for generating emotions. More precisely, the nucleus accumbens, is associated with the appearance of the sensation of pleasure.

This mixture of pleasant emotions and sensations of pleasure passes to the frontal lobe, where information is integrated in the form of more or less abstract motivations which lead to the planning of sequences of voluntary actions which make it possible to approach the goal.

So, the reward circuit begins in one of the most basic and automated places in the brain and moves up to the frontal lobe, which is one of the places most related to learning, flexible behavior, and grasping. decision making.

The dark side: addictions

The reward system allows us to stay connected to a sense of pragmatism that allows us to survive while choosing from a variety of action options and not having to stick to automatic and stereotypical behaviors determined by our genes. (which happens, for example, in ants and insects in general).

however, this possibility of giving us leeway when choosing what to do also carries a risk called addiction. Initially voluntary and fully controlled actions, such as choosing to try heroin, may be the only option left if we become addicted.

In these cases, our reward system will only be activated when we consume a dose, leaving us completely incapable of feeling satisfaction with anything else.

Of course, there are many types of addictions and the one that depends on heroin use is one of the most extreme. However, the mechanism behind them all is basically the same: the reward center becomes a “hacker” and becomes a tool that guides us towards a single goal, causing us to lose control of what we do.

In the case of substance use, certain molecules can directly interfere with the opening of the reward circuit by causing it to undergo a transformation in a short time, but addictions can also appear without drug use, simply because of the excessive repetition of certain behaviors. In these cases, the substances that produce changes in the reward system are the neurotransmitters and hormones that our own bodies generate.

The ambiguities of dependence

The study of the reward system leads us to consider where the line between addiction and normal behavior lies.. In practice, it is clear that a person who sells all his goods to sell drugs has a problem, but if we keep in mind that addictive behaviors can appear without taking anything and that they arise from functioning with a brain system that operates on all people all the time, it is not easy to set the threshold for addiction.

This has led, for example, to talking about love as a kind of relatively benign addiction: the reward system activates by relating to certain people and stops responding until they are no longer present, at least for a period of time. time. Something similar happens with cell phone and internet addiction: maybe if we don’t take it very seriously, it’s just because it’s socially accepted.

Bibliographical references:

  • Govaert, P .; de Vries, LS (2010). An atlas of neonatal cerebral ultrasound: (CDM 182–183). John Wiley and sons.
  • Moore, SP (2005). Final review of the Neurological Surgery Council. Lippincott Williams and Wilkins.
  • Parent, A .; Fuster, MB (1995). “Chapter 1.” Carpenter’s human neuroanatomy. Williams and Wilkins.

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