The limbic system is one of the most interesting and important networks of neurons when studying human behavior, since it is one of the parts of the brain with the most relevant role in the appearance of moods.

That’s why it’s sometimes called “the emotional brain.” But… what exactly is the limbic system and what are its functions?

What is the limbic system?

The limbic system is a set of structures in the brain with diffuse boundaries that are especially connected to each other and whose function has to do with the appearance of emotional states or with what can be understood as “instincts”, if we use this concept in its broadest sense. Fear, happiness or anger, as well as all emotional states full of nuances, have their main neurological basis in this network of neurons .

Thus, at the center of the usefulness of the limbic system are the emotions, that which we link with the irrational. However, the consequences of what happens in the limbic system affect many processes that, theoretically, we do not have to associate with the emotional side of the human being, such as memorization and learning.

The limbic system in learning

More than 200 years ago, an English philosopher named Jeremy Bentham, one of the fathers of utilitarianism , proposed the idea of a way to calculate happiness based on a classification of criteria to differentiate pain from pleasure. In theory, from this calculation we could know how useful or not useful each situation was, depending on how happy it made us according to this formula.

Simplifying a lot, it can be said that, in a similar way to that proposed by Bentham, the limbic system is something like the judge who determines what deserves to be learned and in what way it has to be memorized depending on the pleasant or painful sensations that each situation produces.

That is to say, the way in which the positive or negative value of each of the experiences that are lived depends on the limbic system. But, in addition, the way in which the limbic system influences our way of learning will have repercussions on our personality.

Some examples

For example, a mouse that has gone through operant conditioning and has come to associate the action of moving a lever with the appearance of food in a drawer in its cage, learns that moving the lever is good thanks to the pleasant sensations it gets from seeing the food and tasting it, that is, based on something based on the euphoria of discovering a piece of cheese when it is hungry and on the pleasant sensations that eating it produces.

In human beings, too we can understand that those situations in which pleasure is more sublimated in a complex way , like what it feels like to listen to a good poetry reading, teaches us that returning to the cultural association in which we have heard it is “useful”. The limbic system remains the part of the brain responsible for this.

The parts of the limbic system

It should be remembered that the limbic system is not exactly an anatomically exact region of the brain , but rather a network of neurons distributed throughout the brain and which are mixed among many different structures. In other words, the concept of the limbic system has more to do with the function these areas have than with their nature as a specific and well-defined part of the brain.

However, it is possible to point out parts of the brain that have a very important role within the network of interconnections that is the limbic system and that, therefore, serve to give us an idea of the areas through which this circuit passes. The parts of the limbic system are the following:

Hypothalamus

One of the areas of the diencephalon most involved in the regulation of emotions , because of its connection with the pituitary gland and therefore with the endocrine system and all parts of the body in which all kinds of hormones are released.

  • To read more about this part of the brain you can read this article about the thalamus

Hippocampus

The hippocampus has a very important role in the mental processes related to memory , both in the memorization of experiences and abstract information and in the recovery of memories. The hippocampus is located on the inner side of the temporal lobes, very close to the thalamus and the tonsils.

The hippocampus is framed within what is known as the cortex of the limbic lobe, or archaicortex, which is one of the oldest parts of the cerebral cortex; that is, it appeared very early in the line of evolution that has led to the appearance of the human being.

Amygdala

The cerebral tonsils are located next to each hippocampus , and therefore there is one in each of the hemispheres of the brain. Their role is related to the learned emotional response that certain situations arouse, and therefore they are involved in emotional learning, and therefore they have a role in the limbic system.

Orbital-Front Bark

At the limits of the limbic system is the orbitofrontal cortex, which is the outlet for “emotional” commands to areas of the frontal lobe responsible for planning and strategizing. Therefore, has an important role in placating the “irrational impulses” that come from the limbic system and passing on only part of these signals, those that will serve to well define the objectives of the actions with medium or long term goals.

Is it right to talk about an “emotional brain”?

In popular culture there is a widespread idea that the human brain has an emotional and a rational part . The emotional brain, which we would have inherited from our most primitive ancestors, would be the one thanks to which we have emotions, feelings and impulses that are difficult to repress, while the rational one would be in charge of the most conscientious and logical analysis of the situations we live or imagine.

However, as we have seen, the limbic system is deeply interconnected with other areas of the brain not directly identified with what we know as the emotions, so the idea that we have an emotional brain is, in large part, an overly imaginative way of understanding this network of connections .

Moreover, we must take into account that if we talk about an emotional brain, it is to contrast this concept with the idea of a rational brain, which would be represented by the most superficial areas of the frontal and parietal lobes. However, if in the case of the limbic system we at least know that it is a set of fairly old structures in our evolutionary line, the idea that there is in us a part of our body made to think rationally with a certain autonomy is directly an illusion.

Rationality is not innate

There are our ancestors who lived only with a limbic system and without the capacity to think along the lines of what we understand as rationality, but in the history of human beings rational thought is rather an exception . Not only do we not think rationally most of the time, but until a few thousand years ago rationality did not exist and, in fact, in some cultures little westernized adults tend not to reach the fourth stage of cognitive development proposed by Jean Piaget .

In other words, that which we call rationality is more a product of history than the fruit of a set of brain structures designed for it. The limbic system is, in any case, one of the regions of the brain that allows the appearance of rational thought, and not the other way around.

Bibliographic references:

  • Herculano-Houzel, S. (2009). The Human Brain in Numbers: A Linearly Scaled-up Primate Brain. Hum Neurosci.
  • Maton, Anthea; Jean Hopkins; Charles William McLaughlin; Susan Johnson; Maryanna Quon Warner; David LaHart; Jill D. Wright (1993). Human Biology and Health. Englewood Cliffs, New Jersey, USA: Prentice Hall.
  • Rosenberger, Peter B. MD; Adams, Heather R. PhD. Big Brain/Smart Brain. December 17, 2011.