Limbic system: the emotional part of the brain

What is the limbic system and how does this region of the brain function?

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 is why it is 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 of the brain with diffuse limits 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 limbic system's usefulness are emotions, that which we associate 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 utilitarianismproposed the idea of a way to calculate happiness based on a classification of criteria to differentiate Pain from pleasure. Theoretically, 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, we can say that, in a way similar to what Bentham proposed, the limbic system is something like the judge that determines what deserves to be learned and in what way it should be memorized and in what way it has to be memorized depending on the pleasant or painful sensations that each situation produces in us.

That is to say, the way in which the positive or negative value of each of the experiences we live 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 undergone the operant conditioning and has come to associate the action of moving a lever with the appearance of food in a drawer in its cage, it learns that moving the lever is okay because of the pleasurable sensations of seeing the food and tasting it, i.e., based on the euphoria of discovering a piece of cheese when hungry and the pleasurable sensations of eating it.

In human beings, it can also be In human beings, it can also be understood that those situations in which the pleasure is more sublimated in a complex way, such as what is felt when listening to a piece of cheese when we are hungry, can besuch as what we feel when listening to a good poetry recital, teaches us that returning to the cultural association in which we have listened to it is "useful". The limbic system remains the part of the brain responsible for this.

The parts of the limbic system

It is worth remembering that the limbic system is not exactly an anatomically exact region of the brain.Rather, it is a network of neurons distributed throughout the brain and which are mixed among many different structures. In other words, the concept of limbic system has more to do with the function of these areas than with their nature as a concrete and well delimited part of the brain.

However, it is possible to point out parts of the brain that play an extremely 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, due to its connection with the limbic gland.It is connected to the pituitary gland and therefore to 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 plays a very important role in mental processes related to memory, both in the memorization of experiences and abstract information and in the retrieval of memories.Both in the memorization of experiences and abstract information and in the retrieval of memories. The hippocampi are located in the inner aspect of the temporal lobes, very close to the thalamus and the amygdalae.

The hippocampus is framed within what is known as the limbic lobe cortex, or archicortex, 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 emergence of the human being.

Amygdala

The cerebral amygdalae are situated next to each hippocampusand therefore there is one in each of the hemispheres of the brain. Their role is related to the learned emotional response aroused by certain situations, and therefore they are involved in emotional learning, and therefore have a role in the limbic system.

Orbitofrontal cortex

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

Is it correct to speak of 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 more 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 emotions, so the idea that we have an emotional brain is, to a large extent, an overly imaginative way of understanding this network of connections..

Moreover, we must bear in mind that if we speak of an emotional brain it is to contrast this concept with the idea of a rational brain, which would be represented by the more superficial areas of the frontal lobe and the parietal lobe. However, if in the case of the limbic system at least we know that it is a set of structures quite ancient in our evolutionary line, the idea that there is in us a part of our body made to think rationally with some autonomy is straightforwardly an illusion.

Rationality is not innate

There are ancestors of ours 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, thinking is not innate. 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 less Westernized cultures adults tend not to reach the fourth stage of cognitive development proposed by Jean Piaget.

In other words, what 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 brain regions that allow the emergence of rational thought, and not the other way around.

Bibliographical 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.