What is the limbic system and how does this region of the brain work?
The limbic system is one of the most interesting and important neuron networks when studying human behavior, since it is one of the parts of the brain with a more 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 brain structures with diffuse limits that are specially connected to each other and whose function has to do with the appearance of emotional states or with what can be understood by “instincts”, if we use this concept in its sense wider. The fear, the happiness or anger, and all emotional states full of nuances, have their main neurological basis of 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 face 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 for differentiating pain from pleasure. In theory, from this calculation we could know how useful or not very useful in each situation, 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 that determines what deserves to be learned and how it has to be memorized depending on the pleasant or painful sensations that we experience. produces each situation.
That is to say, the limbic system depends on the way in which the positive or negative value of each of the experiences that is lived is learned. But, in addition, the way in which the limbic system influences our way of learning will have repercussions on our personality.
For example, a mouse that has undergone operant conditioning and has come to associate the action of moving a lever with the appearance of food in a drawer of its cage, learns that moving the lever is okay thanks to the pleasurable sensations it produces. see the food and taste it, that is, based on something based on the euphoria of discovering a piece of cheese when you are hungry and on the pleasant sensations that eating it produces.
In human beings, it can also be understood that those situations in which pleasure is more sublimated in complex ways, such as what it feels like to listen to a good poetry recital, teaches us that returning to the cultural association in which we have heard is “useful”. The limbic system is still 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 is a network of neurons distributed throughout the brain and that are mixed between many different structures. In other words, the concept of the limbic system has more to do with the function of these areas 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 about which are the areas through which this circuit passes . The parts of the limbic system are as follows:
One of the areas of the diencephalon most involved in the regulation of emotions, due to 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
The hippocampus has a very important function in the mental processes related to memory, both in the memorization of experiences and abstract information and in the retrieval of memories. The hippocampi are located on the inside 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 archicortex, which is one of the oldest parts of the cerebral cortex; that is to say, it appeared very early in the line of evolution that led to the appearance of the human being.
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 with emotional learning, for which they have a role in the limbic system.
At the limits of the limbic system is the orbitofrontal cortex, which is the outlet valve for “emotional” orders to areas of the frontal lobe in charge of planning and creating strategies. Therefore, it plays an important role when it comes to appeasing the “irrational impulses” that come from the limbic system and passing only part of these signals, those that will serve to well define the objectives of 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 part 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 brain would be responsible for the most conscientious and logical analysis of the situations that 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, in large part, a way overly imaginative to understand this web of connections.
Furthermore, it must be borne 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 most superficial areas of the frontal and parietal lobe. However, if in the case of the limbic system we at least know that it is a set of quite 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 ancestors of ours who lived only with a limbic system and without the ability to think following the guidelines of what we understand as rationality, but in human history, 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 that are not very Westernized, 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 regions of the brain that allow the appearance of rational thought, and not the other way around.
- 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.