Epithalamus: parts and functions of this brain structure

The human brain is not a homogeneous, amorphous mass., but in it can be found a large number of structures and substructures with great differences from each other, which work with different neurotransmitters and have various functions.

Although some of these brain structures are familiar to many people, such as the amygdala or the hippocampus, others are less known despite having an important role in regulating our conduct. For example, by helping to regulate hormones and follow circadian rhythms. This is the case of the epithalamus, which we are going to talk about in this article.

• Related article: "Parts of the human brain (and functions)"

What is the epithalamus?

The epithalamus is a relatively small structure that is part of the diencephalon and? can be found just above the thalamus and touching the roof of the third ventricle. It is a structure mainly linked to the limbic system, being relevant in the management of instinct and emotions.

It is also associated with the neuroendocrine system through the pineal gland, one of the main structures that is part of the epithalamus that is also part of said system. We are dealing with a structure with a wide range of connections with the rest of the brain regions, including the olfactory system (also related to the perception and reaction to odors) and many other structures of the brain.

• Related article: "What is the thalamus and what is its function in our nervous system?"

Parts of the epithalamus

The epithalamus is made up of a set of structures of great importance to humans. Apart from the spinal striae, nerve fibers that establish connections with other regions of the brain, we can find two large structures, which are the most relevant and well-known of the epithalamus.

epiphysis or pineal gland

The best known structure of the epithalamus is the pineal gland. It is an element known since antiquity (specifically the first information that has been found about it date from the 3rd century BC), Descartes proposing the existence in it of animal spirits related to the emotions.

Innervated by the autonomic nervous system and being connected with other nuclei such as the septals, The pineal gland is an important regulatory brain structure of the neuroendocrine system., participating in functions such as energy regulation and sexuality.

One of the most important aspects of the pineal gland is the fact that it is in charge of secreting melatonin from serotonin, when lighting is non-existent or very low. Thus, the epiphysis is essential in regulation of circadian rhythms and sleep and wakefulness.

It is also involved in the synthesis of endorphins and sex hormones such as luteinizing hormone, as well as growth and sexual maturation (which its activity delays).

• Related article: "Pineal gland (or epiphysis): functions and anatomy"

Habenula or habenular nuclei

In addition to the pineal gland, the other major structure of the epithalamus is the habenula or habenular nuclei (since there are actually two structures). It is linked to the previous one, and is of great relevance when it comes to receiving and send connections nuclei of the limbic system and the reticular formation. The habenular nuclei are elements that, unlike epiphyses, do not have endocrine functions.

It acts to a large extent as a bridge between various brain areas (including the thalamic nuclei, those of the forebrain or preoptic area) although precisely Due to these connections, it also seems to be involved in the motivation not to act, fear and negative evaluations of events similar to those that could have caused us in the past. damage. Finally, they are also linked to the ability to provide emotional information to odors.

Its functions

As we have previously indicated, although the epithalamus is not particularly well known about its existence and functioning in the The brain is of great relevance for the human being, having important functions for our adaptation and survival.

As part of the limbic system, participates in the management of emotion and motivation. In this sense, its role in different disorders such as depression or anticipatory anxiety can be explored.

One of these functions is the management of circadian rhythms, our biological clock that regulates at what times of the day we have and use more or less energy. In this sense, it is also of great importance in sleep management, because the pineal gland present in the epithalamus reacts to the absence of light by producing melatonin and decreasing energy levels, facilitating dream.

It is also involved in growth and sexual maturation., adjusting the biological rhythm in which we develop and become adults. Lastly, their connections with the olfactory pathways make them relate to the ability to perceive odors and give them an emotional meaning.

Bibliographic references

• Kandel, E.R.; Schwartz, J.H. & Jessell, T.M. (2001). Principles of neuroscience. Fourth edition. McGraw-Hill Interamericana. Madrid.