Epithalamus: Parts And Functions Of This Brain Structure
The human brain is not an amorphous and homogeneous mass but in it a large number of structures and substructures can be found with great differences from each other, that function with different neurotransmitters and that have various functions.
Although some of these brain structures are known to many people, such as the amygdala or the hippocampus, others are less known despite having an important role in regulating our behavior. For example, 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.
The epithalamus is a relatively small structure that is part of the diencephalon and that 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, which is also part of said system. We are faced with a structure with a wide range of connections with the rest of the brain regions, including the olfactory system (also having a relationship with the perception and reaction to odors) and many other brain structures.
Parts of the epithalamus
The epithalamus is made up of a set of structures of great importance for human beings. Apart from the medullary striae, nerve fibers that establish connections with other regions of the brain, we can find two large structures, which are the most relevant and known of the epithalamus.
The best known structure of the epithalamus is the pineal gland. It is an element known since ancient times (specifically, the first information found about it dates back to the 3rd century BC), Descartes proposing the existence in it of animal spirits related to emotions.
Innervated by the autonomic nervous system and connected to other nuclei such as the septal nuclei, The pineal gland is an important brain structure that regulates the neuroendocrine system participating in functions such as the regulation of energy and sexuality.
One of the most important aspects of the pineal gland is the fact that it is responsible for secreting melatonin from serotonin, when lighting is non-existent or very low. In this way the epiphysis is essential in regulating circadian rhythms and sleep and wakefulness
It is also involved in the synthesis of endorphins and sex hormones such as lutenizing hormone, as well as in growth and sexual maturation (which its activity delays).
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 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 largely acts as a bridge between various brain areas (including, in addition to the previous ones, the thalamic nuclei, those of the forebrain or preoptic area), although precisely because of these connections it also seems to be involved in the motivation not to act, fear and negative evaluations of others. events similar to those that could have caused us harm in the past. Lastly, they are also linked to the ability to provide emotional information to smells
As we have indicated previously, although the epithalamus is not especially known, its existence and functioning in the brain is of great relevance for human beings, 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 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 reducing energy levels, facilitating sleep.
It also participates in growth and sexual maturation, adjusting the biological rhythm in which we develop and become adults. Finally, their connections with the olfactory pathways make them related to the ability to perceive odors and give them emotional meaning.
