The limbic system is a brain system, formed by different structures of the brain.They participate in functions such as memory, learning, emotion regulation, fear management, etc. This is one of the most ancient regions of our brain.
In addition, it is a system heavily involved in survival functions and metabolic functions. In this article we will learn what the limbic system is, and why it is also called the “emotional brain. In addition, we will explain what their structures are, where they are located and what function(s) each of them has.
Limbic system: what is it?
The limbic system, also known as the “emotional brain,” is a system made up of several brain structures which are connected to each other, and which is located in the temporal zone of the brain. This is a brain system especially related to emotions. Specifically, it is in charge of coordinating autonomous and endocrine responses with emotional states.
In addition, it also participates in the storage of information. Among its outstanding structures are the hippocampus and the amygdala.
The first person to talk about the limbic system was Paul Brocareferring to this as “the great limbic lobe”. Broca placed this system near the pineal gland. Its name comes precisely from there, because such a system made “limbo” or border with this gland, as well as with other structures.
Years later, in 1949, the physiologist MacLean conceptualized the limbic system as we know it today. In addition, he gave it its current name and added structures to it.
Structures and Functions
Thus, the limbic system is made up of various structures that connect to each other.
Let’s see what structures these are and what function(s) each one has. of them below.
1. Hypothalamus
This is a small structure formed by a large number of cores and fibers. It deals with the autonomic nervous system and the endocrine system; specifically, it is in charge of coordinating both systems. Another of its functions is to enable the survival of the species, thanks to its participation in processes of struggle, flight, feeding and reproduction.
The hypothalamus is located below another structure, the thalamus; specifically, it is located at the base of the brain, on both sides of the ventral portion of the third ventricle.
On the other hand, within it we find the mamilitary bodies, in charge of receiving impulses from other structures also of the limbic system: the amygdala and the hippocampus. Once these impulses are received, the mamilitary bodies send them back to the thalamus.
Hippocampal formation
Hippocampal formation as part of the limbic system is located in the medial temporal lobe.. Its main function is to enhance long-term memory and learning processes. It is composed of the following structures: the hippocampus, the trine/fornix and the limbic cortex. Let’s get to know each of these substructures of the limbic system:
2.1. Hippocampus
The hippocampus, a structure located in the prosencephalonplays a very important role in regulating the basic processes of survival. It is also one of the oldest regions of the human brain.
The hippocampus also plays a relevant role in memory processes; specifically, one of the memories that “regulates” is remote memory (distant past memories). This makes it a key structure for knowing who we are and where we come from, that is, for our identity.
Another memory that is in charge is the most emotional memory; the hippocampus filters those experiences that we have lived with intensity and that have “marked” us emotionally. The hippocampus, together with the hypothalamus, as parts of the limbic system, allow us to remember certain experiences and we also remember what we feel with them (that is, the emotion associated with them).
2.2. Trine/Fornix
The trine or fórnix consists of a set of axons that connects the hippocampus with other regions of the brain.. Its connection to the hippocampal mamilitary bodies is of great importance. This structure has a fundamental function in the transmission of information between different structures of the limbic system.
Limbic bark
This structure of the hippocampal formation is located in the medial temporal lobe of the brain. Its functions are related to memory processes; specifically, it is in charge of consolidating and recovering declarative memories (episodic and semantic).
Episodic memories are related to autobiographical experiences, and semantics to the learning of words and the world around us.
On the other hand, the limbic cortex connects different structures within the limbic system, just like the previous structure (trine/fornix).
3. Amygdala
The amygdala is another key structure of the limbic system, located in the medial temporal lobe.. Specifically, it is located in the lateral ventricle of the temporal lobe (inside the rostral temporal lobe). It is considered the main “centre of emotions”.
The amygdala has the following functions: to value the emotional meaning of the experiences and to coordinate the somatic expression of the emotion with the conscious feeling. In addition, it is closely related to the experience of fear, to the survival instinct and to the basic emotions of the human being. The amygdala is composed of various nuclei, which are:
3.1. Medial nucleus of the amygdala
This nucleus projects the Medial Preoptic Area and the Ventromedial Nucleus of the hypothalamus. He is involved in processes related to hunger.
Basolateral amygdala nuclei
On the contrary, these nuclei are involved in satiety processes and in learned emotional responses.
3.3. Central nucleus of the amygdala
Finally, the central nucleus of the amygdala controls the expression of the components of the emotional response (behavioural, autonomous and endocrine). It’s related to emotional experience, to feeling.
The Emotional Brain
As we have already advanced, the limbic system is also sometimes referred to as the “emotional brain. This is explained by their great involvement in diverse emotional processes.. However, more and more studies show that talking about “emotional brain” in reference to the limbic system is, if not simplistic.
Beyond emotions
We say simplistic because in reality, the limbic system is involved in many other processes, such as memory, learning, and even metabolic functions (thermal regulation, reproductive and vegetative functions).
On the other hand, the limbic system is also heavily involved in processes related to the survival of the species, such as the regulation of fear, anger, hatred, sadness and passion (although the latter are also emotions).
Bibliographic references
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Carlson, N. (2014). Behavioral physiology. Madrid: Pearson.
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Kolb, B. and Whishaw, I. (2006). Human neuropsychology. Madrid: Editorial Médica Panamericana.
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Rosenweig, M.; Breedlove, S.; Watson, N. (2005) Psychobiology. An introduction to Behavioural, Cognitive and Clinical Neuroscience. Barcelona: Ariel.