Lenticular nucleus: parts, functions and associated disorders

The basal ganglia They are a series of parts of the brain located deep in the brain that are of great importance for the performance of various functions. It is a set of various structures and substructures, which can be grouped based on their connections between them.

One of these structures or rather a set of them is the so-called lenticular nucleus, which is especially relevant in motor skills management, as well as in learning and motivation.

• Related article: "Basal ganglia: anatomy and functions"

The lenticular nucleus: parts and characteristics

The lenticular nucleus is a subcortical structure of the brain, located in the inner part of the brain. This nucleus is part of the basal ganglia, a set of structures configured by Gray matter (that is, it is mainly neuronal somas and dendrites).

Also called the extraventricular nucleus of the striatum, the lenticular nucleus is configured by three segments, although said three segments can be divided mainly into two structures; putamen (which would be the outermost segment) and

pale balloon (which would collect the middle and internal segments).

Thus, it can be considered that the lenticular nucleus is the union of two other structures of the basal ganglia, putamen and pale globe.

This wedge-shaped structure is in contact with the internal capsule, which separates it from the thalamus and the caudate, and with the external capsule that separates it from the cloister and the insula. It connects with the aforementioned thalamus, the cerebral cortex and the set of structures that make up the Brain stem.

Functions associated with this subcortical structure

The lenticular nucleus, like the set of structures that make up the basal ganglia, is a structure or set of structures of great importance for the correct vital functioning of the being human. Specifically, it has been observed to be of great importance in the following areas.

1. Motor skills

One of the aspects in which the most research has been done and which has been known for the longest time is the great importance of the lenticular nucleus in motor skills and movement management and coordination. Its main task in this sense passes through the adaptation of the movement to the situations that are being experienced and through the adjustment to the situational demands.

2. Posture maintenance

The lenticular nucleus participates not only in the realization of specific movements, but is also related to the maintenance of posture. Damage to the lenticular nucleus can lead to gait difficulties, incoordination or uncontrollable shaking.

3. Automation of movements

The automation of movements is also affected by the lenticular nucleus, allowing habituation to its performance.

4. Learning

The lenticular nucleus influences learning processes. Specifically, it helps to generate procedural learning. Furthermore, through its various connections, the lenticular nucleus contributes to the creation of categories when organizing and structuring the world.

5. Motivation

Like other areas such as the caudate nucleus, the lenticular nucleus also contributes greatly in link the rational with the emotional, allowing both types of information to be integrated. This means that thanks to their connections we can link a knowledge or stimulus to an emotion, which can motivate or demotivate us.

• Related article: "Are we rational or emotional beings?"

Lenticular nucleus-related disorders

The presence of alterations and lesions in the basal ganglia can have devastating repercussions on the health of the organism, as well as diminish its most basic capacities. Some of the alterations that are linked to damage to the lenticular nucleus are the following.

1. Subcortical dementias

The progressive degeneration caused by this type of dementia tends to begin in different subcortical structures, one of the most frequent being the basal ganglia. The dementias produced by the Parkinson'sor by Huntington's chorea are two of the best known, which involve uncoordinated gait, performing different jerky movements either at rest or during movements and a loss of memory and abilities executive.

2. Psychomotor disorders

Disorders such as tic disorders or Gilles de la Tourette's, or Parkinson's disease itself without this may cause dementia, they are also influenced by the alteration of the basal ganglia.

3. Obsessive-compulsive disorder

OCD has also been associated in part with overactivation of the basal ganglia, especially the caudate nucleus and the putamen (the latter forming part of the lenticular nucleus).

• Related article: "Obsessive-Compulsive Disorder (OCD): what is it and how does it manifest itself?"

4. ADHD

The ADHD It is another of the disorders that is influenced by the presence of damage to the lenticular nucleus, making it difficult to maintain motivation and enhancing the appearance of tics and agitation.

Bibliographic references:

• Carlson, N.R. (2014). Physiology of Behavior (11 Edition). Madrid: Pearson Education.

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