When we think of the brain, we usually imagine the surface and outermost layer, the cerebral cortex.However, underneath it we can find a large number of structures of fundamental importance for the survival of the human being, all of them participating in different types of functions such as the integration of information.

One of these subcortical structures is the caudate nucleus, whose characteristics we will see below .

What is the caudate nucleus?

The caudate nucleus is a subcortical structure, that is, located inside the brain, which is part of the basal ganglia . Together with the putamen and the nucleus accumbens it forms the so-called striated body, an element closely linked to the control of movement.

Located above the thalamus and below the orbitofrontal cortex and then curved towards the occipital lobe, the caudate nucleus is connected both to the rest of the basal ganglia and to the frontal cortex and limbic system. We have two units of this nucleus, each one located in a cerebral hemisphere. At the level of neurotransmitters, the caudate nucleus is mainly influenced by dopamine and GABA.

The caudate nucleus is usually divided into three parts , the head, the body and the tail. While the first is one of the thickest parts and is in more contact with the frontal cortex, the tail is connected to the limbic system. Head and body are in close contact with the lateral ventricles.

Main functions of the caudate nucleus

The caudate nucleus and the set of basal ganglia have a high importance in the human nervous system, participating in essential functions to guarantee both a correct adaptation to the environment and survival itself by allowing the regulation of behavior through aspects such as memory and motivation. Furthermore, they have also been linked to a great extent to the realization and coordination of movements .

Below you can find details of some of the functions that have been attributed to the caudate kernel.

Movement control

Together with the rest of the basal ganglia, it has been traditionally considered that the caudate nucleus has a high participation in motor control and coordination . The maintenance of the position of the members of the body, and precision in fine movement are some of the aspects in which the caudate participates. This can be seen in the consequences of their dysfunction, in disorders such as Parkinson’s and Huntington’s disease.

Memory and learning

Learning and memory are elements in which it has been found that the caudate nucleus also plays an important role. For example, procedural learning depends on this brain area . Specifically, the caudate nucleus allows the organism to obtain feedback from the outside world about what is happening and what is being done. It also participates in the understanding of auditory stimuli, such as those of language.

Sensation of alarm

Another of the main functions of this brain region is the perception of the sensation of alarm , thanks to which we can identify that something is not working properly and respond accordingly.

Motivation

The caudate nucleus is of paramount importance in terms of the motivational capacity of the human being. It is a structure that connects the limbic system with the frontal cortex , so that cognitive information is transformed and linked to an emotional meaning. Its destruction can generate the appearance of extreme abulia and PAP syndrome.

Disorders and alterations in which it participates

The caudate nucleus and in general the set of basal ganglia, due to their multiple connections with other brain areas such as the orbitofrontal cortex or the limbic system, are structures of great importance for the correct functioning of the nervous system and for our adaptation to the environment.

The presence of alterations can generate or participate in the genesis or maintenance of various types of disorder. Some of the disorders in which the caudate nucleus participates are the following.

1. Obsessive-Compulsive Disorder and other obsessive disorders

As we have mentioned, the caudate nucleus has an important role in the response mechanism to a specific situation, as well as in the sense of alarm. In OCD this mechanism is overactivated , and it is found that patients with this disorder usually have a high level of neural activation in the caudate.

In addition to OCD itself, other disorders of a similar nature, such as accumulation disorder, excoriation disorder, or trichotillomania, may also have this high level of activity.

2. Attention Deficit Hyperactivity Disorder

ADHD is another disorder in which the caudate nucleus has some level of involvement. Specifically, in this case a lower than usual activation is observed, which reduces the capacity for recall, feedback and motivation .

3. Huntington’s Korea

In Huntington’s Korea, the caudate nucleus is one of the first areas to present neuronal death, and in the long run it ends up generating a progressive loss of executive functions and memory and the performance of uncontrolled movements in the form of twists and turns of body parts similar to a dance.

4. Parkinson’s

Parkinson’s is another disease linked to the caudate nucleus. Specifically, Parkinsonian symptoms are produced by the degradation and death of the neurons that form the nigrostriatal pathway .

5. Psychic self-activation loss syndrome

Damage to the caudate nucleus causes loss of motivation and makes the connection between emotion and cognition difficult. This is why its destruction generates a deep sense of indifference whatever happens, even if it threatens one’s survival.

6. Hypermnesia

Although generally not considered a disorder, the presence of hypermnesia in some people has been linked, among other brain regions, to the caudate nucleus. Specifically, it has been observed that people with above-average memory abilities have a larger caudate nucleus than most people.

Bibliographic references:

  • Carlson, N.R. (2014). Physiology of Behavior (11th Edition). Madrid: Pearson Educación.
  • Kandel, E.R.; Schwartz, J.H. & Jessell, T.M. (2001). Principles of neuroscience. Fourth edition. McGraw-Hill Interamerican. Madrid.
  • Melnick, M.E. (2013). Basal ganglia disorders. In: Umphred DA, Burton GU, Lazaro RT, Roller ML, eds. Philadelphia, PA: Elsevier Mosby; chap 20.
  • Packard, M.G. & Knowlton, B.J. (2002). Learning and memory functions of the basal ganglia. Annu Rev Neurosci 25:563-59.