Subthalamus: parts, functions and associated disorders.

This brain region is part of the diencephalon and is essential in the control of movements.

The human brain is made up of a large number of structures and substructures that account for different body systems and different cognitive and emotional abilities and capacities.

All the information we take infor example, must be integrated in order to form a concrete representation of reality. In the same way that different processes must also be integrated when responding to environmental stimulation.

There are different relay centers where these associations are made, such as the thalamus. But in addition to the thalamus, there are different brain structures with similar functions, such as the thalamus. brain structures with similar functions, such as the subthalamus..

What is the subthalamus?

The subthalamus is a complex structure linked to the management of bodily movement and which has a great multitude of connections with different brain regions, such as the substantia nigra and the red nuclei, although some of its most important connections are with the globus pallidus.

This structure is part of the diencephalon and is located between the diencephalon and the diencephalon. and is located between the brainstem and the cerebral hemispheres. Specifically, it can be found below the thalamus, from which it is separated by the interthalamic limiting zone, and above the midbrain (specifically the tegmentum). It also connects with the hypothalamus.

In addition to those already mentioned, other structures with which the subthalamus connects include the motor and prefrontal cortex or the basal ganglia.

Main divisions of the subthalamus

The subthalamus can be divided into the different structures that make up the subthalamus.. The main sections that can be considered within this brain region are the following.

1. Subthalamic nucleus

One of the main structures of the subthalamus, the subthalamic nucleus, is an oval-shaped nucleus located in the central part of the zona incerta (to be discussed later). This brain region is of great importance due to the large amount of afferents it receives. The most relevant due to its link with the management of movement is the relationship it has with the ganglia. the relationship it has with the basal gangliawith which it interacts through the use of glutamate.

It also has glutamatergic connections with the primary motor, prefrontal and premotor cortex, as well as with the thalamus and the reticular formation.

2. Uncertain zone

Located between the lenticular and thalamic fasciculus, the zona incerta is one of the substructures of the subthalamus. This lamina-shaped nucleus is involved in movement control, part of the extrapyramidal pathway and in connection with the motor cortex.. In its center is the subthalamic nucleus.

3. Forel's nuclei

Nuclei of Forel's areas are three small white matter areas of the subthalamus, also called Forel's fieldswhich act as nerve projections to different brain regions.

Main functions

The subthalamus is a structure of great importance for the correct functioning of the human being, having a great role in the integration of motor information that allows the management of movement. It is especially linked to involuntary aspects of movement and its precise control.It has a great impact on its connection and influence with the basal ganglia.

In addition to motor control, it has also been observed that the subthalamus influences orientation and balanceIn the event of injury, a greater risk of falls is observed in the uncertain area.

Lesions in the subthalamus

The presence of subthalamic lesions usually causes symptoms related to movement control.. In general, a lesion in this area tends to produce sudden and involuntary movements, such as spasms and choreic movements of the extremities.

Regarding the latter, the lesion of the subthalamus is especially linked to Huntington's chorea, in which the subthalamic nucleus is particularly affected. The same occurs in Sydenham's chorea, of infectious origin.of infectious origin. The degeneration of this structure causes the choreic movements characteristic of these diseases.

It is also observed that the lesion of the subthalamus in its connection with the globus pallidus can generate hyperkinesia or excessive uncontrolled movements. On the other hand, it has been proposed that stimulation of this region could be useful in alleviating the symptoms of Parkinson's disease. could be useful in alleviating the symptoms of Parkinson's disease or other movement disorders, due to its effect on aspects such as locomotion and posture, through or other movement disorders, due to its effect on aspects such as locomotion and posture, through transcranial magnetic stimulation.

Bibliographic references:

• Snell, R.S. (2006). Clinical Neuroanatomy. 6th edition. Editorial Médica Panamericana. Madrid.

• López, L.(2003). Functional Anatomy of the Nervous System. Noriega Editores. Mexico.

• Afifi, A.K. & Bergman, R.A. (2007). Functional neuroanatomy. 2nd edition. Mc Graw-Hill Interamericana.