Subthalamus

Part of the diencephalon in the brain

The subthalamus is a part of the diencephalon located beneath the thalamus. It plays a crucial role in the regulation of movements and is involved in the basal ganglia system. The subthalamus is primarily composed of the subthalamic nucleus and the zona incerta.

Anatomy

Anatomical illustration of the basal ganglia

The subthalamus is situated between the thalamus and the midbrain. It is bordered superiorly by the thalamus, medially by the hypothalamus, and laterally by the internal capsule. The subthalamus is continuous with the tegmentum of the midbrain.

Subthalamic Nucleus

The subthalamic nucleus is a small, lens-shaped structure that is a key component of the basal ganglia circuitry. It receives input from the cerebral cortex and the globus pallidus and projects to the globus pallidus and the substantia nigra. The subthalamic nucleus is involved in the regulation of motor functions and is implicated in the pathophysiology of Parkinson's disease.

Zona Incerta

The zona incerta is a region of gray matter located between the subthalamic nucleus and the thalamus. It is less well understood than the subthalamic nucleus but is thought to play a role in modulating sensory and motor pathways.

Function

The subthalamus is primarily involved in the regulation of movement. It is part of the indirect pathway of the basal ganglia, which helps to inhibit unwanted movements. The subthalamic nucleus, in particular, is critical for the modulation of motor activity and is involved in the control of voluntary movements.

Clinical Significance

Lesions or dysfunctions in the subthalamus can lead to movement disorders. One such disorder is hemiballismus, which is characterized by involuntary, flinging movements of the limbs. This condition is often caused by a lesion in the subthalamic nucleus, typically due to a stroke.

The subthalamic nucleus is also a target for deep brain stimulation (DBS) in the treatment of Parkinson's disease. DBS of the subthalamic nucleus can help alleviate symptoms such as tremor, rigidity, and bradykinesia.

Related pages

• Thalamus
• Basal ganglia
• Parkinson's disease
• Deep brain stimulation