Organ
Subthalamic nucleus
A glutamatergic node in basal-ganglia circuits
High-yield
The subthalamic nucleus contributes to the indirect pathway and the direct cortex-to-subthalamic, or hyperdirect, pathway. Damage can cause contralateral hemiballismus, but the movement disorder can also arise from lesions elsewhere in the connected network.
Overview
This small biconvex nucleus lies below the thalamus and above substantia nigra, medial to the internal capsule. It receives inhibitory input from external globus pallidus and excitatory cortical input. Its predominantly glutamatergic projections reach internal globus pallidus and substantia nigra pars reticulata, helping regulate their inhibitory output.
Reference facts
- Location
- Subthalamic region near the diencephalon–midbrain junction, medial to the internal capsule and dorsal to substantia nigra.
- Parts
- A biconvex nucleus with overlapping motor, associative and limbic territories.
- Blood supply
- Perforating branches from posterior communicating and posterior cerebral arterial systems; studies differ on the relative contribution of particular branches.
- Relations
- Thalamic and zona-incerta regions above, substantia nigra below, and internal-capsular fibers lateral and anterolateral.
- Function
- Excites basal-ganglia output nuclei and participates in action selection and restraint, alongside nonmotor circuits.
Clinical correlation
Hemiballismus consists of large, irregular flinging limb movements, often after a contralateral vascular lesion. The STN is also one of the commonly selected deep-brain-stimulation targets for Parkinson disease; selection depends on the person's clinical circumstances.
Frequently asked questions
Where is the subthalamic nucleus located?
Subthalamic region near the diencephalon–midbrain junction, medial to the internal capsule and dorsal to substantia nigra.
What does the subthalamic nucleus do?
Excites basal-ganglia output nuclei and participates in action selection and restraint, alongside nonmotor circuits.
What are the parts of the subthalamic nucleus?
A biconvex nucleus with overlapping motor, associative and limbic territories.
What is the blood supply of the subthalamic nucleus?
Perforating branches from posterior communicating and posterior cerebral arterial systems; studies differ on the relative contribution of particular branches.