Subthalamic nucleus

The subthalamic nucleus refers to an important aggregation of neuronal cell bodies, which is situated within the subthalamic region. The latter is the most ventral part of diencephalon, located inferior to the thalamus, sandwiched between the thalamus and the mid-brain.

Functionally, the subthalamic nucleus works in close association with the basal nuclei to modulate the voluntary motor activities. The subthalamic nucleus receives inhibitory GABAergic afferents from globus pallidus externum, while it shoots off excitatory glutaminergic efferents towards globus pallidus internum and substantia nigra (pars reticularis). This way it augments the inhibitory GABAergic outflow of the basal ganglia towards the thalamus. It forms part of the indirect basal neuronal circuitry that contributes towards inhibition of the voluntary motor actions.

A lesion, such as a stroke, in the subthalamic region could lead to hemiballismus in the opposite half of the body, wherein the limbs on one side of the body suddenly start flying, involuntarily, out of control, in all directions.