subthalamus

The subthalamus is a component of the brainstem, located beneath the diencephalon and consisting primarily of the subthalamic nucleus. This lens-shaped structure is situated behind and to the sides of the hypothalamus and on the dorsal surface of the internal capsule. The subthalamic region is traversed by fibers related to the globus pallidus. Discrete lesions in the subthalamic nucleus can result in hemiballismus, a severe form of dyskinesia characterized by involuntary flinging movements of the limbs. The thalamus, a paired organ forming much of the third ventricle's walls, translates neural impulses from receptors to the cerebral cortex and is involved in sensory relay, motor activity, emotion, and memory.123