Pallidothalamic tracts

The pallidothalamic connections (or pallidothalamic tracts) are a part of the basal ganglia. They provide connectivity between the globus pallidus and the thalamus, primarily the ventral anterior nucleus and the ventral lateral nucleus.

Anatomy
It is composed of the Ansa lenticularis, the Lenticular fasciculus (Forel's Field H2), and Thalamic fasciculus (Forel's Field H1).


 * The ansa lenticularis is composed of fibers that pass from the ventral aspect of the globus pallidus and sweep around the posterior limb of the internal capsule. They connect with the fibers of the lenticular fasciculus in the Field of Forel (H) to form the thalamic fasciculus.


 * The lenticular fasciculus (also known as Forel's Field H2) is composed of fibers that pass from the internal part of the globus pallidus, through the posterior limb of the internal capsule, around the zona incerta. These fibers connect with the fibers of the ansa lenticularis in the Field of Forel (H) to form the thalamic fasciculus.


 * The thalamic fasciculus (also known as Forel's Field H1) is formed by the fibers of the ansa lenticularis and the lenticular fasciculus that merge in the Field of Forel (H). The fibers of this fasciculus then travel to the thalamus and primarily terminate in the ventral anterior nucleus and ventral lateral nucleus. Some fibers travel to the interthalamic nuclei.