Fields of Forel
The fields of Forel is a complex region in the posterior subthalamus, consisting of a concentrated collection of bundles of fibers. The tracts formed include the thalamic fasciculus that includes the ansa lenticularis and lenticular fasciculus, cerebellothalamic tracts, and pallidothalamic tracts. Other included fibers connect to other brain regions. These tracts are described in regions known as H fields.
H fields
- Field H1, is the thalamic fasciculus, a horizontal white matter tract composed of the ansa lenticularis, lenticular fasciculus, and cerebellothalamic tracts between the subthalamus and the thalamus. These fibers are projections to the ventral anterior and ventral lateral thalamus from the basal ganglia and the cerebellum. H1 is separated from H2 by the zona incerta.
- Field H2 is also made up of projections from the pallidum to the thalamus, but these course the subthalamic nucleus.
- Field H is a large zone of mixed grey and white matter from the pallidothalamic tracts of the lenticular fasciculus and the ansa lenticularis which combine in an area just in front of the red nucleus. The grey matter from this field is said to form a prerubral nucleus.