The fields of Forel are areas in a deep part of the brain known as the diencephalon. They are below the

thalamus The thalamus (from Greek θάλαμος, "chamber") is a large mass of gray matter located in the dorsal part of the diencephalon (a division of the forebrain). Nerve fibers project out of the thalamus to the cerebral cortex in all directions, ...

and consist of three defined,

white matter White matter refers to areas of the central nervous system (CNS) that are mainly made up of myelinated axons, also called tracts. Long thought to be passive tissue, white matter affects learning and brain functions, modulating the distributi ...

areas of the subthalamus. These three regions are also named "H fields": *Field H₁, is the

thalamic fasciculus The thalamic fasciculus is a component of the subthalamus. It is synonymous with field H1 of Forel. Nerve fibres form a tract containing cerebellothalamic (crossed) and pallidothalamic (uncrossed) fibres, that is insinuated between the thalamus ...

, a horizontal white matter tract composed of the ansa lenticularis,

lenticular fasciculus The lenticular fasciculus is a tract connecting the globus pallidus (internus) to the thalamus and is a part of the thalamic fasciculus. It is synonymous with field H2 of Forel. The thalamic fasciculus (composed of both the lenticular fasciculus a ...

, and

cerebellothalamic tract The cerebellothalamic tract or the ''tractus cerebellothalamicus'', is part of the superior cerebellar peduncle. It originates in the cerebellar nuclei, crosses completely in the decussation of the superior cerebellar peduncle, bypasses the red nu ...

s between the subthalamus and the thalamus. These fibers are projections to the ventral anterior and ventral lateral thalamus from the

basal ganglia The basal ganglia (BG), or basal nuclei, are a group of subcortical nuclei, of varied origin, in the brains of vertebrates. In humans, and some primates, there are some differences, mainly in the division of the globus pallidus into an exter ...

( globus pallidus) and the cerebellum. H₁ is separated from H₂ by the

zona incerta The zona incerta (ZI) is a horizontally elongated region of gray matter in the subthalamus below the thalamus. Its connections project extensively over the brain from the cerebral cortex down into the spinal cord. Its function is unknown, though ...

. *Field H₂ (synonymous with

) is also made up of projections from the

pallidum The globus pallidus (GP), also known as paleostriatum or dorsal pallidum, is a subcortical structure of the brain. It consists of two adjacent segments, one external, known in rodents simply as the globus pallidus, and one internal, known in rod ...

to the thalamus, but these course the subthalamic nucleus (dorsal). *Field H (sometimes called field H₃) is a large zone of mixed

grey Grey (more common in British English) or gray (more common in American English) is an intermediate color between black and white. It is a neutral or achromatic color, meaning literally that it is "without color", because it can be composed o ...

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 red nucleus or nucleus ruber is a structure in the rostral midbrain involved in motor coordination. The red nucleus is pale pink, which is believed to be due to the presence of iron in at least two different forms: hemoglobin and ferritin. ...

. The grey matter from this field is said to form a ''prerubral'' nucleus.

Nuclei campi perizonalis

Nuclei campi perizonalis or the nuclei of the perizonal fields (of Forel) are a group of nuclei in the ventral

and are considered part of the subthalamus, they comprise 3 groups of nuclei arranged as follows: *Nucleus campi medialis: the nucleus of prerubral field (field H) *Nucleus campi dorsalis: Neurons scattered along the thalamic fasciculi in field H1 of Forel *Nucleus campi ventralis: Neurons scattered along the lenticular fasciculi in field H2 of Forel

External links

Fields of Forel - Biology Online Dictionary
*Forel, A. (1877). "Untersuchungen über die Haubenregion und ihre oberen Verknüpfungen im Gehirne des Menschen und einiger Säugethiere, mit Beiträgen zu den Methoden der Gehirnuntersuchung". Archiv für Psychiatrie und Nervenkrankheiten 7: 393–495. .

References

{{Diencephalon Subthalamus