Zona incerta

Zona incerta refers to a group of neuronal cell bodies which are situated inside the subthalamic region. They lie between the ventral part of external medullary lamina of thalamus above and the cerebral peduncle below. Laterally, they are related to the reticular nucleus, while medially, a matrix of white matter tract fibers–called the H-Field of Forel–can be found.

Zona incerta receives afferent neurons from various sources, such as, the sensorimotor cortex, the pregeniculate nucleus, deep cerebellar and trigeminal nuclei and the spinal cord. Efferents from the zona incerta project to the spinal cord and the pretectal region.

Exact function of zona incerta cells is unknown, however, since these cells give off dopaminergic projections, therefore deep brain stimulation of this region has been attempted to relieve tremors in Parkinson disease patients.