Derivatives of the diencephalon include the dorsally-located epithalamus (essentially the habenula and annexes) and the perithalamus (prethalamus) containing the zona incerta and the thalamic reticular nucleus.
Due to their different ontogenetic origins, the epithalamus and the perithalamus are formally distinguished from the thalamus proper.
The metathalamus is made up of the lateral geniculate and medial geniculate nuclei.

The thalamus comprises a system of  lamellae (made up of myelinated fibers) separating different thalamic subparts.
Other areas are defined by distinct clusters of neurons, such as the periventricular nucleus, the intralaminar elements, the "nucleus limitans", and others.
These latter structures, different in structure from the major part of the thalamus, have been grouped together into the allothalamus as opposed to the isothalamus.
This distinction simplifies the global description of the thalamus.
Derivatives of the diencephalon include the dorsally-located epithalamus (essentially the habenula and annexes) and the perithalamus (prethalamus) containing the zona incerta and the thalamic reticular nucleus. Due to their different ontogenetic origins, the epithalamus and the perithalamus are formally distinguished from the thalamus proper. The metathalamus is made up of the lateral geniculate and medial geniculate nuclei.
The thalamus comprises a system of  lamellae (made up of myelinated fibers) separating different thalamic subparts. Other areas are defined by distinct clusters of neurons, such as the periventricular nucleus, the intralaminar elements, the "nucleus limitans", and others. These latter structures, different in structure from the major part of the thalamus, have been grouped together into the allothalamus as opposed to the isothalamus. This distinction simplifies the global description of the thalamus.
Thalamus