Prosencephalon

The prosencephalon (or forebrain), the mesencephalon (midbrain), and rhombencephalon (hindbrain) are the three primary portions of the brain of vertebrates. They develop very early during development of the central nervous system.

Brain: Forebrain (Prosencephalon)
Diagram depicting the main subdivisions of the embryonic vertebrate brain. These regions will later differentiate into forebrain, midbrain and hindbrain structures.

When the embryonic prosencephalon fails to divide the brain into two lobes, it results in a condition known as holoprosencephaly.

Other websites

• Sylvius: 400+ structure neuroanatomical visual glossary; used by over half of U.S. medical schools
• High-Resolution Cytoarchitectural Primate Brain Atlases