Forebrain

In the anatomy of vertebrates, the prosencephalon (or forebrain) is the rostral-most portion of the brain. The prosencephalon, the mesencephalon (midbrain), and rhombencephalon (hindbrain) are the three primary portions of the brain during early development of the central nervous system.

At the five-vesicle stage, the prosencephalon separates into the diencephalon (thalamus and hypothalamus) and the telencephalon (cerebrum). The cerebrum consists of the cerebral cortex, underlying white matter, and the basal ganglia.