Prosencephalon

Overview
In the anatomy of the brain 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 (prethalamus, thalamus, hypothalamus, subthalamus, epithalamus, and pretectum) and the telencephalon (cerebrum). The cerebrum consists of the cerebral cortex, underlying white matter, and the basal ganglia.

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