[2] It consists of structures that are on either side of the third ventricle, including the thalamus, the hypothalamus, the epithalamus and the subthalamus.

During the third week of development a neural tube is created from the ectoderm, one of the three primary germ layers.

The tube forms three main vesicles during the third week of development: the prosencephalon, the mesencephalon and the rhombencephalon.

The thalamus serves as a relay centre for sensory and motor impulses between the spinal cord and medulla oblongata, and the cerebrum.

This article incorporates text in the public domain from page 807 of the 20th edition of Gray's Anatomy (1918)