Pa of neural tube from which corpus callosum develops
Initially, corpus callosum forms a small bundle in the lamina terminalis and later extends first anteriorly and then posteriorly, arching over the thin roof of the diencephalon. It connects the nonolfactory areas of the right and the left cerebral coices. Ref: Gray's39e/p-518
Lamina terminalis
Basal lamina
Alar lamina
Roof plate
Brain 