embryology

After gastrulation of the blastula, 3 layers are formed (ectoderm, mesoderm, and endoderm. Parts of the ectoderm are induced to give rise to neural tissue, including the neural plate. The thicker, upper portion of the neural plate eventually gives rise to the brain. The early brain is divided into three major subdivisions: prosencephalon, mesencephalon, and rhombencephalon. The mesencephalon eventually gives rise to the superior colliculus, as well as other brain structures.

To provide more detail on the further development of the mesencephalon that eventually gives rise to the superior colliculi, it has to be explained that the midbrain tectum, develops into the corpora quadrigemina (both the superior and inferior colliculi) which come from tissue in the alar plate during early development. As for the complete development of the superior colliculi from the tectum, I am unsure...any help?