Myelencephalon
The myelencephalon (plural: myelencephala or myelencephalons) is a secondary vesicle of the neural tube derived from the rhombencephalon.
The myelencephalon goes on to become the medulla oblongata, and its CSF-filled cavity, the central canal. However it should be noted that the myelencephalon also contributes to the formation of the floor of the fourth ventricle . The medulla oblongata houses the reticular formation, which is involved in wakefulness, attention and multiple survival reflexes.