And we also have these two tiny extensions known as the neural crest. Now the neural tube eventually forms the brain and the spinal cord. So it's the neural tube that eventually forms the central nervous system. On the other hand, it's these two neural crests that give rise to the peripheral nervous system so they give rise to the ganglia that is found outside the brain and the spinal cord. And this process by which we form the neural tube and the neural crest and eventually they give rise to the central nervous system and the peripheral nervous system. This process is known as neuralization.