In the early embryonic epiblast, some cells develop into the neural system and thus become neural ectoderm
, including the neural tube and neural crest.
Because the notochord is surrounded by the muscle, endoderm, and neural ectoderm
, these tissues are thought to affect the orientation of notochord cell movement during convergent extension.
In addition to the border, individual transcription factors that are proposed to play this role in establishing the competence of the neural plate border to give rise to the crest are often expressed in either adjacent non-neural or neural ectoderm