[Early differentiation of the nervous system (author's transl)].
D000818:Animals; D002454:Cell Differentiation; D002490:Central Nervous System / Q000166:cytology / Q000196:embryology*; D002540:Cerebral Cortex / Q000196:embryology; D002642:Chick Embryo; D004475:Ectoderm / Q000166:cytology; D005260:Female; D006801:Humans; D009024:Morphogenesis; D009474:Neurons / Q000648:ultrastructure; D011247:Pregnancy; D013997:Time Factors