at 2 weeks

I had been looking for a few days now for pictures of the very earliest embryonic development, that showed very early neural development. Thank you Institut National de Recherche Pédagogique.



This is what a human embryo looks like at three weeks. The disk itself is only a couple of cells thick. The black line over on the left there is wonderfully called the primitive streak.

- Courtesy of Institut National de Recherche Pédagogique

After the primitive streak fully forms, the neural tube begins to close. This picture is taken at about 22 days after fertilization.

- Courtesy of Institut National de Recherche Pédagogique