Changes in neural ectoderm cell shape are induced by chordamesoderm. Cells lateral to the neural plate flatten and push toward the center over the neural folds.
Convergent extension causes narrowing and lengthening of the neural plate.
Cell shape changes at the floorplate near the midline and at the connection of the neural plate to surface ectoderm cause bending of the neural plate. The neural tube closes when the neural folds adhere to one another at the midline. In mammals, several different places close at the same time. Expression of specific genes is important for neural tube closure and formation. Pax 3 in mouse and humans is critical for neural tube closure.