Mechanisms of Neural Plate Formation

You are familiar with the concept that the neurulation comprises of two processes

i) The neural plate formation and

ii) The neural tube formation.

The mechanisms accountable for these two processes are not very clear. The shaping of neural plate from an oval to a long, narrow plate is believed to take place by the elongation of neural epithelial cells and the accompanying apical shrinkage. Even though it was earlier believed that microtubules may be involved in the elongation process, proof is inconclusive to suggest a role for microtubules in the elongation process. The role of microtubule appears to be significant in stabilizing the elongated state of the cells rather than in the elongation itself. Various hypotheses have been put forward to explain the bending of neural plate to form neural tube. The much more acceptable one is that during the rolling of neural plate, the apical surface of neural epithelial cells contract at the site of bending due to the contraction of actin microfilaments.