The Sonic hedgehog gene also plays a role in attenuating BMP expression, forming the medial hinge point while inhibiting the formation of the dorsolateral hinge points, and in ensuring the proper closure of the neural folds.The prechordal plate, notochord, and non-neural ectoderm are believed to be important inducer tissues that release these chemical signals, in order to trigger neural plate folding.

The final adhesion of the converging neural folds is due to several different types of intercellular