It begins in the third and fourth weeks of pregnancy.
Various cell signaling and gene regulation are needed for the complex morphogenic process of neural tube formation during gestation.
Neural plates build the neural tube through a process called neurulation.
The lateral borders of the neural plates thicken around the end of the third week, forming neural folds. The midsection's depression creates neuronal grooves.
The midline of the neural folds subsequently meets and fuses. Starting from the cervical region, fusion progresses caudally and cranially. The neural tube develops as a result.
The embryonic brain, spinal cord, and central nervous system are all formed from this neural tube.
Errors during this process could lead to congenital defects such as neural tube deformities.