Neural tube
and folate
The BRAIN magazine
The human central nervous system (the brain and spinal cord) contains around 100 billion neurons distributed between four main areas: the forebrain, midbrain, hindbrain and spinal cord. A fascinating question immediately arises: what are the embryonic origins of such a complex organ?
We now know that the central nervous system begins as a simple sheet of cells, called the neural plate, on the dorsal surface (think the dorsal fin of a shark) of the very young embryo three weeks after conception.
Between four and six weeks, the neural plate lengthens along the entire head-to-tail axis of the growing embryo. The plate’s edges curl upwards and fuse to form the neural tube, a cylinder comprising stem cells that eventually produce all cells in the central nervous system.
Failure of the neural tube to fuse lengthways can result in devastating conditions, such as anencephaly, where the neural tissue bulges from the brain, or spina bifida, where the end of the spinal cord remains open.
Neural tube defects occur frequently in the population (~1/1000 pregnancies). The introduction of B vitamin folate, an important ingredient in the production of key metabolic molecules, into the diet of pregnant mothers and women of childbearing age greatly reduces the risk.