Embryonic Development of the Central Nervous System

in vitro fertilization

The central nervous system appears in the middle of the 3rd week of the development as a thickened area of the embryonic ectoderm, the neural plate. Its lateral edges become elevated to form the neural folds, which approach each other and fuse in the middle, thus forming the neural tube. At the cranial and caudal end of the embryo the neural tube is temporarily open and communicates with the amniotic cavity by the way of the cranial and caudal neuropores. The neural tube differentiates into the central nervous system, consisting of the brain and spinal cord, and the neural crest, which gives rise to the most of the peripheral nervous system. The neural canal becomes the ventricular system of the brain and the central canal of the spinal cord.

NEURAL PLATE then NEURAL GROOVE then NEURAL TUBE then ANTERIOR END NEURAL TUBE becomes brain and brain stem then POSTERIOR END NEURAL TUBE becomes spinal cord

If the neural tube fails to close- Anterior end- Anacephalic child Posterior end- Spina Bifida

In-utero surgery to treat spina bifida delivery after fetal surgery considering in-utero fetal surgery In-utero surgery to treat spina bifida delivery after fetal surgery

By the end of the 4th week- Brain Body cavities Somites Tail

4 Week Embryo

Embryo at 6 Weeks

At 12 Weeks

What can cause problems with CNS development? Maternal infection- Oxygen deprivation- Hydrocephalus- Premature birth- Radiation, drugs, etc.-

Thalidomide

CNS after birth

WHILE BRAIN MASS DECLINES WITH AGE, FUNCTION MAY BE MAINTAINED Soooooooooooo… WHILE BRAIN MASS DECLINES WITH AGE, FUNCTION MAY BE MAINTAINED