Fetal development of the central nervous system
From the 8th week of gestation, the human brain undergoes prodigious growth due to high proliferative activity in the ventricular and subventricular germinal zones of the forebrain. Registration of ventricular germinal compartments with destinations in the developing pallium, striatum, and diencephalon is achieved in part by CD15 immunoreactive radial glia and these glia also demarcate neuromeric organization at least in the forebrain. Formation of connections occupies the middle and third trimester and myelination proceeds from the last trimester into postnatal life. Understanding of the key developmental events in fetal brain development is essential for determining the causes of a variety of modern medical probelms including intellectual disability and schizophrenia.