Astrocytes in the developing human brain. An immunohistochemical study.

Patterns of appearance and maturation of astrocytes, as demonstrated by the immunohistochemical detection of glial fibrillary acidic protein (GFAP), were studied in fetal and mature neonatal brains. Mature astrocytes were present throughout much of the normal central nervous system at 15 weeks of gestation, but they varied in density in different parts. Glioneogenesis continued throughout the fetal and postnatal ages. Marginal glia were conspicuous with strong reaction and probably constituted a distinct subpopulation of glia. There was no temporal relationship between astrocytic proliferation and "myelination gliosis". Radial glia and Bergmann fibers in normal brains did not react to GFAP antiserum.