ABSTRACT
We began to work on this project over a decade ago to produce a comprehensive, multi-volume Atlas of Human Central Nervous System Development (CNS). Our aim in starting this project was to try to interpret normal human CNS development in light of the understanding we have gained in the preceding three decades from an experimental analysis of the prenatal and postnatal development of the rat CNS. In that extensive work, we injected 3H-thymidine at daily intervals to groups of pregnant rats. Those injections labeled DNA in the proliferating progenitors of neurons and neuroglia in the rat embryos and fetuses. We also injected 3H-thymidine at varied intervals to groups of infant, juvenile, and adult rats to study the postnatal course of cell proliferation during late CNS development. By varying survival times after administration of the radiochemical from hours, to days and months, we used the techniques of short-survival, sequential-survival, and long-survival autoradiography to achieve the following. (1) Determine the proliferation dynamics of progenitor cells in the various compartments (mosaics) of the primary neuroepithelium (NEP) and in the various secondary germinal matrices-cortical and striatal subventricular zones (SVZ), cerebellar external germinal layer (EGL), hippocampal subgranular zone (SGZ)—as a function of prenatal and postnatal age. (2) Track the migratory routes of different populations of young neurons, their sojourn in transitional fields, and their final settling in the developing CNS. (3) Construct quantitative timetables of the birth dates of different classes of mature neurons in different components of the adult rat CNS. The results of these studies were published in a series of journal articles (see Introduction, Part ID), and were reviewed in chapters contributed to edited books (Altman, 1992; Altman and Bayer, 1975, 2004; Bayer and Altman, 1995a, 1995b, 2004b).
