[Development of the human fetal brain: volumetric analysis of the component parts]

Development of human fetus brain was morphometrically evaluated through measuring volumes of the cerebrum and its component parts (i.e. cerebral cortex, subcortical white matter, basal ganglia, diencephalon, ventricles, embryonal periventricular cell layer, etc.) in the second trimester of gestational period. For the measurement of volumes, authors employed a unique method which consisted of a combination of serial celloidin sections, electric image-analyzer and computer. We found that each component part of fetus brain developed heterochronously from the view point of volumetric analyses. In the component parts of cerebrum, diencephalon developed first, followed by subcortical white matter and ganglia, and cerebral cortex developed last. It is concluded that a combined method of serial sections, image-analyzer and computer analyses is reliable and useful to obtain more precise and objective information for the morphometrical evaluation of brain development.