Prenatal human lateral geniculate nucleus: a quantitative light microscopic study.

Using morphometric methods, a quantitative study has been carried out on the lateral geniculate nucleus (LGN) of human fetuses ranging in gestational age from 13 to 38 weeks. The volume of the nucleus as well as the neuronal, glial and dead cell populations have been studied in Nissl preparations. While the volume of the LGN shows a progressive increase throughout the period of study, the age period of 15-20 weeks is identified as a period of spurt in volumetric growth. Neuronal density and total neuronal number fall continuously while glial density and total glial population show a steady increase with advancing gestational age. Pyknotic dead cells are seen throughout the period of study with a peak die off between 14 and 18 weeks. The study, for the first time, outlines the critical period for volumetric spurt and neuronal death in the developing human LGN.