Some quantitative morphological aspects of post-natal human cerebellar growth.

Using a Quantimet 720 image analysing computer, the cellularity of the external and internal granular layer and the molecular layer has been measured in standard blocks of the lateral and central lobes of the cerebellum of apparently normal children. The DNA content of the nerve cells has also been measured and related to post-natal age. Standard cell concentrations per unit area have been established from birth to 14 years. The different lobules of the central lobe show different patterns of cellular development but all lobules reach their fully mature cellularity by 2 years. The maximum cellularity of the internal granular layer is maintained for several years, after which there is an apparent progressive reduction in the concentration of cells per unit area. Alterations in the DNA staining properties of the cell nuclei of the internal granular layer during normal development are presented.