Age related changes in Purkinje cell number in the cerebellar nodulus of the mouse.

The cortex of the cerebellar nodulus of mice aged 6, 15, 22, 25, 28 and 31 months was examined in parasagittal sections using quantitative histological techniques. The number of Purkinje cells per mm declined from 11.2 +/- 0.8 or 6 months to 7.0 +/- 0.6 at 31 months. Granule cell density remained constant (2.58 x 10(6) per mm3) between 6 and 31 months of age. The granule cell to Purkinje cell ratio increased from 119 +/- 7 at 6 months of age to 173 +/- 7 at 31 months of age. The change in Purkinje cell number began between 15 and 22 months of age. These results do not differ significantly from those of a similar study of quantitative histological changes in the anterior lobes of the same cerebella. This suggests that loss of Purkinje cells occurs in a similar fashion throughout the cerebellum despite differences in afferent and efferent connections in different regions.