On the relationship between human and experimental granule cell type cerebellar degeneration

The fine structural alterations in a case of granule cell type cerebellar degeneration were examined and compared with the fine structure of the murine mutant "weaver." By means of both conventional processing and especially with the use of the phosphotungstic acid procedure, it was determined that the alterations in both the human disease and the murine mutant were morphologically similar. In both cases, granule cells were almost totally absent but unattached Purkinje cell dendritic spines were numerous and virtually indistinguishable from those found in the control tissue. On this basis, it is suggested that the weaver mouse may be useful as an experimental model for granule cell type cerebellar degeneration in humans. The use of the phosphotungstic acid technique on formalin-fixed tissue is discussed and its value for the examination of human pathological material is illustrated.