On three types of large nerve cells in the granular layer of the human cerebellar cortex.

The large nerve cells of the granular layer of the human cerebellar cortex have been investigated by means of a newly developed Golgi technique that reveals the pigmentation pattern of individual nerve cells through transparent impregnations of their cell bodies and cellular processes. Three types of large nerve cells have been distinguished: Type I cells correspond to the Golgi cells. They have a rounded or polygonal cell body with only a few dendrites that radiate in all directions. The axon ramifies profusely, close to the parent soma. Cells of this type are most frequently encountered among the large cells of the granular layer. Type I cells contain only a few pigment granules. Type II cells have a fusiform or triangular cell body with a few rather extended dendrites that rarely ramify. Cells of this type are either devoid of pigment or contain a few large pigment granules that can be stained intensely by aldehydefuchsin. Type III cells are multipolar neurons with a fair number of dendrites originating from any point of the soma. The dendrites extend into the deep portions of the molecular layer. Here and also within the Purkinje cell layer they repeatedly branch off forming a dense dendritic arborization. Cells of this type are evenly distributed throughout the entire granular layer and throughout the adjacent portions of the Purkinje cell layer and the white matter as well. Type III cells are filled with tightly packed lipofuscin granules. The pattern of pigmentation is characteristic for each of these neuronal types. The three types of large nerve cells within the granular layer of the human cerebellar cortex can therefore be distinguished not only in Golgi impregnations but also in pigment-Nissl preparations.