Figure 1.

Parasagittal sections through the cerebellar cortex of 4-month-old tbl/tbl mice. 1.5 μm-thick sections illustrate that disappeared Purkinje cells are substituted by glial Golgi-epithelial cells (g, A,B). Remaining degenerating Purkinje cells possess degenerative dark accumulations within the cytoplasm of the soma (A,B, asterisk, arrows) and thick, dark dendritic trees (A, small arrow). Note the swelling of glial processes surrounding Purkinje cells (B, arrowhead). Degenerative signs consisting of lysosomes, electron-dense debris, and autophagosomes with different degrees of evolution (arrows in C–F), are present in the dendrites of the molecular layer and in the Purkinje cells’ cytoplasm (arrows, in C,F). Necrotic debris is also engulfed by glial cell processes (D,E, g). n, nucleus of a Purkinje cell. Pf, parallel fiber. Bars = 20 μm (A,B), 2 μm (C), and 0.5 μm (D–F).