Golgi impregnation of individual cerebellar Purkinje cells shows dendritic abnormalities in the adultrocker mutants. A, B, Branching in the wild-type Purkinje cell usually appears very dense, with an increasing number of branching points near the distal tips.C, D, Purkinje cells in older rockermutants show a decrease in branching and have downturned distal ends of their dendritic tree (D, arrow). Scale bars: A, C, 50 μm; B,D, 25 μm.