DAB immunostaining for the CB₂ receptor in the Purkinje layer and dentate nucleus of the cerebellum of SCA patients (B, B.I, D and D.I) and control subjects (A, A.I, C and C.I). The arrows indicate the Purkinje cells that are CB₂ receptor-positive, whereas the arrowheads indicate other CB₂ receptor-positive cells that presumably are Bergmann glial cells (scale bars: A–D = 100 μm; A.I-D.I = 25 μm). The microphotographs of SCA samples correspond to subject #9 (SCA7) for the Purkinje layer and to subject #10 (SCA6) for the dentate nucleus. The bar panel corresponds to the quantification of CB₂ receptor immunostaining in the two structures of SCA patients and control subjects. Values correspond to the mean density of labelling in individual cells and are expressed as means ± SEM of five subjects per group. Data were assessed by Student's t-test (*P < 0.05; **P < 0.01).