Restoration of normal Purkinje cell morphology in 6 week gene-on—6 week gene-off conditional SCA1[82Q] mice. A, In 6 week gene-on mice, calbindin immunostaining revealed a detectable degree of Purkinje cell dendritic atrophy. B, Calbindin immunostaining showing the severe level Purkinje cell atrophy in 12 week gene-on mice. C, In 6 week gene-on—6 week gene-off animals, calbindin immunostaining showed an essentially normal Purkinje cell morphology with the typical robust dendritic trees. D, Calbindin immunostaining showing Purkinje cell morphology in 12-week-old wild-type mice. E, A diagram of a mid-sagittal cerebellar section depicting the posterior location of the folia presented in A-D. F, Thickness of the cerebellar molecular layer in conditional SCA1 mice. Thickness of the molecular layer was determined by measuring the distance between the Purkinje cell body layers and dividing in half (n = number animals measured).