A, Mean area of the median cerebellar vermis in 3- to 8-month-old WT mice (n = 2), 3- to 13.5-month-old Chi3Prnp+/+ mice (n = 4), 3-month-old tga20+/− mice (n = 2), and Chi3tga20+/− mice (n = 2) (*p < 0.01). B, Mean number of PCs per millimeter of PCL in Toluidin blue-stained semithin sections of the median cerebellar vermis of 3- to 8 month-old WT mice (n = 2), 3- to 13.5-month-old Chi3Prnp+/+ mice (n = 4), 3-month-old tga20+/− mice (n = 2), and 3-month-old Chi3tga20+/− mice (n = 2) (*p < 0.01). C, Mean density of NeuN immunolabeled GCs in the IGL in sagittal paraffin sections of the median cerebellar vermis of 3- to 8-month-old WT (n = 2) and 3- to 13.5-month-old Chi3Prnp+/+ (n = 4) mice (*p < 0.05).