Normative cerebellar scaling. Scatter plots of volumetric data and best-fit scaling models for selected cerebellar regions. Gray points indicate volumetric observations for females (circles) and males (triangles) in the allometric sample. Superimposed lines show the best fit log–log relationship between aTBVs and cerebellar volumes (±95% confidence intervals). Sexes are modeled separately in regions with statistically significant sex differences in scaling or offset (p < 0.05). The cerebellum as a whole scales hypoallometrically with aTBV, and shows an aTBV-independent volume increase in males vs females. Note the diversity of scaling models across different cerebellar subregions. These plots show the reference fit lines used for “allometrically corrected” reanalysis of cerebellar anatomy in SCA.