Figure 2.

Residual variability (i.e., total entropy) for normalizations performed by varying more than one parameter at a time: frequency cutoff (25 mm* or 70 mm) and regularization (light, medium* or heavy), for both SPM5 methods (top graph: standard, bottom graph: unified). Regularization had little effect when applying a larger frequency cutoff. The unified model was relatively insensitive to the choice of frequency cutoff or regularization. The unified method provided greater values of total entropy relative to the standard method. One outlier was excluded from the figure (unified method) because the total entropy for this subject was consistently more than three fold lower than the first quartile of the diabetic group. (* denotes default parameters for nonlinear transformation in SPM).