Figure 7: Model comparison for d = 1, d = 2 and d = 3 structural disorder classes, and for the kärgermodel.

a)Mean kurtosis K(t) in cortical gray matter plotted as a function of t^−0.5. b) K(t) plotted as a function of t⁻¹. c) K(t) plotted as a function of $[\ln (t/\delta )+\frac{3}{2}]/(t-\delta /3).$ d) Mean kurtosis along with the Kärger 2 model fit, Eq. (3), with K_∞ ≡ 0 in blue, and the Kärger model with an added constant K∞ as black dashed line. All the fit results are summarized in Section 4.2 and 4.3. The residuals between the fit curves and measured data are shown in the bottom row.