Fig. 5.

The constants, C₀ and C₁, derived from the linear orientation model correlate positively with OD of ScR staining for myelin in both major white matter tracts and cortical gray matter. (A) A representative coronal section of the rat brain stained for myelin. (B) map corresponding to the myelin stain. Black boxes in A and B indicate the ROIs in which the OD of myelin, C₀ and C₁ were measured in white matter. Green boxes in A and B indicate the ROIs in which the OD of myelin, C₀ and C₁ were measured in cortical gray matter. Red boxes indicate reference ROIs employed in the computation of OD. C₀ (C and D) and C₁ (E and F) correlated positively with the myelin OD in major white matter tracts and cortical gray matter. Each data point represents a voxel from the chosen ROIs. (G and H) Linear relations between the value of C₁, calculated from fitting the linear model, and Δχ, calculated from the GL model for both white (G) and gray (H) matter. C₁ and Δχ are related through Eq. 3. The OD was used as a surrogate for the volume fraction (ζ) of perturbers in these plots.