Figure 2.

Graphic representation of the tensor shapes in voxel containing (A) Single group of axon bundle, (B) two groups of crossing axon bundles. In voxels with crossing fibers the secondary eigenvector (V₂), perpendicular to the primary eigenvector orients in the direction parallel to the plane containing the crossing fibers. However, the tertiary eigenvector (V₃) remains perpendicular to both crossing axonal fibers (Wiegell et al., 2000) and hence more closely represents the water diffusion in the direction perpendicular to the axon bundles.