FIG 1. Axial FA map (left) and color coded map of mean diffusion direction (right) at the level of the basal ganglia, thalami and internal capsulae in a healthy control subject. Left, Gray-scale FA map displays a high degree of anisotropic diffusion (bright) within the internal capsule and the splenium of the corpus callosum. The cortex and the central gray matter are dark because of their low degree of anisotropic diffusion. Right, Color-coded image displays a predominant left-right-left mean diffusion direction (red) within the center of the splenium of the corpus callosum, an anteroposterior direction (green) within the optic radiations, and a superior-inferior direction (blue) within the posterior internal capsule.