Fig. 1.

Reconstructions of the MdLF in a single healthy control and a PPA subject. Tracts are superimposed onto the subject's T1-weighted image normalized into the DTI space. A. The color of these tracts was scaled by the mean FA value of each tract. B. The color of these tracts was scaled by the mean MD value of each tract. The mean FA value of the MdLF was lower (more blue) in this PPA patient than in healthy control, especially in left hemisphere. The mean MD value of the MdLF was higher (more yellow) in this PPA patient than in healthy control, especially in left hemisphere. Abbreviations: MdLF = middle longitudinal fascicle; PPA = primary progressive aphasia; FA = fractional anisotropy; MD = mean diffusivity; R = right; L= left; STG = superior temporal gyrus; SPL = superior parietal lobe; AG = angular gyrus.