The structural data were passed through the FSL Brain Extraction Tool (Smith 2002) to extract the brain. Eddy current-induced image distortions in the diffusion-weighted images for each direction were minimized by alignment with an average made of all 12 diffusion-weighted images using a 2-D six-parameter affine correction on a slice-by-slice basis (Woods et al. 1998). The DTI data were then aligned using the FSE data by a non-linear 3D warp (third-order polynomial), which provided in-plane and through-plane alignment. On a voxel-by-voxel basis, fractional anisotropy and apparent diffusion coefficient, the latter decomposed into its longitudinal and (λL = λ1) and transverse \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$ \left( {\lambda {\hbox{T}} = \left[ {{\lambda_{{2}}} + {\lambda_{{3}}}} \right]/{2}} \right) $$\end{document} diffusivity components, were computed. FA ranged from 0 to 1, and diffusivity was expressed in units of 10−6 mm2/s.
