APOE and Atrophy: These MRI measures will include volumetric characteristics (i.e. regional and whole-brain atrophy), functional characteristics (i.e. activated regions), microstructural tissue properties (i.e. FA, MD, RD, and DA), network properties (e.g., functional and structural connectivity), and H-MRS metabolite characteristics (NAA, mI, Cho, NAA/Cr, NAA/mI, and mI/Cr) correlated to APOE genotyping and neuropsychological test scores.