 The study is a randomized, parallel, 4-dose design in subjects with mild-to-moderate Alzheimers Disease. Subjects will be randomized to one of 4 doses of T3D-959. Subjects will be evaluated for changes from baseline in cerebral metabolic rate of glucose FDG-PET imaging, functional connectivity of the hippocampus BOLD-fMRI, and cognitive function ADAS-Cog11 and DSST as well as assessed for safety and tolerability to T3D-959. 