A 5 month study comparing 3 different doses of BMS-241027 vs. placebo.  To assess safety, tolerability, and the effects of 9 weekly IV infusions on CSF Tau, MRI functional connectivity, cognitive performance, and pharmacokinetics.

• Ages 50-90
• MMSE score of 20-26
• Must be on a stable dose (at least 3 months) of cholinesterase inhibitors or NMDA antagonists