neurologists at UCLA Alzheimers center have developed a formulation of Curcumin called "Longvida" which appears to reduce the accumulation of this brain plaque: http://alzheimer.neurology.ucla.edu/Curcumin.html

Curcumin and Alzheimer’s disease. Our group has tested curcumin in several models and found that it not only reduces oxidative damage and inflammation (as expected), but also reduces amyloid accumulation and synaptic marker loss while promoting both amyloid phagocytosis and clearance. In in vitro studies, we found curcumin worked to prevent synaptic marker and cognitive deficits caused by amyloid peptide infusion and abeta oligomer toxicity. Our work on curcumin and AD is discussed in detail in our publications

its important to note that it is only the Longvida formulation of Curcumin which effect because it crosses the blood-brain barrier, although other types seem beneficial for other conditions.