The focus on plaque I think has been seriously misdirected, which is why the search for effective therapeutics has been such a dismal failure. I had attended a fascinating and well-documented talk 8-10 years ago at the Integrative Healthcare Symposium in which amyloid appears in reality to be an endogenous antimicrobial. The perspective was that an infection in the brain is the initiating cause, and this endogenous antimicrobial is synthesized in increasing amounts in an attempt to fight it. And interestingly, an op-ed piece appeared in the July 11: "All the Alzheimer's Research We Didn't Do."

nytimes.com - Alzheimers missed opportunities

It's by the science journalist Charles Piller, and the premise is that the cause is actually a virus. When you think that some viruses hibernate in neural tissue for years after the infection has disappeared, this fits. And especially when you realize that this is more likely to occur in immune-privileged tissues, such as the central nervous system. We can see shingles, so that was relatively easy to come to understand as the result of hibernating chickenpox virus that are awakened.