For years, scientists have been focused on trying to come up with new treatments for Alzheimer's by preventing the formation of brain-damaging clumps of this mysterious protein called beta-amyloid.

In fact, we scientists have arguably got ourselves into a bit of an intellectual rut concentrating almost exclusively on this approach, often neglecting or even ignoring other possible explanations.

Regrettably, this dedication to studying the abnormal protein clumps has not translated into a useful drug or therapy. The need for a new "out-of-the-clump" way of thinking about Alzheimer's is emerging as a top priority in brain science.

My laboratory at the Krembil Brain Institute, part of the University Health Network in Toronto, is devising a new theory of Alzheimer's disease.

Based on our past 30 years of research, we no longer think of Alzheimer's as primarily a disease of the brain. Rather, we believe that Alzheimer's is principally a disorder of the immune system within the brain.