The original amyloid hypothesis regarded Aβ deposited in plaque amyloid as the toxic species. However, subsequently it became clear that plaque counts correlate relatively poorly with the level of cognitive decline and that in fact the number of NFTs correlates more strongly with the degree of dementia.73 This led to a reevaluation of what form of amyloid might constitute the most toxic species, and recently, soluble forms of Aβ have been proposed as the more toxic species.
