1) Note that Abeta 42 deposition is constant in FAD and non-FAD AD, while Ab 40 deposits are not
2) Note that sometimes the temporal cortex is more affected by Ab deposits (MY.74), while sometimes, and more generally, it is the occipital cortex
3) Note that the occipital cortex which is the brain area generally the most affected by Ab deposition is the last to have a tau pathology.This paradox is a burden for the "amyloid cascade hypothesis"

Delacourte A et al.  Nonoverlapping but synergetic Tau and APP pathologies in sporadic Alzheimer's disease.
Neurology 2002; 59: 398-407

In aging, in non-demented patients, the question is to know if amyloid deposition precedes tau aggregation.