An examination of the brains of three groups of deceased individuals (13 cognitively normal, aged 20-66; 16 non-demented older adults, aged 70-99; 21 individuals with Alzheimer's, aged 60-95) has found that amyloid starts to accumulate and clump inside basal forebrain cholinergic neurons in young adulthood. Other neurons didn't show the same extent of amyloid accumulation. Basal forebrain cholinergic neurons are the first to be affected, and to die, in aging and Alzheimer's.
 . Neuronal amyloid-β accumulation within cholinergic basal forebrain in ageing and Alzheimer’s disease. Brain [Internet]. 2015 . Available from: http://brain.oxfordjournals.org/content/early/2015/03/15/brain.awv024