Distribution, progression and chemical composition of cortical amyloid-beta deposits in aged rhesus monkeys: similarities to the human.

A comprehensive investigation of the incidence, distribution, progression and chemical composition of Abeta deposits in the brains of two young (5 years) and seven aged (25-30 years) rhesus monkeys was conducted to determine the similarity of this phenomenon to that in the human. The brains of the young rhesus were devoid of Abeta deposits. In contrast, Abeta deposits were observed within the cerebral cortex of all aged animals.