Fig. 2.

Pathological hallmarks of AD. A schematic of the pathological changes in AD brains compared with normal brains. Brain atrophy resulting from neuronal loss is recognized at the gross anatomical level. Accumulation of toxic amyloid-β, formation of intraneuronal neurofibrillary tangles, loss of synapses, activation of microglia, astrogliosis, overproduction of cytokines, and dystrophy of neurites are observed at the microscopic level