CHRNA4 and Alzheimer disease: PET with 2-[18F]F-A-85380 ([18F]2FA), a radioligand selective for α4β2 nAChR, has shown significant reductions in nAChR availability in the hippocampus, and frontal, temporal and parietal cortices of AD patients, which furthermore correlated with the level of cognitive impairment [38].