Association of Olfaction and Microstructural Integrity of Brain Tissue in Community-Dwelling Adults: Atherosclerosis Risk in Communities Neurocognitive Study.

Neuronal microstructural integrity in multiple brain regions, in particular the MTL (the regions known to be affected in early Alzheimer's), is associated with odor-identification ability. Differential associations in the MTL regions among cognitively normal individuals compared to those with MCI may reflect the earlier vs. later effects of the dementia pathogenesis. It is likely that some of the associated regions may not have any functional relevance to olfaction.