%0 Journal Article
%T Imaging the evolution and pathophysiology of Alzheimer disease
%J -
%D 2018
%R https://doi.org/10.1038/s41583-018-0067-3
%X Technologies for imaging the pathophysiology of Alzheimer disease (AD) now permit studies of the relationships between the two major proteins deposited in this disease ¡ª amyloid-¦Â (A¦Â) and tau ¡ª and their effects on measures of neurodegeneration and cognition in humans. Deposition of A¦Â in the medial parietal cortex appears to be the first stage in the development of AD, although tau aggregates in the medial temporal lobe (MTL) precede A¦Â deposition in cognitively healthy older people. Whether aggregation of tau in the MTL is the first stage in AD or a fairly benign phenomenon that may be transformed and spread in the presence of A¦Â is a major unresolved question. Despite a strong link between A¦Â and tau, the relationship between A¦Â and neurodegeneration is weak; rather, it is tau that is associated with brain atrophy and hypometabolism, which, in turn, are related to cognition. Although there is support for an interaction between A¦Â and tau resulting in neurodegeneration that leads to dementia, the unknown nature of this interaction, the strikingly different patterns of brain A¦Â and tau deposition and the appearance of neurodegeneration in the absence of A¦Â and tau are challenges to this model that ultimately must be explained
%U https://www.nature.com/articles/s41583-018-0067-3