A hallmark of Alzheimer’s disease is the aggregation of insoluble amyloid-beta plaques and tau protein neurofibrillary tangles. A key histopathological observation is that tau protein aggregates follow a clear progression pattern through the brain; characterized by six distinct stages. This so-called `Braak staging pattern’ has become the gold standard for Alzheimer’s disease progression. It has also been suggested, via a histopathological analysis, that soluble seed-competent tau seeding precedes tau aggregation in the same manner. Mathematical models such as prion-like propagation on networks have the ability to capture key feature of the dynamics. Here, we study the staging of tau proteins using a model of proteopathy that include both local growth due to autocatalytic effects and diffusion along axonal pathways. We develop new methods to capture the staging patterns and use these as a qualitative criterion to identify the best model for diffusion process on networks and to identify possible parameter regimes. Our analysis provides a systematic way to study Braak staging in neurodegenerative processes.
bioRxiv Subject Collection: Neuroscience