Microtubules are small tubular structures present inside human cells playing important role in maintaining the structure of cells and also in several other cellular processes. These microtubules are critical structures for stable neuronal morphology serving as tracks for long-distance transport, providing dynamic and mechanical functions, and controlling local signaling events \cite{Kapitein_2015}. The major protein associated to microtubule in healthy neurons is tau which promotes the assembly of tubulin into microtubules and aids in the stabilization of their structure \cite{Weingarten_1975}.
The abnormal hyperphosphorylation of tau proteins and its aggregation into bundles of filaments can lead to a class of neurodegenerative diseases called as taupathies. AD is the best known tauopathy with the aggregation of hyperphosphorylated tau proteins leading to the deposition of neurofibrillary tangles (NFTs) within neurons. The presence of NFTs is one of the two major hallmarks of AD, the other being the senile plaques described in previous section. The progression of cognitive impairment in AD follows more closely the spatio-temporal spread of NFTs rather than the senile plaques \cite{braak1995staging,Jack_2013}.