This piece from PENN Medicine News is illustrative of the class of research into the mechanisms of Alzheimer's presently taking place. More researchers focus on the role of amyloid than on tau proteins, but progress in understanding is still being made: "In Alzheimer's and other neurodegenerative diseases, misfolded tau and other proteins accumulate inside neurons. Proteins used to make healthy synapses are moved via microtubules to the synapse along the nerve axon. However, accumulation of tau in clumps inside nerve cells (that is, the tangles described 100 years ago by Alzheimer in the first reported AD patient) impairs the function of nerve cells and causes them to degenerate. This is because tau is needed to stabilize microtubules like cross-ties stabilize train tracks. But if tau clumps, the microtubules break up, thereby disrupting the transportation network in normal nerve cells. This has lethal consequences because nerve-cell axons and dendrites are critically dependent on this normal transportation network." But understanding how this comes about and what to do about it - the process of the root cause, in other words - is a good deal more complex than just this.