MAPT and Mental deterioration: Together with dysfunctional synapses, Braak stage correlates best with cognitive decline.9-12 Present scientific data indicate that toxic tau species predominantly propagate in the brain in the form of soluble tau oligomers.13 These oligomers seem to exhibit greater toxicity compared with larger tau fibrils found in NFTs or tau monomers.13,14 Although many rigorous investigations have utilized recombinant tau (rTau), showing that it causes synaptic toxicity,15-17 direct analysis of brain-derived tau oligomers could offer novel insights.