Extracellular application of tau preparations to cell and animal models elicits disease‐related molecular, electrophysiological, and cognitive changes in these systems,3, 8, 9, 10, 11, 12, 13, 14 and treatment with antibodies to extracellular tau ameliorates tau‐related impairments in animal tauopathy models.15 Here, MAPT is linked to tauopathy.