Such a mechanism is supported by the observation that D-ISO (15 mg g−1 chow) reduces Sarkosyl-insoluble tau and blocks neuronal loss in the hippocampus of PS19 mice (a model of tauopathy which also displays severe hippocampal neuronal loss20); the latter conclusion is supported by the magnetic resonance imaging data presented in Supplementary Fig. 2. This evidence concerns the gene MAPT and tauopathy.