MAPT and Alzheimer disease: Functional deficiencies linked to phospho-tau deposition in oligodendrocytes and threads is also supported in the present study by the demonstration of slightly disrupted myelin and the occasional presence of PLP1-immunoreactive balls and dots in the ipsilateral corpus callosum following inoculation of sarkosyl-enriched fractions from AD, PART, ARTAG and less commonly with GGT, PSP, PiD, and fFTLD-301L.