MAPT and Alzheimer disease: Compared to non-Tg mice, Tau4RTg2562 mice displayed mild TOC1 immunoreactivity in the CA1 region of the hippocampus (Fig. 4a,b), but TOC1 levels were nowhere near as robust as in another tau Tg mouse line (PS19) or in human AD hippocampus (Fig. 4, c and d, respectively).