Fig. 4.

Tau4RTg2652 mice lack oligomeric or fibrillar tau species. Oligomeric tau as detected by antibody TOC1, was undetectable in most brain regions of one year old Tau4RTg2652 mice, with the exception of the hippocampal CA1 region, which demonstrated very mild immunoreactivity (a) compared to non-Tg mice (b). Hippocampal CA1 TOC1 immunoreactivity is much more robust in another tau Tg mouse model, PS19 (c) and in AD hippocampus (d). Mature neurofibrillary tangles were also lacking as evidenced by negative Thioflavin-S (f) and Gallyas silver stain (h) in aged Tau4RTg2652 mice compared to another tau Tg mouse model, PS19 (e,g). Scale bar = 50um (a-d) and 100 um (g,h)