Fig. 3.

Microglial degeneration can occur independent of age and is evident in cases of young subjects with minimal tau pathology. Double-label immunohistochemistry for microglia (iba1) and tau (AT8) is shown in the hippocampus of two young subjects with no (b) or minimal (d) tau pathology (case nos. 1, 5). a, c Focus series of four individual micrographs taken 10–15 μm apart, and reassembled into composite images in b and d. Note the difference in microglial morphology in the two young subjects, one of which shows minimal tau pathology evident as neuropil threads (arrows in d). Microglia in b show normal ramified appearance but are fragmented in d. Scale bars 20 μm (a, c); 10 μm (b, d)