The fractal dimension of microglial cells (i.e., the complexity of ramifications37) was significantly increased in macaques injected with AD‐tau, with a stronger effect size in animals co‐injected with Aβ (Figure 5A; Mann‐Whitney test: “pooled CTL” vs. AD‐tau/sham, p = 0.036; “Pooled CTL” vs. AD‐tau/Aβ p = 0.033). This evidence concerns the gene MAPT and Alzheimer disease.