DLG4 and Alzheimer disease: PSD‐95 expression level was significantly decreased in macaques injected with AD‐tau, with a stronger effect size in animals co‐injected with Aβ (Figure 6A,B; Mann‐Whitney test: “pooled CTL” vs. AD‐tau/sham, p = 0.007; “pooled CTL” vs. AD‐tau/Aβ, p = 0.003).