HOMER1 and infection: In the older mice, there were no significant differences in the number of engulfed Homer-1-positive terminals in the lysosomes of microglial cells induced by H7N7 IAV infection in unvaccinated mice (Δ20%, p = 0.52, Figure 7H) and vaccinated mice (Δ50%, p = 0.14, Figure 7H) compared with the corresponding control groups receiving PBS in the CA1 subregion, although this postsynaptic engulfment induced by the infection was apparently more pronounced in older mice even after vaccination [two-way ANOVA Finfection(1, 10) = 0.29, p = 0.59, Figure 7H].