Cognitive dysfunction in LPS-treated E4FAD+ mice. (a) Spatial memory was unaffected by LPS treatment when assessed by spontaneous alternation (Y-maze). (b) LPS-induced recognition memory deficits in LPS-treated E4FAD+ mice compared to PBS-treated E4FAD+ mice. (c) In the cortex, post-synaptic density-95 (PSD-95) protein levels (normalized to actin) were higher in E3FAD+ mice treated with LPS compared to PBS, indicating a potential adaptive response. In the cortex, there was a nonsignificant trend where, compared to PBS, LPS treatment resulted in lower levels of PSD-95 of E4FAD+ mice. In the hippocampus, E4FAD+ mice treated with LPS had lower PSD-95 levels compared to PBS-treated mice. Solid black boxes indicate samples were run on the same gel; bands on the same gel in nonadjacent positions are separated by a dashed line. Data are expressed as the mean ± SEM. *p < .05 by three-way ANOVA followed by Bonferroni post hoc analysis comparing PBS- with LPS-treated mice within each group. The exception is for PSD-95 levels in the hippocampus for (c) where *p < .05 by t-test.