PSEN1 and Alzheimer disease: In the present study, we applied Poly (I:C), a specific agonist, to activate TLR3 in a male APPswe/PSEN1dE9 transgenic mice model of AD (App + Psen1 + , AD mice) to evaluate the effect of activated TLR3 on neuropathology and neurobehavioral functions in AD and their underlying mechanisms.