TLR4 and Alzheimer disease: In addition, in early stages of AD when Aβ is increased but microglia are still in resting state, co-stimulation of TLR2 and TLR4 with PAMP ligands like LPS, MPL, and Pam3Cys, appears to promote microglia-mediated autophagy, as evidenced by lowering of Aβ deposits in the rat brain, and the rescue of spatial and working memory [41].