APP and Alzheimer disease: Since microglial proliferation has been also recognized as a characteristic of AD in humans and blocking microglial proliferation can improve short-term memory and synaptic density in the hippocampus of APP/PS1 [33], we supposed that the reductions of Aβ level and microglial proliferation in the brain might contribute to the TSA-induced improvement of cognitive behaviors in the APP/PS1 mice.