MAPT and Alzheimer disease: In this context, so far we know that studies from transgenic AD animal models have confirmed that the application of extraneous 40 Hz gamma can significantly reduce Aβ load and hyper tau-phosphorylation via vasodilation and activation of microglia, although these studies did not intend to reveal the mechanistic involvement of gamma in AD pathogenesis (Iaccarino et al., 2016; Adaikkan et al., 2019; Martorell et al., 2019; Chan et al., 2021a).