Icariin, isolated from Epimedium brevicornum Maxim, attenuates Aβ-induced synaptic dysfunction through the activation of BDNF/TrkB/Akt/CREB-mediated signaling in the hippocampus at 28 days after Aβ1–42-induced AD [98]. This evidence concerns the gene NTRK2 and Alzheimer disease.