In this study, we utilized rAAV vectors to increase local BDNF levels in hippocampal neurons through direct intraparenchymal injection in the early adult stages of three strains of transgenic AD mice, and the approach improved learning and memory behaviors across all strains, further supporting the hypothesis that gene therapy via local AAV delivery at the early stages of pathology offers long-term protective effects, preventing disease progression. Here, BDNF is linked to Alzheimer disease.