BDNF and Alzheimer disease: Exercise-induced BDNF upregulation, with newly generated hippocampal neurons facilitating the re-establishment of neural networks within the hippocampal region: Studies on running-trained adult mice (3×Tg-AD mice) have demonstrated elevated levels of cell proliferation (ki67+ cells increased 1.67-fold, p < 0.001), migration (DCX+ neurons in the DG increased 2.0-fold, p < 0.0001), and local circuitry remodeling (the number of dendritic spines increased, p < 0.05) [121] compared to sedentary counterparts [122,123].