The beneficial effects of exercise may be attributed to the increased release of neurotrophic factors via activation of the PI3K/Akt pathway: exercise after brain injury increased the production of nerve growth factor and brain-derived neurotrophic factor and the activation of TrkA/B receptor, which activated the PI3K/Akt pathway and inhibited apoptosis of hippocampal neurons [48]. The gene discussed is NTRK1; the disease is brain injury.