Studies in the last decade have shown that brain-derived neurotrophic factor (BDNF) plays an important role in brain plasticity after ischemia in the central nervous system, and that increased concentrations of BDNF in the cerebral cortex may complete synaptogenesis and enhance dendritic spine formation and branching, which contributes to neuronal plasticity in stroke survivors (11, 12). The gene discussed is BDNF; the disease is ischemia.