Stress can induce dendritic spine loss in prefrontal cortex,2 amygdala3 and hippocampus.4 Such effects are likely to be caused by neurotrophic factors such as brain-derived nerve growth factor (BDNF).5 The suppressed spinogenesis in hippocampus may further contribute to stress-induced memory deficit.6 Our previous findings showed the improvement of hippocampal neurogenesis and depression-like behavior by physical exercise.7 However, it is still unclear whether exercise has similar antidepressant effect in cortical regions. The gene discussed is BDNF; the disease is major depressive disorder.