Adult mice engineered to have more newborn neurons in their brain memory hub excelled at accurately discriminating between similar experiences -- an ability that declines with normal aging and in some anxiety disorders. Boosting such neurogenesis in the adult hippocampus also produced antidepressant-like effects when combined with exercise. The study pinpointed effects of enhanced adult neurogenesis by creating mice lacking a gene required for programmed cell death of newborn neurons in the adult hippocampus.