““All of that was eventually shown—there’s considerable adult neuro-genesis in the hippocampus (where roughly 3 percent of neurons are replaced each month) and lesser amounts in the cortex.22 It happens in humans throughout adult life. Hippocampal neurogenesis, for example, is enhanced by learning, exercise, estrogen, antidepressants, environmental enrichment, and brain injuryfn9 and inhibited by various stressors.fn10,23 Moreover, the new hippocampal neurons integrate into preexisting circuits, with the perky excitability of young neurons in the perinatal brain. Most important, new neurons are essential for integrating new information into preexisting schemas, something called “pattern separation.””
