Learning enhances adult neurogenesis in the hippocampal formation

Thousands of hippocampal neurons are born in adulthood, suggesting that new cells could be important for hippocampal function. To determine whether hi ppocampus-dependent learning affects adult-generated neurons, we examined t he fate of new cells labeled with the thymidine analog bromodeoxyuridine fo llowing specific behavioral tasks. Here we report that the number of adult- generated neurons doubles in the rat dentate gyrus in response to training on associative learning tasks that require the hippocampus. In contrast, tr aining on associative learning tasks that do not require the hippocampus di d not alter the number of new cells. These findings indicate that adult-gen erated hippocampal neurons are specifically affected by, and potentially in volved in, associative memory formation.