The hippocampus is a critical structure involved in many forms of learning and memory. It is also one of the only regions in the mammalian brain that continues to generate new neurons throughout adulthood. This process of adult neurogenesis may increase the plasticity of the hippocampus which could be beneficial for learning but has also been demonstrated to decrease the stability of previously acquired memories. Here we test whether exposure to voluntary running (which increases the production of new neurons) following the formation of a gradually acquired paired associates task will result in forgetting of this type of memory. We trained mice in a touchscreen-based object/location task and then increased neurogenesis using voluntary running. Our results indicate that running increased neurogenesis and resulted in poor recall of the previously established memory. When subsequently exposed to a reversal task we also show that running reduced the number of correction trials required to acquire the new task contingencies. This suggests that prior forgetting reduces perseveration on the now outdated memory. Together our results add to a growing body of literature which indicates the important role of adult neurogenesis in destabilizing previously acquired memories to allow for flexible encoding of new memories.

海马体是参与多种形式的学习和记忆的关键结构。它也是哺乳动物大脑中在整个成年期继续产生新神经元的唯一区域之一。成人神经发生的这一过程可能会增加海马体的可塑性，这可能对学习有益，但也已被证明会降低先前获得的记忆的稳定性。在这里，我们测试了在逐渐获得的成对关联任务形成后暴露于自愿跑步（这会增加新神经元的产生）是否会导致忘记这种类型的记忆。我们在基于触摸屏的对象/定位任务中训练老鼠，然后使用自愿跑步增加神经发生。我们的结果表明，跑步会增加神经发生并导致对先前建立的记忆的回忆不佳。当随后暴露于逆转任务时，我们还表明运行减少了获得新任务突发事件所需的校正试验次数。这表明先前的遗忘减少了对现在过时记忆的坚持。我们的结果一起添加到越来越多的文献中，这些文献表明成人神经发生在破坏先前获得的记忆以允许灵活编码新记忆方面的重要作用。