It has been thought that lost nerve cells will never regenerate in the adult brain, but in recent years it has become clear that the hippocampus, a brain region deeply involved in memory, produces a very small number of new neurons even in adults. ..In addition, since sleep is known to play an important role in memory retention, in this study, we investigated the activity of newborn neurons during sleep in mice that were trained to experience fear while awake. By observing, we investigated the relationship between memory retention and the activity of newborn neurons during sleep.

　As a result, only the newborn neurons that were active during the scary experience reactivated during the dreaming period, REM sleep, even though the activity of the newborn neurons was generally reduced during sleep. It turned out that.Furthermore, when the activity of newborn neurons was manipulated by light stimulation in various ways, the mice forgot their fear memory only when the activity of newborn neurons growing for about one month after development was suppressed during REM sleep. It turned out that it would end up.Newborn neurons grow into complete neurons about two months after they are born from neural stem cells, but the same phenomenon does not occur in newborn neurons that have just been born or have grown up, and the activity of newborn neurons during non-rem sleep. No similar phenomenon was observed when suppressed.

　These results suggest that the activity of developing neoneurons during REM sleep is important for memory consolidation.In the future, by elucidating the mechanism by which newborn neurons establish memory during sleep, we will develop new treatments for diseases such as Alzheimer's disease in which neurons are lost and diseases such as PTSD that cause abnormalities in memory processing. It may be applicable.

Paper information:[Neuron] Sparse Activity of Hippocampal Adult-Born Neurons during REM Sleep Is Necessary for Memory Consolidation