Sleep is widely known to be essential for memory processing and consolidation, but its underlying mechanisms are unclear. Researchers from Japan have made significant progress in understanding the dual role of sleep in memory processing. A recent study, published in Nature Communications, explored how the brain preserves past memories while preparing for future ones during sleep periods.
The research team employed an advanced imaging system that combined live calcium imaging with engram cell labeling to track neuronal activity in mice before, during, and after learning experiences. Their findings revealed two parallel processes occur during post-learning sleep: reactivation of engram cells, confirming the established consolidation process, and a new population of “engram-to-be cells” that became synchronized during sleep. These cells encoded a new learning experience.
The study suggests that synaptic depression and scaling, which adjust connection strengths between neurons during sleep, are essential for the emergence of engram-to-be cells. Increased co-activation between existing engram cells and engram-to-be cells during post-learning sleep implies some form of information transfer or coordination between neural networks representing past and future memories.
The research has significant implications for learning and memory, suggesting that quality of sleep between learning sessions may determine how well we remember what we’ve learned and how effectively we can learn new information. Manipulating brain activity during sleep or sleep patterns may uncover methods to enhance memory by unlocking the brain’s latent potential.
Overall, this study highlights the critical role of sleep in maintaining cognitive function and overall well-being. Sleep is not just about rest; it plays a crucial role in processing information, and valuing sleep can lead to improved quality of life.
Source: https://medicalxpress.com/news/2025-04-dual-role-memories-brain.html