A recent study from the University of Toyama, published in May 2025, sheds light on how sleep prepares the brain for future learning. Researchers have discovered that sleep isn't just about consolidating past experiences; it also actively primes the brain to record upcoming events.
The study, led by Kaoru Inokuchi, investigated the role of specialized neurons called 'engram cells,' which physically encode our life experiences. They found that during sleep, a separate population of neurons, termed 'engram-to-be cells,' become increasingly synchronized. These 'engram-to-be' cells later encode new and different learning experiences.
The researchers used advanced imaging to track the activity of engram cells in mice before, during, and after learning experiences, as well as during sleep. Their neural network model indicated that synaptic depression and scaling, mechanisms adjusting connection strengths between neurons during sleep, are key for developing and preparing engram-to-be cells. This research highlights the dual role of sleep in memory consolidation and preparing for future memories, potentially opening new avenues for cognitive enhancement and treating memory disorders.