“Sleep frees the hippocampus for new memory contents”
Using imaging, the research team demonstrated that repetitive training allows new memory trails to be established in the cerebral cortex within a short time frame. However, these are only sufficient on their own if the learning follows a sleep phase – otherwise the brain has to resort additionally to the hippocampus for the permanent storage of new memory contents.
The role of sleep therefore seems to go beyond providing additional rehearsal through memory trace reactivation, as previously thought. We conclude that repeated study induces systems consolidation, while sleep ensures that these transformations become stable and long lasting. Thus, sleep and repeated rehearsal jointly contribute to long-term memory consolidation.