Patterns of brain activity that occur during the day are replayed at fast-forward speed when we sleep, which may help consolidate our memories, according to a new study.
The findings provide further evidence for the benefits of a good night's sleep, researchers said.
Brain activity during sleep sorts through the huge number of experiences we encounter every day, filing only the important information in memory, they said.
This is important because the bad nights of sleep often experienced by both the healthy population, and people with schizophrenia or Alzheimer's disease, lead to impaired mental function, researchers said.
The findings, from University of Bristol in UK, show that patterns of brain activity that occur during the day are replayed at fast-forward speed during sleep.
This replayed activity happens in part of the brain called the hippocampus, which is our central filing system for memories.
The key new finding is that sleep replay strengthens the microscopic connections between nerve cells that are active a process deemed critical for consolidating memories.
Therefore, by selecting which daytime activity patterns are replayed, sleep can sort and retain important information.
"These findings are about the fundamental processes that occur in the brain during the consolidation of memory during sleep," lead researcher Jack Mellor, from University of Bristol.
"It also seems that the successful replay of brain activity during sleep is dependent on the emotional state of the person when they are learning. This has major implications for how we teach and enable people to learn effectively," said Mellor.
The study was published in the journal Cell Reports.
