Scientists have discovered the mechanism by which a good night’s sleep improves learning and memory.
The scientific team in China and the US used advanced microscopy to witness new connections between brain cells – synapses – forming during sleep.
Their study, published in the journal Science, showed even intense training could not make up for lost sleep.
Experts said it was an elegant and significant study, which uncovered the mechanisms of memory.
It is well known that sleep plays an important role in memory and learning. But what actually happens inside the brain has been a source of considerable debate.
Researchers at New York University School of Medicine and Peking University Shenzhen Graduate School trained mice in a new skill – walking on top of a rotating rod.
They then looked inside the living brain with a microscope to see what happened when the animals were either sleeping or sleep deprived.
Their study showed that sleeping mice formed significantly more new connections between neurons – they were learning more.
And by disrupting specific phases of sleep, the research group showed deep or slow-wave sleep was necessary for memory formation.
During this stage, the brain was “replaying” the activity from earlier in the day.
Further tests showed how significant sleep was.
Mice doing up to an hour’s training followed by sleep were compared with mice training intensively for three hours but then sleep deprived.
The difference was still stark, with the sleepers performing better and the brain forming more new connections.