Sleep's memory role discovered
http://www.bbc.com/news/health-27695144
The mechanism by which a good night's sleep improves learning and memory has been discovered by scientists.
The team in China and the US used advanced microscopy to witness new connections between brain cells - synapses - forming during sleep.
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.
Prof Wen-Biao Gan, from New York University, told the BBC: "Finding out sleep promotes new connections between neurons is new, nobody knew this before.
"We thought sleep helped, but it could have been other causes, and we show it really helps to make connections and that in sleep the brain is not quiet, it is replaying what happened during the day and it seems quite important for making the connections."