Researchers have found a clue to the mystery of retaining selective memories.

Scientists have made a breakthrough in understanding how sleep controls what we remember and what we forget. It may all come down to the kind of brainwaves rippling through your grey matter as you snooze.

Catching the right number of zzz’s is already known to be important for laying down memories, hence the advisory that students swotting for a major test back up with a good night’s sleep.

Dreamland is also where memories can be selectively faded, something that prevents the mind’s finely tuned mechanics getting clogged with useless info.

But just how sleep can amp up the signal and dial down the noise isn’t clear.

A team, led by neurologist Karunesh Ganguly at the University of California, San Francisco in the US, has set about fixing that, aided by mice with some very sophisticated hardware in their noggins.

Ganguly’s team put the mice to work learning how to get water to flow from a spout. With their minds.

Read the full story in Cosmos magazine here