Brain scans have revealed how information we learn during the day is squirrelled away into long-term memory while we sleep.

During a good night's rest, memories of recent events are shifted from one part of the brain to another, a process that is crucial for developing long-term memories, according to a report published today in the journal Proceedings of the National Academy of Sciences.

The researchers, lead by Dr Philippe Peigneux at the University of Liege in Belgium, gave two teams the task of learning their way around a virtual 3D town by training them on a computer.

Using functional magnetic resonance imaging (fMRI), which can take repeated snapshots of activity in the brain, they witnessed people's memories of how to navigate being transferred from a region of the brain that deals with remembering directions, the hippocampus, to a part that governs how we move, the striatum.

One of the teams was then told to stay awake all night, playing video games. Two days later, both groups were again given brain scans, and the scans showed that the group which had rested well was using a different part of the brain to navigate around the virtual town, the striatum.

The sleep-deprived team was still using the hippocampus, suggesting that the information had not yet been committed to long-term memory.