Thanks to our ability to learn and to remember, we can perform tasks that other living things can not even dream of.

However, we are only just beginning to get the gist of what really goes on in the brain when it learns or forgets something.

What we do know is that changes in the contacts between nerve cells play an important role. But can these structural changes account for that well-known phenomenon that it is much easier to re-learn something that was forgotten than to learn something completely new?

Scientists at the Max Planck Institute of Neurobiology have been able to show that new cell contacts established during a learning process stay put, even when they are no longer required.

The reactivation of this temporarily inactivated "stock of contacts" enables a faster learning of things forgotten.