How the brain forgets

Memory tends to worsen with age

Scientists have found a molecule that may be to blame for loss of memory as we get older.

It raises the tempting prospect of new therapies to restore memory.

The brain has a limited capacity and like many other organs in the body seems to have to be balanced

Professor Isabelle Mansuy

The enzyme helps the brain delete unwanted information.

But a team from the Swiss Federal Institute of Technology in Zurich believe it may become too active as we get older.

The researchers carried out tests on mice that showed those animals with low levels of the enzyme, called protein phosphatase-1 (PP1), were less likely to forget what they had learned.

It appears that PP1 actively suppresses memories in mice, both during and after a learning exercise.

And as the mice get older, the level of PP1 increases.

When the scientists blocked the action of PP1 the mice recovered their full learning and memory abilities.

Natural filter

Researcher Professor Isabelle Mansuy told the BBC: "The brain has a limited capacity and like many other organs in the body seems to have to be balanced.

"So there are positive processes which help us remember things and store information, and there are negative processes which help us to sort existing information.

"It is a kind of filter to avoid saturation of the brain. Except it is not selective, so there is a lot of information that we would like to keep that we end up forgetting."

Professor Mansuy said it was possible that the finding could be used to develop new therapies to help elderly people recover some of their ability to remember things. However, she said such therapies were a long way off.

The research is published in the journal Nature.