Once you learn to ride a bike you never forget – it was once thought, but scientists have found that while learning, the brain is actively trying to forget.
And this could be because the brain has limited space so it forgets or ‘overwrites’ old memories to make room for new ones.
The findings could help develop a new drug that activates this ‘forgetting’ route in the brain to help people forget traumatic experiences.
Senior scientists Dr Cornelius Gross at the European Molecular Biology Laboratory said: ‘This is the first time that a pathway in the brain has been linked to forgetting, to actively erasing memories.
‘One explanation for this is that there is limited space in the brain, so when you’re learning, you have to weaken some connections to make room for others.
‘To learn new things, you have to forget things you’ve learned before.’
At the simplest level, learning involves making associations, and remembering them.
The study looked at the hippocampus, a region of the brain that’s long been known to help form memories.
Information enters this part of the brain through three different routes.
As memories are cemented, connections between neurons along the ‘main’ route become stronger.
When this main route was blocked in mice it was found they were no longer capable of learning a Pavlovian response – associating a sound to a consequence, and anticipating that consequence.