Neuroscientists at MIT have found a chemical way to make mice forget bad memories.
By deactivating a 'memory gene' - Npas 4 - they found that mice would 'forget' their fear of a chamber where they had previously been given electric shocks.
The scientists believe they could be 'closing in' on the areas of the brain where long-term memories are stored - and a technique for controlling these memories.
The researchers think that the gene could be crucial for all types of memory.
The knowledge would be a breakthrough in our understanding of the brain - and might open up new avenues of knowledge such as altering or even creating memory.
To investigate the genetic mechanisms of memory formation, researchers gave mice a mild electric shock when they entered a specific chamber.
Within minutes, the mice learn to fear the chamber, and the next time they enter it, they freeze.
The gene - Npas4 - activates strongly when this happens.
When the researchers knocked out the gene for Npas4, they found that mice could not remember their fearful conditioning.
The research could also lead to understanding where memories are stored in the brain - right down to which individual cells store each one.
The Npas 4 gene turns on when memories are 'stored' in your brain - and think that this could be the start of a chemical trail that leads to the part of the brain where memories are stored, and even to individual brain cells - known as neurons - which store single memories.