Researchers found a special gene. It is in mice. It could help us forget painful memories. Many people have painful memories that make them ill. The illness is called post-traumatic stress disorder (PTSD). Researchers want to change painful memories into nice thoughts and feelings. This would help millions of people with PTSD.

The researchers made mice forget their fear. The mice went into a cage and had electric shocks. The mice became afraid. They had "cage shock". The mice went into the cage again without an electric shock. Their fear changed to good feelings. The researchers found a gene that erased bad memories. They want to find it in humans too.