The movie Eternal Sunshine of the Spotless Mind gave us a glimpse of what could happen if science were able to erase old memories. However, new research shows that it may not be as far-fetched as we think. Research teams reported that when a memory is recalled, it can be erased or rewired so that a painful memory is linked in the brain to joy, or conversely, a happy memory linked to pain.
The research was revealed in the publication Nature and has been described as a possible treatment for those suffering from PTSD (Post Traumatic Stress Disorder). CBS spoke with Susumu Tonegawa of the Massachusetts Institute of Technology (MIT) who led one of the memory studies.
“Recalling a memory is not like playing a tape recorder. It’s a creative process.”
The MIT research team then set out to find out exactly how creative of a process memory could be. The team used male rodents to complete the study. To begin, the male mice were placed in a cage and electrically shocked when they entered a certain portion of the cage. This created a fear and negative memory associated with that part of the cage. In a separate part of the cage, male mice were allowed to be with female mice which gave them a positive memory with that part of the cage.
After the good and bad memories had been set, the team watched the brain neurons in action. These specific mice had been engineered so that specific brain neurons could be activated with light, a technique called optogenetics. Therefore, the scientists were able to see when the fear or negative memory was active in the mice and when the positive memories of female socialization were activated.
Not only were the research teams able to see the specific area of the brain that both positive and negative experiences were logged, they were also able to activate those feelings without changing the environment simply by administering light to that specific area of the nerve and brain.
The team then began manipulating the memories by activating the specific regions of the brain and changing the environment surrounding the mice. For example, the team activated the negative memory with the light but then offered the mice female companionship as the nerve was activated. In turn, the mice’s mental memory wiring was switched and now that negative feeling became a positive one.
The research sheds light on a potential cure for PTSD patients. However, there is still ethical concerns over the use of the procedure. Psychologist Elizabeth Phelps of New York University, spoke to CBS about both studies and said they were interesting, but that manipulating the human memory may not be ethical, even for therapeutic purposes. She also notes that there is still much research to be done.
“I think we are still a long way from translating this research to good clinical interventions,” since memories that contribute to PTSD are “likely much more complex” than in mice and rats.