The search for memory “engrams,” a collection of identifiable neurons that physically represent a memory, has occupied scientists for over a hundred years. When memories are formed, physical changes and a strengthening of connections between neurons encode the information so it can be recalled later. Now, teams of researchers have discovered that these memories, or “engrams” can be manipulated in the mind of mice.
In several different studies, scientists were able to eliminate and implant memories of fear into mice. Utilizing optogenetics, a biological technique that uses light to control cells, these mice were given a fear response in boxes they previously deemed safe and enjoyable. These studies focused on the amygdala, the brain’s emotional processing center. Results from these experiments suggest that the right stimulation in the brains of humans could help recall important information or forget traumatic experiences like those associated with PTSD.