Scientists have demonstrated proof of principle" that traumatic memories can be erased from the brain - as seen in the science fiction film Eternal Sunshine Of The Spotless Mind. Studies in mice demonstrated that fearful memories prompted by a sound associated with an electric shock could be turned off and on. The researchers said attempting to do this in humans was full of ethical problems. But their studies suggest it will be possible at some point in the future. Professor Sheena Josselyn said they had been able to discover the specific brain cells where a particular memory was stored. "So we can target where in the brain a memory has gone," she said. "We can then decrease the activity in these cells And it is as if we erase the memory." After this was done, the mice were unperturbed when they heard the sound they had previously learned to associate with the shock. Increasing the cells' activity restored the memory. "We can turn memory on and turn memory off," Professor Josselyn said. "We can erase a fearful memory in mice, suggesting in people there might be a way of targeting just those cells that are important in just this traumatic memory, perhaps getting rid of this traumatic memory." Asked about the ethical considerations, Professor Josselyn said ... that she did not see a future in which brain cells would be killed off to remove memories. But she added: "For something that really interferes with your everyday life ... a treatment that targets just those cells could be appropriate."