Scientists could soon be able to erase memories — but should they?

Everyone has a memory or two they’d rather forget. For me, it’s the harrowing period I spent in hospital with my three-week-old daughter as she underwent multiple life-saving operations. She’s now a healthy six-year-old, but even the briefest recollection of that time still has the ability to reduce me to a sobbing wreck in the shower or the supermarket aisle. Such is the power of memory. But what if we had the ability to change or even erase painful memories? Would we do it? Should we do it?Up until now, questions like these have only cropped up in sci-fi novels and films. But new scientific research has revealed there could actually be a way to manipulate or remove memories in the not-too-distant future. Steve Ramirez, associate professor of psychological and brain sciences at Boston University, is leading this research. At the end of last year, he released a book on the topic, How to Change a Memory, in which he reveals how memory can be turned on and off like a switch, edited and even constructed from nothing.Ramirez has been working in this realm since 2010, when he joined the lab of Nobel prize winner Susumu Tonegawa at MIT. There he was paired with Xu Liu, a postdoc fellow. They had an instant connection, both as friends and lab partners. Their first major breakthrough came in 2012, when they were able to activate specific brain cells in genetically engineered mice by using light from a fibre optic cable. They then identified which brain cells in the hippocampus — the brain’s memory centre — lit up when the animal received a shock.Next, they removed the mouse from the box where the shock had occurred and placed it in a completely new environment. Again, using millisecond-long pulses of light, they activated those same brain cells, only this time without the physical shock. The mouse froze in fear, even though this time there was no shock. It appeared Ramirez and Liu had turned on a memory just through cellular stimulation. A year later, they used a similar method to create a false memory in mice. A salve for depressionSadly, Liu died in 2015, at the age of 37, but over a decade later Ramirez and his team are still discovering extraordinary insights. “One of the central goals of doing this kind of science is to discover fundamental truths about how the brain works and to use these to help people,” Ramirez writes in his book. “If we could activate a memory, then we could think of memory as something our brain naturally produces as well as a potential antidote that the brain contains to rid itself of suffering. The possibilities would be endless.”Closer to home, a team at King’s College London is working on similar research. Led by Dr Laith Alexander, a clinical lecturer in psychiatry and experimental medicine, they are using non-invasive deep brain stimulation to target regions involved in memory and emotion — mainly the hippocampus and the amygdala, which processes emotions.“We’re using brain stimulation aimed at a specific emotional circuit in humans, guided by each person’s own brain anatomy,” says Alexander. “The first question is whether we can change activity in these deep regions while people recall personally significant negative memories in an MRI scanner. The second is whether stimulation can reduce the emotional intensity of a memory without causing amnesia; whether, by stimulating the amygdala, we can update how a memory feels without altering what it contains. If that works, we’d want to develop the technique for depression and anxiety disorders, targeting the circuits involved in negative emotional memories. The goal is never to take away the episode itself — it’s to stop the memory returning with the force of the original experience.”“Memories are interconnected. If you interfere with one, you don’t know what else you’re affecting”Dr Emma Facer-Irwin, clinical psychologistUnintended consequencesWhile both Alexander and Ramirez are working to help humanity, there’s no denying the concept of tampering with or erasing memories could easily open a Pandora’s Box if used in the wrong way. “As a professional, I have enormous ethical concerns about the idea of memory erasure,” says Dr Emma Facer-Irwin, clinical psychologist with the London Psychiatry Clinic. “Memories aren’t video recordings — they’re interconnected. So, if you interfere with one memory, you don’t know what else you’re affecting.”Brian Rock, consultant clinical psychologist at the Sok, agrees. “I don’t think we’re anywhere close to being able to erase people’s memories, but if you could, how would you know where to begin and end? In the case of something like loss or grief, often the pain can come from positive memories of experiences shared, rather than negative ones. So, how would we even know which memories to delete?” All the experts I spoke to agreed the benefits of this sort of research would be most apparent when used alongside psychological therapy, such as trauma-focused CBT or eye movement desensitisation and reprocessing therapy (EMDR). “For psychiatric conditions where memories form a key part of the illness — depression, PTSD, phobias, addiction — a technique like this could shorten the time it takes for treatment to work and make it more effective when used alongside therapy or medication,” says Alexander. “As a clinician, I don’t think the therapeutic goal is a person with a gap where their history used to be. Memories make us who we are. But in some psychiatric conditions the memory stops being part of a past that we can integrate into a life story and becomes a constant, distressing feature of the present. Returning it to the past, so that it can be approached with compassion and understanding, is close to the opposite of erasing it.”