Rita Magil was driving down a Montreal boulevard one sunny morning in 2002 when a car came blasting through a red light straight toward her. “I slammed the brakes, but I knew it was too late,” she says. “I thought I was going to die.” The oncoming car smashed into hers, pushing her off the road and into a building with large cement pillars in front. A pillar tore through the car, stopping only about a foot from her face. She was trapped in the crumpled vehicle, but to her shock, she was still alive. The accident left Magil with two broken ribs and a broken collarbone. It also left her with post-traumatic stress disorder (PTSD) and a desperate wish to forget. Long after her bones healed, Magil was plagued by the memory of the cement barriers looming toward her. “I would be doing regular things — cooking something, shopping, whatever — and the image would just come into my mind from nowhere,” she says. Her heart would pound; she would start to sweat and feel jumpy all over. It felt visceral and real, like something that was happening at that very moment.
Most people who survive accidents or attacks never develop PTSD. But for some, the event forges a memory that is pathologically potent, erupting into consciousness again and again. “PTSD really can be characterized as a disorder of memory,” says McGill University psychologist Alain Brunet, who studies and treats psychological trauma. “It’s about what you wish to forget and what you cannot forget.” This kind of memory is not misty and watercolored. It is relentless.
More than a year after her accident, Magil saw Brunet’s ad for an experimental treatment for PTSD, and she volunteered. She took a low dose of a common blood-pressure drug, propranolol, that reduces activity in the amygdala, a part of the brain that processes emotions. Then she listened to a taped re-creation of her car accident. She had relived that day in her mind a thousand times. The difference this time was that the drug broke the link between her factual memory and her emotional memory. Propranolol blocks the action of adrenaline, so it prevented her from tensing up and getting anxious. By having Magil think about the accident while the drug was in her body, Brunet hoped to permanently change how she remembered the crash. It worked. She did not forget the accident but was actively able to reshape her memory of the event, stripping away the terror while leaving the facts behind.
Brunet’s experiment emerges from one of the most exciting and controversial recent findings in neuroscience: that we alter our memories just by remembering them. Karim Nader of McGill — the scientist who made this discovery — hopes it means that people with PTSD can cure themselves by editing their memories. Altering remembered thoughts might also liberate people imprisoned by anxiety, obsessive-compulsive disorder, even addiction. “There is no such thing as a pharmacological cure in psychiatry,” Brunet says. “But we may be on the verge of changing that.”
These recent insights into memory are part of a larger about-face in neuroscience research. Until recently, longterm memories were thought to be physically etched into our brain, permanent and unchanging. Now it is becoming clear that memories are surprisingly vulnerable and highly dynamic. In the lab they can be flicked on or dimmed with a simple dose of drugs. “For a hundred years, people thought memory was wired into the brain,” Nader says. “Instead, we find it can be rewired—you can add false information to it, make it stronger, make it weaker, and possibly even make it disappear.” Nader and Brunet are not the only ones to make this observation. Other scientists probing different parts of the brain’s memory machinery are similarly finding that memory is inherently flexible.
