Another way to shape memory is to change the first memory. This is part of what Phelps carried out in a recent study, in which she gave participants a light shock when a blue square appeared on a computer screen. The next day, she showed some of the participants the blue square, which triggered the reconsolidation process. During this process, Phelps showed the blue square repeatedly, without a shock. The fearful memory of the previous day became a banal one: watching a blue square on a screen. On the third day, the fear didn’t return for those people who learned that the square was safe during their memories’ reconsolidation process. Though Phelps is hesitant to claim that her experiment can work on every person suffering from post-traumatic stress disorder (PTSD), she does say her study shows, in theory, how it’s possible to “create new, pain-free memories” to replace old, painful ones. She asserts that she is unsure, however, whether this theory will be applicable in practice.
But a relapse to fear can sometimes occur, and that’s what the second form of memory shaping hopes to address. A team of researchers at Johns Hopkins University published a paper last October that dealt with the amygdala, the part of the brain that conditions people to fear something. Lead researcher Richard L. Huganir and his team exposed mice to a loud, sudden sound. They then removed the proteins in the amygdala that heightened mice’s fears. The scientists then blasted the noise again. This time, the mice weren’t scared. Huganir writes in his study that if a drug can be developed that decreases the creation of the protein in the amygdala, the memory itself could be erased completely.
Pharmacology is not yet at that point. But the fear associated with the memory is another story. Propranolol is a hypertension drug that tends to reduce symptoms associated with fear. Alain Brunet and Roger Pitman, psychiatry professors at McGill University and Harvard Medical School, respectively, experienced success with the medication, which restricts protein creation in the amygdala, in a 2008 study. They gave a Montreal man with PTSD propranolol for six psychiatric sessions. After ingesting the drug, the man would describe the event — a bank robbery — and then his symptoms would be recorded. By the end of his time with the psychiatrists, the man said he could remember the event but not necessarily the fear of that day. Two years later, he still can’t recall the fear.
Brunet and Pitman were so encouraged, they launched another study in 2009. They took 19 people who had long been suffering from PTSD and gave some of them propranolol, while the rest received a placebo. They then asked the participants to recall the traumatic event that had come to define their lives, while Pitman or Brunet recorded the recollection. A week later, the participants were brought back into the labs.
Normally, these people would respond physically to their stories: with an increased heart rate, sweaty palms or some other sign of discomfort. But this time, the people who’d taken the propranolol showed little discomfort at all. “The decrease in symptoms was moderate but significant, especially for a one-week study,” Brunet says. The data showed that the symptoms had decreased by 19 percent for those who had taken the drug. Meanwhile, there’d been no decrease in symptoms for those who’d taken the placebo.
Brunet and Pitman increased the treatment. “In doing so, we decreased the PTSD symptoms by 50 percent,” Brunet says. “Looking at that from a diagnostic point of view, a 50 percent decrease in symptoms means 70 to 80 percent no longer met the criteria for PTSD. And people do not seem to relapse. The gains seem to be maintained.”
Brunet is encouraged by the results, and he’s confident that the reach of his research — and that of others in his field — will be significant. “I’m never, as a scientist, going to find anything better than this,” he says. “This is a life-changing thing.”