“Do you feel that?” Schiller asked, somewhat remotely. “It’s twenty volts, a small charge.” I said no. She moved the lever to thirty. Yes, but only barely, I told her. Finally, at forty volts, I began to feel the shock. It was by no means a dangerous level; nonetheless, it was a sensation that few people would welcome. Schiller was planning to do to me what she had spent so much time doing to others: teach me to fear a meaningless symbol. Colored spheres began to float onto a computer screen in front of me, in no particularly discernible pattern: just a random, rapid-fire procession—purple, yellow, and blue. It didn’t take long to realize that nearly every time a blue sphere appeared a shock would follow; by the time I felt the voltage, my pulse and heart rate had already spiked in anticipation. The shock itself quickly became superfluous. The day after learning to fear the spheres, Schiller’s subjects see them again many times—but without the accompanying shock. “If you present a negative memory over and over again, without anything bad happening, it is possible for most people to overcome the fear,” Schiller explained. Extinction training has for a long time been one of the principal treatments for many phobias and fears; psychiatrists refer to it as exposure therapy. The more you see something, the less it scares you, and the less it scares you the more able you are to deal with it. There has always been a problem, though, in using extinction to treat people who have experienced profound trauma: the process leaves them with a pair of memories: blue sphere predicts shock; blue sphere doesn’t predict shock. Over time, the two memories can compete for expression. That is a significant characteristic of anxiety disorder. People will be fine for months or years, but if they encounter a particularly stressful situation the fear memory often overwhelms the calm memory. Schiller’s study demonstrated that the competing memories can become one. “If we zap it at just the right time, there are no new memories,” she told me with a look of restrained satisfaction. “There is a different memory. You will still know what happened, and the information will be available to you. But the emotion will be gone.” [...] Reconsolidation has already been shown, in promising if limited research, to help treat drug addiction. Addicts are compelled by the same persistent emotional memories that drive other disorders. “The biggest problem for most addicts is how to deal with relapse,” Schiller told me. “Let’s say somebody is drug-free and then goes and hangs out with friends at a park. He might see a cue associated with his drug use, and that will induce a craving that will cause him to seek the drug.” Reconsolidation presents a chance to disrupt that process; you don’t lose the memory—you just lose the pleasant feeling it creates. The idea is simple enough: you cannot be addicted to a desire that you don’t remember. Jonathan Lee, a behavioral neuroscientist now at the University of Birmingham, in England, has already put that notion to a test. He used Pavlovian conditioning to induce cravings in rats, by pairing light with a narcotic. The next time he showed the animals the light, they automatically reached for the drug. But, as was the case with Nader’s experiments, when Lee interrupted the process of reconsolidation the association disappeared. Researchers in the U.S. and China have had similar success with human addicts. Once again, timing was critical: the effect worked only if extinction training took place within ten minutes of retrieving the old memory. “If you block that association, you can erase the craving,” Schiller said. “This is the first time we have seen a treatment like that lead to a cessation of addiction.” Even six months later, the addicts showed no sign of relapse, suggesting, as with Schiller’s work, that when fearful memories are disturbed at the right moment the fear may be gone for good.
Posted on: Wed, 11 Jun 2014 19:37:22 +0000
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