Study: Drug Can Erase Fearful Memories
MICHELE NORRIS, host:
From NPR News, this is ALL THINGS CONSIDERED. I'm Michele Norris. The idea of using technology to erase specific memories from people's brains sounds like science fiction.
(Soundbite of film, "Eternal Sunshine of the Spotless Mind")
Mr. TOM WILKINSON (Actor): (as Dr. Howard Mierzwiak) Here at Lacuna, we have perfected a safe, effective technique for the focused erasure of troubling memories.
(Soundbite of music)
NORRIS: That's an ad for a fictional company in the movie "Eternal Sunshine of the Spotless Mind." Now, scientists say they actually have been able to get rid of one specific fearful memory in a number of people by using a common blood pressure drug. NPR's Nell Greenfieldboyce reports.
NELL GREENFIELDBOYCE: Joseph LeDoux studies memory at New York University. He says if you picture your memory as a kind of storage cabinet that's full of unchanging stuff, you're wrong.
Dr. JOSEPH LEDOUX (Neuroscientist, New York University): Each time you take a memory out, each time it's retrieved, it's got to be restored. And sometimes when you restore it, you put in additional information. This is a good thing because it allows you to update the memory.
GREENFIELDBOYCE: It also means the memory can be changed if you catch it at the right point.
Dr. LEDOUX: There's just this window, or temporary state, where the memories lay (unintelligible) and subject to disruption.
GREENFIELDBOYCE: In fact, the memory can even be erased. Ladue has done studies with rats showing he can wipe out a fearful memory using certain drugs. Now scientists have done a similar experiment in people. It involved college students, spiders and electric shocks. Meryl Kynt(ph) led the study at the University of Amsterdam. First, she wanted to give the student volunteers a new, fearful memory. So they came into a lab, sat in front of a computer screen and were shown picture of big spiders.
Ms. MERYL KYNT (University of Amsterdam): Two different pictures. One spider's on a shoulder, the other on the leaves of a plant.
GREENFIELDBOYCE: The study was designed so that only one of the spider images would become linked to a scary memory. Every time that image appeared, the student would get a mild electric shock on the wrist.
Ms. KYNT: During the procedure, you see that a fear evolves. So they fear only one spider, and they don't fear the other spider.
GREENFIELDBOYCE: Kynt and her colleagues could actually measure that fear by monitoring people's startle response. The students were sent home with their nasty spider memory. And the next day, the researchers tried to erase that memory.
They gave the students either a placebo pill or a real drug - a common blood-pressure drug, a beta blocker called Propranolol. Then they showed the students the picture of the scary spider to make them recall the memory of being shocked. The researchers wanted to see if the drug could prevent that bad memory from being put back into storage. And that appears to be the case.
When people who got the drug were later shown both the good and the bad spiders, their reaction was identical. Their learned fear response was gone.
Ms. KYNT: It was completely eliminated.
GREENFIELDBOYCE: She says if you asked them, do you remember the scary spider. They said, sure.
Ms. KYNT: Because they were aware that this picture was followed by a shock, but the emotional impact, the emotional meaning was gone since there was no fear response anymore.
GREENFIELDBOYCE: And she says that emotional association is a kind of memory, one that was essentially erased by the drug. The study is described in the journal Nature Neuroscience.
Some researchers, like Kareem Nadir(ph) at McGill University, have already been studying whether this drug can be used as a treatment for people who are tormented by painful memories. People with post-traumatic stress disorder are asked to recount troubling memories and are given the drug. Nadir says the preliminary results are promising.
Mr. KAREEM NADIR (Researcher, McGill University): Some of these guys have had PTSD for like 30 years. And then, like, they feel better.
GREENFIELDBOYCE: He knows that some people have raised ethical concerns about the idea of weakening specific memories with a drug. But he thinks if people are suffering, it's something worth trying. Nell Greenfieldboyce, NPR News.
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