Dr. Richard Huganir, the 57-year-old director of Johns Hopkins University's Neuroscience Dept., has spent more than 30 years researching how memories form. His recent discoveries may pave the way for a drug that selectively erases them.
Huganir and his postdoctoral fellow, Roger Clem, have been investigating calcium-permeable AMPARs, protein molecules that appear in the brain for about 48 hours after a person experiences a traumatic event. Scientists previously considered them unimportant to memory formation, but Huganir and Clem thought otherwise. Over the past two years they administered electric shocks to a group of about 100 mice while simultaneously playing a tone. They also administered a drug to some of the mice that kept their brains flooded with AMPARs. Those mice retained fearful memories of the sound long after the initial jolt, while the drug-free group gradually became inured to it, essentially forgetting its link to the painful experience. The experiment proved that the proteins are essential to building the brain circuitry that forms a memory, and to recalling the memory later. "It's a huge step forward," says Joseph E. LeDoux, a professor at New York University and an authority on memory and emotions.
Huganir and Clem are now experimenting with a drug that removes AMPARs and could prevent memories from forming in the first place. They hope to publish the results next year, and Huganir says that in as little as a decade the research could lead to drugs that help people forget painful experiences. Blocking AMPARs won't erase the entire memory of an event, says Huganir, but it would eliminate the strong emotions attached to it. That could be a game-changer for the nearly 8 million American adults with post-traumatic stress disorder. Huganir says he regularly gets e-mails from PTSD sufferers asking to be part of human drug trials if and when he holds them. His research may also lead to drugs that aid memory retention by stimulating AMPARs, a potential boon for test takers and Alzheimer's patients.
Huganir began his first, informal neuroscience studies while in high school in Philadelphia. He owned 10 goldfish and tested them for intelligence by observing their reactions to sudden flashes of light. "I sacrificed the smart one and ground up its brain and injected it into the brain of another," says Huganir. "He seemed fine, but he wasn't smarter." After earning his PhD at Cornell University, he first focused his research on how muscles respond to signals from the brain.
Huganir's recent work recalls the 2004 movie Eternal Sunshine of the Spotless Mind, in which two characters erase memories of their failed relationship. Will real-life ex-lovers soon be able to do the same? "No," Huganir says. "That's science fiction."
EARLY LAB WORK
Experimented on goldfish in high school
That a short-lived protein is essential to memory formation
A drug that could help PTSD sufferers forget traumas