Phelps and her colleagues have found non-invasive techniques to rewrite emotional memories that trigger fear during the storing of those memories -- a process known as reconsolidation, as new neural connections are made.
When psychologists use behavioral exposure therapy to rid patients of fears, they are merely creating a new memory that competes with the old one, according to Phelps.
"One overrides the other," she said. "But the big problem is that the first memory is still there," she said. "You get stressed and the fear comes back, like smoking -- quitting and starting up again."
By exposing a person to a bad memory at exactly the right time, the information associated with a painful memory can be rewritten, a process that could have huge implications in the treatment of post-traumatic stress disorder.
"We don't know if this can extend to complicated situations like phobias," Phelps said.
But if a patient can undergo exposure therapy during just the time window when memory is being restored, negative memories can be rewired to positive ones.
Said Phelps, "It's all about timing."