"Here, we were trying to artificially make an association between the light-reactivated memory and the foot shocks. We were just trying to artificially connect the two," Ramirez said.
The next day, they put the mouse back into box A, the safe zone. Instead of behaving normally, though, exploring the box and acting calm, the mouse froze in place or ran into the corner as if were agitated and scared. It seemed to have "remembered" being shocked in box A, even though the negative experience had occurred in box B. When the researchers removed the mouse and put it into a third or fourth box, the mouse behaved calmly. The researchers conducted the same experiment dozens of times on different mice, with similar results.
"They appeared to be recalling being shocked in box A, even though that had never happened," Ramirez said. "A false memory had been formed and recalled."
Jason Snyder, an assistant professor of psychology at the University of British Columbia, who was not involved in the study, said the group's research was interesting because it demonstrated not only where memories go, but also how to modify them. And knowing more about the neurological mechanisms associated with disorders like PTSD could open up avenues for therapy.