ARI SHAPIRO, HOST:
Now here's a story for anyone who's forgotten where they just left their car keys. It's possible to revive this sort of memory by zapping the brain with a magnetic pulse. That finding is part of a new study that challenges the traditional view of how the brain keeps short-term memories. NPR's Jon Hamilton reports.
JON HAMILTON, BYLINE: The study involves a type of memory known as working memory, and it's not just for car keys. Nathan Rose, a psychologist at Notre Dame, explains working memory this way. He says, imagine you're at a cocktail party.
NATHAN ROSE: You have two people that you meet, and you learn the names of both people.
HAMILTON: Then the conversation shifts, and you find yourself focusing on just one of those people.
ROSE: All the while, you don't want to forget who the other person is in case the conversation shifts back.
HAMILTON: If you do manage to remember the other name, it's because you've placed it in working memory. Rose says the question is, how?
ROSE: How does the brain accomplish this task of keeping this information active while you're focused on other ongoing activities?
HAMILTON: For decades, scientists thought the trick required continuous activity in the brain cells associated with a particular memory. If the activity level dropped, the memory was gone forever. But Rose and a team of researchers weren't so sure, so they did a series of experiments.
In one, people were asked to remember two items while researchers monitored the activity in their brains. When the people focused on one of the items, brain activity associated with the other item disappeared.
ROSE: Almost as if the item has been forgotten.
HAMILTON: But it wasn't forgotten, and the researchers showed this in a dramatic way. They delivered a magnetic pulse to the areas of the brain that were supposed to keep track of the item being ignored.
ROSE: And when we did that, we saw a brief reactivation of the unattended memory item as if it was brought back into focal attention.
HAMILTON: The pulse zapped the memory back to life like some creature in a horror film.
ROSE: My buddy, when I first showed it to him - he dubbed it the Frankenstein effect.
HAMILTON: And it wasn't just something the scientists saw on a screen. When people got zapped, it helped them remember the item they'd been ignoring. Rose says the study, which appears in the journal Science, offers strong evidence that brain cells don't have to remain active to sustain a fresh memory. But he's concerned that the public will read too much into the results with magnetic pulses.
ROSE: I imagine that the response that we'll get is that this may be a way to stimulate the brain to recover memories. And, boy, wouldn't that be great? But I think we're a ways away from that.
HAMILTON: Joel Voss, a brain scientist at Northwestern University, says this research is important because we know so little about memory.
JOEL VOSS: Honestly, we're in the Dark Ages (laughter). There are more questions than there are answers.
HAMILTON: Voss says this study does provide some answers about how working memories are stored in the brain.
VOSS: It indicates that holding an item in working memory or short-term memory causes a dynamic reconfiguration of the structural connections between neurons.
HAMILTON: In other words, it's not just neurons firing continuously. There's an underlying change in the way the neurons are wired together. Voss says that means working or short-term memories appear to be a lot like long-term memories, which are also thought to be stored in the connections between neurons. And he says that could explain how a short-term memory like the name of someone you just met becomes a long-term memory.
VOSS: In order for a long-term memory to happen, there has to be some physical trace of that memory.
HAMILTON: Which is exactly what this study appears to have found. Jon Hamilton, NPR News.
NPR transcripts are created on a rush deadline by Verb8tm, Inc., an NPR contractor, and produced using a proprietary transcription process developed with NPR. This text may not be in its final form and may be updated or revised in the future. Accuracy and availability may vary. The authoritative record of NPR’s programming is the audio record.