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A Tiny Pulse Of Electricity Can Help The Brain Form Lasting Memories

Feb 6, 2018
Originally published on February 9, 2018 6:00 pm

A little electrical brain stimulation can go a long way in boosting memory.

The key is to deliver a tiny pulse of electricity to exactly the right place at exactly the right moment, a team reports in Tuesday's Nature Communications.

"We saw a 15 percent improvement in memory," says Michael Kahana, a professor of psychology at the University of Pennsylvania and an author of the study.

The approach hints at a new way of treating people with memory problems caused by a brain injury or Alzheimer's disease, Kahana says. But the technology is still far from widespread use.

Kahana has spent years trying to understand why the brain often fails to store information we want it to keep.

"When we're trying to study a list of items, sometimes the items stick and sometimes we have momentary lapses where we don't seem to remember anything," he says.

Kahana and a team of researchers thought there must be a way to help the brain do better. So they had a computer learn to recognize patterns of electrical activity indicating that the brain was about to have a memory lapse.

Then the team had the computer intervene by delivering a pulse of electricity to different areas of the brain just before the lapse was going to occur. And in the area involved in recalling words, the approach worked.

"When we stimulated the left temporal cortex, we found that memory was improved significantly," Kahana says. "When we stimulated other parts of the brain, memory was, by and large, impaired."

The experiment was done with 25 patients with epilepsy who were in the hospital awaiting surgery to treat their seizures. That meant doctors had already inserted wires into their brains to monitor electrical activity.

But epilepsy patients tend to have memory problems and other brain anomalies, says Michael Sperling, an author of the study and director of the Comprehensive Epilepsy Center at Thomas Jefferson University in Philadelphia.

"We still really lack any experiments in people with other conditions to know for certain whether [the treatment] would prove effective or not," Sperling says.

Even so, Sperling is optimistic that the research will lead to an implantable device that can improve memory in at least some patients. "There's a good chance that something like this will come available," he says, "I would hope within the next half dozen years, or so."

The memory research is being funded by the military's Defense Advanced Research Projects Agency. It's part of an effort by the agency to develop technologies to help military personnel and veterans with memory problems caused by brain injuries.

"We didn't just do this for the sake of science," says Justin Sanchez, who directs DARPA's biological technologies office. "We wanted a real technology that could ultimately make its way out into the world."

DARPA-funded scientists are already working on a version of the brain stimulation system that could be implanted in a person, Sanchez says. And this sort of technology could eventually extend beyond people who have memory impairments, he says.

"If any of us could get a 15 percent boost in our memory, that would be transformative," Sanchez says.

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Scientists have shown that a tiny pulse of electricity delivered to just the right place in the brain can improve a person's memory. This technology could one day help people whose memories have been impaired by a brain injury or by Alzheimer's disease. Here's NPR's Jon Hamilton.

JON HAMILTON, BYLINE: Forming memories is never a sure thing. Michael Kahana of the University of Pennsylvania says the brain often fails to store information we want it to keep.

MICHAEL KAHANA: When we're trying to study a list of items - for example, for a test - sometimes the items stick, and sometimes we have momentary lapses where it seems like the items are going by and we don't seem to remember anything.

HAMILTON: Kahana is part of a team that thought they might be able to help the brain do better. So they had a computer learn to recognize signals indicating that the brain was about to have a memory lapse. Kahana says then they had the computer intervene by delivering a pulse of electricity.

KAHANA: When we stimulated the left temporal cortex, we found that memory was improved significantly. And when we simulated other parts of the brain, memory was by and large impaired.

HAMILTON: Kahana says when a pulse reached the left temporal cortex at just the right time, people remembered about 15 percent more words from a list they'd studied. The experiment was done in 25 patients with epilepsy who were waiting to get surgery for their seizures. Dr. Michael Sperling of Thomas Jefferson University in Philadelphia says that allowed direct access to their brains.

MICHAEL SPERLING: Patients are in a hospital bed, typically, or in a chair in their room with electrodes in their brain, wire then coming out, linked to a system.

HAMILTON: But there could be a problem with that. Sperling says epilepsy patients tend to have memory problems and brains that aren't typical. He says that makes it tricky to evaluate the new treatment.

SPERLING: We know that it has some benefit in people with epilepsy. We still really lack any experiments in people with other conditions to know for certain whether it would prove effective or not.

HAMILTON: Even so, Sperling is optimistic that the research will lead to an implantable device that can improve memory.

SPERLING: There's a good chance that something like this will come available. I'm not exactly sure when. I would hope within the course of the next half dozen years or so.

HAMILTON: The research is funded by the military's Defense Advanced Research Projects Agency. Dr. Justin Sanchez directs the Biological Technologies Office at DARPA. He says the initial goal was to help military personnel and veterans with memory problems caused by brain injuries.

JUSTIN SANCHEZ: We didn't just do this for the sake of science. We wanted a real technology that could ultimately make its way out into the world after the DARPA investment is done.

HAMILTON: Sanchez says an implanted device that improves memory could also make a difference to people with Alzheimer's. And he said the technology might eventually help anyone who just wants to remember things better.

SANCHEZ: If any of us could get a 15 percent boost in our memory in our everyday lives, that would be transformative. Just think if you're trying to recall a phone number, if you're trying to recall a friend's name.

HAMILTON: The research appears in the journal Nature Communications. Sanchez says scientists are already working on ways to miniaturize the technology. Jon Hamilton, NPR News.

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