INNOVATION

Brain Implants May Be Able to Shock Damaged Memories Back Into Shape

With funding from the Defense Department, scientists have begun work on devices that would use electric pulses to realign a memory process gone awry

Randy Rieland

April 15, 2015

brain image — Scientists are sharpening their focus on ways to revive a memory gone awry. NIH

Baby boomers must be pleased to see that scientists are going down so many different paths in not only tackling the enduring mystery of how our brains function, but also in seeing if lost memories can be found. A few weeks ago, for instance, a team of researchers at the Yale University School of Medicine reported that a drug that had not been very effective as a cancer treatment has helped restore the memories of mice with Alzheimer’s disease. And last month, scientists in Australia announced that mice with Alzheimer’s whose brains were scanned with ultrasound waves performed just as well on three different memory tests as healthy mice.

But the most intriguing research on the enigma of memory may be going on at the University of Pennsylvania. There, a team under neuroscientist Michael Kahana, is exploring whether implants in the brain can gently shock it into storing and recovering memories.

It's all about connections

The study is being funded by DARPA, the research arm of the Defense Department, with the purpose of finding a way to help victims of traumatic brain injury (TBI) relearn the memory-making process. This has become a critical issue for the Pentagon—it estimates that since 2000, more than 300,000 service members have suffered TBI.

DARPA plans to invest more than $40 million into brain implant research through 2018—more than $22 million of that is committed to the Penn project. What makes that approach different from more conventional brain imaging is that it’s based on conducting experiments while tracking the brain’s neural circuits in real time.

For instance, researchers could “watch” the electrical activity inside a person’s brain as he or she plays a memory game and ideally identify biomarkers as memories are formed or retrieved. Then, the goal would be to use low doses of electricity to stimulate the pattern of memory that has been most effective for that person.

Kahana and his team have been working with epilepsy patients who have had a mesh of electrodes temporarily implanted under their skulls. The electrodes collect brain activity readings that can help doctors calculate where seizures originate in their brains. A number of patients were asked if they’d be willing to play a series of memory games on a laptop while wearing the electrodes.

As the patients played and memories took shape, the researchers recorded the firing of thousands of their neurons, with the goal of then zeroing in on electrical signals that corresponded with specific memory behavior. In short, the scientists, through analysis of a brain’s electrical pulses, intend to map how that person shapes and recovers memories.

A big leap

But that’s only phase one of the project. The second half would focus on designing an implant that would constantly track how a brain is functioning and, if certain neural signals aren’t at the best level to process memories, it would stimulate the appropriate neurons with low-level electrical pulses. The device would act like a kind of memory thermostat, adjusting the pulses to ensure that the brain does this part of its job effectively.

It sounds fascinating, but as with most research involving the brain, nothing is certain. Most neurosurgeons will tell you that for all the operations that have been done, all the scans that have been studied, all the behavior that’s been analyzed, we still have a lot to learn about brain functions and what could happen if you start experimenting with neural connections inside it.

Will stimulating different neurons with electrical devices actually mimic how the brain works? Do what seem like patterns to scientists truly mean something in the brain’s language? Could introducing this kind of artificial stimulation end up doing more harm than good?

The classic example of unforeseen consequences of brain-altering is the case of Henry Molaison, better known as “H.M.” to generations of psychology students. Since a bicycle accident in his childhood, Molaison suffered epileptic seizures so severe that high doses of medication no longer helped him. His doctor concluded that the best remaining treatment was to remove part of his brain.

So, in August, 1953, when Molaison was 27, a surgeon cut out most of his hippocampus. The operation did get his epilepsy under control, but as a series of experiments later showed, Molaison was left with no ability to form new memories. For the rest of this life—he died in 2008—Molaison lived in the present tense. His story provided great insights into how human memory works, particularly the role of the hippocampus. It also taught doctors never to do that surgery again.

For their part, Kahana and his team are proceeding cautiously. They want to understand as much as they can about the mechanics of memory before they start implanting devices in people’s brains and zapping neurons with electricity. They’re hopeful that well-placed pulses can realign a memory process gone awry, but they’re also realistic.

As Kahana told the MIT Technology Review: “We want the brain to exhibit a certain pattern of electrical activity. It’s a big leap to say we can somehow nudge it into that state by giving it a little push."