For more than 30 years, University of Pennsylvania psychologist Michael Kahana has been studying memory: how it works, and what happens when it doesn't work.
She's not just fascinated by memory loss caused by traumatic brain injury — which affects more than 5 million people in this country — or the nearly 7 million Americans with Alzheimer's. Her research has also focused on memory loss that affects everyone, regardless of their cognitive health.
“We all have bad memories sometimes,” Kahana told The Post. “It fluctuates throughout the day, and it can fluctuate from moment to moment. That's how our brain circuits work. When I realized that, the question was, how do I keep my brain in good mode all the time?”
Kahana's investigations into memory culminated in a landmark study published last January, in which he and a team of researchers used computer intervention on a group of 47 epileptic patients, delivering a pulse of electricity directly to the brain at the time of memory loss. They did this through electrodes that had been implanted directly into the patients' brains as part of treatment for epilepsy.
These electrodes – between 100 and 200 per person – are able to recognise brain signals when a patient is trying to remember something, and send a shock of electricity at a precise time to the lateral temporal cortex, the part of the brain used to store and process memories.
The results were even better than Kahana had expected, with brain stimulation improving memory by 28%. Although he remains cautiously optimistic, he can't contain his excitement.
“I think we are on the threshold of a new era in human neuroscience and human neurotherapeutic science,” he said.
Kahana isn't the only person exploring the possibilities of brain-computer interfaces. Across the country, scientists are developing brain-computer interfaces (BCIs) that could be used to treat everything from memory loss to speech disabilities and paralysis.
Just last year, in a study conducted at Stanford Medicine, after a 90-day treatment with a brain implant, patients were so astonished at the improvements in their memory that some of them refused to turn off the devices.
And in August, Elon Musk-owned neurotechnology startup Neuralink announced plans to insert a BCI — designed to give paralyzed patients the ability to use digital devices by thinking alone — into a second human test subject.
Noland Arbaugh, a 30-year-old Arizona man who was paralyzed from the neck down after a diving accident eight years ago, received the first Neuralink implant in January this year. In a March on X livestream, Arbaugh demonstrated how he could Controlling the computer cursor using your thoughts for playing games and emailing. In May, it was announced that the device had started acting up unexpectedly Separation from Arbog's skullBut the problem was resolved.
Musk said, Predicted Hundreds of thousands of people will be using Neuralinks within a few years, and “millions of people within 10 years.”
In August, researchers at Switzerland's École Polytechnique Fédérale de Lausanne unveiled a brain that converts thoughts into text with 91% accuracy and is even smaller than Neuralink's chip.
Progress is happening so rapidly that the FDA will hold a workshop later this month on assessing clinical outcomes for BCIs.
“If the initial results are replicated, we may be years, not decades, away from any kind of meaningful assistive technology for individuals with serious illness and disability,” said Anna Wexler, a professor at the Perelman School of Medicine who studies the ethical, legal and societal issues associated with emerging technology.
When we think of computers helping ALS (formerly known as Lou Gehrig's disease) patients speak, the first name that comes to mind is Stephen Hawking, the acclaimed theoretical physicist who spoke to a microprocessing computer powered by Intel. Although he could communicate, his voice sounded metallic, like a robot from a science fiction movie.
But Casey Harrell, 45, who lost the ability to speak due to ALS, has had his voice back — his real voice — thanks to a brain-computer interface called BrainGate2.
This has given Harrell the ability to communicate with his 5-year-old daughter.
“For about two years she didn't talk to me much…” Harrell told Scientific American in a story from August 2024. “I can help her mother raise her. I can form a deeper bond with her and tell her what I'm thinking. I can just tell her how much I love her.”
David Brandman, a neurosurgeon at UC Davis who helped develop the brain chip, said the BCI interprets brain signals, which are then reproduced by voice assistant software.
“The system is about 97% accurate and allows him to speak words from a 125,000-word dictionary,” Brandman told the Post. “Using artificial intelligence, we also recreated the sound of his voice so that the text can be spoken aloud by the computer to make it sound like he did before he was diagnosed with ALS.”
For memory, the challenges get a little more complicated. A person's memory fluctuates, and the problem isn't always the same. According to Brent Roeder, Ph.D., it's not always about trying to provide a general improvement in memory performance, but rather about “improving memory performance for specific important or necessary information, such as, 'Did I take my medication this morning?'”
Roeder, a researcher in the Department of Translational Neuroscience at Wake Forest University School of Medicine, is studying how individual codes are replicated within hippocampal activity for specific memory information.
He and his fellow researchers accomplished this with a “memory prosthesis,” an electrode inserted into the brain that interacts with the hippocampus, making neural recordings when a patient performs a specific memory task. “Once these unique memory codes were created, we used them to stimulate them during the memory task to determine if we could enhance the patient's memory performance,” says Roeder.
In other words, they encoded memories for future reference, and created Post-it notes to remind the brain of what it had forgotten.
As they found, it helped patients remember very specific details. It not only improved their overall memory — though it did so, increasing recall by anywhere from 11% to 54% — but also specifically improved memory deficits that interfere with daily life, such as forgetting where they put their car keys or whether they turned off the stove.
Roeder said one advantage of this type of approach is that it's not limited to any specific condition: “The hope is that once it's ready for clinical use, it will be able to be used to treat any condition that impairs memory function, whether it's traumatic brain injury or dementia and Alzheimer's.”
As exciting as the research is, questions still remain about how this technology will be used. Or, as Wexler said, “the lines between BCIs for treatment and enhancement are blurring.”
“If an implanted BCI allows people to type at the same speed that we can type with our fingers or write with our voices, I doubt most people would be interested,” Wexler said. “But if it can make a really significant or measurable improvement — something that hasn't been demonstrated yet — then things will get interesting.”
Musk seems to be counting on this. In a video posted on X on July 10, he stressed that the long-term goal of Neuralink is to “give people superpowers” and “provide far superior functionality beyond the average human being.”
But scientists like Roeder don't share such ambitions. “The focus of our research has always been on restoring functions that have been impaired due to disease or injury,” he told the Post. “We think giving someone back what they've lost is a superpower.”
Getting the technology to the point where it becomes widely available will be no small feat. After all, it involves brain surgery. According to Tom Oxley, chief executive of brain-interface startup Synchron said during a 2022 TED talk“The brain really doesn’t like being pricked with needles.”
Kahana agrees that this is a hurdle. “We can't remotely control your brain with a raygun,” he said. “So for it to work, you have to go into the brain.” But, he added, it's becoming safer to do so. “A lot has changed in the last few years. The imaging is better, the electrodes are smaller. When the time comes, I wouldn't hesitate to have this procedure done on myself.”
He co-founded Nia Therapeutics with funding from the Defense Advanced Research Projects Agency to help commercialize brain implants, part of an effort to help veterans with brain injuries. But it's also personal for him.
“I have a son who can't speak, he can't say a single word. He uses a device to communicate, which as you can imagine is incredibly awkward. Searching through menus to find the right words. He knows what he wants to say, but how do you translate those brain patterns into spoken language?” Kahana explained. “You and I do it so easily, we take it for granted. But if someone could develop a technology to decode those brain signals, well… that would really be something.”
