Playing Pac-Man With Your Thoughts: How a Minimally Invasive BCI Is Giving Paralyzed Patients Their Independence Back
Sixty-five-year-old Mark Jackson controls a computer game entirely with his thoughts, no hands or external input required. As he reclines in bed, three blue circles appear on a laptop across the room. One flips red: that’s the target. Jackson guides a small white circle, maneuvering it into the red target without touching the surrounding blue obstacles. The game reads like a modern twist on Pac-Man—except there is no joystick, keyboard, or controller. Jackson controls every move with his mind alone. To move left, he imagines clenching his right fist once. To move right, he imagines two quick clenches in a row, just like a double-click on a mouse.
Jackson, who lives with paralysis from neurodegenerative disease, has mastered the game. He glides the white circle into the red target, which shifts blue and dings a satisfying confirmation. He moves to the next round, where the circles reposition, and then the next, finishing with 14 successful hits out of 15 attempts. He’s even scored a perfect 100% before, after months of practice.
A couple of years ago, surgeons in Pittsburgh implanted Jackson with an experimental brain-computer interface, or BCI, built by New York-based startup Synchron. The device decodes Jackson’s brain signals to execute commands on his laptop and other devices. He is one of just 10 people—six in the U.S. and four in Australia—to receive the Synchron implant as part of an early feasibility study. Beyond gaming, the BCI lets him send texts, write emails, and shop online independently.
Jackson’s health journey began five years ago, when he was living in Georgia working his dream job at a wholesale floral company. He initially wrote off his neck pain as a pinched nerve, but in January 2021, Emory University doctors delivered a far more serious diagnosis: amyotrophic lateral sclerosis (ALS). ALS is a progressive neurodegenerative disease that breaks down nerve cells in the brain and spinal cord over time, gradually robbing patients of muscle control. When his doctor asked if he wanted to join a clinical trial for an experimental ALS drug, Jackson jumped at the chance.
But by December 2022, he had lost the ability to type or lift flower buckets for work, and was forced to retire. He moved in with his brother just outside Pittsburgh. “The loss of mobility, the loss of independence that goes with this disease—it’s a lot to take in, it’s a lot to process,” Jackson says. He stayed positive as his condition progressed, and when his first drug trial ended in summer 2023, he leapt at the chance to join another study that could restore some function lost to ALS.
Synchron’s BCI trial was just launching at the University of Pittsburgh around that time. While the implant would not slow ALS progression, it could give him back a measure of the autonomy he had lost. “I was immediately excited about it,” Jackson says.
He began the screening process in July 2023, and six weeks later he was in the operating room. During the roughly three-hour procedure, surgeons first inserted the Stentrode—Synchron’s matchstick-sized wire-mesh tube device—into the jugular vein at the base of Jackson’s neck. Using a catheter, they carefully threaded the device up through the vessel, past his ear, and into the side of his head, where it rests against the motor cortex, the region of the brain that controls voluntary movement. Next, they implanted a small rectangular transmitter under Jackson’s collarbone, which processes brain signals and sends them via infrared to a receiver outside the body. Those signals are picked up by a paddle-shaped receiver worn on Jackson’s chest, then sent via wire to a unit that translates them into actionable device commands. When the system is active, two small green lights glow through his shirt.
After surgery, it took months to get a stable connection working. Jackson’s chest was swollen from the procedure, which interfered with signal quality, and the external receiver has to stay relatively close to the internal transmitter. So much trial and error followed that Jackson worried the device would never work for him. “There was a lot of anticipation,” he says. When the system finally connected successfully in October 2023, Jackson felt a huge weight lift off his shoulders.
When a patient receives a BCI, they practice thinking through specific movements (like opening and closing a fist) so the system’s AI software can learn to associate a unique pattern of brain activity with that specific action. Even though Jackson is paralyzed and cannot physically move his hand, the neurons linked to that movement still fire when he attempts to clench a fist. BCIs are designed to read this intention to move.
If undergoing the Synchron process sounds intense, it is far less invasive than competing BCI designs that require open brain surgery. Synchron’s main rival, Elon Musk’s Neuralink, removes a section of a patient’s skull and replaces it with a coin-sized device that connects directly to brain tissue via 64 robot-placed wire threads. Neuralink has implanted nine volunteers with its device to date, and some have even been discharged from the hospital the day after surgery. While invasive implants like Neuralink’s carry risks of brain tissue damage and bleeding, the primary risks for Synchron’s device are blood clots and stroke. All implanted medical devices carry some risk of infection, regardless of design.
Synchron’s minimally invasive approach has put it ahead in the race to bring BCIs to commercial market. Though the company has raised just $145 million to date compared to Neuralink’s $1.3 billion, it has secured backing from high-profile investors including Jeff Bezos and Bill Gates. Musk himself reportedly considered investing in Synchron when Neuralink’s development hit a stall. The company has also steadily expanded its BCI’s functionality, making it compatible with a wide range of existing consumer technologies.
Last year, Synchron rolled out a generative chat feature powered by OpenAI to help users with communication. It also integrated its device with the Apple Vision Pro, which Jackson now uses regularly for entertainment. Next came an integration with Amazon Alexa, letting Stentrode recipients control the virtual assistant with just their thoughts. Earlier this year, Synchron and Apple released a custom Bluetooth protocol for BCIs, so Synchron’s system automatically detects and connects to iPhones, iPads, and Vision Pro devices when turned on. Synchron is now preparing for a large pivotal trial required for full regulatory approval and commercialization.
Where Musk envisions a long-term transhumanist fusion of human mind and machine, Synchron’s immediate focus is meeting the urgent needs of people like Jackson living with severe disabilities. If Synchron can secure approval from regulators and coverage from insurance companies, it could usher in a new era of brain devices that restore communication and movement, treat neurological disorders and mental illness, and detect and monitor brain health and disease. Though expanding BCI access to the general public is not Synchron’s current goal, its minimally invasive technology could eventually lead to safe, unobtrusive devices that let anyone play video games or browse the web with only their thoughts.
Synchron co-founder and CEO Tom Oxley did not set out to build a mind-reading company. After graduating medical school in 2005 from Australia’s Monash University, he knew he wanted to specialize in brain care (either neurology or psychiatry), which required he first train in internal medicine. As part of that training, Oxley spent three months working in a palliative care clinic for ALS patients. “It was extremely intense,” he says.
Later, during a clinical rotation in rural Mildura, he befriended Rahul Sharma, a cardiology trainee. Sharma would cook homemade Indian food, and the pair would have long philosophical conversations about the future of medicine. Sharma told Oxley about the industry shift from open-heart surgery to minimally invasive catheter-based techniques that access the heart through blood vessels. Oxley wondered: what if those same techniques could be used to access the brain? After all, the brain has an enormous network of blood vessels. Soon, the two were brainstorming the possibility of placing stents in the brain to deliver treatment, says Sharma, now Synchron’s co-founder and medical director.
Then in 2008, Oxley came across a landmark 2006 paper in the journal Nature that described how two paralyzed patients with an implanted BCI successfully controlled a computer with their thoughts; one patient was even able to move a robotic arm. To achieve those groundbreaking results, the team from Brown University and Massachusetts General Hospital used a device called the Utah Array, a 4-by-4-millimeter grid with 100 tiny metal spikes that penetrate brain tissue to record activity from individual neurons. Placing the array requires a craniotomy, a procedure that temporarily removes a section of the skull. The first person to receive the implant, Matthew Nagle, was able to move a cursor, read emails, play Pong, and draw circles on a screen.
“At that moment, I got excited about BCI,” Oxley says.
He and Sharma began developing the idea of placing electrodes on stents to record brain activity, and the concept for the Stentrode began to take shape. After finishing his internal medicine fellowship in 2009, Oxley cold-called the U.S. Defense Advanced Research Projects Agency (DARPA), which was already funding BCI research. A DARPA program manager thought the invention could help soldiers who had lost limbs control robotic prosthetics, and invited Oxley to pitch his idea at Walter Reed Army Medical Center.
DARPA ended up funding Oxley and Sharma’s rough early concept with $1 million, and two years later they founded a company called SmartStent, which eventually rebranded as Synchron. The startup received an additional $5 million grant from the Australian government, and later another $4 million from DARPA and the Office of Naval Research. They recruited biomedical engineer Nicholas Opie, who was working on a bionic eye at the time, to design the Stentrode, and by 2012 the company had begun implanting the device in sheep. In 2019, the first human received the Stentrode in an early feasibility study in Australia—years before Neuralink completed its first human surgery in January 2024.
Vinod Khosla, whose venture firm has invested in Synchron, argues the Stentrode can scale far faster than other BCIs in development that require invasive open brain surgery. Those devices also need specially trained neurosurgeons, or in Neuralink’s case, custom-built surgical robots. Far more cardiologists are already trained to implant stents, Khosla points out.
But Synchron’s approach comes with tradeoffs. From inside the blood vessel, the device uses 16 electrodes dotted across the stent’s surface to capture brain activity. Because it sits farther away from individual neurons than the Utah Array and Neuralink’s device, it picks up a weaker signal.
BCI researchers call this the “stadium effect.” If you are sitting inside a stadium, you can hear individual conversations around you. If you are sitting outside the stadium, you only hear the roar of the crowd, and might be able to tell when a goal is scored. “The question is, how much do you need this to hear to do something useful for the subject?” says Kip Ludwig, a professor at the University of Wisconsin-Madison and co-director of the Wisconsin Institute for Translational Neuroengineering, who is not involved with Synchron.
Neuralink’s implant has more than 1,000 electrodes spread across 64 flexible wire threads. More electrodes mean more information can be extracted from the brain, but more does not necessarily equal better, especially for relatively simple tasks like moving a cursor on a computer screen. “The minimal viable product is the ability to navigate and select on an iPhone,” Oxley says. “That’s what we think is going to be the basic use case.”
Beyond that, Oxley sees huge potential in using small blood vessels as pathways to access new regions of the brain. “We believe that opens up 10 times more brain coverage,” he says. Multiple Stentrodes placed across the brain could enable more natural control and more complex functions down the line.
As Synchron moves toward its 2026 pivotal trial, which will enroll between 30 and 50 participants, it will face key unresolved questions about its technology: what are its clear benefits, and how can those benefits be consistently measured? “These technologies are so new, and they’re providing the opportunity to restore functions that no other device or approach is yet able to restore,” says Leigh Hochberg, a BCI researcher at Massachusetts General Hospital and Brown University, and an author on the 2006 Nature paper that inspired Oxley. There are no “validated outcome measures that can be easily applied” to this new category of devices, he says.
For Synchron’s implant to win U.S. approval, the Food and Drug Administration will require proof that the device’s benefits outweigh its risks. And if approved, it remains unclear how much of the cost insurance companies will cover for patients. Unlike most drugs and medical devices, BCIs do not treat the underlying condition—they are more closely aligned with assistive technology. As the field matures and more startups work toward commercialization, companies and regulators are working to adapt existing assessment tools (used to measure functional ability and quality of life) for BCI use.
When asked about the future of the technology, Jackson has no doubt BCIs will eventually have a positive impact on patients’ health and well-being. “I can see down the road where this would give someone their independence,” he says. For now, though, the current setup is not fully practical for daily use. “I have to be physically connected with an exterior wire. So the only time that I am using the device itself is when I’m hooked up,” he says. That currently only happens twice a week during training sessions with Synchron’s field clinical engineer. In Synchron’s second-generation design, which will be tested in the pivotal trial, the internal and external units will connect wirelessly, so users will no longer need to be tethered to the system.
Despite having a BCI, Jackson still relies on voice assistants for most of his daily needs. “If I’m being honest, that’s the easier route,” he says. But voice technology fails regularly, and many apps do not support full voice control. For example, when Jackson tried to use the payment app Venmo, there was no voice-controlled way to add a required note explaining the purpose of the payment.
“The voice assist technology is nowhere near where it needs to be,” Sharma says. Anyone who has used Alexa or Siri is familiar with accuracy issues and lag between a request and a response. If BCIs can complete tasks more naturally than voice control, Sharma thinks that could be a game-changer for users. BCIs also offer far more privacy: “If there are other people in your environment, you may not wish to be sharing what it is you are trying to do or express out loud,” he says. And for patients with paralysis who have lost the ability to speak, a BCI may be their only means of communicating and interacting with the world around them.
Jackson knows he is a pioneer and test subject for this technology, and that Synchron’s device will get better, faster, and more seamless over time. He enjoys testing new apps with his BCI, and says his favorite thing to do with it is use the Apple Vision Pro. He can no longer travel, but the headset transports him to the Swiss Alps or a temperate rainforest in New Zealand. But there are still hobbies beyond the digital world he misses that BCI cannot yet help with: painting, for example, and wood carving.
Above his bed hangs a painting of two yellow fruit warblers. He painted it himself when he was 20 years old, and his mother kept it and had it framed. He was looking forward to doing more oil painting in retirement. Jackson knows, of course, that ALS is progressive, and his condition will inevitably get worse. He could eventually lose his speech and what little voluntary movement he has left. He may develop cognitive impairment and no longer be able to control his BCI; the average life expectancy for an ALS patient is just two to five years after diagnosis. Of the 10 people who have received Synchron’s BCI, only Jackson and one other participant are still using it. The others stopped either due to ALS progression or their death.
Before his ALS diagnosis, Jackson had started woodworking, and wanted to learn how to carve birds. A wood carving of a cardinal he bought sits on his nightstand as a reminder of the hobby he will never be able to return to because of his ALS. “If there could be a way for robotic arm devices or leg devices to be incorporated down the road, that would be freaking amazing,” he says. Neuralink is currently testing that capability, but modern robotic prosthetics are far from lifelike, and can only complete simple tasks with jerky movements. It could be decades before BCIs give people the ability to do something as complex as carving wood.
For now, Jackson can use the BCI to explore art museum apps, and he hopes to one day find a way to create digital art with his thoughts. And while the current setup is still limited in many ways, it enables Jackson to do more than he ever thought possible. He is, after all, able to move objects on a screen without using his hands, feet, eyes, shoulders, face, or even his voice. “There’s a reason why this is pretty groundbreaking technology,” he says.
Update: 7/23/2025, 11:30 AM EDT: Wired has updated the number of patients that have received Neuralink implants, which was announced following this story's publication.
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