A. The FDA Approval Process and the Launch of the PRIME Study

On May 25, 2023, Elon Musk posted a single short sentence on Twitter. "FDA has approved human clinical trials." That was it. But behind that one line lay years of setbacks and second attempts.

Neuralink first applied to the FDA for clinical trial approval in early 2022. The answer was no. The FDA raised three concerns. First, the safety of the lithium battery used in the implant. Second, the possibility that electrode threads thinner than a human hair could migrate to other areas inside the brain. Third, the risk of brain tissue damage when removing the device. Neuralink spent over a year working to resolve these issues.

What Neuralink received was not an FDA "Breakthrough Device" designation. It was an Investigational Device Exemption, or IDE. This is an approval that permits human testing for research purposes, not commercial sale. After reviewing Neuralink's data, the FDA authorized the company to test the implant on a limited number of patients under restricted conditions.

In September 2023, Neuralink began recruiting patients. The clinical trial was named PRIME, short for Precise Robotically Implanted Brain-Computer Interface. The name itself captured the core of the technology.

The criteria for the PRIME Study were specific. Patients with quadriplegia caused by cervical spinal cord injury, or patients unable to move their limbs due to ALS. Age 22 or older. At least one year since the injury. People who met these conditions began submitting applications through the Neuralink website. Over 1,000 applied, but fewer than a tenth actually qualified.

The partner institution for the clinical trial was the Barrow Neurological Institute, located in Phoenix, Arizona. The hospital is considered one of the top neurosurgery centers in the United States. Neuralink chose to work with an established medical institution rather than its own facilities. The goal was to meet medical safety standards and conduct the procedure under the supervision of independent physicians.

The PRIME Study had three objectives. First, verifying the safety of the N1 implant and the R1 surgical robot. Second, confirming practical usefulness in daily life. Third, developing a solution for electrode thread retraction. Neuralink had to achieve all three before it could move to the next stage.

The clinical trial registration number was NCT06429735. Anyone can look up this number on ClinicalTrials.gov. Considering the criticism Neuralink had faced for its secrecy, this was a small step toward transparency.

By January 2024, all preparations were complete. It was time for the first patient to go under the knife.

B. The First Patient: Noland Arbaugh

(1) The Surgery and Recovery: Implanting a Chip in a Quadriplegic Patient's Skull

Noland Arbaugh was born in 1993 or 1994 in Yuma, Arizona. He was a student at Texas A&M University. In the summer of 2016, he was working as a counselor at Island Lake Camp in Starrucca, Pennsylvania. One day, he dove into a lake and something went wrong. His spine dislocated between the C4 and C5 vertebrae.

From that moment on, he felt nothing below his shoulders. He couldn't move a single finger. He was twenty-two years old.

Eight years later, on January 28 or 29, 2024, Arbaugh lay on an operating table at the Barrow Neurological Institute in Phoenix. He was twenty-nine.

The surgery took several hours. First, the medical team drilled a coin-sized hole in his skull. This part was done by human hands. Then it was the R1 robot's turn.

The R1 inserted 64 electrode threads into the motor cortex of his brain. Each thread carried 16 electrodes, putting a total of 1,024 electrodes in contact with brain tissue. These electrodes were placed precisely in the area of the left motor cortex responsible for right-hand movement. When Arbaugh thought about moving his right hand, the neural signals would be picked up by the electrodes.

The reason the R1 was necessary was straightforward. Human hands tremble. Blood vessels in the brain are thinner than a strand of hair. The robot could avoid those vessels while inserting each electrode thread to the exact right depth.

When the surgery was over, the N1 chip sat flush in Arbaugh's skull. It was about as thick as five coins stacked together. It charged wirelessly and transmitted data over Bluetooth. Nothing was visible from the outside. Once his hair grew back, even the scar would be hidden.

Arbaugh was discharged the day after surgery. His cognitive abilities were completely intact. There are accounts that Elon Musk called him via video chat in the recovery room just hours after the procedure.

"How are you feeling?" a nurse asked.

Arbaugh could only answer that he didn't know yet. Whether the chip was working could only be confirmed after recovery. He later recalled that if he had woken up with no memory of the procedure, he wouldn't have believed anyone who told him something had been implanted in his brain. He couldn't feel the chip at all.

(2) Achievements: Chess, Mario Kart, and Eight Straight Hours of Use, All by Thought Alone

On March 20, 2024, Noland Arbaugh went live on X (formerly Twitter). A chess game was on screen. He moved pieces without lifting a finger. The cursor followed his thoughts.

When he first connected to the Link app, it took him only minutes to gain control of the cursor. The Neuralink team measured his performance with a standardized task called the WebGrid test. In his very first session, Arbaugh broke the world record for BCI cursor control. The previous record had been set using a different BCI device.

Over the following weeks, Arbaugh spent eight to ten hours a day training the system with the Neuralink team. The software was learning his brain signals, and he was adapting to the new interface.

In his free time, he played video games. He stayed up all night playing Civilization VI. He played Mario Kart. He had tried voice recognition software and adaptive mice before, but never got the level of control he wanted. Neuralink was different.

"The games were so fun I played for hours on end," Arbaugh said in an interview. "It felt like an entirely new world had opened up."

Chess was only the beginning. He browsed the web. He sent emails. He typed text messages. Before, a single text took five to fifteen minutes. Now it took seconds. He controlled his smartphone. He operated the home automation system.

Neuralink engineers also built a custom speech-to-text program for him. Arbaugh said it was better than anything on the market. They seemed capable of solving anything.

In September 2024, Arbaugh flew to Paris to watch the Speed Chess Championship finals. In September 2025, he played a live match against women's chess master Anna Cramling at the Fortune Brainstorm Tech conference. Moving pieces with his thoughts alone.

He went back to school to pursue a neuroscience degree. He started his own business. He began traveling again. Neuralink had given him his life back.

"My entire life has changed." Arbaugh said this in August 2025, eighteen months after surgery. He used Neuralink roughly ten hours a day, for studying, reading, gaming, and scheduling interviews.

(3) Crisis and Recovery: Thread Retraction and Algorithmic Resilience

Not everything went smoothly. About a month after surgery, warning signs appeared. The data transmission speed from the implant started dropping.

At first, Arbaugh assumed it was a software bug. But when the Neuralink team analyzed the electrode signals, it turned out to be a hardware problem. The electrode threads were pulling out of the brain tissue.

The phenomenon was called "thread retraction." Over the weeks following surgery, a significant number of the 64 electrode threads shifted from their original positions. In the end, roughly 85% of the electrodes stopped functioning properly. Out of 1,024 electrodes, only 100 to 150 could still pick up brain signals.

The cause was brain movement. The human brain moves inside the skull far more than expected. About three times more than Neuralink had predicted. Residual air inside the skull after surgery (pneumocephalus) was also identified as a contributing factor. The electrode threads began shifting immediately after the procedure and never fully stabilized.

"It was really tough," Arbaugh recalled. "I had just gotten a taste of what was possible, and a month in, it felt like everything was falling apart. I thought I was going to be dropped from the study."

On the morning he was set to visit Neuralink headquarters, the team delivered the news about the thread retraction. Arbaugh felt deflated, but he steadied himself quickly. He remembered why he was there. As the first patient, the problems he faced and the process of solving them would help future patients.

Neuralink chose a software fix over reopening his skull. Engineers revised the recording algorithms. Instead of tracking signals from individual neurons, they switched to detecting signals from neuron clusters. They also improved the technique for translating signals into cursor movement.

The results were striking. Even though the number of working electrodes had plummeted, system performance recovered. Arbaugh's bits-per-second (BPS) rate surpassed his earlier records. He more than doubled the previous world record for BCI cursor control.

One inconvenience remained. The click method had to change. Originally, he could click by thought alone. After the thread retraction, the system switched to a dwell-click: holding the cursor in one spot for 0.3 seconds triggered an automatic selection. Neuralink said it was still working to restore the single-click function.

The electrode threads eventually stabilized. They stopped shifting. Arbaugh's Neuralink kept working. He still uses it more than ten hours a day.

"The whole point of this study is figuring out what works and what doesn't," Arbaugh said. "Everything I've been through will help other people down the line."

C. Alex and the Achievements of Subsequent Participants

(1) Alex: 3D Design in CAD Software, Counter-Strike Gaming

In August 2024, the second patient underwent surgery. His name was Alex. His last name was not disclosed. He was the opposite of Noland Arbaugh in temperament. He avoided media exposure. He valued his privacy. Most of what we know about him comes from Neuralink blog posts.

Alex was a quadriplegic due to a spinal cord injury. Before the injury, he had worked as an auto mechanic. He was someone who loved building and fixing things with his hands.

The surgery took place at the Barrow Neurological Institute, the same facility as Arbaugh's procedure. But the technology had changed.

Neuralink applied the lessons learned from its first patient. Several measures were taken to prevent thread retraction. Brain movement during surgery was minimized. The gap between the implant and the brain surface was reduced. The electrode threads were inserted deeper: from 3 to 5 millimeters in Arbaugh's case to 8 millimeters for Alex.

The results were successful. No thread retraction was observed in Alex. All 64 electrode threads stayed in place. He was discharged the day after surgery. Recovery went smoothly.

When Alex first connected the Link to a computer, it took him less than five minutes to control the cursor. Within hours, he had surpassed the speed and accuracy of every assistive technology he had used before. On day one, he broke the world record for cursor control set by a non-Neuralink BCI device.

Then he started playing Counter-Strike 2.

Alex had loved first-person shooters before his injury. He didn't give them up afterward. He used a QuadStick, a mouth-operated controller that works with sip-and-puff pressure sensors and lip-position sensors. But it had limits. He could move or aim, one or the other. Not both at the same time.

Neuralink broke through that barrier. Now Alex could move his character with the QuadStick and aim with Neuralink. Both at once. Just like any other player.

"Just moving around is so much fun," Alex said on the Neuralink blog. "When I look side to side, I don't need to move the quad stick. I think about where I want to look, and it goes there. It's insane."

Gaming wasn't all. On the second day, Alex started using CAD software, a 3D design program called Autodesk Fusion 360. As a former auto mechanic who missed building things with his hands, this opened up new possibilities.

His first design was a charging stand for the Neuralink charger. He came up with the idea, designed it in the software, and printed it on a 3D printer. The finished product was something he could actually use.

"Coming up with an idea, turning it into a design, and making it into a real object. It feels like I'm building things again," Alex said.

Neuralink is continuing to develop the system with Alex. The team is working on mapping intended movements to different types of mouse clicks (left, right, and middle). This will allow rapid switching between modes like zoom, scroll, pan, and click-and-drag in CAD software.

"I'm already amazed at how well this works," Alex said. "The Link is a huge step on the path to reclaiming my own freedom and independence."

(2) Restoring Speech for an ALS Patient Combined with AI Voice Generation

Bradford Smith. That was the third patient's name. He was fundamentally different from the first two. Noland Arbaugh and Alex had spinal cord injuries. Smith had amyotrophic lateral sclerosis, ALS.

ALS attacks motor neurons. The nerve cells that control muscles gradually die. Patients lose the ability to walk, eat, speak, and breathe, one by one. But the mind remains fully intact. The body becomes a prison.

That was Smith's reality. He was a father of three living in Arizona. He went to the doctor because a shoulder injury wouldn't heal and received an ALS diagnosis. When the neurologist hugged him, he understood how serious it was. He wept and prayed in the parking lot.

As the disease progressed, he lost the ability to move anything except his eyes. He depended on a ventilator. He could not speak. He had become a nonverbal patient.

In November 2024, Smith received a Neuralink implant. He was the third person in the world, the first ALS patient, and the first nonverbal patient to get one.

On April 27, 2025, he posted on X: "I am the third person in the world to receive a Neuralink brain implant. I am the first with ALS. I am the first nonverbal patient. I am typing this with my brain. This is my primary means of communication."

The system worked differently for Smith. Arbaugh and Alex controlled the cursor by thinking about moving their hands. That method didn't work well for Smith. After extensive trial and error, engineers found that thinking about moving his tongue and jaw was more effective.

"Neuralink doesn't read my deepest thoughts or words," Smith explained. "It interprets my intention of how and where to move the cursor." Just as you don't consciously think about your wrist or arm when using a mouse, Smith no longer thinks about his tongue. He moves the cursor unconsciously.

Then his voice came back. Thanks to AI.

Smith and the Neuralink team gathered old videos and audio files recorded before his ALS diagnosis. These were recordings of his real voice. They used them to train a voice synthesis AI. The result was a synthetic voice that replicated how he once sounded.

Now when Smith types text with his brain, the computer reads it aloud in his old voice. After years, he could speak in his own voice again.

In May 2025, Smith made a YouTube video. He edited it with the brain implant and narrated it with his AI-restored voice. He called it the first YouTube video ever edited using a BCI.

"It took years to get here, and there are still moments when I get choked up," Smith said. "It feels really good to exist for a purpose bigger than myself. I'm truly glad that this work will help other people going forward."

Before Neuralink, Smith communicated using an eye-tracking device. But the technology was sensitive to light. It only worked properly in a dark room. He couldn't use it outdoors. "I was basically Batman. Trapped in a dark room."

Now he can communicate outside. He watched his son's soccer game. He spoke to teenagers at church. He played Mario Kart with his kids. "Brad played Mario Kart with his kids," said Neuralink co-founder DJ Seo. "That moment was... incredible."

Smith also uses Elon Musk's AI chatbot Grok. It helps him write replies and carry on conversations on X. A brain implant combined with generative AI. It offers a glimpse of what the future of neurotech might look like.

On May 2, 2025, the FDA granted Neuralink's speech restoration technology a Breakthrough Device Designation. The goal was to accelerate the development of technology for patients with severe speech impairments caused by ALS, stroke, spinal cord injury, cerebral palsy, multiple sclerosis, and similar conditions.

D. Global Expansion in 2025: Clinical Trials in the UK, Canada, and the UAE

In 2025, Neuralink crossed America's borders. Clinical trials expanded to three continents.

Canada came first. In November 2024, Health Canada approved clinical trials. The trial site was Toronto Western Hospital, part of the University Health Network at the University of Toronto. The team was led by Dr. Andres Lozano.

On August 27 and September 3, 2025, the first Neuralink surgeries outside the United States took place. Two patients received implants. Both had cervical spinal cord injuries and were in their early thirties. Within days of surgery, they could control a computer cursor with thought alone. The trial, named CAN-PRIME, has a target enrollment of six participants.

Britain came next. In July 2025, the launch of the GB-PRIME trial was announced. The partnering institutions were University College London Hospitals (UCLH) and Newcastle Hospitals. The trial received approval from the UK's Medicines and Healthcare products Regulatory Agency (MHRA) and the Health Research Authority (HRA).

In October 2025, Britain's first patient underwent surgery. His name was Paul. He had motor neuron disease. Hours after the operation, he began controlling a cursor with his thoughts. He was discharged the following day. It was the moment that proved the technology worked across different countries, different hospitals, and different surgical teams.

The Middle East was part of the picture too. In 2025, the Abu Dhabi Department of Health approved the UAE-PRIME trial. The trial site was Cleveland Clinic Abu Dhabi. The UAE is known for fast-tracking approvals of innovative medical technologies. For Neuralink, it was a strategic choice.

This global expansion served several purposes. The first was speeding up patient recruitment. Spinal cord injuries and ALS are rare conditions, making it difficult to recruit enough patients in any single country. Running enrollment across multiple nations meant trials could move faster.

The second was spreading regulatory risk. Even if the US FDA's requirements turned out stricter than expected, approvals in other countries could open the door to commercialization first.

The third was proving the technology's universality: gathering data showing the device worked across different healthcare systems, different surgical teams, and different patient populations.

By mid-2025, Neuralink had implanted devices in at least seven to nine patients. Some reports put the number at twelve as of September 2025. The goal was to enroll twenty to thirty new participants by the end of that year.

Elon Musk posted on X: "If everything goes well, hundreds of people in a few years, tens of thousands in five years, millions in ten years will be using Neuralink." Whether that is exaggeration or prophecy remains to be seen. One thing, though, is clear. What began on the morning of January 29, 2024, in a Phoenix operating room is now spreading across the globe. A small chip placed inside Noland Arbaugh's skull marked the start of an experiment that is changing the relationship between humanity and machines.