Neuralink, founded in 2016 by Elon Musk, is developing ultra-thin neural probes implanted by a neurosurgical robot to interface directly with the motor cortex.
Each probe can hold dozens of electrodes, and the system supports thousands of channels through an application-specific integrated circuit.
In May 2023, the US FDA cleared Neuralink’s device for human trials under an investigational device exemption, targeting patients with quadriplegia from cervical spinal cord injury or ALS.
The first human recipient, Noland Arbaugh, underwent implantation in January 2024 at Barrow Neurological Institute. [] What happened next has the medical community buzzing.
Human trials: Early recipients and outcomes
Arbaugh, a 29-year-old man paralyzed from the shoulders down after a diving accident, quickly showed post-implantation that he could control a computer cursor, play chess, and communicate using only his thoughts.
However, within weeks, up to 85% of the ultra-thin threads retracted, reducing the number of functional channels.
Neuralink engineers partially compensated by modifying signal processing algorithms, but the episode showed the difficulty of maintaining stable, long-term electrode-tissue integration in the brain.
Arbaugh described the experience this way: “If I had lost my memory, and I woke up, and you told me there was something implanted in my brain, then I probably wouldn’t believe you.”
He added, “I have no sensation of it—no way of telling it’s there unless someone goes and physically pushes on it.” Arbaugh said the implant allowed him to “reconnect with the world.”
Inside the PRIME trial
In early 2025, the Miami Project to Cure Paralysis at the University of Miami became the second US site in Neuralink’s PRIME study (Precise Robotically Implanted Brain-Computer Interface).
In April 2025, a military veteran named RJ, paralyzed after a motorcycle accident, received the implant at the University of Miami. RJ gained the ability to play video games, operate a cursor, and control his television using thought.
“They’re giving me my spark back … my drive back. They’ve given me my purpose back," RJ said. "I think my favorite thing's probably [being] able to turn on my TV, like the first time in two and a half years I was able to do that. That was a pretty sweet move.”
As of July 2025, only seven patients nationwide have been implanted under the Neuralink protocol, showing both the limited access and the experimental stage of the trial.
"This is an amazing development that now the third person to use Neuralink has gained the ability with the use of AI to type with neural thoughts," said Mary Ann Picone, MD, medical director of the MS Center at Holy Name Medical Center in Teaneck, NJ. "The now-realized potential of Neuralink is to allow patients with quadriplegia to control computers and mobile devices with their thoughts."
Peter Konrad, MD, PhD, chairman of neurosurgery at WVU Rockefeller Neuroscience Institute, said Brad Smith, the first patient with ALS to receive the implant, is an "incredible hero for those who are severely disabled from diseases such as ALS."
Dr. Konrad also expressed his interest in future brain-computer interface (BCI) developments.
“It is encouraging to see faster progress being made with neural devices reaching clinical trials in the past 5 to 10 years.”
However, he acknowledged that “we are still awaiting development of a BCI device that does not require a team of engineers and experts to customize every severely disabled patient with this technology.”
Technical and safety considerations
Despite early successes, major technical and safety issues remain. Electrode retraction, as in Arbaugh’s case, highlights the challenge of keeping probes stable in the moving brain. []
The FDA cited concerns regarding lithium-ion battery stability, migration of implanted wires, and the safety of explantation before it gave approval for human trials.
These risks are partly mitigated by the use of flexible electrodes and by ensuring robotic precision, but such measures still need long-term validation.
“Any time we operate near the most important areas of the brain we are concerned about complications that could result in temporary or permanent neurological disability," Julie Pilitsis, MD, PhD, professor and chair of neurosurgery at the University of Arizona College of Medicine, tells MDLinx.
The main concern is hemorrhage and injury to blood vessels that can result in stroke or damage to the area, Dr. Pilitsis explains. Less severe, but still significant complications, may be seizures. Likely these will only occur right after surgery.
"Infection can lead to prolonged times in the hospital or antibiotic use or, worst case scenario, removal of the hardware itself," Dr. Pilitsis says.
Ethical and societal concerns also exist. Who owns neural data, and how should it be protected from misuse? Neural signals are not only medical data but may reveal thought processes and intent.
The possibility of moving from therapy to augmentation raises debates about access, equity, and medical necessity.
