Photo from Neuroscience.
The U.S. Food and Drug Administration has approved Neuralink, Elon Musk’s company, to implant its brain chip in a second individual, after approving the company's proposed solutions to an issue encountered with the first test participant. According to a source familiar with the company, the adjustments involve implanting some of the device’s ultrathin wires further into the brain.
As Neuralink gets ready for its second test participant, the first, Noland Arbaugh, is sharing his experiences with the device, discussing its impact on his life and the emotional ups and downs he went through before, during, and after it partially malfunctioned.
In the days following his implantation in January, Arbaugh used the Neuralink implant to control a computer cursor solely with his thoughts. As a quadriplegic who had been unable to move below his shoulders for the past eight years, Arbaugh suddenly found himself able to communicate with friends, play games, and engage with his environment in ways that had seemed impossible since his accident.
However, a month after his surgery, Arbaugh noticed a decline in the device's performance. Most of the threads implanted in his brain had become dislodged and were no longer detecting the electrical signals necessary to translate his thoughts into cursor movements.
In an interview, Arbaugh shared that the experience was incredibly challenging, as he went from feeling elated to deeply disappointed when the device malfunctioned. He found it very tough and said he ended up crying.
The Neuralink N1 implant is a device roughly the size of a U.S. quarter that houses electronics and a battery. It features 64 ultra-thin external threads, each finer than a human hair, which are inserted into the brain's motor cortex to transmit neural signals.
Arbaugh mentioned that Neuralink informed him that about 15% of the threads implanted in his brain are still in place. These threads have stabilized, and subsequent software updates by the company helped him recover many of the device's functions, which he has showcased in livestreams.
Arbaugh explained that because this device had never been implanted in a human before, Neuralink was uncertain about the extent of brain movement within the skull. The company discovered that his brain moved up to three times more than they had anticipated.
One of the solutions proposed by Neuralink, approved by the FDA, to secure the threads in place involves implanting them deeper into the brain's motor cortex, approximately eight millimeters, compared to Arbaugh's original implantation depth of about three to five millimeters.
With approval from the FDA, Neuralink aims to implant a second participant in June, as per a source familiar with the company. Over 1,000 quadriplegics have enrolled in its patient registry, but only fewer than 100 meet the criteria for the study.
Although some individuals are eligible, Musk announced on X on Thursday that the company is still open to receiving applications.
Neuralink's goal for this year is to implant its device in 10 individuals, with the aim of having a diverse range of recipients to study various behaviors. However, a challenge they face is that the individuals signing up for their patient registry are predominantly white and male.
Neuralink plans to submit applications to regulatory authorities in Canada and Britain in the next few months to initiate similar trials in those countries, according to the source. The patient registry is currently available for Canada and will soon be accessible for Britain.
Upon discovering why his implant ceased to respond to his thoughts, Arbaugh inquired about the possibility of removing and repairing it, or potentially replacing it. He was informed of this development by a team, including three Neuralink staff, at his hotel near the company's California headquarters. Arbaugh, who had traveled from Arizona with his family for a scheduled tour of Neuralink's facilities, recounted that his medical team expressed reluctance to pursue another brain surgery and opted to wait for further information.
He expressed feeling as though he had only begun to explore the potential of the incredible technology, only for it to be suddenly taken away. However, he quickly recovered from this disappointment and recognized that everything he had accomplished up to that moment would benefit future users of the technology.
Several weeks after informing Arbaugh about the issue, Neuralink was still investigating the exact cause. However, Arbaugh explained in the interview how the company's engineers enhanced the performance of his device by modifying how it interpreted his brain signals.
The focus was on clusters of neurons generating robust signals, with many electrodes receiving weaker or no signals being deactivated. In a recent blog post, the company mentioned adjusting its recording algorithm to increase sensitivity to signals from neural populations.
The enhancements were so significant that Arbaugh mentioned he has now exceeded his previous capabilities prior to the threads retracting, filling him with great hope for the future. He remarked that it appears substantial progress has been made and that things are moving positively forward.