Elon Musk says Neuralink has implanted its experimental N1 brain-computer interface (BCI) in a second human volunteer and that it “works very well.” But as with the coin-sized device in the company’s first patient, only a fraction of the electrodes are believed to be working properly.
“I don’t want to jinx it, but it looks like the second implant went really well,” Neuralink’s CEO said in an Aug. 2 podcast interview with computer scientist Lex Fridman. “There’s a lot of signals, a lot of electrodes. It works really well.”
“A lot of electrodes” is a relative number, though. During his lengthy conversation with Fridman, Musk clarified that while early results seem “good so far,” he estimates that only about 400 of the BCI’s 1,024 electrodes surgically implanted in the user’s motor cortex are currently providing signals. While that’s about a 10 percent improvement over the 80 to 85 percent electrode failure rate reported in Neuralink’s first volunteer, it illustrates the immense hurdles still facing a technology that Musk says will resemble telepathy in just a few years.
[Related: 85% of Neuralink implant wires are already detached, says patient.]
“Imagine if Stephen Hawking could communicate faster than a typist or an auctioneer. That’s the goal,” Elon Musk posted on his social media platform, X, in January 2024.
Earlier this year, reports confirmed that up to 870 electrodes had completely detached in Neuralink’s first patient, Noland Arbaugh, after the implant moved within his skull up to three times more than the company had anticipated. Arbaugh, a 30-year-old man with quadriplegia, told The Wall Street Journal Arbaugh began experiencing a degradation in the performance of his BCI after it allowed him to control computer inputs and a mouse cursor with his mind. Arbaugh said Neuralink was uncomfortable with performing another brain surgery to remove the implant, and he spent weeks improvising a solution. Engineers eventually devised a modification to the “recording algorithm” that made the implant “more sensitive to neural population signals, improved the techniques for translating those signals into cursor movements, and improved the user interface.” There is currently no information available explaining exactly what caused Arbaugh’s electrodes to detach, or whether these faulty components could pose health problems in the future.
Neuralink faced numerous regulatory delays and investigations over alleged animal rights violations and safety concerns in the years leading up to its first human trials. In 2023, a medical ethics organization focused on animal rights warned volunteers against enrolling in the company’s PRIME study, saying they “should have serious concerns” about the device’s safety.
During his podcast appearance last Friday, Musk didn’t elaborate on what caused the latest complications, focusing instead on Neuralink’s ambitious goals for future patients, including eight more volunteers who are set to receive N1 devices by the end of the year. He said that even with 10 to 15 percent functionality in Arbaugh’s implant, engineers “were able to achieve a computational rate of bits per second.”
Elon Musk later claimed that this was “twice the world record,” though it’s unclear exactly which record it was. In 2017, researchers at Stanford University published a clinical study detailing the results of three patients who had tested earlier iterations of different BCIs. Despite being externally installed and physically wired, two ALS patients achieved computational rates of 2.2 and 1.4 bits per second, while another volunteer with Lou Gerig’s disease recorded 3.7 bits per second, four times the previous speed record at the time.
“In the coming years, it’s going to be massive,” Musk said Friday. “… I think we’re going to start to go way beyond the world record by orders of magnitude in the coming years… to, I don’t know, 100 bits per second, [a] thousand.”
