Elon Musk’s Neuralink brain chip: what scientists think of the first human trial

Researchers are worried about the lack of transparency surrounding an implant that enables people to control devices using their thoughts.

Neuralink, the company through which entrepreneur Elon Musk hopes to revolutionise brain–computer interfaces (BCIs), has implanted a ‘brain-reading’ device into a person for the first time, according to a tweet posted by Musk on 29 January.

BCIs record and decode brain activity, to allow a person with severe paralysis to control a computer, robotic arm, wheelchair or other device through thought alone. Apart from Neuralink's device, others are under development and some have already been tested in people. Neurotechnology researchers are cautiously excited about Neuralink’s human trial. “I hope to see that they can demonstrate that it is safe. And that it is effective at measuring brain signals — short term, but, most importantly, long term,” says Mariska Vansteensel, a neuroscientist at University Medical Centre Utrecht in the Netherlands and president of the international BCI Society.

Elon Musk tweeted about a Neuralink trial, but there’s no official confirmation. A study brochure invites participation, but lacks important information like implant locations and trial outcomes. Tim Denison, a neuroengineer at the University of Oxford, is concerned about this. Neuralink’s trial has not been registered at ClinicalTrials.gov, which is required by many universities and medical journals to ensure ethical principles and the safety of clinical trial participants. Neuralink has not commented on why the trial has not been registered despite Nature’s request for comment.

Nature has examined how Neuralink's implants compare to other BCI technologies, how the trial will advance BCIs, and the concerns of researchers.

What will scientists learn from the Neuralink human trial?

Experts anticipate that safety will be the top priority in Neuralink’s trial, as the company has not disclosed much information about its goals. The device’s immediate impact will be monitored for complications, including strokes, bleeds, and vasculature damage, as well as for infections. Long-term follow-up will ensure the device remains safe for implantation.

Neuralink’s study brochure says that volunteers will be followed for five years. It also indicates that the trial will assess the device’s functionality, with volunteers using it at least twice weekly to control a computer and feedback on the experience.

Vansteensel would like to know whether the quality of the detected neuronal signals degrades over time, which is common in existing devices. “You’re not going to replace electrodes easily after implantation,” she says. “If, in a month from now, they demonstrate beautiful decoding results — impressive. But I will want to see long-term results.”

Denison is also keen to learn how a wireless system that can be used in non-laboratory settings performs.

What concerns do scientists have about the Neuralink BCI?

Now that human trials have begun, volunteer safety and well-being are a pressing question. The trial was approved by the US Food and Drug Administration (FDA), which rejected an earlier application from Neuralink. However, some researchers are uncomfortable that the trial is not listed on ClinicalTrials.gov. “I would assume that the FDA and Neuralink are following the playbook to a certain extent,” says Denison. “But we don’t have the protocol. So we don’t know that.”

Transparency is important for those who may benefit from BCIs. Ian Burkhart, a BCI Pioneers Coalition co-founder, spent 7.5 years with a Blackrock array implanted in his brain after breaking his neck. He thinks Neuralink could do better with information release, for the sake of patients eagerly waiting for the technology to improve their lives.