The first patient implanted with Neuralink would have succeeded in moving a cursor on a screen

Implanted on a first tetraplegic volunteer patient last month, Neuralink's brain chip has started to prove itself. “Progress is good, and the patient appears to have made a full recovery, with no ill effects that we are aware of. The patient is able to move a mouse on the screen by just thinking,” said Elon Musk during an audio discussion broadcast live on the social media platform X (which he owns).

However, no studies or data have been disclosed. “Neuralink does not share what it finds like researchers in the public domain,” underlines Adrien Rapeaux, doctor in bioelectronics at Imperial College London, who works on bioelectric implants in the brain to fight against dementia (like Alzheimer's or Parkinson's diseases). “We do not know the performance of the transplant recipient's use of technology, such as the number of clicks that the person makes, willingly or unwillingly. This type of error exists but we do not know the evaluation of these errors for Neuralink. Elon Musk's comments only confirm that the implant works. Not really a surprise according to him, “especially since we knew for more than 2 years that it worked on macaques”. “These announcements encourage us to continue our research,” he nevertheless acknowledges.

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“It is good news that their technology (which is superb) works, but it is not surprising that it can allow the patient to control a cursor,” also analyzes Grégoire Courtine, research professor at the Faculty of Geneva in neuroengineering. This experiment had already been successfully carried out by the American laboratory Blackrock Neurotech, which even went further with its own implant. This laboratory states on its website that “some pioneers use their BCI [implant, Editor's note] to play video games, use Photoshop and even paint using robotic arms controlled by the brain.”

For Adrien Rapeaux, Neuralink “is still far from the more complex control of an exoskeleton or wheelchair. » Elon Musk has big ambitions for his technology such as fighting obesity, autism, depression and schizophrenia. Remember that certain existing implants already make it possible to limit the symptoms of Parkinson's and limit associated treatments without curing the disease.

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How do these brain implants and the Neuralink one in particular work? The brain is an organized and complex network made of cables (neurons and glial cells) which exchange electrical information between them. This information can be captured on the surface of the network. But deciphering them is not easy. “The quantity of signals captured by the interfaces are numerous and their uses differ depending on the technology chosen,” explains Adrien Rapeaux.

Neuralink technology relies on patient learning, who must modulate their brain activity in order to generate signals that will be picked up by the implant and then transformed into a learned action: such as moving a cursor. Neuralink offers an implant with 3000 electrodes, approximately ten times more than its current competitors, to capture as many signals as possible. It remains to be demonstrated that these capabilities are of real interest in practice.

Another burning question: how these implants will evolve over time. “Scar tissue forms around the implants, which modifies the perception and processing of brain signals,” recalls Adrien Rapeaux. Currently, they must be removed or changed after a few months or a few years at most, which limits the potential applications as the implantation procedure is cumbersome.