From our correspondent in the United States,
Control a smartphone or computer by thought. Regain rudimentary vision after losing it. Walking again despite a spinal cord injury. Boost intelligence or memory. These are some of the promises of Elon Musk and the brain implant of his start-up Neuralink, which has received the green light from American medical authorities to begin the first human clinical trials.
Science or science fiction? 20 minutes takes stock of the possibilities of this type of direct neural interface (brain computer interfaceor BCI, in English) that scientists have been working on for decades.
How does the Neuralink brain implant work?
A robot surgeon cuts out a small portion of the skull – of a monkey or a pig
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The operation takes place in less than an hour, without general anesthesia. The implant, which communicates via Bluetooth with a computer, is recharged wirelessly by induction. “The real breakthrough of Neuralink is their technology to implant these microwires with a robot that carefully avoids the blood vessels (of the brain) to limit the damage”, explains neuroscientist Bradley Greger, professor-researcher at Arizona State University , which has been working for years to partially restore vision by directly stimulating the visual cortex. According to him, these flexible electrodes, and not rigid like most of those currently used, are the key to implants that could be kept for life.
The scientist recalls that implants have been used routinely for thirty years in deep brain stimulation, in order to minimize tremors in patients with Parkinson’s disease, with “a very low rate of surgical complications”. And cochlear implants already stimulate the auditory nerve.
Is controlling a computer by thought new?
Two years ago, Neuralink released a video of Pager, a 9-year-old macaque playing Pong by mere thought power. Greger recalls that humans were already able to move a slider or control a robotic arm to drink from a straw more than fifteen years ago. For the researcher, “Neuralink is moving from a laboratory-tested proof of concept to a consumer medical device”. Which could change the lives of people with neuromotor disorders like Charcot’s disease, from which Stephen Hawking suffered.
And how does it work ?
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When he presses left/right/up/down, the neural signals that control the muscles of the arm and hand are decoded by the system, and his intention is followed by an action on the screen. Then Neuralink completely removes the joystick. The monkey plays telepathically.
Other companies, like Meta, are experimenting with headsets that don’t require you to go under the knife. But, “the quantity and quality of information that can be exchanged” via electrodes directly connected to the brain are much higher”, insists Greger.
Can we really allow blind people to see (again)?
If our eye is comparable to a camera that captures the light reflected by surrounding objects, the information is processed by the visual cortex. Shapes, colors, movement… What we “see” is in fact a cerebral interpretation of electrical signals.
By connecting them to a camera, “implants like those of Neuralink are able to activate neurons by stimulating a specific area of the visual cortex, which allows a patient to perceive flashes of light” in his field of vision, explains the searcher. Who however insists strongly: “It is an extremely rudimentary vision. We are talking here about lines and contours, without color, just enough to recognize an object – and, at the present time, probably not a face. But even basic vision can help a blind person orient themselves. “Patients tell us it’s better than nothing. »
Currently, this approach gives better results for people who have lost their sight than those who were born blind. For the latter, “the visual cortex and the connections of the neurons have developed differently”, but the researcher says he is “convinced” that offering them limited bionic vision will one day be possible. Eventually going from 1,024 electrodes to twice 16,000 should also improve image resolution.
How do implants help people with paralyzed legs to walk again? I think, therefore I move. Even if we don’t realize it, our movements start in our brain. But when a lesion – partial or total – of the spinal cord cuts off the nerve message, the legs no longer respond. Implants have already enabled patients to walk again in recent years, such as the Dutchman Gert-Jan Oskam, whose progress has been chronicled In Nature
last week. The principle is the same for Neuralink: it involves creating a “bridge” by placing an implant in the brain, and another in the spinal cord, after the lesion. Thanks to a calibration of several months and advances in artificial intelligence, “the message is redirected to the nerves and the muscles”, specifies Bradley Greger.
Will we one day be humans with intelligence augmented by implants?
If priority is given to medicine, Elon Musk does not hide his transhumanist aspirations, with implants that he wants to make “as accessible” as surgery for myopia. According to him, a chip boosting our cognitive abilities or allowing us to interact directly with the machine without being limited by the slowness of our thumbs and our eyes embodies “the only solution if we do not want to become obsolete” in the face of the potential emergence of a strong artificial intelligence. Will we be able to store our memories in implants, as in black-mirror ? Learn kung fu like Neo inMatrix
, or speak any language, with the risk of even more fundamental inequalities between rich and poor? “It’s speculation and science fiction,” says Greger.
“It is very poorly understood how complex cognitive information – our ability to understand advanced math, to have certain feelings – is encoded. When we learn to play an instrument, the physical structure of our brain changes, with neural connections rewired. You have to train for years. »
If he does not exclude that science will one day allow us to reconfigure our neurons, the 50-year-old does not think he will see this in his lifetime: “This poses many ethical problems. And in all seriousness, I don’t think many people want to have a chip implanted in their brain unless they absolutely need to. » According to revelations from
Reuters , Neuralink is under investigation by the US Department of Agriculture for possible cases of animal abuse, with more than 1,500 animals dead since 2018 as part of its research. However, this figure does not mean that Neuralink broke the regulations: in the context of medical research on animals, they are often slaughtered after the fact to be autopsied.
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