The difficult part of connecting a slimy thinking brain to a cold, one-way and zero-way computer is getting information through the thick skull (or my skull or anyone̵
Therefore, if your brain is not your brain, then the only way to tell what is happening inside it is by reasoning. People make educated guesses based on what the brain tells the body to do, for example, if the body makes some sounds that you can understand (that is, speech) or moves around in a recognizable way. This is a problem for people trying to understand how the brain works, and for people who are unable to move or speak due to injury or illness, it is even a bigger problem. Complex imaging techniques such as functional magnetic resonance can provide you with some clues. However, something more direct would be great. For decades, technicians have been trying to make the brain interact with the computer keyboard or robotic arm to connect meat with silicon.
On Wednesday, a team of scientists and engineers demonstrated the results of a promising new method. It involves mounting electrodes on expandable flexible tubes called stents and passing them through blood vessels leading to the brain. In the test on two people, the researchers took the cervical spine literally, and used a wire with a stent to extend up the veins of the larynx, and then into the blood vessels near the main motor cortex of the brain, where springs were ejected. . The electrodes are placed on the blood vessel wall according to the ugg and begin to sense when people’s brains send out signals that they intend to move, and an infrared transmitter inserted into the subject’s chest through a surgical operation sends these signals wirelessly to the computer.Published in Journal of Interventional Neurosurgery, Researchers in Australia and the United States describe how two people paralyzed due to amyotrophic lateral sclerosis (better known as Lou Gehrig’s disease) can use this device to send texts and wander around using only brain control. .
“Self-expanding stent technology has been fully proven in the treatment of other diseases of the heart and nervous system applications. We just use this function, and then put the electrode on top of the stent.” Interventional neurologist and Synchron CEO Thomas Oxley said , The company hopes to commercialize the technology. “It is fully implantable. The patient goes home within a few days. And it’s plug and play.”
Once the subjects went home, they were trained. A stent equipped with electrodes can receive signals from the brain, but the machine learning algorithm must figure out what those signals (not working even under ideal conditions) reflect. But after a few weeks of work, both patients can use the eye tracker to move the cursor and then use the implant to generate ideas. It doesn’t sound like much, but it is enough for both of them to send text messages, shop online, and digitize daily life.
The US Food and Drug Administration has not approved Oxley’s so-called “welding gun” for widespread use. The company is still seeking funding for more testing, but these preliminary results indicate that this is an effective brain-computer interface. The signal it received was not full of information. So far, all extensions have only one piece of information-telepathic mouse clicks or no clicks. But for some applications, it may be sufficient. “There is a lot of discussion about data and channels. What is really important is whether you provide patients with life-changing products?” Oxley said. “As long as the small amount of output they control is restored to the patient, we can control Windows 10.”
Recently, more and more ambitious brain-computer interfaces and nerve repair techniques have become news. Last month, Elon Musk’s company Neuralink demonstrated a wireless BCI with more than a thousand flexible electrodes inserted directly into the brain by a specialized robotic surgeon. (So far, the company has only shown short-term use in pigs.) Inserting electrodes is tricky. Although brain surgery is not entirely rocket science, there are risks to whether the surgeon is a robot. Even if the soft and delicate electrodes shown by Neuralink are sufficiently invasive, the brain will try to resist them by coating them with glial cells, thereby reducing their ability to conduct the electrical impulses they seek. Although implanted electrodes (such as the more commonly used “Utah Array” electrodes) can obtain clear signals from individual neurons, understanding the meaning of these signals is still in science. In addition, the brain moves around like jelly in a doughnut. Fixing the electrode will damage it. But getting it right, they can do more than just brain research. Despite the need for training, maintenance, surgery, etc., “locked” ALS patients still use it as a successful brain-computer interface.
At the same time, electrodes placed directly on the scalp absorb brain waves (electroencephalogram or EEG), but these electrodes lack the spatial details of implanted electrodes. Neuroscientists generally understand which part of the brain is doing what, but the more you know which neurons are firing, the more clearly you will know what they are firing.
Cortical EEG is a recent innovation that places the electrode net directly on the surface of the brain. Combined with the intelligent spectrum processing of the signals received by these electrodes, ECoG is sufficient to convert the movements of the parts of the motor cortex that control the lips, jaws and tongue into text or even speech. There are other ways. Facebook acquired CTRL-labs for as much as $1 billion in 2019 in an attempt to obtain motion signals from wrist neurons. The inner core uses functional near-infrared spectroscopy on the head to sense brain activity.
Oxley and his colleagues’ stent electrodes, if they continue to show good results, will fit somewhere in the spectrum between the implanted electrodes and the EEG. Its inventor hopes that the second thing is closer to the first thing. But this is still in its infancy. Vikash Gilja said: “The core technology and core ideas are very cool, but considering where they access the signal, compared to other brain-computer interface strategies, this is a relatively low-fidelity signal.” He is responsible for the transformational neural engineering of the University of San Diego UC laboratory. “We at least know that high-density ECoG recordings from the surface of the brain can convey information beyond the scope of this article.”
One possible problem is that the tissue conducts electrical impulses, but the electrodes in the stent receive signals from the brain through blood vessel cells. This reduces the signal content. “If we were to record the recording of the cortical surface and compare it with the Utah array experiment (a lot of clinical experience with implanted electrodes), I would say that the recording method in ECoG limits the rate,” Gilja said. (Just for transparency reasons, I should point out that Gilja has done paid work with BCI companies including Neuralink. In theory, Synchron can compete with it one day.)
Therefore, it may not be good enough for neuroscience, but it may be useful for paralyzed patients who wish to maintain a low BCI and do not need to drill the skull. Andrew Pruszynski, a neuroscientist at Western University in Canada, said: “If it is to become an invasive technology, there must be a trade-off between the degree to which information is collected.” “This is an attempt. Reach the middle ground and insert the catheter close to the nerve activity.” It is obviously invasive, but certainly not as invasive as inserting electrodes into the brain. “
And there is more work to be done. Oxley’s team hopes to extend their research to more human subjects. They will look for possible side effects, such as the possibility that the stent may cause a stroke (although this possibility seems less likely because it is embedded in the blood vessel wall, a process called endothelialization). They may find better stent locations in blood vessels near other brain regions of interest. Oxley said it is fair to play anywhere within 2 millimeters of the large blood vessels of the stent graft. The software may be improved to clarify the actual meaning of the brain’s electric bells and whistles. Some of their tests have shown that the system can obtain more details, such as the specific muscle the user is trying. contract. This may lead to more useful repair or control devices for devices other than Windows 10. “Now, the motor system will provide treatment for paralyzed people,” Oxley said. “But when we start interacting with other areas of the brain, you will start to see how this technology will develop the brain’s processing power.” It is difficult to predict what will happen when scientists actually figure out how to get into someone’s head.
This story originally appeared on wired.com.