Computer-brain interface

A neuroimplant implanted in humans can control a cursor

With a neurotechnological implant, patients who are paralyzed due to a stroke, a spinal injury or other illnesses and can no longer speak can now communicate with the outside world, at least via computer. Until now, this could only be done by recording brain waves (EEG) through the crude attachment of electrodes to the head. Here, EEG patterns that relate to the planning or imagination of a movement are classified by the computer via a neural network and can then be translated into the movement of a cursor on the screen, for example. The coupling of neurons and chip poses particular difficulties for permanent implantation.

This has often been done with rats (see z.B. neurons of rats control a robotic arm), Roy Bakay and Phillipp Kennedy of the Department of Neurosurgery at Emory University have successfully tested it on two human subjects. A neurotrophic electrode surrounded by glass was inserted into the motor cortex. Neurotrophic growth factors were placed on the glass, which stimulated the neurons to grow into the electrode and establish a contact. This process took several weeks. In the electrode, the signals of the "firing" Neurons picked up and then sent to wirelessly to a head-mounted receiver and amplifier, and then further processed by a computer to which they are transmitted by a small antenna. These signals can then in turn be used to control the cursor on a screen: "The trick is to teach the patient how to control the strength and pattern of the electrical impulses generated in the brain. After a training period they can "at will" move a cursor and make it stop at a certain point on the screen. If you can move the cursor, you can direct it to certain icons, send emails, turn a light on or off, and interact with the environment." Learning happens through feedback, as patients can hear the signals picked up by their neurons.

Of course, the possibilities are still very limited – and the communication is cumbersome. While one patient died within a few weeks of implantation due to lateral sclerosis, the other patient, paralyzed by a heart and brain stroke, can no longer speak but otherwise has "quite awake and intelligent" is, with the neuroimplant at least learned to move a cursor horizontally from icon to icon on the computer screen. In this case, each icon represents a sentence. When the cursor comes over an icon, the computer speaks a sentence. "The patient’s favorite saying is", according to Bakay: "See you later. Nice talking with you." The two neurosurgeons want to continue their research: "Our hope is that soon we will be able to connect the neural signals to a muscle stimulator in the paralyzed arm of a patient and they will be able to move their arm according to the same principle as they do with the cursor."

Kennedy has a patent for both the trophic substances that grow the neurons and the implant chips, which are said to be easily mass-marketable. There is now a waiting list of 50 patients who have had a chip of this type implanted. Medical companies are also interested in the technology. In an article in Salon, Kennedy admittedly voiced his own concerns: "There are a couple of little things that worry me in the back of my mind, I’m thinking of using it for some purpose in people who are not patients." Some people are already thinking about it, but he thinks it’s absurd, because why control a computer directly with your brain when you can do it much more easily with your hand without an implant?. "To interface directly between machines and a brain is a bit cruel in conception, but it opens up possibilities if you have a biologically intact brain, supply it with blood and oxygen, and then remove the external life, d.h. when a brain was controlling a machine. And that is really a bit worrying. But now of course it is already too late."

In any case, his colleague Bakay is convinced that this technology will open up great possibilities for patients, "who are unable to move or speak due to a stroke, spinal cord injury, or conditions such as sclerosis." After all, 700,000 people suffer a stroke every year in the USA alone.

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