A healthy person can control the movement of his limbs with high accuracy. This is because people feel where the limbs and their elements are at the present moment. Thanks to this, the hand and its individual components move in a coordinated way, for example, when we want to scratch our nose.
But dentures, even bionic ones, are another matter. When the owner of such a prosthesis wants to scratch his nose, he must be very careful. Otherwise, you can just gouge out your eyes or knock out your teeth, but not achieve the desired. But in the future they promise to fix this problem.
Work has
begun already now - scientists from MIT are working on new neural prosthetic control interfaces. If everything works out, then the management of artificial limbs will be as easy as the operations of the legs, hands and their elements.
The interface will connect to the nervous system of the remaining active muscles of the injured leg or arm. If a person wants to make a movement of a non-existent foot, the parts of the brain that are responsible for this action are still activated, setting in motion the muscles of the leg. But the signals of muscles and nerves will be perceived by the prosthesis, which will perform the movements needed by the person.
Researchers have advanced far enough in their work, the results of which were published on the tributes to Science Translational Medicine. The interface, which was discussed above, was called “agonist-antagonist myoneural interface” (AMI). A volunteer participated in the experiment - a person who lost his foot. A prosthesis was created for him, which he could manage almost as accurately as his foot.
Scientists are very close to forming a single bionic system from a damaged leg. It is, in fact, a whole, with cybernetic and biological elements. “Since muscles are controlled by nerves, everything is controlled by the brain, the signals of which are transmitted to the nervous system, after which the muscular system is activated,” says one of the developers.
The bionic prosthesis is capable of capturing electrical signals from the nervous system. A person, thinking, for example, of changing the position of the foot, controls the prosthesis. The most difficult thing is deciphering the signals of the nerve endings and converting them into signals that are “understandable” to the bionic prosthesis. Actually, this is the main problem for the modern industry of developing bionic "smart" artificial limbs.
Scientists from MIT managed to do this work and to make sure that the actions of an artificial foot exactly repeat a person’s desire to manage it. As a result, the patient can perform synchronous movements both with the prosthesis and the remaining foot + prosthesis. According to experts, the most promising development path for limb prosthetics is the combination of technological and natural elements.
The developers of the cybernetic foot believe that their research will allow in the near future to create perfect bionic prostheses for patients with amputated parts of the arms or legs.
And scientists from the Seoul University were able to create an analogue of a nerve - though not for humans, but for a cockroach. By connecting this nerve to the leg of a cockroach, experts were able to simulate the transmission of signals from the cockroach's own nerves to a limb. In the end, she moved.
This nerve, which is called afferent, is responsible not only for movement, but also for the transmission of signals when a limb touches a certain object. And these are receptors, synapses, and several other elements, the analogs of which nobody had previously created. The researchers in question are a group of scientists led by Tae-Woo Lee.
The role of mechanoreceptors in the design of scientists is played by resistive pressure sensors. It consists of a flat gold electrode and a carbon electrode consisting of nanotubes. The second is directly above the first, so that with increasing pressure, the contact area between them increases. And this, in turn, makes it possible to measure the pressure. Probably, full-fledged prostheses with sensory sensors will appear in the near future, which is good news.