Touch for virtual limbs
Biologists have taught monkeys to control a virtual hand with the power of thoughtRIA News
American biologists have connected a virtual hand to the brain of monkeys and taught them to touch objects in cyberspace, which will help doctors develop full-fledged artificial limbs in the near future, according to an article published in the journal Nature (O'Doherty et al., Active tactile exploration using a brain–machine–brain interface; a short retelling of another article by this group scientists published on the BBC: Monkeys' brain waves offer paraplegics hope – VM).
"Our invention opens up a new class of "layers" between the brain and the computer – neurocomputer interfaces that allow the exchange of signals in both directions – from the brain to the machine and back. In our experiment, the brain directly controls the virtual body, which in turn transmits electrical signals of touch to another part of the brain," explained the head of the team of scientists Miguel Nicolelis from Duke University in Durham (USA), who has been dealing with this problem for more than a decade.
Nicolelis and his colleagues, including Mikhail Lebedev, a native of Russia, built a lot of ultrathin electrodes into the brains of two rhesus monkeys. Several hundred artificial nerve endings were connected to the motor center of the brain of these primates, and several thousand other "cyberneurons" – to the center of touch.
The scientists connected the electrodes to a computer that processed and executed motion signals and transmitted tactile sensations experienced by the primate's virtual hand to the center of touch.
Then the scientists taught the macaques to move the cursor or virtual hand on the computer screen. During the first experiments, monkeys could use joysticks, which were disabled after a few rounds of the game.
When the monkey moved the "hand" or cursor in the right direction or "touched" the desired object, she received a glass of fruit juice. The number of objects, the arrangement of their "surface" and the correct sequence of touches were constantly changing.
Macaques quickly learned to move their new "limb" – the first monkey mastered this skill in nine attempts, and the second – in four rounds of the game. After several successful attempts, the monkeys remembered the "winning" type of surface and always chose cyber objects with such a surface.
"This is the first time we have observed how the brain controls a virtual limb and receives feedback signals. The interaction between the brain and the "avatar" body occurred independently of the real body of the monkey, since the animal did not move its real hands and hands, and did not touch objects with its skin. In fact, we created a new sensory channel that the brain used to process information that was inaccessible through traditional "windows" to the real world," Nicolelis said.
Scientists believe that their technology will help create artificial limbs with feedback, as well as restore mobility and tactile sensitivity of people whose spinal cord is damaged in one way or another.
"In the near future, people with limb paralysis will be able not only to move their arms and legs with the help of such technologies, but also to feel the shape and structure of things they will touch and step on," the scientist concludes.
Portal "Eternal youth" http://vechnayamolodost.ru06.10.2011