General, Research, Technology

Scientists have restored the motor functions of a paralyzed monkey

Scientists first used a neural implantto restore motor ability in paralyzed primates. Until the real possibility of conducting clinical trials in humans, it may take several more years, but recent successes indicate an important step in the development of this direction.

Recently published in the scientific journal NaturteThe article describes a new neuro-prosthetic interface that acts as a bridge between the brain and spinal cord and acts to bypass existing damage. The system, called the “cerebrospinal interface”, allowed to restore the motor functions of the right paws of two rhesus monkeys. The implant was developed by neuroscientist Gregoire Curtin and his colleagues from the Lausanne Swiss Higher Technical School with the support of scientists from the University of Bordeaux, Motac Neuroscience and University Hospital Lausanne (CHUV).

Since 2012, Kurtin has been working on a project“Awakening” of damaged spinal neural connections in paralyzed laboratory mice and restoration of their motor functions, allowing rodents to walk, run and overcome obstacles again. Then special chemicals were used. In the experiment described today, the Kurtin team decided to choose a different approach and use brain implants in the lesion sites. For science, this turned out to be the first case of using neuro prostheses to restore motor functions in primates. And the team of scientists is very optimistic about the possibility of adapting the system for conducting clinical trials in humans.

Paralysis is usually caused by a break in communication intransmission of brain signals from the motor cortex (the part of the brain responsible for movement) and the spinal cord. When a break occurs, the sent signals do not reach the neurons responsible for muscle activity. Unfortunately, neural connections in the spinal cord do not have the property of self-repair after an injury. Scientists have been struggling for many years to develop effective pharmacological and regenerative methods of recovery from such injuries, but no particular success has been achieved in this area. According to statistics from the World Health Organization, annually from 250,000 to 500,000 people worldwide receive spinal cord injuries, so the question of finding effective methods of treatment and recovery is a critical aspect for modern medicine.

Spinal implant, in turn,allows you to bypass the damaged connection of the spinal cord and brain using modern wireless technologies. In an experiment conducted by scientists, a neuro prosthetic device was implanted in the monkey’s brain. The device receives signals supplied by the motor cortex, processes them and transmits them to the spinal cord using electrodes implanted in it. An electrical discharge of just a few volts applied to the correct area activates the muscles of the legs. As a result, just six days after receiving a spinal cord injury, the monkeys were returned the opportunity to walk. It is noted that the ability to walk again and lead your usual lifestyle was achieved without the use of numerous wires. The primates that had previously suffered partial spinal cord injuries fully restored their mobile functions three months after the start of the experiment.

“Once the spinal interface was activated, the monkeys immediately got the opportunity to move fully,” says study co-author Irvan Bezard of the University of Bordeaux.

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"No physiotherapy or training was carried out, as there was no need for them."

Scientists express hope that the developedwith them, the device will be able to solve problems with more serious injuries of the spinal cord. According to Andrew Jackson of Newcastle University, this will be possible with other aids such as chemical and electrical stimulation. A similar system in the future as a base will rely on one of the main features of the brain - plasticity. The interneuronal connection becomes stronger with the simultaneous activity of neurons on both sides of this chain. It is possible that the device will be able to strengthen these neural connections, which will positively affect further rehabilitation.

According to researchers, a similar systemstimulation can be used in human cases, however, additional research is required on issues related to balance, fine motor skills and the peculiarities of overcoming obstacles, that is, motor functions, which were not considered of primary importance in the current study. The advantage of the new method is that many of the components used to create the spinal interface have already been approved for use in humans. If everything works out, then clinical trials can begin in a few years.

“Thanks to this implant I can for the first timeimagine that a paralyzed patient can regain the lost opportunity to use his limbs, ”says Joyslin Bloch, lead neurosurgeon in this study.

It is also important to note that Kurtin and his colleaguesdeliberately partially damaged the canal of the spinal cord in two monkeys, which caused paralysis of the hind right paws in both. Given the pressure often faced by scientists conducting such experiments on the part of animal advocates in most countries, researchers had to carry out their work in China.

"The use of primates in neuroscienceexperimentation remains a serious topic of discussion. Numerous animal rights groups are actively attempting to ban such experiments in the United States and Europe. Therefore, it is obvious that the scientists who participated in this experiment and were originally based in Europe would have to face obstacles from the European Union, whose principles stand in the way of these experiments. For this reason, scientists had to conduct their research in China. Gregoard Curtin, director of these studies, notes that this is far from an ideal solution. Such experiments are very difficult to conduct abroad. The issues of lack of time, energy and resources remain open. ”

Experts agree on the needintroducing more ethical standards for using animals as scientific experiments in Asia. Many agree that science needs to move away from examples of using primates in such practices. And instead of traveling and conducting experiments on animals in other countries where laws are more loyal to such scientific approaches, it is necessary to develop alternative methods of testing new theories, systems and practices. An example is computer models or volunteers. It is possible some people with paralysis will themselves be ready to accept the opportunity to participate in such studies, despite all the risks associated with this.