The surgical implantation of flexible electrodes and the application of electrical pulses controlled from outside have restored nerve transmission in rats with spinal cord severed and the hind legs paralyzed, up to allow the recovery of the natural gait. The study, which was attended by researchers from the Sant'Anna of Pisa, opens the way for the experimental realization of neuroprostheses "smart" also apply in humans.
the movement of the hind legs of paralyzed rats can be restored with a series of electrical impulses transmitted through electrodes to the nervous system of animals: it showed a study conducted within the European project NEUWalk, which brings together a range of research on rehabilitation techniques of neurological damage.
Illustrated in the journal "Science Translational Medicine" by an international collaboration which includes the Scuola Superiore Sant'Anna of Pisa and the Polytechnic of Lausanne, Switzerland, the study is a first step towards the realization of neuroprostheses able to restore at least in part of the transmission of impulses in the spinal cord daneggiato.
The authors studied rats in which the spinal cord was completely severed at the level of the trunk: the animals were then paralyzed the movements of the body parts downstream of the damage that prevented the passage of nerve impulses.
Towards the development of neuroprosthesis electrical "smart"
One of the rats with prostheses used in the study: the capture of the movement of the legs, as evidenced by the patterns in red, has allowed us to restore a natural gait (Courtesy Wenger et al. / Science Translation Medicine)
Surgically implanting a series of flexible electrodes precisely where the spinal damage, the researchers tested the response of the hind legs, those paralyzed, with different patterns of nerve impulses. They are thus able to establish that the height at which the paw was raised was directly proportional to the frequency of the transmitted signal.
These data were then combined with those relating to the movement patterns of the legs during walking in healthy animals, to define exactly how far in advance it was necessary to transmit the impulse to allow the rat to not only walk, but also to overcome obstacles and climb a scale. In tests, the rodents were able to make prostheses up to 1000 steps without errors.
"We were able to have complete control of the hind legs of the rat," said Grégoire Courtine, who participated in the study. "The rat has no voluntary control of the legs, but the injured spinal cord can be reactivated to produce, with an appropriate pattern of electrical stimulation, a natural gait: we can determine in real time if the animal has to move in forward and how to lift their legs. "
The long-term goal is to get to the human applications in the first instance on patients who have suffered a spinal cord injury is not complete: in these cases the neuroprosthesis should offer an "intelligent assistance" and adaptive, providing electrical stimulation from time to time required to move. The trial is expected to begin next summer at the Center for NEUROPROSTHESIS EPFL.
"Simple discoveries about the workings of the nervous system can be exploited to develop technologies neuroprotesiche effective," said Silvestro Micera, researcher Anne and coauthor of the study. "We believe this technology could one day improve the quality of life of people affected by neurological disorders."...
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