Enlarge this image toggle caption Alain Herzog/Swiss Federal Institute of Technology (EPFL) Alain Herzog/Swiss Federal Institute of Technology (EPFL) 
 
 "It will take at least another decade in order to achieve the full translation in humans, with no guarantee whatsoever that it will be a successful endeavor," says Gregoire Courtine, a neuroscientist at the Swiss Federal Institute of Technology and a co-author of the study. And this week, he and his team report1 the results of experiments in Beijing, in which a wireless brain implant — that stimulates electrodes in the leg by recreating signals recorded from the brain — has enabled monkeys with spinal-cord injuries to walk. From rats to primates 
 
 The experiments are more of a progression than a sudden breakthrough: they are based on a decade of work in rats, Courtine says, and the monkeys reacted in very similar ways. The team first mapped how electric signals are sent from the brain to leg muscles in healthy monkeys, walking on a treadmill. Then they recreated those signals in monkeys with severed spinal cords, focusing on particular key points in the lower part of the spine. The rhythm of the leg movement was imperfect, but the monkeys’ feet were not dragging and the movement was coordinated enough to support the primates’ weight. The primate study, for example, used electrical activity recorded from the spinal cord before the injury and “played it back” to restore movement, notes Bouton. Courtine has started a clinical trial at the CHUV University Hospital of Lausanne, geared towards rehabilitation by helping to stimulate coordinated walking in people who are paralysed.
– In what could someday prove to be a major step forward for people with spinal cord injuries, scientists out of Switzerland are reporting in the journal Nature that they've gotten paralyzed monkeys to walk again. NPR describes the surgery on the rhesus macaques thusly: A neurosurgeon "placed electrodes in the part of the monkey's brain that controls leg movement, and docked a wireless transmitter on the outside of his skull. Then, she put another set of electrodes along the spinal cord, below the injury." The idea is that the brain device beams instructions to the spine, which tells the legs to move. Using this "brain-spine interface," they used electrical activity they recorded in the monkeys' spinal cords prior to the injuries and "played it back" to restore movement. "That’s an approach that wouldn’t be practical after an actual spinal-cord injury," says the lead researcher. "The whole team was screaming in the room as we watched," the lead researcher, who travels between Switzerland and China (where regulations are more lenient on experimenting with primates) tells Nature News. Experts around the world have seen many failed experiments to restore walking over the years, and while the rhythm of the leg movement wasn't totally natural, the monkeys were able to support their weight enough to walk on a treadmill without dragging their feet. A small clinical trial is already underway in Switzerland for two people with spinal cord injuries to further test the interface. "It will take at least another decade in order to achieve the full translation in humans, with no guarantee whatsoever that it will be a successful endeavor," says the lead researcher. (Meanwhile, a monkey's head has been successfully transplanted.)