An implant that beams instructions out of the brain has been used to restore movement in paralysed primates for the first time, say scientists.
Rhesus monkeys were paralysed in one leg due to a damaged spinal cord.
The team at the Swiss Federal Institute of Technology bypassed the injury by sending the instructions straight from the brain to the nerves controlling leg movement.
Experts said the technology could be ready for human trials within a decade.
Spinal-cord injuries block the flow of electrical signals from the brain to the rest of the body resulting in paralysis.
It is a wound that rarely heals, but one potential solution is to use technology to bypass the injury.
In the study, a chip was implanted into the part of the monkeys' brain that controls movement.
Its job was to read the spikes of electrical activity that are the instructions for moving the legs and send them to a nearby computer.
It deciphered the messages and sent instructions to an implant in the monkey's spine to electrically stimulate the appropriate nerves.
The process all takes place in real time.
The results, published in the journal Nature, showed the monkeys regained some control of their paralysed leg within six days and could walk in a straight line on a treadmill.
Dr Gregoire Courtine, one of the researchers, said: "This is the first time that a neurotechnology has restored locomotion in primates."
He told the BBC News website: "The movement was close to normal for the basic walking pattern, but so far we have not been able to test the ability to steer."
The technology used to stimulate the spinal cord is the same as that used in deep brain stimulation to treat Parkinson's disease, so it would not be a technological leap to doing the same tests in patients.
"But the way we walk is different to primates, we are bipedal and this requires more sophisticated ways to stimulate the muscle," said Dr Courtine.
Jocelyne Bloch, a neurosurgeon from the Lausanne University Hospital, said: "The link between decoding of the brain and the stimulation of the spinal cord is completely new.
"For the first time, I can image a completely paralysed patient being able to move their legs through this brain-spine interface."
Using technology to overcome paralysis is a rapidly developing field:
However, he said, rhesus monkeys used all four limbs to move and only one leg had been paralysed, so it would be a greater challenge to restore the movement of both legs in people.
"Useful locomotion also requires control of balance, steering and obstacle avoidance, which were not addressed," he added.
The other approach to treating paralysis involves transplanting cells from the nasal cavity into the spinal cord to try to biologically repair the injury.
Following this treatment, Darek Fidyka, who was paralysed from the chest down in a knife attack in 2010, can now walk using a frame.