Researchers have successfully used a wireless connection to transmit signals from a paralyzed monkey’s brain to control its legs. They say it’s now at least conceivable to use such a technique on humans.

The aim is to treat people with damaged spinal cords that mean the brain can’t pass on electrical signals that act as instructions to nerves in legs.

The tests involved putting a chip in a monkey’s brain such that it measured spikes in electrical activity that corresponded to the movement instructions. The chip passed on the measurements to a computer that “translated” them into instructions and sent an appropriate signal to a spinal implant to stimulate the nerves.

The technique has been developed on rodents over the past decade but this was the first test on primates. The test involved intentionally creating a lesion on a rhesus macaque’s spinal cord to paralyze one leg, then implanting the chip and electrodes. The researchers then waited six days before switching the equipment on.

The monkey’s paralyzed leg was moving within seconds and a few days later it was able to stand up, at which point the researchers put it on to a treadmill and found it was able to walk without support. A repeat trial on a second monkey produced similar results.

The technique is now being trialled in Switzerland on human patients with pre-existing spinal injuries. One potential hold-up is that the technique might not work as well in humans because they walk upright on two feet. Another question is how much control the system gives over “steering” the leg rather than walking in a straight line.