'Promising & exciting': Brain implants with wireless signal let paralyzed monkeys move normally

© Antonio Bronic
At least two primates with severed spinal cords regained control of their limbs after a new wireless implant was placed in their brains. Neuroscientists now hope the brain-spine interface could help immobile human patients too.

Neuroscientists from the Swiss Federal Institute of Technology in Lausanne (EPFL) developed a technology which allows the sending of signals from the brain to the muscles bypassing the damaged part of the spinal cord.

By adding a wireless brain implant and electrodes in the primates' spinal cord, scientists enabled monkeys with spinal cord injuries to walk again, research published in the journal Nature showed.

"We developed an implantable, wireless system that operates in real-time and enabled a primate to behave freely, without the constraint of tethered electronics," neuroscientist Gregoire Courtine who led the experiment said, as quoted by Reuters.

The scientist, who treated two monkeys in China, each with one leg paralyzed by a partial spinal cord lesion, explained that he and his team got to understand "how to extract brain signals that encode flexion and extension movements of the leg with a mathematical algorithm."

They then linked the decoded signals associated with leg movement to particular key points in the lower part of the spine, below the injury. Devices receiving a wireless signal from the brain then generate electrical pulses that activate leg muscles into motion.

With the wireless brain implant in place, both monkeys partially regained the use of their paralyzed legs within two weeks of sustaining their injury, without any special training.

"They have demonstrated that the animals can regain not only coordinated but also weight-bearing function, which is important for locomotion. This is great work," the Nature quoted neuroscientist Gaurav Sharma as saying.

Independent experts not directly involved in the work said it was an important step towards a potential treatment for immobile people, Reuters reported.

"In principle this is reproducible in human patients," a specialist in restorative neuroscience at Imperial College London, Simone Di Giovanni said, adding that the results his Swiss colleagues achieved are "solid, very promising and exciting."

Although applying the brain-spine interface to the treatment of human patients is more complicated because the human brain decoding is much more complex, according to Courtine, the neuroscientist has already started a trial in two people with spinal-cord injury in Switzerland, using a pared-down version of the technology.