An incredible scientific breakthrough, allows partially-paralyzed monkeys to gain their opportunity of learning how to walk again.
Using a wireless brain implant to sidestep the spinal cord injuries of two paralyzed rhesus macaques, scientists allowed for their useless limbs to be reignited. This system involves wirelessly transmitting decoded brain signals in order to stimulate the muscles in charge of leg mobility. It marks the first time a neural prosthetic has regained movement in a primate.
Though the brain-spinal interface has only been tested on macaques to date, the researchers believe this may open doors to discovering technology that could allow for the same to be done in humans paralyzed by spinal cord injuries.
Engineer David Borton from Brown University explains:“The system we have developed uses signals recorded from the motor cortex of the brain to trigger coordinated electrical stimulation of nerves in the spine that are responsible for locomotion.” “With the system turned on, the animals in our study had nearly normal locomotion.”
It is unbelievable that one rhesus macaque fitted with the new implant was able to walk a mere six days after it was partially paralyzed from a surgical procedure that caused some of the nerves in its right hind leg to be severed.
“It was a big surprise for us,” noted Grégoire Courtine, a neuroscientist that led the research at the Swiss Federal Institute of Technology. “The gait was not perfect, but it was almost like normal walking. The foot was not dragging and it was fully weight bearing.”
Another animal in the study, with more serious nerve damage in its right hind leg, recovered its ability to walk just two weeks with the help of the device. Both monkeys had full mobility in three months.
This is the latest breakthrough for the “brain-spine interface” within neuroprosthetics, and it has given scientists great hope for reading intentions in the brain’s activity and using the activity to control computer, robotic arms, and paralyzed limbs.
The researchers, wanted to restore the lost movement that is caused from injuries in the upper spine that cause a disconnect in the communication channel of the brain’s motor cortex and lumbar region in the lower spinal cord that makes us able to walk. Their vision was to do this wirelessly, therefore completely bypassing the severed nerves.
The system involves a pill-sized electrode array that is implanted in the brain. It is stemming from technology called BrainGate. There, it gathers movement signals created by the motor cortex. The wireless sensor could work to provide the signals to a computer, where they are decoded, and sent back wirelessly via an electrical stimulator that is implanted in the lumbar spine south of the spinal injury. When this stimulation signals spinal nerves, the leg muscles are then activated.
The researchers call the ability to restore movement without wires a pivotal breakthrough, because wired brain-sensing systems can hinder the ability to move freely.
“Doing this wirelessly enables us to map the neural activity in normal contexts and during natural behaviour,” explains Borton.
As for how this would translate to humans, Courtine says: “I don’t imagine someone walking down the street with a brain-spine interface. That’s a bit extravagant at this stage. But in the next five years, someone with a spinal injury could have a better recovery after being implanted with this and having robot-assisted rehabilitation.”
Although there is still many limitations of the system, it is clearly an impressive accomplishment. For instance, the interface is still in need of a separate computer that is able to decode the signals, specifically the wireless signals that, in their current state, can only get sent one way, which is from the brain to the legs.
Andrew Jackson at Newcastle University’s Institute of Neuroscience celebrated the breakthrough as a “major step” toward recovering lost movement with neural implants. He explains: “When you think about bipedal walking, balance and steering are a challenge, but optimistically this could be used to allow people to walk with some kind of support, such as a frame.”