MONTREAL — Montreal researchers who are at the forefront of work in this field have developed an interface that allows an animal whose hind legs are paralyzed to walk again by alternately stimulating the two hemispheres of its brain.
These preclinical studies were conducted on what the researchers call a “large animal model,” which looks a lot more like humans than mice. Their results are so conclusive that they are now ready to proceed with clinical trials in a few years.
“We will alternately stimulate the left and right cortex to allow the movement of the two legs to be restored,” explained Marina Martinez, a regular researcher at the Hôpital du Sacré-Cœur-de-Montréal and a professor in the Department of Neurosciences at the University of Montreal .
“As soon as we start the alternating stimuli in the brain, the animal immediately begins to walk again.”
Ms. Martinez’s team is the only one in the world working on such a strategy that may one day allow people with SCI to walk again. Her latest work was published by ScienceDirect.
The researchers had previously tested the same approach on mice, whose wounds looked less like humans. This time they used larger animals and wounds very similar to human wounds.
In the first study, a single cortex was stimulated with electrodes to alleviate paralysis of a single mouse leg. This time, the two cortices were alternately stimulated to mobilize the two paralyzed legs of a larger animal, which clearly resembles paraplegia in humans.
“When you walk, you alternate movements with both legs, and that’s what we’re trying to achieve with this technique and we’ve done that in this animal model,” said Ms. Martinez.
Also, the technologies used are much more similar to what could potentially be implemented in humans, which should facilitate knowledge transfer.
“We’ve really reached a higher level,” Ms. Martinez appreciated. With the rat we had a proof of concept. We are in a very clinical stage here.
The technology she and her colleagues are working on applies only to incomplete spinal cord injuries. They’re trying to recreate normal brain activity to give the spinal cord the instructions it should naturally receive when walking, which means certain nerve fibers still connect the brain to the lower body.
While this technology can never be used in total spinal cord injuries, Ms. Martinez said, “Each step gives us an opportunity to get that little bit closer to being human.”
“The ultimate goal of our team is to help patients and those who need it. That’s what we work for, it’s really for them, it’s our main motivation,” she concluded.