The scientists, from the University of Zurich and the Swiss Federal Institute of Technology reported their findings in the journal Science.
The authors explained that researchers and experts have been trying for years to find ways of getting patients with spinal cord injuries to walk again. Approximately half of all human spinal cord injuries lead to long-term paralysis.
Although previous studies have had some success in restoring some kind of movement in the limbs, even helping patients to walk in a limited way, this experiment uses a completely novel technique.
In an Abstract in the journal Science, the authors wrote:
“Here, we introduce an electrochemical neuroprosthesis and a robotic postural interface designed to encourage supraspinally mediated movements in rats with paralyzing lesions.”
The scientists managed to get the rats to walk and climb stairs. They stimulated the spinal nerve circuits of rats, and used physical training. Electrodes had been implanted and the rats were given injections with a neuron-activating chemical mix.
The scientists fitted the rats with harnesses, so that their back legs could reach the ground. They were then placed on a conveyor belt which only moved if their feet pushed (reflexive stepping). They were also placed on stationary ground. In order to reach a piece of chocolate (on fixed ground) they would have to move their hind legs.
About two to three weeks after training started, they managed to take their first voluntary steps. However, in order not to fall over, they still needed to wear the harnesses.
According to the scientists, the training resulted in an extensive rewiring in the spinal cord and brain. Over 100 of the rats in their experiment are able to walk to some extent, to varying degrees.
Lead researcher, Gregoire Courtine, said “This kind of approach will not cure spinal cord injury.” However, it appears most likely that it may help paralyzed patients regain some independent mobility. In order to find out, human studies will need to be conducted.
The authors concluded:
“By encouraging active participation under functional states, our training paradigm triggered a cortex-dependent recovery that may improve function after similar injuries in humans.”
Written by Christian Nordqvist