Medical researchers in Switzerland have used a combination of spinal cord stimulation and robot-aided therapy to get paralysed rats to learn to walk again.

A team at the Ecole Polytechnique Federale de Lausanne (EPFL) -- led by Gregoire Courtine -- found that the key to the technique's success was to get the rats to participate in their own rehabilitation.

The team took paralysed rats and injected them with chemicals to bind to dopamine, adrenaline and serotonin receptors on the spinal cord's neurons. This replaced the neurotransmitters that are usually released in healthy spinal cords. After preparing the spine in this way, the neurons were stimulated using electrodes implanted in their spinal canal.

In this stimulated state, the rats were trained to use their limbs using a robotic harness. The harness comprised of a vest that went around the rats' bodies and held them in an upright position so the rats were standing on their paralysed hind legs. The rats were lured with a piece of chocolate at the other end of the treadmill. This encouraged them to try to move their legs. This "willpower-based" training helped to build up new nerve fibres which allowed them to move their limbs again within five to six weeks. 

The team believes that the technique could be used to help humans regain some nerve activity after spinal cord injuries. The therapeutic technique relied on the fact that neural networks can be rerouted in order to take on different tasks. The combination of the electrochemical stimulant and the robotic assistance was crucial for rerouting the nervous system not only at the level of the injury, but in the brain, brain stem and spinal cord.

More than 100 rats were tested, and they observed a "very high" percentage of success, with recovery of some degree voluntary movement in all of the animals.

Similar therapy has been successfully tested on an American man called Rob Summers who was paralysed from the chest down. He can now stand using a walker.

Courtine said in an EPFL release "This is the world-cup of neurorehabilitation. Our rats have become athletes when just weeks before they were completely paralysed. I am talking about 100 percent recuperation of voluntary movement." 

Courtine and his team hope to start trials on people in the next few years. One hurdle is finding a way to keep the electrochemical stimulation going -- even though the neural paths get rerouted, the rats still rely on the this stimulation to regain the maximum movement. The aim is to design a spinal "neuroprosthetic system" that could be implanted into humans to do this.

The findings are detailed in a paper in Science


  1. What a fantastic video, thanks for posting this up Wired! Hopefully this technology will eventually lead to making paralysis a temporary condition.  

    Alex Penn
    Jun 4th 2012

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