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Rats with spinal cord injury and severe paralysis are now walking (and running) thanks to researchers at the Federal Polytechnic School of Lausanne (EPFL). The findings published in June 2012 in the Science journal, show that interrupted spinal cord can regain its function when it awakens its own intelligence and ability to regenerate. The research, which began five years ago at the University of Zurich, indicated profound changes in our understanding of the central nervous system. It is not yet clear whether similar techniques and rehabilitation would work in humans, but there is nerve growth that suggests new methods for treating paralysis.


"After a few weeks of neurorehabilitation with a combination of robotic armor and electrochemical stimulation, our rats not only moved their legs, but also ran, climbed the stairs and avoided obstacles”, said Courtin, who holds the Chair of recovery of the spinal cord at the EPFL.


It is well known that the brain and spinal cord can adapt and recover from moderate injuries, and this is a quality known as neuroplasticity. So far, the spinal cord showed so little neuroplasticity following severe injuries from which the recovery was impossible. Courtin’s research shows that, under certain conditions, plasticity and recovery can occur even in these difficult cases, but only if the dormant spinal cord in the spine first wakes up.

Waking Up The Spinal Cord

To do this, Courtine and his team injected in the laboratory rat a chemical solution of monoamine agonists. These chemicals trigger responses of the cells by binding to specific receptors for dopamine, adrenaline and serotonin, which are located on neuron surface in the spinal cord. This cocktail of drugs replaces the neurotransmitters in healthy subjects, release pathways in the brainstem and activates stimulation of neurons preparing them for coordination of the movement of the lower parts of the body when the time is right.

Five to ten minutes after the injection, the researchers electrically stimulated the spinal cord with electrodes implanted in the outermost layer of the channel, which is called the epidural space. "This way localized continuous epidural stimulation sends electrical signals through the nerve fibers to chemically excited neurons that control the movement of the legs. All that remains is to move the leg, "explains Rubia van den Brand, co-author of the research.

The article in 2009. in the journal Nature Neuroscience, Courtine reported that stimulated spinal cord of rats - physically isolated from the brain - has developed very surprisingly. It started by assignments of sliding leg movements, allowing the earlier paralyzed rats to walk, though not by their own will. These experiments have revealed that the scroll wheel has created sensory feedback that initiated walking. "The back brain" then took over further walking and basic walking happened with no information received from rat’s actual brain. It was a surprise for researchers which led them to believe that animals need a very weak signal from the brain to run the limbs of their own accord.

To test this theory, Courtine replaced the scroll wheel with a robotic device that adhered to the body, which was turned on only when the rat lost his balance, giving the impression that he is healthy and able-bodied spine. This has encouraged the rats themselves to go for chocolate as a reward waiting at the other end of the platform. "They concluded that exercising will encourage movement and speed-up the regeneration of nerve fibers four times. That statement shows that nerve cells, opposite to the previous statements has a great neuroplasticity and regeneration potential.

Courtine called the growth of fibers "new ontogenesis," which is a kind of duplication of child growth phase. Researchers have found that newly formed fibers bypassed the original lesion in the spinal cord and thus allowed the signals from the brain to reach electrochemically awakened spine. The signal was strong enough to start moving on the field, and without the car. This means that the rats began to walk alone, by their own will toward the prize at the end of tracks, fully supporting its own weight on its hind legs.

"This is the world cup of neurorehabilitation," said Courtine. "Our rats have become athletes even though, only a few weeks ago, they were completely paralyzed. I'm talking about complete recovery of voluntary movements. "

In principle, a radical reaction of the rat spinal cord in this type of treatment gives us the reason to believe that the persons with spinal cord injury will soon have some new options for treatment. Courtine is optimistic that the new phase of experimentation on humans will begin within a year or two at The Spinal Cord Injury Center at the Balgrist University Hospital in Zurich.