Paralyzed rats regain mobility with a combination of robotics and chemical stimulation
June 1, 2012
Researchers working at the Swiss Federal Institute of Technology have successfully made use of electrical and chemical stimulation techniques to excite neurons in the lower spinal cord of previously paralyzed rats, enabling the subject rodents to walk and even run when suspended by a vest which provides balance and restricts movement to the hind legs only.
Previous studies of this nature have shown that it is possible to circumvent the severed connection between brain and legs in paralyzed rats by stimulation of a subject's spinal-chord, but such movement is involuntary and therefore not thought to require input from the brain. The new research by the Swiss Federal Institute of Technology (EPFL) however, proves that with a specialized regime of training coupled with an injection of a chemical solution of monoamine agonists, the rodents can regain voluntary control over their legs, encouraged as they were by chocolate rewards and vocal praise from the researchers at EPFL.
For their part, the scientists at EPFL used a vest to suspend the rats on their hind legs without providing forward momentum. Ten paralyzed rats were trained daily to walk while suspended in this way, both on a treadmill and with a robotic system which moved their legs automatically. After just two to three weeks of this routine, the rats were able to walk up small steps and, in due course, run. The procedure even led to the creation of new neuronal connections between the brain and the lower spine, "this is the first time we have seen voluntary control of locomotion in an animal with [an injury] that normally leaves it completely paralyzed," said Grégoire Courtine, senior author of the study and holder of the International Paraplegic Foundation (IRP) Chair in Spinal Cord Repair at EPFL.
The eventual aim of the research is to design and implement a fully operative spinal neuroprosthetic system for humans and to this end, the researchers at EPFL are embarking on a €9 million (approximately US$11.1 million) project titled NeuWalk, though Courtine was keen to stress that while the research showed much promise, it most definitely is not evidence of a cure in of itself. Speaking to AFP, Courtine said "We are not thinking this will cure spinal cord injury. We need to be very clear on this. This is not a cure".
The video below shows the vest in action.
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