Neuroscientist Grégoire Courtine and his fellow researchers from the École polytechnique fédérale de Lausanne, Switzerland have made a rat with a completely severed spinal cord walk again with electrical signals as part of a project dubbed "NEUWalk."

The project works on the principle the body needs electrical impulses to be operative. By sending electrical signals down the spinal cord into the motor neurons of the nervous system, the brain moves the body.

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But when the spinal cord is severed, the signals can no longer travel to the organ or muscle, paralyzing the part of the body beyond the cut.

The higher the cut in the cord, the greater the paralysis.

Courtine and his team, however, found that brain signals can be substituted by electrical signals sent directly through the spinal cord below a cut through the use of electrodes.

A number of rats had their spinal cords cut in the middle of their backs, utterly rendering the lower limbs of the animal useless. The team then implanted flexible electrodes into the spinal cord where it was cut to send artificial signals down the cord.

Implanting the electronics isn't adequate enough to allow the rat to advance in a walking motion, however. The method by which the brain fires electrical impulses isn't random. Instead, the frequency of the stimulation governs how high or low the rat lifts its legs, for example.

"We have complete control of the rat's hind legs," Courtine said.

"The rat has no voluntary control of its limbs, but the severed spinal cord can be reactivated and stimulated to perform natural walking. We can control in real-time how the rat moves forward and how high it lifts its legs."

Tagsdevice, Neuroscience, Paralyzed, Neuwalk, Implant, Electrode, brain, Spinal cord, Electrical signals