A new study has revealed that paralysed rats whose spinal cords had been severed from their brains were made to run again using a technique that scientists say can work for people.

Consistent electrical stimulation and drugs enabled the rats to walk on their hind legs on a treadmill -- bearing the full weight of the body -- within a week of being paralysed.

With the addition of physical therapy, the rodents were able after several weeks to walk and run without stumbling for up to 30 minutes, reported the study, published in the journal Nature Neuroscience.

Remarkably, the animals could adjust their movements in response to stimuli despite the lack of signals to and from the brain: when the treadmill was reversed, for example, the rats walked backwards.

"This means that the spinal network is almost capable of cognitive processing," explained Gregoire Courtine, a professor at Zurich University.

"It can understand that the external world is changing, and interpret this information to modify the way it activates muscle," he told AFP by phone.

Earlier studies had shown that nerve networks in the spinal cord can produce limited motion in the muscles independent of the brain or sensory organs.

But this is the first time that researchers have been able to restore normal or nearly normal functions.

"We can optimise the use of the circuitry in the spinal cord to the point where the animals can sustain full weight-bearing locomotion," said Courtine.