They said the new discovery - if confirmed - could lead to improved treatment for neurological conditions such as the injury caused by strokes.

Their work started by examining the cerebral cortex - the highest brain centre - and its relationship with lower components dedicated to routine tasks such as movement and maintaining body temperature.

Puzzle

Professor Jonathan Dostrovsky, lead author of the research, said: "While it has been obvious to scientists for some time that sensory information must flow up each level of the brain, it has always been a puzzle why there is such heavy feedback from higher levels back down."

The answer could be that the cortex re-trains the lower brain centres when they need to adapt to change.

To test this, they removed the sensory connection between laboratory rats' back legs and the part of the brain that controls them - the thalamus.

The thalamus had to re-organise in order to cope with this change - a process known as plasticity - and the scientists found that the cortex guided it through this process, only ceasing to be involved after the thalamus had got used to the change.

Adaptive powers

"Our main aim was to look at plasticity - the ability of the brain to reorganise or adapt to change - particularly after injury," Professor Dostrovsky told BBC News Online.

"We were looking at changes that happened in the part of the brain responsible for the limbs. We found that when the brain reorganised it involved the cortex."

The results were "preliminary, but very promising," and added considerably to understanding how the brain adapted to injury, he said.

Further down the line they may lead to treatments for conditions such as stroke by stimulating the cortex into retraining the lower brain centres.

"It's all speculation now, but it might lead to making this process more robust," he said.