Secrets of a changing brain

Accepted wisdom tells us that when we are children, our minds are like sponges, and as we get older the brain becomes stuck in its ways.

But Oxford scientists have made a counterintuitive discovery that tells us the brain might be more flexible than previously thought.

The Oxford University researchers worked with Oxford University Hospitals NHS Trust to study how patients’ brains adapted to their bodies losing a limb.

Over five years, they compared those who had been born without a hand, “congenitals”, with those who had lost one through trauma.

And what they found showed the brain has a remarkable ability to reallocate sections of itself that are no longer being used.

This means the part of the cortex that was previously used by the lost hand can allow itself to be used for something new.

And one key aspect of the scientists’ findings was that it is believed the function to do this is affected not by age, but by behaviour.

Experts believe the findings could lead to new ways to treat people who have had amputations, a stroke or suffered a brain injury.

Study leader Dr Tamar Makin told The Oxford Times: “This study tells us a lot about how the brain adapts to compensate for a disability.

“Whichever body part is being used to compensate for a hand loss takes over the brain territory of the missing hand.”

The scientists based themselves at the John Radcliffe Hospital in Headington for the study, which was funded by the Wellcome Trust.

They watched about 50 patients carry out tasks such as opening bottles of water, tying their shoelaces and using mobile phones, to see how they did things differently to each other.

To pinpoint what was going on in their brains, many were placed inside MRI scanners and asked to perform simple movements.

That allowed Dr Makin and her colleagues to see how the part of the brain cortex previously assigned to a lost hand was activating, in response to other parts of the body being used instead.

Of particular interest was the difference between those who were born without a hand and those who lost it later in life.

Remarkably, the scientists found the brain did not make much of a distinction between the two.

Dr Makin said: “The brain isn’t fussy about whether there’s a hand at the end of the arm, a prosthetic or a ‘stump’, so long as it’s used in a similar way.”

Headington resident Clay Wesenberg, originally from Canada, was born without a left hand and lower arm and instead uses specially-made prosthetics.

Like others who took part in the study, the 38-year-old’s brain responses to certain actions were measured in an MRI machine.

Mr Wesenberg said he had grown used to using prosthetics from a young age, although didn’t always use them for activities such as sports.

He said: “You learn strategies for how to do things your own way. If you asked me to do something in the way you’re doing it, I might find it difficult.

“But although I will do it differently, the outcome will be the same.

“For me there was no stop-change growing up, this is how it has always been.

“And when I look back at my childhood, my parents just let me carry on doing normal things children do.”

Another patient, Kirsty Mason, from Bracknell, lost her lower right arm in an accident.

However, the 24-year-old has since learned to use what remains of her lower arm to do a number of things, including tying her hair in a ponytail and doing up zips and buttons on a coat.

She said: “I was also dominantly right-handed before my accident, so I had to learn to write left-handed.

“Now, after a lot of practice, I write just as well with it as I did with my right.”

What the researchers noted was how the brain adapted to use whatever “residual” limb was left over without the hand.

This could mean, as in Miss Mason’s case, becoming increasingly dexterous with her remaining lower arm, or — as in Mr Wesenberg’s case — becoming skilled with a prosthetic.

And there are hopes that in the future scientists could even learn how to “tap into” this ability and train the brain to transfer activity to different areas of the body.

The researchers’ findings have been published in the scientific journal eLife.

The co-author of the paper, Dr David Henderson Slater, of the Nuffield Orthopaedic Centre, said: “We have always known that some people adapt to the loss of a limb very soon, and make changes in the way they use other parts of their body to compensate.

“This study helps us to understand the basis for this and we may be able to incorporate this knowledge into the therapy we offer to new amputees.”

He added: “It could help with the rehabilitation of people who have suffered from strokes and brain injuries.”