UCL News


UCL in the News: A switch in handedness changes the brain

17 July 2007

A study of such 'converted' left-handers has found that the way their brains are organized, and how hard particular regions work, changes as a result of this switch.

Some areas of the brain continue to look like those of a practising lefty, whereas other areas switch to the patterns of a righty, the research reveals. "The question now is, 'do converts suffer because of this extra attention that they exert?'," says Stefan Klöppel [UCL Institute of Neurology], who led the work. The answer to that is as yet unknown. …

Converting from being left-handed to right-handed doesn't simply move brain activity to the other half of the brain, Klöppel and his colleagues found.

The team tested right-handers, left-handers and converts (from left- to right-handedness) on a simple task, in which they pressed a button with one or the other hand in response to seeing particular symbols. Throughout the task their brain activity was monitored with a magnetic resonance imaging (MRI) scan.…

Brain regions involved in planning movement stubbornly refuse to switch, and continue to act like those of left-handers in people who have switched to right-handedness. These stubborn regions were also more active in converts than in those who stuck with left-handedness. "They still look like left handers, but even more emphasised," says Klöppel, whose results are published in the Journal of Neuroscience. …

The new study could reveal things about the brain beyond its involvement in handedness, says Klöppel. It shows how flexible the brain is in terms of which regions can do what, for example. "The key thing is that there are areas that can be influenced by training and areas that resist this," he says. "It's not only interesting in regard to handedness, but also in terms of plasticity."

Kerri Smith, 'Nature'