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Saturday, 10 July 2010 11:35

Paradoxical improvement of performance after virtual brain damage

Can the performance of a person solving a task be improved by specific brain lesions? In certain cases that is indeed the case, e.g. when the lesion suppress an impulse that would normally make it difficult to solve the task. This was the focus of a study that has just been published in Journal of Neuroscience with contributions from the DRCMR research leader Hartwig R. Siebner.

Real brain lesions caused by blood clots, for example, differ a lot, and they are not optimal for studying this aspect of brain function. The neuro scientists at Hvidovre Hospital and elsewhere, however, have an amazing tool called rTMS available for inducing temporary virtual lesions in healthy persons: By applying strong magnetic pulses to a particular part of the brain, the neurons there can be triggered repeatedly and be gradually exhausted, so they no longer respond to normal inputs. The effect only lasts for a couple of minutes, and during this period the person will behave as if she had a real lesion in the affected brain area. 

Hartwig R. Siebner and co-workers from London, Kiel and Lausanne showed that rTMS applied to the part of the brain called premotor cortex can have a lasting positive influence on task performance, i.e. give less errors.

 Rererence:

Title: Low-frequency transcranial magnetic stimulation over left dorsal premotor cortex improves the dynamic control of visuospatially cued actions.

Published in: Journal of Neuroscience. 2010 Jul 7;30(27):9216-23.

Authors: Ward NS, Bestmann S, Hartwigsen G, Weiss MM, Christensen LO, Frackowiak RS, Rothwell JC, Siebner HR.