Thursday, 03 October 2013 17:17

New understanding: The right side of the brain helps the left speak when the language is impaired by stroke

A study of brain function by DRCMR research leader Hartwig R. Siebner and international co-workers was published in the prestigious journal PNAS, September 2013. Using transcranial magnetic stimulation and functional MRI (TMS & fMRI), the study demonstrated how the right side of the brain actively supports the language function in the left side following virtual brain lesioning similar to left-side stroke. This may well be important for understanding stroke recovery.

The significance of the study is summarized in the paper: "The role of the right hemisphere in aphasia recovery is unclear. We demonstrate that a virtual lesion of left inferior frontal gyrus (IFG) decreased activity in the targeted area and increased activity in the contralateral homologous area during pseudoword repetition. This was associated with a stronger facilitatory drive from the right IFG to the left IFG. Importantly, responses became faster with increased influence of the right IFG on the left IFG. Our results shed new light on the dynamic regulation of interhemispheric interactions in the human brain. Particularly, these findings are of potential importance for understanding language recovery after left-hemispheric stroke, indicating that homologous right hemisphere areas actively contribute to language function after a left hemisphere lesion."

Hartwigsen G, Saur D, Price CJ, Ulmer S, Baumgaertner A, Siebner HR, Perturbation of the left inferior frontal gyrus triggers adaptive plasticity in the right homologous area during speech production, Proc Natl Acad Sci U S A. 2013 Sep 23. Full text link.