An international team led by researchers from the Max Planck Institute for Psycholinguistics and the Donders Institute in Nijmegen investigated brain imaging and genetic data from 3,062 left-handers and 28,802 right-handers.
Being left-handed was associated with differences in brain asymmetry in areas related to working memory, language, manual control, and vision. “Hemispheric specialization is important for language and other cognitive functions. Several psychiatric traits implicate increased rates of left-handedness, including autism, schizophrenia, and intellectual disability, although of course most left-handed people do not, ”explains MPI’s Clyde Francks.
To examine the differences between left and right handed, the team used images from a large data set (the UK Biobank) to measure asymmetries. According to researcher Zhiqiang Sha, “it took about three months of processing on twelve computer cluster servers, running in parallel.”
Results
Right-handers differed on average from left-handers in their brain asymmetry in ten specific regions, spread widely across the surface of the brain. In all ten of these regions, the gray matter in the right hemisphere tended to be relatively larger in the left-handed, consistent with increased neural resources to support the role of that hemisphere in left-hand control. “This is the first time that specific parts of the brain anatomy have been safely linked to the hand,” says Francks.
Referencia: Handedness and its genetic influences are associated with structural asymmetries of the cerebral cortex in 31,864 individuals. Zhiqiang Sha, Antonietta Pepe, Dick Schijven, Amaia Carrión-Castillo, James M. Roe, René Westerhausen, Marc Joliot, Simon E. Fisher, Fabrice Crivello and Clyde Francks. Proceedings of the National Academy of Sciences (PNAS) (2021). DOI:https://doi.org/10.1073/pnas.2113095118
