Brain Stimulation (Jul 2023)

Functional connectivity explains how neuronavigated TMS of posterior temporal subregions differentially affect language processing

  • Maria Vasileiadi,
  • Anna-Lisa Schuler,
  • Michael Woletz,
  • David Linhardt,
  • Christian Windischberger,
  • Martin Tik

Journal volume & issue
Vol. 16, no. 4
pp. 1062 – 1071

Abstract

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Background: “Wernicke's area” is most often used to describe the posterior superior temporal gyrus (STG) and refers to a region traditionally thought to support language comprehension. However, the posterior STG additionally plays a critical role in language production. The purpose of the current study was to determine to what extent regions within the posterior STG are selectively recruited during language production. Methods: 23 healthy right-handed participants completed an auditory fMRI localizer task, resting-state fMRI and underwent neuronavigated TMS language mapping. We applied repetitive TMS bursts during a picture naming paradigm to probe speech disruptions of different categories (anomia, speech arrest, semantic paraphasia and phonological paraphasia). We combined an in-house built high precision stimulation software suite with E-field modeling to map the naming errors to cortical regions and revealed a dissociation of language functions within the temporal gyrus. Resting state fMRI was used to explain how E-field peaks of different categories differentially affected language production. Results: Peaks for phonological and semantic errors were found in the STG while those for anomia and speech arrest were located in the MTG. Seed-based connectivity analysis revealed a local connectivity pattern for phonological and semantic errors, while anomia and speech arrest seeds resulted in a larger network between IFG and posterior MTG. Conclusions: Our study provides important insights into the functional neuroanatomy of language production and might help to increase the current understanding of specific language production difficulties on a causal level.

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