**5. Conclusions**

Language-positive and language-negative areas as determined by nTMS language mapping show differences in cortical and subcortical characteristics among patients diagnosed with GBMs. Specifically, language-positive areas demonstrate lower GMI and an enhanced connectivity profile with higher volume ratios for U-fibers, interhemispheric fibers, and fibers projecting to the cerebellum. While future studies may confirm these results in larger cohorts in the context of a prospective study design, these findings facilitate confidence in the technique of nTMS language mapping and nTMS-based tractography to detect language-involved structures of the human cortico-subcortical language network.

**Author Contributions:** Conceptualization, H.Z., S.S. and N.S.; methodology, H.Z., S.S., S.M.K. and N.S.; software, H.Z.; validation, S.M.K. and N.S.; formal analysis, H.Z., S.S., A.S. and N.S.; investigation, H.Z., S.S. and A.S.; resources, C.Z., B.M. and S.M.K.; data curation, H.Z. and N.S.; writing—original draft preparation, H.Z. and N.S.; writing—review and editing, S.M.K.; visualization, H.Z.; supervision, C.Z., B.M., S.M.K. and N.S.; project administration, S.M.K. and N.S.; funding acquisition, C.Z., B.M. and S.M.K. All authors have read and agreed to the published version of the manuscript.

**Funding:** This research received no external funding.

**Conflicts of Interest:** N.S. received honoraria from Nexstim Plc (Helsinki, Finland). S.M.K. is a consultant for Nexstim Plc (Helsinki, Finland) and Spineart Deutschland GmbH (Frankfurt, Germany) and received honoraria from Medtronic (Meerbusch, Germany) and Carl Zeiss Meditec (Oberkochen, Germany). S.M.K. and B.M. received research grants and are consultants for Brainlab AG (Munich, Germany). B.M. received honoraria, consulting fees, and research grants from Medtronic (Meerbusch, Germany), Icotec ag (Altstätten, Switzerland), and Relievant Medsystems Inc. (Sunnyvale, CA, USA); honoraria and research grants from Ulrich Medical (Ulm, Germany); honoraria and consulting fees from Spineart Deutschland GmbH (Frankfurt, Germany) and DePuy Synthes (West Chester, PA, USA); and royalties from Spineart Deutschland GmbH (Frankfurt, Germany). The other authors declare no conflicts of interest.
