Exploring the spatial resolution of TMS-EEG coupling on the sensorimotor region
Brice Passera,
Alan Chauvin,
Estelle Raffin,
Thierry Bougerol,
Olivier David,
Sylvain Harquel
Affiliations
Brice Passera
Univ. Grenoble Alpes, Inserm, U1216, Grenoble Institut Neurosciences, Grenoble 38000, France; Univ. Grenoble Alpes, CNRS, UMR5105, Laboratoire Psychologie et NeuroCognition, LPNC, Grenoble F-38000, France; Berenson-Allen Center for Noninvasive Brain Stimulation, Division of Cognitive Neurology, Department of Neurology, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA, United States
Alan Chauvin
Univ. Grenoble Alpes, CNRS, UMR5105, Laboratoire Psychologie et NeuroCognition, LPNC, Grenoble F-38000, France
Estelle Raffin
Univ. Grenoble Alpes, Inserm, U1216, Grenoble Institut Neurosciences, Grenoble 38000, France; Defitech Chair of Clinical Neuroengineering, Center for Neuroprosthetics (CNP) and Brain Mind Institute (BMI), Ecole Polytechnique Federale de Lausanne (EPFL), Chemin des Mines 9, Geneva 1202, Switzerland; Defitech Chair of Clinical Neuroengineering, Center for Neuroprosthetics (CNP) and Brain Mind Institute (BMI), Ecole Polytechnique Federale de Lausanne (EPFL Valais), Clinique Romande de Réadaptation, Sion, Switzerland
Thierry Bougerol
Univ. Grenoble Alpes, Inserm, U1216, Grenoble Institut Neurosciences, Grenoble 38000, France; Centre Hospitalier Univ. Grenoble Alpes, Service de Psychiatrie, Grenoble F-38000, France
Olivier David
Univ. Grenoble Alpes, Inserm, U1216, Grenoble Institut Neurosciences, Grenoble 38000, France; Aix Marseille Univ, Inserm, U1106, INS, Institut de Neurosciences des Systèmes, Marseille, France
Sylvain Harquel
Univ. Grenoble Alpes, CNRS, UMR5105, Laboratoire Psychologie et NeuroCognition, LPNC, Grenoble F-38000, France; Defitech Chair of Clinical Neuroengineering, Center for Neuroprosthetics (CNP) and Brain Mind Institute (BMI), Ecole Polytechnique Federale de Lausanne (EPFL), Chemin des Mines 9, Geneva 1202, Switzerland; Defitech Chair of Clinical Neuroengineering, Center for Neuroprosthetics (CNP) and Brain Mind Institute (BMI), Ecole Polytechnique Federale de Lausanne (EPFL Valais), Clinique Romande de Réadaptation, Sion, Switzerland
The use of TMS-EEG coupling as a neuroimaging tool for the functional exploration of the human brain recently gained strong interest. If this tool directly inherits the fine temporal resolution from EEG, its spatial counterpart remains unknown. In this study, we explored the spatial resolution of TMS-EEG coupling by evaluating the minimal distance between two stimulated cortical sites that would significantly evoke different response dynamics. TMS evoked responses were mapped on the sensorimotor region in twenty participants. The stimulation grid was composed of nine targets separated between 10 and 15 mm on average. The dynamical signatures of TMS evoked activity were extracted and compared between sites using both local and remote linear regression scores and spatial generalized mixed models. We found a significant effect of the distance between stimulated sites on their dynamical signatures, neighboring sites showing differentiable response dynamics. Besides, common dynamical signatures were also found between sites up to 25-30 mm from each other. This overlap in dynamical properties decreased with distance and was stronger between sites within the same Brodmann area. Our results suggest that the spatial resolution of TMS-EEG coupling might be at least as high as 10 mm. Furthermore, our results reveal an anisotropic spatial resolution that was higher across than within the same Brodmann areas, in accordance with the TMS induced E-field modeling. Common cytoarchitectonic leading to shared dynamical properties within the same Brodmann area could also explain this anisotropy. Overall, these findings suggest that TMS-EEG benefits from the spatial resolution of TMS, which makes it an accurate technique for meso-scale brain mapping.
