title: Mapping dynamical properties of cortical microcircuits using robotized TMS and EEG: Towards functional cytoarchitectonics.
abstract: Brain dynamics at rest depend on the large-scale interactions between oscillating cortical microcircuits arranged into macrocolumns. Cytoarchitectonic studies have shown that the structure of those microcircuits differs between cortical regions, but very little is known about interregional differences of their intrinsic dynamics at a macro-scale in human. We developed here a new method aiming at mapping the dynamical properties of cortical microcircuits non-invasively using the coupling between robotized transcranial magnetic stimulation and electroencephalography. We recorded the responses evoked by the stimulation of 18 cortical targets largely covering the accessible neocortex in 22 healthy volunteers. Specific data processing methods were developed to map the local source activity of each cortical target, which showed inter-regional differences with very good interhemispheric reproducibility. Functional signatures of cortical microcircuits were further studied using spatio-temporal decomposition of local source activities in order to highlight principal brain modes. The identified brain modes revealed that cortical areas with similar intrinsic dynamical properties could be distributed either locally or not, with a spatial signature that was somewhat reminiscent of resting state networks. Our results provide the proof of concept of "functional cytoarchitectonics", that would guide the parcellation of the human cortex using not only its cytoarchitecture but also its intrinsic responses to local perturbations. This opens new avenues for brain modelling and physiopathology readouts.
authors.affiliation: Univ. Grenoble Alpes, F-38000 Grenoble, France; CNRS, UMR5105, Laboratoire Psychologie et NeuroCognition, LPNC, F-38000 Grenoble, France; Inserm, U1216, Grenoble Institut des Neurosciences, F-38000 Grenoble, France; CNRS, INSERM, Univ. Grenoble Alpes, CHU Grenoble, IRMaGe, F-38000 Grenoble, France.
authors.forename: Sylvain
authors.initials: S
authors.lastname: Harquel
authors.affiliation: Univ. Grenoble Alpes, F-38000 Grenoble, France; CNRS, UMR5105, Laboratoire Psychologie et NeuroCognition, LPNC, F-38000 Grenoble, France.
authors.forename: Thibault
authors.initials: T
authors.lastname: Bacle
authors.affiliation: Univ. Grenoble Alpes, F-38000 Grenoble, France; CNRS, UMR5105, Laboratoire Psychologie et NeuroCognition, LPNC, F-38000 Grenoble, France.
authors.forename: Lysianne
authors.initials: L
authors.lastname: Beynel
authors.affiliation: Univ. Grenoble Alpes, F-38000 Grenoble, France; CNRS, UMR5105, Laboratoire Psychologie et NeuroCognition, LPNC, F-38000 Grenoble, France.
authors.forename: Christian
authors.initials: C
authors.lastname: Marendaz
authors.affiliation: Univ. Grenoble Alpes, F-38000 Grenoble, France; CNRS, UMR5105, Laboratoire Psychologie et NeuroCognition, LPNC, F-38000 Grenoble, France.
authors.forename: Alan
authors.initials: A
authors.lastname: Chauvin
authors.affiliation: Univ. Grenoble Alpes, F-38000 Grenoble, France; Inserm, U1216, Grenoble Institut des Neurosciences, F-38000 Grenoble, France. Electronic address: Olivier.David@inserm.fr.
authors.forename: Olivier
authors.initials: O
authors.lastname: David
mesh_terms: D000328:Adult; D001931:Brain Mapping / Q000379:methods*; D004569:Electroencephalography / Q000379:methods*; D005071:Evoked Potentials / Q000502:physiology*; D005260:Female; D006801:Humans; D008297:Male; D019579:Neocortex / Q000502:physiology*; D009415:Nerve Net / Q000502:physiology*; D012016:Reference Values; D012371:Robotics / Q000379:methods*; D050781:Transcranial Magnetic Stimulation / Q000379:methods*
keywords: Cortical mapping; Cytoarchitectonics; Electroencephalography; Functional neuroanatomy; Transcranial magnetic stimulation