title: Structure predicts function: combining non-invasive electrophysiology with in-vivo histology.
abstract: We present an approach for combining high resolution MRI-based myelin mapping with functional information from electroencephalography (EEG) or magnetoencephalography (MEG). The main contribution to the primary currents detectable with EEG and MEG comes from ionic currents in the apical dendrites of cortical pyramidal cells, aligned perpendicularly to the local cortical surface. We provide evidence from an in-vivo experiment that the variation in MRI-based myeloarchitecture measures across the cortex predicts the variation of the current density over individuals and thus is of functional relevance. Equivalent current dipole locations and moments due to pitch onset evoked response fields (ERFs) were estimated by means of a variational Bayesian algorithm. The myeloarchitecture was estimated indirectly from individual high resolution quantitative multi-parameter maps (MPMs) acquired at 800μm isotropic resolution. Myelin estimates across cortical areas correlated positively with dipole magnitude. This correlation was spatially specific: regions of interest in the auditory cortex provided significantly better models than those covering whole hemispheres. Based on the MPM data we identified the auditory cortical area TE1.2 as the most likely origin of the pitch ERFs measured by MEG. We can now proceed to exploit the higher spatial resolution of quantitative MPMs to identify the cortical origin of M/EEG signals, inform M/EEG source reconstruction and explore structure-function relationships at a fine structural level in the living human brain.
authors.affiliation: Institute of Medical Psychology, Goethe University Frankfurt, Heinrich-Hoffmann-Str. 10, 60528 Frankfurt am Main, Germany.
authors.forename: Saskia
authors.initials: S
authors.lastname: Helbling
authors.affiliation: Institute of Neuroscience, Newcastle University, Framlington Place, Newcastle-upon-Tyne NE2 4HH, UK.
authors.forename: Sundeep
authors.initials: S
authors.lastname: Teki
authors.affiliation: Wellcome Trust Centre for Neuroimaging, Institute of Neurology, University College London, 12 Queen Square, WC1N 3BG London, UK.
authors.forename: Martina F
authors.initials: MF
authors.lastname: Callaghan
authors.affiliation: Institute of Neuroscience, Newcastle University, Framlington Place, Newcastle-upon-Tyne NE2 4HH, UK.
authors.forename: William
authors.initials: W
authors.lastname: Sedley
authors.affiliation: Wellcome Trust Centre for Neuroimaging, Institute of Neurology, University College London, 12 Queen Square, WC1N 3BG London, UK; Department of Systems Neuroscience, University Medical Center Hamburg-Eppendorf, Martinistraße 52, 20246 Hamburg, Germany.
authors.forename: Siawoosh
authors.initials: S
authors.lastname: Mohammadi
authors.affiliation: Institute of Neuroscience, Newcastle University, Framlington Place, Newcastle-upon-Tyne NE2 4HH, UK.
authors.forename: Timothy D
authors.initials: TD
authors.lastname: Griffiths
authors.affiliation: Wellcome Trust Centre for Neuroimaging, Institute of Neurology, University College London, 12 Queen Square, WC1N 3BG London, UK.
authors.forename: Nikolaus
authors.initials: N
authors.lastname: Weiskopf
authors.affiliation: Wellcome Trust Centre for Neuroimaging, Institute of Neurology, University College London, 12 Queen Square, WC1N 3BG London, UK.
authors.forename: Gareth R
authors.initials: GR
authors.lastname: Barnes
mesh_terms: D000328:Adult; D001303:Auditory Cortex / Q000033:anatomy & histology* / Q000502:physiology*; D004569:Electroencephalography; D055724:Electrophysiological Phenomena; D005072:Evoked Potentials, Auditory; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging; D015225:Magnetoencephalography; D008297:Male
keywords: Auditory; MEG; MPM; Myelin or myeloarchitecture; Quantitative MRI; Source reconstruction