title: Using high-resolution quantitative mapping of R1 as an index of cortical myelination.
abstract: A fundamental tenet of neuroscience is that cortical functional differentiation is related to the cross-areal differences in cyto-, receptor-, and myeloarchitectonics that are observed in ex-vivo preparations. An ongoing challenge is to create noninvasive magnetic resonance (MR) imaging techniques that offer sufficient resolution, tissue contrast, accuracy and precision to allow for characterization of cortical architecture over an entire living human brain. One exciting development is the advent of fast, high-resolution quantitative mapping of basic MR parameters that reflect cortical myeloarchitecture. Here, we outline some of the theoretical and technical advances underlying this technique, particularly in terms of measuring and correcting for transmit and receive radio frequency field inhomogeneities. We also discuss new directions in analytic techniques, including higher resolution reconstructions of the cortical surface. We then discuss two recent applications of this technique. The first compares individual and group myelin maps to functional retinotopic maps in the same individuals, demonstrating a close relationship between functionally and myeloarchitectonically defined areal boundaries (as well as revealing an interesting disparity in a highly studied visual area). The second combines tonotopic and myeloarchitectonic mapping to localize primary auditory areas in individual healthy adults, using a similar strategy as combined electrophysiological and post-mortem myeloarchitectonic studies in non-human primates.
authors.affiliation: Wellcome Trust Centre for Neuroimaging, UCL Institute of Neurology, University College London, London, UK; LREN, Département des neurosciences cliniques, CHUV, University of Lausanne, Lausanne, Switzerland. Electronic address: a.lutti@ucl.ac.uk.
authors.forename: Antoine
authors.initials: A
authors.lastname: Lutti
authors.affiliation: Birkbeck/UCL Centre for NeuroImaging, London, UK; Department of Psychological Sciences, Birkbeck College, University of London, UK.
authors.forename: Frederic
authors.initials: F
authors.lastname: Dick
authors.affiliation: Birkbeck/UCL Centre for NeuroImaging, London, UK; Department of Psychological Sciences, Birkbeck College, University of London, UK; Perceptual and Language Sciences Division, UCL, London, UK.
authors.forename: Martin I
authors.initials: MI
authors.lastname: Sereno
authors.affiliation: Wellcome Trust Centre for Neuroimaging, UCL Institute of Neurology, University College London, London, UK.
authors.forename: Nikolaus
authors.initials: N
authors.lastname: Weiskopf
mesh_terms: D001931:Brain Mapping / Q000379:methods*; D002540:Cerebral Cortex / Q000033:anatomy & histology* / Q000378:metabolism; D006801:Humans; D007091:Image Processing, Computer-Assisted; D008279:Magnetic Resonance Imaging / Q000379:methods*; D009186:Myelin Sheath / Q000378:metabolism / Q000502:physiology*
keywords: Anatomy; Auditory; MRI; Myelin; Myeloarchitecture; Quantitative; R1; T1; Visual