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Association fibre pathways of the brain: parallel observations from diffusion spectrum imaging and autoradiography

Jeremy D. Schmahmann, Deepak N. Pandya, Ruopeng Wang, Guangping Dai, Helen E. D'Arceuil, Alex J. de Crespigny, Van J. Wedeen
DOI: http://dx.doi.org/10.1093/brain/awl359 630-653 First published online: 9 February 2007

Summary

Understanding the long association pathways that convey cortical connections is a critical step in exploring the anatomic substrates of cognition in health and disease. Diffusion tensor imaging (DTI) is able to demonstrate fibre tracts non-invasively, but present approaches have been hampered by the inability to visualize fibres that have intersecting trajectories (crossing fibres), and by the lack of a detailed map of the origins, course and terminations of the white matter pathways. We therefore used diffusion spectrum imaging (DSI) that has the ability to resolve crossing fibres at the scale of single MRI voxels, and identified the long association tracts in the monkey brain. We then compared the results with available expositions of white matter pathways in the monkey using autoradiographic histological tract tracing. We identified 10 long association fibre bundles with DSI that match the observations in the isotope material: emanating from the parietal lobe, the superior longitudinal fasciculus subcomponents I, II and III; from the occipital-parietal region, the fronto-occipital fasciculus; from the temporal lobe, the middle longitudinal fasciculus and from rostral to caudal, the uncinate fasciculus, extreme capsule and arcuate fasciculus; from the occipital-temporal region, the inferior longitudinal fasciculus; and from the cingulate gyrus, the cingulum bundle. We suggest new interpretations of the putative functions of these fibre bundles based on the cortical areas that they link. These findings using DSI and validated with reference to autoradiographic tract tracing in the monkey represent a considerable advance in the understanding of the fibre pathways in the cerebral white matter. By replicating the major features of these tracts identified by histological techniques in monkey, we show that DSI has the potential to cast new light on the organization of the human brain in the normal state and in clinical disorders.

  • tract tracing
  • tractography
  • fibre bundles
  • diffusion tensor imaging
  • isotope
  • disconnection
  • Abbreviations:
    Abbreviations:
    AF
    arcuate fasciculus
    ASs
    superior limb of the arcuate sulcus
    CB
    cingulum bundle
    CC
    corpus callosum
    CS
    central sulcus
    DSI
    diffusion spectrum imaging
    DTI
    diffusion tensor imaging
    DWI
    diffusion weighted image
    EmC
    extreme capsule
    EPI
    echoplanar imaging
    FOF
    fronto-occipital fasciculus
    ILF
    inferior longitudinal fasciculus
    IPS
    intraparietal sulcus
    L In
    limen insulae
    MB
    subcallosal fasciculus of Muratoff
    MdLF
    middle longitudinal fasciculus
    RS
    rostral sulcus
    SLF
    superior longitudinal fasciculus
    SMA
    supplementary motor area (M II)
    STS
    superior temporal sulcus
    UF
    uncinate fasciculus

This is an Open Access article distributed under the terms of the Creative Commons Attribution Non-Commercial use License (http://creativecommons.org/lisences/by-nc/2.0/uk/) which permits unrestricted non-commercial use, distributed, and reproduction in medium, provided the original work is properly cited.

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