Degeneration of corpus callosum and recovery of motor function after stroke: A multimodal magnetic resonance imaging study

Authors

  • Ling E. Wang,

    1. Cognitive Neurology Section, Institute of Neuroscience and Medicine (INM-3), Research Centre Juelich, Germany
    2. International Graduate School of Neuroscience and Research School, Ruhr University Bochum, Germany
    3. Neuromodulation and Neurorehabilitation Section, Max Planck Institute for Neurological Research, Cologne, Germany
    4. Division of Speech and Hearing Sciences, Faculty of Education, The University of Hong Kong, China
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  • Marc Tittgemeyer,

    1. Neuromodulation and Neurorehabilitation Section, Max Planck Institute for Neurological Research, Cologne, Germany
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  • Davide Imperati,

    1. Neuromodulation and Neurorehabilitation Section, Max Planck Institute for Neurological Research, Cologne, Germany
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  • Svenja Diekhoff,

    1. Neuromodulation and Neurorehabilitation Section, Max Planck Institute for Neurological Research, Cologne, Germany
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  • Mitra Ameli,

    1. Department of Neurology, University of Cologne, Germany
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  • Gereon R. Fink,

    1. Cognitive Neurology Section, Institute of Neuroscience and Medicine (INM-3), Research Centre Juelich, Germany
    2. Department of Neurology, University of Cologne, Germany
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  • Christian Grefkes

    Corresponding author
    1. Cognitive Neurology Section, Institute of Neuroscience and Medicine (INM-3), Research Centre Juelich, Germany
    2. Neuromodulation and Neurorehabilitation Section, Max Planck Institute for Neurological Research, Cologne, Germany
    3. Department of Neurology, University of Cologne, Germany
    • Neuromodulation and Neurorehabilitation, Max Planck Institute for Neurological Research, Gleueler Str. 50, 50931 Köln, Germany
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Abstract

Animal models of stroke demonstrated that white matter ischemia may cause both axonal damage and myelin degradation distant from the core lesion, thereby impacting on behavior and functional outcome after stroke. We here used parameters derived from diffusion magnetic resonance imaging (MRI) to investigate the effect of focal white matter ischemia on functional reorganization within the motor system. Patients (n = 18) suffering from hand motor deficits in the subacute or chronic stage after subcortical stroke and healthy controls (n = 12) were scanned with both diffusion MRI and functional MRI while performing a motor task with the left or right hand. A laterality index was employed on activated voxels to assess functional reorganization across hemispheres. Regression analyses revealed that diffusion MRI parameters of both the ipsilesional corticospinal tract (CST) and corpus callosum (CC) predicted increased activation of the unaffected hemisphere during movements of the stroke-affected hand. Changes in diffusion MRI parameters possibly reflecting axonal damage and/or destruction of myelin sheath correlated with a stronger bilateral recruitment of motor areas and poorer motor performance. Probabilistic fiber tracking analyses revealed that the region in the CC correlating with the fMRI laterality index and motor deficits connected to sensorimotor cortex, supplementary motor area, ventral premotor cortex, superior parietal lobule, and temporoparietal junction. The results suggest that degeneration of transcallosal fibers connecting higher order sensorimotor regions constitute a relevant factor influencing cortical reorganization and motor outcome after subcortical stroke. Hum Brain Mapp, 2012. © 2011 Wiley Periodicals, Inc.

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