Modulatory effects of 5Hz rTMS over the primary somatosensory cortex in focal dystonia—An fMRI-TMS study

Authors

  • Susanne A. Schneider MD, PhD,

    1. Sobell Department of Motor Neuroscience and Movement Disorders, UCL, Institute of Neurology, London, United Kingdom
    2. Schilling Section of Clinical and Molecular Neurogenetics, University of Luebeck, Germany
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    • Susanne A. Schneider and Burkhard Pleger have contributed equally to the study.

  • Burkhard Pleger MD,

    1. Wellcome Trust Centre for Neuroimaging, Institute of Neurology, UCL, United Kingdom
    2. Department of Cognitive Neurology, Max Planck Institute for Human Cognitive and Brain Sciences, Leipzig, Germany
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    • Susanne A. Schneider and Burkhard Pleger have contributed equally to the study.

  • Bogdan Draganski MD,

    1. Wellcome Trust Centre for Neuroimaging, Institute of Neurology, UCL, United Kingdom
    2. Department of Cognitive Neurology, Max Planck Institute for Human Cognitive and Brain Sciences, Leipzig, Germany
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  • Carla Cordivari MD, FRCP,

    1. National Hospital for Neurology and Neurosurgery, Queen Square, UCLH, London, United Kingdom
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  • John C. Rothwell PhD,

    1. Sobell Department of Motor Neuroscience and Movement Disorders, UCL, Institute of Neurology, London, United Kingdom
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  • Kailash P. Bhatia MD,

    Corresponding author
    1. Sobell Department of Motor Neuroscience and Movement Disorders, UCL, Institute of Neurology, London, United Kingdom
    2. National Hospital for Neurology and Neurosurgery, Queen Square, UCLH, London, United Kingdom
    • Sobell Department of Motor Neuroscience and Movement Disorders, UCL Institute of Neurology, Queen Square, London WC1N 3BG, U.K
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  • Ray J. Dolan MD, PhD

    Corresponding author
    1. Wellcome Trust Centre for Neuroimaging, Institute of Neurology, UCL, United Kingdom
    • Wellcome Trust Center for Neuroimaging, UCL, Queen Square, London, UK
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  • Potential conflict of interest: nothing to report.

Abstract

Dystonia is associated with impaired somatosensory ability. The electrophysiological method of repetitive transcranial magnetic stimulation (rTMS) can be used for noninvasive stimulation of the human cortex and can alter cortical excitability and associated behavior. Among others, rTMS can alter/improve somatosensory discrimation abilities, as shown in healthy controls. We applied 5Hz-rTMS over the left primary somatosensory cortex (S1) in 5 patients with right-sided writer's dystonia and 5 controls. We studied rTMS effects on tactile discrimination accuracy and concomitant rTMS-induced changes in hemodynamic activity measured by functional magnetic resonance imaging (fMRI). Before rTMS, patients performed worse on the discrimination task than controls even though fMRI showed greater task-related activation bilaterally in the basal ganglia (BG). In controls, rTMS led to improved discrimination; fMRI revealed this was associated with increased activity of the stimulated S1, bilateral premotor cortex and BG. In dystonia patients, rTMS had no effect on discrimination; fMRI showed similar cortical effects to controls except for no effects in BG. Improved discrimination after rTMS in controls is linked to enhanced activation of S1 and BG. Failure of rTMS to increase BG activation in dystonia may be associated with the lack of effect on sensory discrimination in this group and may reflect impaired processing in BG-S1 connections. Alternatively, the increased BG activation seen in the baseline state without rTMS may reflect a compensatory strategy that saturates a BG contribution to this task. © 2010 Movement Disorder Society

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