J L K Kramer1, C R Jutzeler2, J Haefeli3, A Curt2, P Freund4. 1. Spinal Cord Injury Center, University Hospital Balgrist, University of Zurich, Zurich, Switzerland; The Hulse Spinal Cord Injury Laboratory, Shepherd Center, Atlanta, GA, USA; ICORD/School of Kinesiology, University of British Columbia, Vancouver, British Columbia, Canada. Electronic address: kramer@icord.org. 2. Spinal Cord Injury Center, University Hospital Balgrist, University of Zurich, Zurich, Switzerland. 3. Spinal Cord Injury Center, University Hospital Balgrist, University of Zurich, Zurich, Switzerland; Brain and Spinal Injury Center, Department of Neurological Surgery, University of California, San Francisco, USA. 4. Spinal Cord Injury Center, University Hospital Balgrist, University of Zurich, Zurich, Switzerland; Wellcome Trust Centre for Neuroimaging, UCL Institute of Neurology, University College London, UK; Department of Brain Repair & Rehabilitation, UCL Institute of Neurology, University College London, UK.
Abstract
OBJECTIVES: The purpose of this study was to determine if local gray and white matter volume variations between subjects could account for variability in responses to CHEP stimulation. METHODS: Structural magnetic resonance imaging was used to perform voxel-based morphometry (VBM) of gray and white matter in 30 neurologically healthy subjects. Contact heat stimulation was performed on the dorsum of the right hand at the base of the thumb. Evoked potentials were acquired from a vertex-recording electrode referenced to linked ears. RESULTS: Controlling for age, total intracranial volume, and skull/scalp thickness, CHEP amplitude and pain rating were not significantly correlated between subjects. A VBM region of interest approach demonstrated a significant interaction between pain rating and N2 amplitude in the right insular cortex (p<0.05, family-wise error corrected, FWE). In white matter, a significant interaction was localized in the right inferior frontal occipital fasciculus (IFOF, p<0.05 FWE). CONCLUSIONS: Accounting for gray matter volume in the right insular cortex, resulted in a significant relationship between CHEP amplitude and pain rating. SIGNIFICANCE: This finding suggests that the discrepancy between pain ratings and the amplitude of evoked potentials is not solely related to measurement artifact, but rather attributable, in part, to anatomical differences between subjects. Crown
OBJECTIVES: The purpose of this study was to determine if local gray and white matter volume variations between subjects could account for variability in responses to CHEP stimulation. METHODS: Structural magnetic resonance imaging was used to perform voxel-based morphometry (VBM) of gray and white matter in 30 neurologically healthy subjects. Contact heat stimulation was performed on the dorsum of the right hand at the base of the thumb. Evoked potentials were acquired from a vertex-recording electrode referenced to linked ears. RESULTS: Controlling for age, total intracranial volume, and skull/scalp thickness, CHEP amplitude and pain rating were not significantly correlated between subjects. A VBM region of interest approach demonstrated a significant interaction between pain rating and N2 amplitude in the right insular cortex (p<0.05, family-wise error corrected, FWE). In white matter, a significant interaction was localized in the right inferior frontal occipital fasciculus (IFOF, p<0.05 FWE). CONCLUSIONS: Accounting for gray matter volume in the right insular cortex, resulted in a significant relationship between CHEP amplitude and pain rating. SIGNIFICANCE: This finding suggests that the discrepancy between pain ratings and the amplitude of evoked potentials is not solely related to measurement artifact, but rather attributable, in part, to anatomical differences between subjects. Crown
Authors: Iara De Schoenmacker; Carson Berry; Jean-Sébastien Blouin; Jan Rosner; Michèle Hubli; Catherine R Jutzeler; John L K Kramer Journal: Sci Rep Date: 2021-03-25 Impact factor: 4.379