Spatial distribution of spinal cord fMRI activity with electrocutaneous stimulation.
9 affiliations
- 1NeuroPoly Lab, Institute of Biomedical Engineering, Polytechnique Montreal, Montreal, Quebec, Canada.
- 2Division of Pain Medicine, Department of Anesthesiology, Perioperative and Pain Medicine, Stanford School of Medicine, Palo Alto, CA, United States.
- 3Department of Neurosurgery, Stanford University School of Medicine, Palo Alto, CA, United States.
- 4Department of Orthopaedic Surgery, Stanford University School of Medicine, Palo Alto, CA, United States.
- 5Department of Neurosurgery, University of Oklahoma Health Sciences Center, Oklahoma City, OK, United States.
- 6Department of Radiology, Stanford University School of Medicine, Palo Alto, CA, United States.
- 7Mila-Quebec AI Institute, Montreal, Quebec, Canada.
- 8Research Center, Ste-Justine Hospital University Centre, Montreal, Quebec, Canada.
- 9Functional Neuroimaging Unit, CRIUGM, University of Montreal, Montreal, Quebec, Canada.
Abstract
Sensory organization at the spinal segment level is commonly inferred from dermatomal maps that assume a fixed correspondence between cutaneous regions and spinal segments. However, based on the complexities of spinal neuroanatomy and neurophysiology, the distribution of sensory signals within the cord may be broader and less segment-specific than dermatomal maps suggest, leaving the segment-level localization of sensory-evoked activity in humans uncertain. Spinal cord functional magnetic resonance imaging (fMRI) is currently the only technique capable of noninvasively mapping sensory activity with high spatial resolution in the human spinal cord. However, its application remains technically challenging and is limited by the uncertainty in segmental localization. In this study, we leveraged recent advancements in spinal cord fMRI, including spinal nerve rootlet-based spatial normalization, to investigate how sensory information is represented and distributed within the human spinal cord during electrocutaneous stimulation of the third digit of the right hand (i.e., C7 dermatome). Forty healthy adults were scanned with electrocutaneous stimulation at four individualized intensities across multiple runs to quantify (i) the rostrocaudal distribution of sensory-evoked activity, (ii) intensity-dependent changes in detectability and localization, and (iii) the effect of normalization strategy on segmental localization. Across participants, stimulation produced activation localized in the lower cervical cord (e.g., C6-C8), with the most consistent segmental localization near C7. Stronger stimulation increased detectability and produced more consistent segmental localization across participants. Importantly, normalization that incorporated nerve rootlet landmarks sharpened localization and improved sensitivity relative to conventional intervertebral disc-based alignment. This highlights the value of functionally relevant anatomical landmarks for group inference in the spinal cord. Responses were strongest in the initial run and attenuated with repetition, suggesting habituation or adaptation that can bias multi-run paradigms if unmodeled. Together, our results define practical acquisition and analysis conditions (e.g., stimulation strength, anatomical alignment strategy, and run structure) under which segment-level spinal sensory responses can be detected, thereby supporting more reliable studies of human spinal cord future basic and translational studies, including pain mechanisms, sensory function, and spinal injury.
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BibTeX
@article{bedard2026spatial,
title = {{Spatial distribution of spinal cord fMRI activity with electrocutaneous stimulation.}},
author = {Sandrine Bédard and Merve Kaptan and Teresa Indriolo and Christine S W Law and Dario Pfyffer and Lindsay Lee and John Ratliff and Serena Hu and Suzanne Tharin and Zachary A Smith and Gary H Glover and Sean Mackey and Julien Cohen-Adad and Kenneth A Weber Ii},
journal = {Imaging neuroscience (Cambridge, Mass.)},
year = {2026},
month = oct,
doi = {10.1162/imag.a.1383},
url = {https://europepmc.org/article/MED/42835601},
note = {CC BY},
}
RIS
TY - JOUR
TI - Spatial distribution of spinal cord fMRI activity with electrocutaneous stimulation.
AU - Sandrine Bédard
AU - Merve Kaptan
AU - Teresa Indriolo
AU - Christine S W Law
AU - Dario Pfyffer
AU - Lindsay Lee
AU - John Ratliff
AU - Serena Hu
AU - Suzanne Tharin
AU - Zachary A Smith
AU - Gary H Glover
AU - Sean Mackey
AU - Julien Cohen-Adad
AU - Kenneth A Weber Ii
PY - 2026
DA - 2026/10/01
JO - Imaging neuroscience (Cambridge, Mass.)
DO - 10.1162/imag.a.1383
UR - https://europepmc.org/article/MED/42835601
AB - Sensory organization at the spinal segment level is commonly inferred from dermatomal maps that assume a fixed correspondence between cutaneous regions and spinal segments. However, based on the complexities of spinal neuroanatomy and neurophysiology, the distribution of sensory signals within the cord may be broader and less segment-specific than dermatomal maps suggest, leaving the segment-level localization of sensory-evoked activity in humans uncertain. Spinal cord functional magnetic resonance imaging (fMRI) is currently the only technique capable of noninvasively mapping sensory activity with high spatial resolution in the human spinal cord. However, its application remains technically challenging and is limited by the uncertainty in segmental localization. In this study, we leveraged recent advancements in spinal cord fMRI, including spinal nerve rootlet-based spatial normalization, to investigate how sensory information is represented and distributed within the human spinal cord during electrocutaneous stimulation of the third digit of the right hand (i.e., C7 dermatome). Forty healthy adults were scanned with electrocutaneous stimulation at four individualized intensities across multiple runs to quantify (i) the rostrocaudal distribution of sensory-evoked activity, (ii) intensity-dependent changes in detectability and localization, and (iii) the effect of normalization strategy on segmental localization. Across participants, stimulation produced activation localized in the lower cervical cord (e.g., C6-C8), with the most consistent segmental localization near C7. Stronger stimulation increased detectability and produced more consistent segmental localization across participants. Importantly, normalization that incorporated nerve rootlet landmarks sharpened localization and improved sensitivity relative to conventional intervertebral disc-based alignment. This highlights the value of functionally relevant anatomical landmarks for group inference in the spinal cord. Responses were strongest in the initial run and attenuated with repetition, suggesting habituation or adaptation that can bias multi-run paradigms if unmodeled. Together, our results define practical acquisition and analysis conditions (e.g., stimulation strength, anatomical alignment strategy, and run structure) under which segment-level spinal sensory responses can be detected, thereby supporting more reliable studies of human spinal cord future basic and translational studies, including pain mechanisms, sensory function, and spinal injury.
SN - 2837-6056
ER -