Interlimb conditioning of lumbosacral spinally evoked motor responses after spinal cord injury

D. A. Atkinson; D. G. Sayenko; J. M. D'Amico; A. Mink; D. J. Lorenz; Y. P. Gerasimenko; S. Harkema

doi:10.1016/j.clinph.2020.03.021

Interlimb conditioning of lumbosacral spinally evoked motor responses after spinal cord injury

D. A. Atkinson, D. G. Sayenko, J. M. D'Amico, A. Mink, D. J. Lorenz, Y. P. Gerasimenko, S. Harkema

Research output: Contribution to journal › Article › peer-review

9 Scopus citations

Abstract

Objective: The importance of subcortical pathways to functional motor recovery after spinal cord injury (SCI) has been demonstrated in multiple animal models. The current study evaluated descending interlimb influence on lumbosacral motor excitability after chronic SCI in humans. Methods: Ulnar nerve stimulation and transcutaneous electrical spinal stimulation were used in a condition-test paradigm to evaluate the presence of interlimb connections linking the cervical and lumbosacral spinal segments in non-injured (n=15) and spinal cord injured (SCI) (n=18) participants. Results: Potentiation of spinally evoked motor responses (sEMRs) by ulnar nerve conditioning was observed in 7/7 SCI participants with volitional leg muscle activation, and in 6/11 SCI participants with no volitional activation. Of these six, conditioning of sEMRs was present only when the neurological level of injury was rostral to the ulnar innervation entry zones. Conclusions: Descending modulation of lumbosacral motor pools via interlimb projections may exist in SCI participants despite the absence of volitional leg muscle activation. Significance: Evaluation of sub-clinical, spared pathways within the spinal cord after SCI may provide an improved understanding of both the contributions of different pathways to residual function, and the mechanisms of plasticity and functional motor recovery following rehabilitation.

Original language	English (US)
Pages (from-to)	1519-1532
Number of pages	14
Journal	Clinical Neurophysiology
Volume	131
Issue number	7
DOIs	https://doi.org/10.1016/j.clinph.2020.03.021
State	Published - Jul 2020

Keywords

Human spinal cord injury
Interlimb pathways
Motor assessment
Neurophysiology

ASJC Scopus subject areas

Sensory Systems
Neurology
Clinical Neurology
Physiology (medical)

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10.1016/j.clinph.2020.03.021

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@article{f1197fc25ed64aee93d892ac711a15c8,

title = "Interlimb conditioning of lumbosacral spinally evoked motor responses after spinal cord injury",

abstract = "Objective: The importance of subcortical pathways to functional motor recovery after spinal cord injury (SCI) has been demonstrated in multiple animal models. The current study evaluated descending interlimb influence on lumbosacral motor excitability after chronic SCI in humans. Methods: Ulnar nerve stimulation and transcutaneous electrical spinal stimulation were used in a condition-test paradigm to evaluate the presence of interlimb connections linking the cervical and lumbosacral spinal segments in non-injured (n=15) and spinal cord injured (SCI) (n=18) participants. Results: Potentiation of spinally evoked motor responses (sEMRs) by ulnar nerve conditioning was observed in 7/7 SCI participants with volitional leg muscle activation, and in 6/11 SCI participants with no volitional activation. Of these six, conditioning of sEMRs was present only when the neurological level of injury was rostral to the ulnar innervation entry zones. Conclusions: Descending modulation of lumbosacral motor pools via interlimb projections may exist in SCI participants despite the absence of volitional leg muscle activation. Significance: Evaluation of sub-clinical, spared pathways within the spinal cord after SCI may provide an improved understanding of both the contributions of different pathways to residual function, and the mechanisms of plasticity and functional motor recovery following rehabilitation.",

keywords = "Human spinal cord injury, Interlimb pathways, Motor assessment, Neurophysiology",

author = "Atkinson, {D. A.} and Sayenko, {D. G.} and D'Amico, {J. M.} and A. Mink and Lorenz, {D. J.} and Gerasimenko, {Y. P.} and S. Harkema",

note = "Funding Information: This work was supported by the Frazier Rehab Institute and Kentucky One Health, Kentucky Spinal Cord & Head Injury Research Trust Grant no. 11-7, National Institute of General Medical Sciences Grant 8 P30 GM-103507 , Helmsley Foundation Grant # 2011PG-MED011 , Commonwealth of Kentucky Challenge of Excellence Trust Fund, Owsley Brown Frazier Chair in Neurological Rehabilitation Endowment, Russian Foundation for Basic Research Grant 16-29-08173 ofi-m. Partial support for data analysis and results interpretation was provided for D.S. and Y.G. from the Russian Science Foundation (RSF, Grant No. 14-45-00024 ). The content is solely the responsibility of the authors and does not necessarily represent the official views of the granting agencies. Publisher Copyright: {\textcopyright} 2020 International Federation of Clinical Neurophysiology",

year = "2020",

month = jul,

doi = "10.1016/j.clinph.2020.03.021",

language = "English (US)",

volume = "131",

pages = "1519--1532",

journal = "Clinical Neurophysiology",

issn = "1388-2457",

publisher = "Elsevier Ireland Ltd",

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T1 - Interlimb conditioning of lumbosacral spinally evoked motor responses after spinal cord injury

AU - Atkinson, D. A.

AU - Sayenko, D. G.

AU - D'Amico, J. M.

AU - Mink, A.

AU - Lorenz, D. J.

AU - Gerasimenko, Y. P.

AU - Harkema, S.

N1 - Funding Information: This work was supported by the Frazier Rehab Institute and Kentucky One Health, Kentucky Spinal Cord & Head Injury Research Trust Grant no. 11-7, National Institute of General Medical Sciences Grant 8 P30 GM-103507 , Helmsley Foundation Grant # 2011PG-MED011 , Commonwealth of Kentucky Challenge of Excellence Trust Fund, Owsley Brown Frazier Chair in Neurological Rehabilitation Endowment, Russian Foundation for Basic Research Grant 16-29-08173 ofi-m. Partial support for data analysis and results interpretation was provided for D.S. and Y.G. from the Russian Science Foundation (RSF, Grant No. 14-45-00024 ). The content is solely the responsibility of the authors and does not necessarily represent the official views of the granting agencies. Publisher Copyright: © 2020 International Federation of Clinical Neurophysiology

PY - 2020/7

Y1 - 2020/7

N2 - Objective: The importance of subcortical pathways to functional motor recovery after spinal cord injury (SCI) has been demonstrated in multiple animal models. The current study evaluated descending interlimb influence on lumbosacral motor excitability after chronic SCI in humans. Methods: Ulnar nerve stimulation and transcutaneous electrical spinal stimulation were used in a condition-test paradigm to evaluate the presence of interlimb connections linking the cervical and lumbosacral spinal segments in non-injured (n=15) and spinal cord injured (SCI) (n=18) participants. Results: Potentiation of spinally evoked motor responses (sEMRs) by ulnar nerve conditioning was observed in 7/7 SCI participants with volitional leg muscle activation, and in 6/11 SCI participants with no volitional activation. Of these six, conditioning of sEMRs was present only when the neurological level of injury was rostral to the ulnar innervation entry zones. Conclusions: Descending modulation of lumbosacral motor pools via interlimb projections may exist in SCI participants despite the absence of volitional leg muscle activation. Significance: Evaluation of sub-clinical, spared pathways within the spinal cord after SCI may provide an improved understanding of both the contributions of different pathways to residual function, and the mechanisms of plasticity and functional motor recovery following rehabilitation.

AB - Objective: The importance of subcortical pathways to functional motor recovery after spinal cord injury (SCI) has been demonstrated in multiple animal models. The current study evaluated descending interlimb influence on lumbosacral motor excitability after chronic SCI in humans. Methods: Ulnar nerve stimulation and transcutaneous electrical spinal stimulation were used in a condition-test paradigm to evaluate the presence of interlimb connections linking the cervical and lumbosacral spinal segments in non-injured (n=15) and spinal cord injured (SCI) (n=18) participants. Results: Potentiation of spinally evoked motor responses (sEMRs) by ulnar nerve conditioning was observed in 7/7 SCI participants with volitional leg muscle activation, and in 6/11 SCI participants with no volitional activation. Of these six, conditioning of sEMRs was present only when the neurological level of injury was rostral to the ulnar innervation entry zones. Conclusions: Descending modulation of lumbosacral motor pools via interlimb projections may exist in SCI participants despite the absence of volitional leg muscle activation. Significance: Evaluation of sub-clinical, spared pathways within the spinal cord after SCI may provide an improved understanding of both the contributions of different pathways to residual function, and the mechanisms of plasticity and functional motor recovery following rehabilitation.

KW - Human spinal cord injury

KW - Interlimb pathways

KW - Motor assessment

KW - Neurophysiology

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Interlimb conditioning of lumbosacral spinally evoked motor responses after spinal cord injury

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