PMID- 34382840
OWN - NLM
STAT- MEDLINE
DCOM- 20211029
LR  - 20220902
IS  - 1522-1601 (Electronic)
IS  - 8750-7587 (Print)
IS  - 0161-7567 (Linking)
VI  - 131
IP  - 3
DP  - 2021 Sep 1
TI  - Recruitment order of motor neurons promoted by epidural stimulation in 
      individuals with spinal cord injury.
PG  - 1100-1110
LID - 10.1152/japplphysiol.00293.2021 [doi]
AB  - Spinal cord epidural stimulation (scES) combined with activity-based training can 
      promote motor function recovery in individuals with motor complete spinal cord 
      injury (SCI). The characteristics of motor neuron recruitment, which influence 
      different aspects of motor control, are still unknown when motor function is 
      promoted by scES. Here, we enrolled five individuals with chronic motor complete 
      SCI implanted with an scES unit to study the recruitment order of motor neurons 
      during standing enabled by scES. We recorded high-density electromyography 
      (HD-EMG) signals on the vastus lateralis muscle and inferred the order of 
      recruitment of motor neurons from the relation between amplitude and conduction 
      velocity of the scES-evoked EMG responses along the muscle fibers. Conduction 
      velocity of scES-evoked responses was modulated over time, whereas stimulation 
      parameters and standing condition remained constant, with average values ranging 
      between 3.0 +/- 0.1 and 4.4 +/- 0.3 m/s. We found that the human spinal circuitry 
      receiving epidural stimulation can promote both orderly (according to motor 
      neuron size) and inverse trends of motor neuron recruitment, and that the 
      engagement of spinal networks promoting rhythmic activity may favor orderly 
      recruitment trends. Conversely, the different recruitment trends did not appear 
      to be related with time since injury or scES implant, nor to the ability to 
      achieve independent knees extension, nor to the conduction velocity values. The 
      proposed approach can be implemented to investigate the effects of stimulation 
      parameters and training-induced neural plasticity on the characteristics of motor 
      neuron recruitment order, contributing to improve mechanistic understanding and 
      effectiveness of epidural stimulation-promoted motor recovery after SCI.NEW & 
      NOTEWORTHY After motor complete spinal cord injury, the human spinal cord 
      receiving epidural stimulation can promote both orderly and inverse trends of 
      motor neuron recruitment. The engagement of spinal networks involved in the 
      generation of rhythmic activity seems to favor orderly recruitment trends.
FAU - Ibanez, Jaime
AU  - Ibanez J
AD  - Department of Bioengineering, Imperial College London, London, UK.
AD  - Department of Clinical and Movement Neurosciences, Institute of Neurology, 
      University College London, London, UK.
FAU - Angeli, Claudia A
AU  - Angeli CA
AD  - Kentucky Spinal Cord Injury Research Center, University of Louisville, 
      Louisville, Kentucky.
AD  - Department of Bioengineering, University of Louisville, Louisville, Kentucky.
AD  - Frazier Rehabilitation Institute, University of Louisville Health, Louisville, 
      Kentucky.
FAU - Harkema, Susan J
AU  - Harkema SJ
AD  - Kentucky Spinal Cord Injury Research Center, University of Louisville, 
      Louisville, Kentucky.
AD  - Department of Bioengineering, University of Louisville, Louisville, Kentucky.
AD  - Frazier Rehabilitation Institute, University of Louisville Health, Louisville, 
      Kentucky.
AD  - Department of Neurological Surgery, University of Louisville, Louisville, 
      Kentucky.
FAU - Farina, Dario
AU  - Farina D
AUID- ORCID: 0000-0002-7883-2697
AD  - Department of Bioengineering, Imperial College London, London, UK.
FAU - Rejc, Enrico
AU  - Rejc E
AUID- ORCID: 0000-0001-9368-2220
AD  - Kentucky Spinal Cord Injury Research Center, University of Louisville, 
      Louisville, Kentucky.
AD  - Department of Neurological Surgery, University of Louisville, Louisville, 
      Kentucky.
LA  - eng
GR  - R01 EB007615/EB/NIBIB NIH HHS/United States
GR  - 1R01EB007615/NH/NIH HHS/United States
PT  - Journal Article
PT  - Research Support, N.I.H., Extramural
PT  - Research Support, Non-U.S. Gov't
DEP - 20210812
PL  - United States
TA  - J Appl Physiol (1985)
JT  - Journal of applied physiology (Bethesda, Md. : 1985)
JID - 8502536
SB  - IM
MH  - Electromyography
MH  - Epidural Space
MH  - Humans
MH  - Motor Neurons
MH  - Spinal Cord
MH  - *Spinal Cord Injuries
MH  - *Spinal Cord Stimulation
PMC - PMC8461808
OTO - NOTNLM
OT  - epidural stimulation
OT  - motor neuron
OT  - recruitment order
OT  - spinal cord injury
OT  - standing
COIS- No conflicts of interest, financial or otherwise, are declared by the authors.
EDAT- 2021/08/13 06:00
MHDA- 2021/10/30 06:00
PMCR- 2022/09/01
CRDT- 2021/08/12 12:16
PHST- 2021/08/13 06:00 [pubmed]
PHST- 2021/10/30 06:00 [medline]
PHST- 2021/08/12 12:16 [entrez]
PHST- 2022/09/01 00:00 [pmc-release]
AID - JAPPL-00293-2021 [pii]
AID - 10.1152/japplphysiol.00293.2021 [doi]
PST - ppublish
SO  - J Appl Physiol (1985). 2021 Sep 1;131(3):1100-1110. doi: 
      10.1152/japplphysiol.00293.2021. Epub 2021 Aug 12.