Journal article
Changes in intra‐ and interlimb reflexes from forelimb cutaneous afferents after staggered thoracic lateral hemisections during locomotion in cats
The Journal of physiology
27 Sep 2024
PMID: 39340178
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Abstract
Abstract In quadrupeds, such as cats, cutaneous afferents from the forepaw dorsum signal external perturbations and send inputs to spinal circuits to co‐ordinate the activity in muscles of all four limbs. How these cutaneous reflex pathways from forelimb afferents are reorganized after an incomplete spinal cord injury is not clear. Using a staggered thoracic lateral hemisections paradigm, we investigated changes in intralimb and interlimb reflex pathways by electrically stimulating the left and right superficial radial nerves in seven adult cats and recording reflex responses in five forelimb and ten hindlimb muscles. After the first (right T5–T6) and second (left T10–T11) hemisections, forelimb–hindlimb co‐ordination was altered and weakened. After the second hemisection, cats required balance assistance to perform quadrupedal locomotion. Short‐, mid‐ and long‐latency homonymous and crossed reflex responses in forelimb muscles and their phase modulation remained largely unaffected after staggered hemisections. The occurrence of homolateral and diagonal mid‐ and long‐latency responses in hindlimb muscles evoked with left and right superficial radial nerve stimulation was significantly reduced at the first time point after the first hemisection, but partially recovered at the second time point with left superficial radial nerve stimulation. These responses were lost or reduced after the second hemisection. When present, all reflex responses, including homolateral and diagonal, maintained their phase‐dependent modulation. Therefore, our results show a considerable loss in cutaneous reflex transmission from cervical to lumbar levels after incomplete spinal cord injury, albeit with preservation of phase modulation, probably affecting functional responses to external perturbations. image Key points Cutaneous afferent inputs co‐ordinate muscle activity in the four limbs during locomotion when the forepaw dorsum contacts an obstacle. Thoracic spinal cord injury disrupts communication between spinal locomotor centres located at cervical and lumbar levels, impairing balance and limb co‐ordination. We investigated cutaneous reflexes from forelimb afferents during quadrupedal locomotion by electrically stimulating the superficial radial nerve bilaterally, before and after staggered lateral thoracic hemisections in cats. We showed a loss/reduction of mid‐ and long‐latency homolateral and diagonal reflex responses in hindlimb muscles early after the first hemisection that partially recovered with left superficial radial nerve stimulation, before being reduced after the second hemisection. Targeting cutaneous reflex pathways from forelimb afferents projecting to the four limbs could help develop therapeutic approaches aimed at restoring transmission in ascending and descending spinal pathways.
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Details
- Title
- Changes in intra‐ and interlimb reflexes from forelimb cutaneous afferents after staggered thoracic lateral hemisections during locomotion in cats
- Creators
- Stephen Mari - Centre Hospitalier Universitaire de SherbrookeCharly G. Lecomte - Centre Hospitalier Universitaire de SherbrookeAngèle N. Merlet - Centre Hospitalier Universitaire de SherbrookeJohannie Audet - Centre Hospitalier Universitaire de SherbrookeSirine Yassine - Université de SherbrookeRasha Al Arab - Centre Hospitalier Universitaire de SherbrookeJonathan Harnie - Centre Hospitalier Universitaire de SherbrookeIlya A. Rybak - Drexel UniversityBoris I. Prilutsky - Georgia Institute of TechnologyAlain Frigon - Centre Hospitalier Universitaire de Sherbrooke
- Publication Details
- The Journal of physiology
- Publisher
- WILEY; HOBOKEN
- Number of pages
- 34
- Grant note
- National Institutes of Health: R01 NS110550
This work was supported by a grant from the National Institutes of Health: R01 NS110550 to AF, IAR and BIP. AF is a Fonds de Recherche-Sante Quebec (FRQS) Senior Research Scholar. JA and JH were supported by FRQS doctoral scholarships and ANM by a FRQS postdoctoral scholarship.
- Resource Type
- Journal article
- Language
- English
- Academic Unit
- Neurobiology and Anatomy
- Web of Science ID
- WOS:001320519000001
- Scopus ID
- 2-s2.0-85205061965
- Other Identifier
- 991021905615404721
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- Collaboration types
- Domestic collaboration
- International collaboration
- Web of Science research areas
- Neurosciences
- Physiology