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Accommodation of the Spinal Cat to a Tripping Perturbation

Adult cats with a complete spinal cord transection at T12–T13 can relearn over a period of days-to-weeks how to generate full weight-bearing stepping on a treadmill or standing ability if trained specifically for that task. In the present study, we assessed short-term (milliseconds to minutes) adapt...

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Autores principales: Zhong, Hui, Roy, Roland R., Nakada, Kenneth K., Zdunowski, Sharon, Khalili, Nicole, de Leon, Ray D., Edgerton, V. Reggie
Formato: Online Artículo Texto
Lenguaje:English
Publicado: Frontiers Research Foundation 2012
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3340914/
https://www.ncbi.nlm.nih.gov/pubmed/22557975
http://dx.doi.org/10.3389/fphys.2012.00112
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author Zhong, Hui
Roy, Roland R.
Nakada, Kenneth K.
Zdunowski, Sharon
Khalili, Nicole
de Leon, Ray D.
Edgerton, V. Reggie
author_facet Zhong, Hui
Roy, Roland R.
Nakada, Kenneth K.
Zdunowski, Sharon
Khalili, Nicole
de Leon, Ray D.
Edgerton, V. Reggie
author_sort Zhong, Hui
collection PubMed
description Adult cats with a complete spinal cord transection at T12–T13 can relearn over a period of days-to-weeks how to generate full weight-bearing stepping on a treadmill or standing ability if trained specifically for that task. In the present study, we assessed short-term (milliseconds to minutes) adaptations by repetitively imposing a mechanical perturbation on the hindlimb of chronic spinal cats by placing a rod in the path of the leg during the swing phase to trigger a tripping response. The kinematics and EMG were recorded during control (10 steps), trip (1–60 steps with various patterns), and then release (without any tripping stimulus, 10–20 steps) sequences. Our data show that the muscle activation patterns and kinematics of the hindlimb in the step cycle immediately following the initial trip (mechanosensory stimulation of the dorsal surface of the paw) was modified in a way that increased the probability of avoiding the obstacle in the subsequent step. This indicates that the spinal sensorimotor circuitry reprogrammed the trajectory of the swing following a perturbation prior to the initiation of the swing phase of the subsequent step, in effect “attempting” to avoid the re-occurrence of the perturbation. The average height of the release steps was elevated compared to control regardless of the pattern and the length of the trip sequences. In addition, the average impact force on the tripping rod tended to be lower with repeated exposure to the tripping stimulus. EMG recordings suggest that the semitendinosus, a primary knee flexor, was a major contributor to the adaptive tripping response. These results demonstrate that the lumbosacral locomotor circuitry can modulate the activation patterns of the hindlimb motor pools within the time frame of single step in a manner that tends to minimize repeated perturbations. Furthermore, these adaptations remained evident for a number of steps after removal of the mechanosensory stimulation.
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spelling pubmed-33409142012-05-03 Accommodation of the Spinal Cat to a Tripping Perturbation Zhong, Hui Roy, Roland R. Nakada, Kenneth K. Zdunowski, Sharon Khalili, Nicole de Leon, Ray D. Edgerton, V. Reggie Front Physiol Physiology Adult cats with a complete spinal cord transection at T12–T13 can relearn over a period of days-to-weeks how to generate full weight-bearing stepping on a treadmill or standing ability if trained specifically for that task. In the present study, we assessed short-term (milliseconds to minutes) adaptations by repetitively imposing a mechanical perturbation on the hindlimb of chronic spinal cats by placing a rod in the path of the leg during the swing phase to trigger a tripping response. The kinematics and EMG were recorded during control (10 steps), trip (1–60 steps with various patterns), and then release (without any tripping stimulus, 10–20 steps) sequences. Our data show that the muscle activation patterns and kinematics of the hindlimb in the step cycle immediately following the initial trip (mechanosensory stimulation of the dorsal surface of the paw) was modified in a way that increased the probability of avoiding the obstacle in the subsequent step. This indicates that the spinal sensorimotor circuitry reprogrammed the trajectory of the swing following a perturbation prior to the initiation of the swing phase of the subsequent step, in effect “attempting” to avoid the re-occurrence of the perturbation. The average height of the release steps was elevated compared to control regardless of the pattern and the length of the trip sequences. In addition, the average impact force on the tripping rod tended to be lower with repeated exposure to the tripping stimulus. EMG recordings suggest that the semitendinosus, a primary knee flexor, was a major contributor to the adaptive tripping response. These results demonstrate that the lumbosacral locomotor circuitry can modulate the activation patterns of the hindlimb motor pools within the time frame of single step in a manner that tends to minimize repeated perturbations. Furthermore, these adaptations remained evident for a number of steps after removal of the mechanosensory stimulation. Frontiers Research Foundation 2012-05-01 /pmc/articles/PMC3340914/ /pubmed/22557975 http://dx.doi.org/10.3389/fphys.2012.00112 Text en Copyright © 2012 Zhong, Roy, Nakada, Zdunowski, Khalili, de Leon and Edgerton. http://www.frontiersin.org/licenseagreement This is an open-access article distributed under the terms of the Creative Commons Attribution Non Commercial License, which permits non-commercial use, distribution, and reproduction in other forums, provided the original authors and source are credited.
spellingShingle Physiology
Zhong, Hui
Roy, Roland R.
Nakada, Kenneth K.
Zdunowski, Sharon
Khalili, Nicole
de Leon, Ray D.
Edgerton, V. Reggie
Accommodation of the Spinal Cat to a Tripping Perturbation
title Accommodation of the Spinal Cat to a Tripping Perturbation
title_full Accommodation of the Spinal Cat to a Tripping Perturbation
title_fullStr Accommodation of the Spinal Cat to a Tripping Perturbation
title_full_unstemmed Accommodation of the Spinal Cat to a Tripping Perturbation
title_short Accommodation of the Spinal Cat to a Tripping Perturbation
title_sort accommodation of the spinal cat to a tripping perturbation
topic Physiology
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3340914/
https://www.ncbi.nlm.nih.gov/pubmed/22557975
http://dx.doi.org/10.3389/fphys.2012.00112
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