Emergence of functionally aberrant and subsequent reduction of neuromuscular connectivity and improved motor performance after cervical spinal cord injury in Rhesus
Wai, Gregory (University of California)
Zdunowski, Sharon (University of California)
Zhong, Hui (Rancho Research Institute)
Nielson, Jessica L. (University of Minnesota)
Ferguson, Adam R. (University of California)
Strand, Sarah C. (University of California)
Moseanko, Rod (University of California)
Hawbecker, Stephanie (University of California)
Nout-Lomas, Yvette S. (Colorado State University)
Rosenzweig, Ephron S. (Veterans Administration Medical Center)
Beattie, Michael S. (University of California)
Bresnahan, Jacqueline C. (University of California)
Tuszynski, Mark H. (University of California)
Roy, Roland R. (University of California)
Edgerton, Victor (Institut Germans Trias i Pujol. Institut Guttmann)
Universitat Autònoma de Barcelona

Data:	2023
Resum:	The paralysis that occurs after a spinal cord injury, particularly during the early stages of post-lesion recovery (∼6 weeks), appears to be attributable to the inability to activate motor pools well beyond their motor threshold. In the later stages of recovery, however, the inability to perform a motor task effectively can be attributed to abnormal activation patterns among motor pools, resulting in poor coordination. We have tested this hypothesis on four adult male Rhesus monkeys (Macaca mulatta), ages 6-10 years, by recording the EMG activity levels and patterns of multiple proximal and distal muscles controlling the upper limb of the Rhesus when performing three tasks requiring different levels of skill before and up to 24 weeks after a lateral hemisection at C7. During the recovery period the animals were provided routine daily care, including access to a large exercise cage (5' × 7' × 10') and tested every 3-4 weeks for each of the three motor tasks. At approximately 6-8 weeks the animals were able to begin to step on a treadmill, perform a spring-loaded task with the upper limb, and reaching, grasping, and eating a grape placed on a vertical stick. The predominant changes that occurred, beginning at ∼6-8 weeks of the recovery of these tasks was an elevated level of activation of most motor pools well beyond the pre-lesion level. As the chronic phase progressed there was a slight reduction in the EMG burst amplitudes of some muscles and less incidence of co-contraction of agonists and antagonists, probably contributing to an improved ability to selectively activate motor pools in a more effective temporal pattern. Relative to pre-lesion, however, the EMG patterns even at the initial stages of recovery of successfully performing the different motor tasks, the level of activity of most muscle remained higher. Perhaps the most important concept that emerges from these data is the large combinations of adaptive strategies in the relative level of recruitment and the timing of the peak levels of activation of different motor pools can progressively provide different stages to regain a motor skill.
Drets:	Aquest document està subjecte a una llicència d'ús Creative Commons. Es permet la reproducció total o parcial, la distribució, la comunicació pública de l'obra i la creació d'obres derivades, fins i tot amb finalitats comercials, sempre i quan es reconegui l'autoria de l'obra original.
Llengua:	Anglès
Document:	Article ; recerca ; Versió publicada
Matèria:	EMG ; Motor performance ; Muscle activity patterns ; Spinal cord injury ; Spinal plasticity
Publicat a:	Frontiers in Rehabilitation Sciences, Vol. 4 (june 2023) , ISSN 2673-6861

DOI: 10.3389/fresc.2023.1205456
PMID: 37378049

14 p, 5.1 MB

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Documents de recerca > Documents dels grups de recerca de la UAB > Centres i grups de recerca (producció científica) > Ciències de la salut i biociències > Institut d'Investigació en Ciencies de la Salut Germans Trias i Pujol (IGTP)
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