Central Plasticity of Cutaneous Afferents Is Associated with Nociceptive Hyperreflexia after Spinal Cord Injury in Rats

Electrical stimulations of dorsal cutaneous nerves (DCNs) at each lumbothoracic spinal level produce the bilateral cutaneus trunci muscle (CTM) reflex responses which consist of two temporal components: an early and late responses purportedly mediated by Aδ and C fibers, respectively. We have previo...

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Main Authors: Hyun Joon Lee, Patrick S. Malone, Jumi Chung, Jason M. White, Natalee Wilson, Jason Tidwell, Keith E. Tansey
Format: Article
Language:English
Published: Wiley 2019-01-01
Series:Neural Plasticity
Online Access:http://dx.doi.org/10.1155/2019/6147878
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author Hyun Joon Lee
Patrick S. Malone
Jumi Chung
Jason M. White
Natalee Wilson
Jason Tidwell
Keith E. Tansey
author_facet Hyun Joon Lee
Patrick S. Malone
Jumi Chung
Jason M. White
Natalee Wilson
Jason Tidwell
Keith E. Tansey
author_sort Hyun Joon Lee
collection DOAJ
description Electrical stimulations of dorsal cutaneous nerves (DCNs) at each lumbothoracic spinal level produce the bilateral cutaneus trunci muscle (CTM) reflex responses which consist of two temporal components: an early and late responses purportedly mediated by Aδ and C fibers, respectively. We have previously reported central projections of DCN A and C fibers and demonstrated that different projection patterns of those afferent types contributed to the somatotopic organization of CTM reflex responses. Unilateral hemisection spinal cord injury (SCI) was made at T10 spinal segments to investigate the plasticity of early and late CTM responses 6 weeks after injury. Both early and late responses were drastically increased in response to both ipsi- and contralateral DCN stimulations both above (T6 and T8) and below (T12 and L1) the levels of injury demonstrating that nociceptive hyperreflexia developed at 6 weeks following hemisection SCI. We also found that DCN A and C fibers centrally sprouted, expanded their projection areas, and increased synaptic terminations in both T7 and T13, which correlated with the size of hemisection injury. These data demonstrate that central sprouting of cutaneous afferents away from the site of injury is closely associated with enhanced responses of intraspinal signal processing potentially contributing to nociceptive hyperreflexia following SCI.
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spelling doaj-art-7874744189224c2cbcb35d91bcf3a13a2025-08-20T03:35:11ZengWileyNeural Plasticity2090-59041687-54432019-01-01201910.1155/2019/61478786147878Central Plasticity of Cutaneous Afferents Is Associated with Nociceptive Hyperreflexia after Spinal Cord Injury in RatsHyun Joon Lee0Patrick S. Malone1Jumi Chung2Jason M. White3Natalee Wilson4Jason Tidwell5Keith E. Tansey6Departments of Neurology and Physiology, Emory University School of Medicine, Atlanta GA 30322, USADepartments of Neurology and Physiology, Emory University School of Medicine, Atlanta GA 30322, USADepartments of Neurology and Physiology, Emory University School of Medicine, Atlanta GA 30322, USADepartment of Biomedical Engineering, Georgia Institute of Technology/Emory University, Atlanta, GA 30322, USADepartments of Neurology and Physiology, Emory University School of Medicine, Atlanta GA 30322, USADepartments of Neurology and Physiology, Emory University School of Medicine, Atlanta GA 30322, USADepartments of Neurology and Physiology, Emory University School of Medicine, Atlanta GA 30322, USAElectrical stimulations of dorsal cutaneous nerves (DCNs) at each lumbothoracic spinal level produce the bilateral cutaneus trunci muscle (CTM) reflex responses which consist of two temporal components: an early and late responses purportedly mediated by Aδ and C fibers, respectively. We have previously reported central projections of DCN A and C fibers and demonstrated that different projection patterns of those afferent types contributed to the somatotopic organization of CTM reflex responses. Unilateral hemisection spinal cord injury (SCI) was made at T10 spinal segments to investigate the plasticity of early and late CTM responses 6 weeks after injury. Both early and late responses were drastically increased in response to both ipsi- and contralateral DCN stimulations both above (T6 and T8) and below (T12 and L1) the levels of injury demonstrating that nociceptive hyperreflexia developed at 6 weeks following hemisection SCI. We also found that DCN A and C fibers centrally sprouted, expanded their projection areas, and increased synaptic terminations in both T7 and T13, which correlated with the size of hemisection injury. These data demonstrate that central sprouting of cutaneous afferents away from the site of injury is closely associated with enhanced responses of intraspinal signal processing potentially contributing to nociceptive hyperreflexia following SCI.http://dx.doi.org/10.1155/2019/6147878
spellingShingle Hyun Joon Lee
Patrick S. Malone
Jumi Chung
Jason M. White
Natalee Wilson
Jason Tidwell
Keith E. Tansey
Central Plasticity of Cutaneous Afferents Is Associated with Nociceptive Hyperreflexia after Spinal Cord Injury in Rats
Neural Plasticity
title Central Plasticity of Cutaneous Afferents Is Associated with Nociceptive Hyperreflexia after Spinal Cord Injury in Rats
title_full Central Plasticity of Cutaneous Afferents Is Associated with Nociceptive Hyperreflexia after Spinal Cord Injury in Rats
title_fullStr Central Plasticity of Cutaneous Afferents Is Associated with Nociceptive Hyperreflexia after Spinal Cord Injury in Rats
title_full_unstemmed Central Plasticity of Cutaneous Afferents Is Associated with Nociceptive Hyperreflexia after Spinal Cord Injury in Rats
title_short Central Plasticity of Cutaneous Afferents Is Associated with Nociceptive Hyperreflexia after Spinal Cord Injury in Rats
title_sort central plasticity of cutaneous afferents is associated with nociceptive hyperreflexia after spinal cord injury in rats
url http://dx.doi.org/10.1155/2019/6147878
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