MCP extensors respond faster than flexors in individuals with severe-to-moderate stroke-caused impairment: Evidence of uncoupled neural pathways
Damage in the corticospinal system following stroke produces imbalance between flexors and extensors in the upper extremity, eventually leading to flexion-favored postures. The substitution of alternative tracts for the damaged corticospinal tract is known to excessively activate flexors of the fing...
| Main Authors: | , , , |
|---|---|
| Format: | Article |
| Language: | English |
| Published: |
Frontiers Media S.A.
2023-03-01
|
| Series: | Frontiers in Neurology |
| Subjects: | |
| Online Access: | https://www.frontiersin.org/articles/10.3389/fneur.2023.1119761/full |
| _version_ | 1797866015086870528 |
|---|---|
| author | Dongwon Kim Dongwon Kim Raziyeh Baghi Kyung Koh Li-Qun Zhang Li-Qun Zhang Li-Qun Zhang |
| author_facet | Dongwon Kim Dongwon Kim Raziyeh Baghi Kyung Koh Li-Qun Zhang Li-Qun Zhang Li-Qun Zhang |
| author_sort | Dongwon Kim |
| collection | DOAJ |
| description | Damage in the corticospinal system following stroke produces imbalance between flexors and extensors in the upper extremity, eventually leading to flexion-favored postures. The substitution of alternative tracts for the damaged corticospinal tract is known to excessively activate flexors of the fingers while the fingers are voluntarily being extended. Here, we questioned whether the cortical source or/and neural pathways of the flexors and extensors of the fingers are coupled and what factor of impairment influences finger movement. In this study, a total of seven male participants with severe-to-moderate impairment by a hemiplegic stroke conducted flexion and extension at the metacarpophalangeal (MCP) joints in response to auditory tones. We measured activation and de-activation delays of the flexor and extensor of the MCP joints on the paretic side, and force generation. All participants generated greater torque in the direction of flexion (p = 0.017). Regarding co-contraction, coupled activation of the extensor is also made during flexion in the similar way to coupled activation of the flexor made during extension. As opposite to our expectation, we observed that during extension, the extensor showed marginally significantly faster activation (p = 0.66) while it showed faster de-activation (p = 0.038), in comparison to activation and de-activation of the flexor during flexion. But movement smoothness was not affected by those factors. Our results imply that the cortical source and neural pathway for the extensors of the MCP joints are not coupled with those for the flexors of the MCP joints. |
| first_indexed | 2024-04-09T23:17:17Z |
| format | Article |
| id | doaj.art-307549feb30747cd9e3a0e246a800990 |
| institution | Directory Open Access Journal |
| issn | 1664-2295 |
| language | English |
| last_indexed | 2024-04-09T23:17:17Z |
| publishDate | 2023-03-01 |
| publisher | Frontiers Media S.A. |
| record_format | Article |
| series | Frontiers in Neurology |
| spelling | doaj.art-307549feb30747cd9e3a0e246a8009902023-03-22T05:31:24ZengFrontiers Media S.A.Frontiers in Neurology1664-22952023-03-011410.3389/fneur.2023.11197611119761MCP extensors respond faster than flexors in individuals with severe-to-moderate stroke-caused impairment: Evidence of uncoupled neural pathwaysDongwon Kim0Dongwon Kim1Raziyeh Baghi2Kyung Koh3Li-Qun Zhang4Li-Qun Zhang5Li-Qun Zhang6Department of Physical Therapy and Rehabilitation Science, University of Maryland, Baltimore, MD, United StatesDepartment of Bioengineering, School of Engineering, University of Maryland, College Park, MD, United StatesDepartment of Physical Therapy and Rehabilitation Science, University of Maryland, Baltimore, MD, United StatesDepartment of Physical Therapy and Rehabilitation Science, University of Maryland, Baltimore, MD, United StatesDepartment of Physical Therapy and Rehabilitation Science, University of Maryland, Baltimore, MD, United StatesDepartment of Bioengineering, School of Engineering, University of Maryland, College Park, MD, United StatesDepartment of Orthopedics, University of Maryland, Baltimore, MD, United StatesDamage in the corticospinal system following stroke produces imbalance between flexors and extensors in the upper extremity, eventually leading to flexion-favored postures. The substitution of alternative tracts for the damaged corticospinal tract is known to excessively activate flexors of the fingers while the fingers are voluntarily being extended. Here, we questioned whether the cortical source or/and neural pathways of the flexors and extensors of the fingers are coupled and what factor of impairment influences finger movement. In this study, a total of seven male participants with severe-to-moderate impairment by a hemiplegic stroke conducted flexion and extension at the metacarpophalangeal (MCP) joints in response to auditory tones. We measured activation and de-activation delays of the flexor and extensor of the MCP joints on the paretic side, and force generation. All participants generated greater torque in the direction of flexion (p = 0.017). Regarding co-contraction, coupled activation of the extensor is also made during flexion in the similar way to coupled activation of the flexor made during extension. As opposite to our expectation, we observed that during extension, the extensor showed marginally significantly faster activation (p = 0.66) while it showed faster de-activation (p = 0.038), in comparison to activation and de-activation of the flexor during flexion. But movement smoothness was not affected by those factors. Our results imply that the cortical source and neural pathway for the extensors of the MCP joints are not coupled with those for the flexors of the MCP joints.https://www.frontiersin.org/articles/10.3389/fneur.2023.1119761/fullMCP jointsflexion synergyhand dexterityextensorstroke |
| spellingShingle | Dongwon Kim Dongwon Kim Raziyeh Baghi Kyung Koh Li-Qun Zhang Li-Qun Zhang Li-Qun Zhang MCP extensors respond faster than flexors in individuals with severe-to-moderate stroke-caused impairment: Evidence of uncoupled neural pathways Frontiers in Neurology MCP joints flexion synergy hand dexterity extensor stroke |
| title | MCP extensors respond faster than flexors in individuals with severe-to-moderate stroke-caused impairment: Evidence of uncoupled neural pathways |
| title_full | MCP extensors respond faster than flexors in individuals with severe-to-moderate stroke-caused impairment: Evidence of uncoupled neural pathways |
| title_fullStr | MCP extensors respond faster than flexors in individuals with severe-to-moderate stroke-caused impairment: Evidence of uncoupled neural pathways |
| title_full_unstemmed | MCP extensors respond faster than flexors in individuals with severe-to-moderate stroke-caused impairment: Evidence of uncoupled neural pathways |
| title_short | MCP extensors respond faster than flexors in individuals with severe-to-moderate stroke-caused impairment: Evidence of uncoupled neural pathways |
| title_sort | mcp extensors respond faster than flexors in individuals with severe to moderate stroke caused impairment evidence of uncoupled neural pathways |
| topic | MCP joints flexion synergy hand dexterity extensor stroke |
| url | https://www.frontiersin.org/articles/10.3389/fneur.2023.1119761/full |
| work_keys_str_mv | AT dongwonkim mcpextensorsrespondfasterthanflexorsinindividualswithseveretomoderatestrokecausedimpairmentevidenceofuncoupledneuralpathways AT dongwonkim mcpextensorsrespondfasterthanflexorsinindividualswithseveretomoderatestrokecausedimpairmentevidenceofuncoupledneuralpathways AT raziyehbaghi mcpextensorsrespondfasterthanflexorsinindividualswithseveretomoderatestrokecausedimpairmentevidenceofuncoupledneuralpathways AT kyungkoh mcpextensorsrespondfasterthanflexorsinindividualswithseveretomoderatestrokecausedimpairmentevidenceofuncoupledneuralpathways AT liqunzhang mcpextensorsrespondfasterthanflexorsinindividualswithseveretomoderatestrokecausedimpairmentevidenceofuncoupledneuralpathways AT liqunzhang mcpextensorsrespondfasterthanflexorsinindividualswithseveretomoderatestrokecausedimpairmentevidenceofuncoupledneuralpathways AT liqunzhang mcpextensorsrespondfasterthanflexorsinindividualswithseveretomoderatestrokecausedimpairmentevidenceofuncoupledneuralpathways |