Bilateral Reflex Fluctuations during Rhythmic Movement of Remote Limb Pairs
The modulation of spinal cord excitability during rhythmic limb movement reflects the neuronal coordination underlying actions of the arms and legs. Integration of network activity in the spinal cord can be assessed by reflex variability between the limbs, an approach so far very little studied. The...
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| Format: | Article |
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Frontiers Media S.A.
2017-07-01
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| Series: | Frontiers in Human Neuroscience |
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| Online Access: | http://journal.frontiersin.org/article/10.3389/fnhum.2017.00355/full |
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| author | Rinaldo A. Mezzarane Rinaldo A. Mezzarane Tsuyoshi Nakajima Tsuyoshi Nakajima E. Paul Zehr E. Paul Zehr E. Paul Zehr E. Paul Zehr |
| author_facet | Rinaldo A. Mezzarane Rinaldo A. Mezzarane Tsuyoshi Nakajima Tsuyoshi Nakajima E. Paul Zehr E. Paul Zehr E. Paul Zehr E. Paul Zehr |
| author_sort | Rinaldo A. Mezzarane |
| collection | DOAJ |
| description | The modulation of spinal cord excitability during rhythmic limb movement reflects the neuronal coordination underlying actions of the arms and legs. Integration of network activity in the spinal cord can be assessed by reflex variability between the limbs, an approach so far very little studied. The present work addresses this question by eliciting Hoffmann (H-) reflexes in both limbs to assess if common drive onto bilateral pools of motoneurons influence spinal cord excitability simultaneously or with a delay between sides. A cross-covariance (CCV) sequence between reflexes in both arms or legs was evaluated under conditions providing common drive bilaterally through voluntary muscle contraction and/or rhythmic movement of the remote limbs. For H-reflexes in the flexor carpi radialis (FCR) muscle, either contraction of the FCR or leg cycling induced significant reduction in the amplitude of the peak at the zero lag in the CCV sequence, indicating independent variations in spinal excitability between both sides. In contrast, for H-reflexes in the soleus (SO) muscle, arm cycling revealed no reduction in the amplitude of the peak in the CCV sequence at the zero lag. This suggests a more independent control of the arms compared with the legs. These results provide new insights into the organization of human limb control in rhythmic activity and the behavior of bilateral reflex fluctuations under different motor tasks. From a functional standpoint, changes in the co-variability might reflect dynamic adjustments in reflex excitability that are subsumed under more global control features during locomotion. |
| first_indexed | 2024-04-14T07:16:55Z |
| format | Article |
| id | doaj.art-9c8f585ad2ed44ac8b5774580cb9974a |
| institution | Directory Open Access Journal |
| issn | 1662-5161 |
| language | English |
| last_indexed | 2024-04-14T07:16:55Z |
| publishDate | 2017-07-01 |
| publisher | Frontiers Media S.A. |
| record_format | Article |
| series | Frontiers in Human Neuroscience |
| spelling | doaj.art-9c8f585ad2ed44ac8b5774580cb9974a2022-12-22T02:06:16ZengFrontiers Media S.A.Frontiers in Human Neuroscience1662-51612017-07-011110.3389/fnhum.2017.00355261817Bilateral Reflex Fluctuations during Rhythmic Movement of Remote Limb PairsRinaldo A. Mezzarane0Rinaldo A. Mezzarane1Tsuyoshi Nakajima2Tsuyoshi Nakajima3E. Paul Zehr4E. Paul Zehr5E. Paul Zehr6E. Paul Zehr7Laboratory of Signal Processing and Motor Control, College of Physical Education, University of BrasíliaBrasília, BrazilRehabilitation Neuroscience Laboratory, School of Exercise Science, Physical, and Health Education, University of VictoriaVictoria, BC, CanadaRehabilitation Neuroscience Laboratory, School of Exercise Science, Physical, and Health Education, University of VictoriaVictoria, BC, CanadaDepartment of Integrative Physiology, Kyorin University School of MedicineTokyo, JapanRehabilitation Neuroscience Laboratory, School of Exercise Science, Physical, and Health Education, University of VictoriaVictoria, BC, CanadaHuman Discovery Science, International Collaboration on Repair Discoveries (ICORD)Vancouver, BC, CanadaCentre for Biomedical Research, University of VictoriaVictoria, BC, CanadaDivision of Medical Sciences, University of VictoriaVictoria, BC, CanadaThe modulation of spinal cord excitability during rhythmic limb movement reflects the neuronal coordination underlying actions of the arms and legs. Integration of network activity in the spinal cord can be assessed by reflex variability between the limbs, an approach so far very little studied. The present work addresses this question by eliciting Hoffmann (H-) reflexes in both limbs to assess if common drive onto bilateral pools of motoneurons influence spinal cord excitability simultaneously or with a delay between sides. A cross-covariance (CCV) sequence between reflexes in both arms or legs was evaluated under conditions providing common drive bilaterally through voluntary muscle contraction and/or rhythmic movement of the remote limbs. For H-reflexes in the flexor carpi radialis (FCR) muscle, either contraction of the FCR or leg cycling induced significant reduction in the amplitude of the peak at the zero lag in the CCV sequence, indicating independent variations in spinal excitability between both sides. In contrast, for H-reflexes in the soleus (SO) muscle, arm cycling revealed no reduction in the amplitude of the peak in the CCV sequence at the zero lag. This suggests a more independent control of the arms compared with the legs. These results provide new insights into the organization of human limb control in rhythmic activity and the behavior of bilateral reflex fluctuations under different motor tasks. From a functional standpoint, changes in the co-variability might reflect dynamic adjustments in reflex excitability that are subsumed under more global control features during locomotion.http://journal.frontiersin.org/article/10.3389/fnhum.2017.00355/fullcross-covariancevariabilityH-reflexhumanspinal cord |
| spellingShingle | Rinaldo A. Mezzarane Rinaldo A. Mezzarane Tsuyoshi Nakajima Tsuyoshi Nakajima E. Paul Zehr E. Paul Zehr E. Paul Zehr E. Paul Zehr Bilateral Reflex Fluctuations during Rhythmic Movement of Remote Limb Pairs Frontiers in Human Neuroscience cross-covariance variability H-reflex human spinal cord |
| title | Bilateral Reflex Fluctuations during Rhythmic Movement of Remote Limb Pairs |
| title_full | Bilateral Reflex Fluctuations during Rhythmic Movement of Remote Limb Pairs |
| title_fullStr | Bilateral Reflex Fluctuations during Rhythmic Movement of Remote Limb Pairs |
| title_full_unstemmed | Bilateral Reflex Fluctuations during Rhythmic Movement of Remote Limb Pairs |
| title_short | Bilateral Reflex Fluctuations during Rhythmic Movement of Remote Limb Pairs |
| title_sort | bilateral reflex fluctuations during rhythmic movement of remote limb pairs |
| topic | cross-covariance variability H-reflex human spinal cord |
| url | http://journal.frontiersin.org/article/10.3389/fnhum.2017.00355/full |
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