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Kinany N, Khatibi A, Lungu O, Finsterbusch J, Büchel C, Marchand-Pauvert V, Ville DVD, Vahdat S, Doyon J. Decoding cerebro-spinal signatures of human behavior: application to motor sequence learning. Neuroimage 2023; 275:120174. [PMID: 37201642 DOI: 10.1016/j.neuroimage.2023.120174] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2023] [Revised: 05/12/2023] [Accepted: 05/15/2023] [Indexed: 05/20/2023] Open
Abstract
Mapping the neural patterns that drive human behavior is a key challenge in neuroscience. Even the simplest of our everyday actions stem from the dynamic and complex interplay of multiple neural structures across the central nervous system (CNS). Yet, most neuroimaging research has focused on investigating cerebral mechanisms, while the way the spinal cord accompanies the brain in shaping human behavior has been largely overlooked. Although the recent advent of functional magnetic resonance imaging (fMRI) sequences that can simultaneously target the brain and spinal cord has opened up new avenues for studying these mechanisms at multiple levels of the CNS, research to date has been limited to inferential univariate techniques that cannot fully unveil the intricacies of the underlying neural states. To address this, we propose to go beyond traditional analyses and instead use a data-driven multivariate approach leveraging the dynamic content of cerebro-spinal signals using innovation-driven coactivation patterns (iCAPs). We demonstrate the relevance of this approach in a simultaneous brain-spinal cord fMRI dataset acquired during motor sequence learning (MSL), to highlight how large-scale CNS plasticity underpins rapid improvements in early skill acquisition and slower consolidation after extended practice. Specifically, we uncovered cortical, subcortical and spinal functional networks, which were used to decode the different stages of learning with a high accuracy and, thus, delineate meaningful cerebro-spinal signatures of learning progression. Our results provide compelling evidence that the dynamics of neural signals, paired with a data-driven approach, can be used to disentangle the modular organization of the CNS. While we outline the potential of this framework to probe the neural correlates of motor learning, its versatility makes it broadly applicable to explore the functioning of cerebro-spinal networks in other experimental or pathological conditions.
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Affiliation(s)
- N Kinany
- Department of Radiology and Medical Informatics, University of Geneva, Geneva, 1211, Switzerland; Neuro-X Institute, École Polytechnique Fédérale de Lausanne (EPFL), Geneva, 1202, Switzerland.
| | - A Khatibi
- Center of Precision Rehabilitation for Spinal Pain, School of Sport, Exercise and Rehabilitation Sciences, College of Life and Environmental Sciences, University of Birmingham, Edgbaston, B15 2TT, United Kingdom
| | - O Lungu
- McConnell Brain Imaging Center, Department of Neurology and Neurosurgery, Montreal Neurological Institute, McGill University, Montreal, QC, Canada
| | - J Finsterbusch
- Department of Systems Neuroscience, University Medical Center Hamburg-Eppendorf, Germany
| | - C Büchel
- Department of Systems Neuroscience, University Medical Center Hamburg-Eppendorf, Germany
| | - V Marchand-Pauvert
- Sorbonne Université, Inserm, CNRS, Laboratoire d'Imagerie biomédicale, Paris F-75006, France
| | - D Van De Ville
- Department of Radiology and Medical Informatics, University of Geneva, Geneva, 1211, Switzerland; Neuro-X Institute, École Polytechnique Fédérale de Lausanne (EPFL), Geneva, 1202, Switzerland
| | - S Vahdat
- Department of Applied Physiology and Kinesiology, University of Florida, Gainesville, Florida, FL 32611, United States
| | - J Doyon
- McConnell Brain Imaging Center, Department of Neurology and Neurosurgery, Montreal Neurological Institute, McGill University, Montreal, QC, Canada
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Dukkipati SS, Walker SJ, Trevarrow MP, Busboom MT, Kurz MJ. Spinal cord H-reflex post-activation depression is linked with hand motor control in adults with cerebral palsy. Clin Neurophysiol 2023; 148:9-16. [PMID: 36773504 PMCID: PMC9998348 DOI: 10.1016/j.clinph.2023.01.004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2022] [Revised: 12/08/2022] [Accepted: 01/01/2023] [Indexed: 01/26/2023]
Abstract
OBJECTIVE Cerebral palsy (CP) is associated with upper extremity motor impairments that are largely assumed to arise from alterations in the supraspinal networks. The objective of this study was to determine if post-activation depression of the spinal H-reflexes is altered in adults with CP and connected with altered upper extremity function. METHODS The post-activation depression of the flexor carpi radialis (FCR) H-reflex of adults with CP and healthy adults (HA) controls were assessed by 1) a 1 Hz continuous single-pulse stimulus train and 2) 0.11 Hz / 1 Hz paired-pulse stimuli. Secondarily, we measured the maximum key grip force and the box and blocks assessment of manual dexterity. RESULTS Our results revealed that adults with CP had reduced post-activation depression of the FCR H-reflex during the stimulus train and the paired pulse protocol. A greater reduction in H-reflex post-activation depression was connected to lower manual dexterity and weaker grip forces. CONCLUSIONS Our results indicate that the post-activation depression of the upper extremity spinal H-reflex pathways is altered in adults with CP and possibly linked with their uncharacteristic upper extremity motor performance. Alterations in the spinal networks may also play a significant role in the altered motor control of adults with CP. SIGNIFICANCE Our results identify spinal H-reflex modulation as a possible locus for hand motor control in CP.
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Affiliation(s)
- Shekar S Dukkipati
- Institute for Human Neuroscience, Boys Town National Research Hospital, Omaha, NE, USA
| | - Sarah J Walker
- Institute for Human Neuroscience, Boys Town National Research Hospital, Omaha, NE, USA
| | - Michael P Trevarrow
- Institute for Human Neuroscience, Boys Town National Research Hospital, Omaha, NE, USA
| | - Morgan T Busboom
- Institute for Human Neuroscience, Boys Town National Research Hospital, Omaha, NE, USA
| | - Max J Kurz
- Institute for Human Neuroscience, Boys Town National Research Hospital, Omaha, NE, USA; Department of Pharmacology & Neuroscience, Creighton University, Omaha, NE, USA.
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Pascual-Valdunciel A, Kurukuti NM, Montero-Pardo C, Barroso FO, Pons JL. Modulation of spinal circuits following phase-dependent electrical stimulation of afferent pathways. J Neural Eng 2023; 20. [PMID: 36603216 DOI: 10.1088/1741-2552/acb087] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2022] [Accepted: 01/05/2023] [Indexed: 01/06/2023]
Abstract
Objective.Peripheral electrical stimulation (PES) of afferent pathways is a tool commonly used to induce neural adaptations in some neural disorders such as pathological tremor or stroke. However, the neuromodulatory effects of stimulation interventions synchronized with physiological activity (closed-loop strategies) have been scarcely researched in the upper-limb. Here, the short-term spinal effects of a 20-minute stimulation protocol where afferent pathways were stimulated with a closed-loop strategy named selective and adaptive timely stimulation (SATS) were explored in 11 healthy subjects.Approach. SATS was applied to the radial nerve in-phase (INP) or out-of-phase (OOP) with respect to the muscle activity of the extensor carpi radialis (ECR). The neural adaptations at the spinal cord level were assessed for the flexor carpi radialis (FCR) by measuring disynaptic Group I inhibition, Ia presynaptic inhibition, Ib facilitation from the H-reflex and estimation of the neural drive before, immediately after, and 30 minutes after the intervention.Main results.SATS strategy delivered electrical stimulation synchronized with the real-time muscle activity measured, with an average delay of 17 ± 8 ms. SATS-INP induced increased disynaptic Group I inhibition (77 ± 23% of baseline conditioned FCR H-reflex), while SATS-OOP elicited the opposite effect (125 ± 46% of baseline conditioned FCR H-reflex). Some of the subjects maintained the changes after 30 minutes. No other significant changes were found for the rest of measurements.Significance.These results suggest that the short-term modulatory effects of phase-dependent PES occur at specific targeted spinal pathways for the wrist muscles in healthy individuals. Importantly, timely recruitment of afferent pathways synchronized with specific muscle activity is a fundamental principle that shall be considered when tailoring PES protocols to modulate specific neural circuits. (NCT number 04501133).
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Affiliation(s)
- Alejandro Pascual-Valdunciel
- Legs & Walking AbilityLab, Shirley Ryan AbilityLab, Chicago, IL, United States of America.,Department of PM&R, Feinberg School of Medicine, Northwestern University, Chicago, IL, United States of America.,Neural Rehabilitation Group, Cajal Institute, Spanish National Research Council (CSIC), Madrid, Spain.,E.T.S. Ingenieros de Telecomunicación, Universidad Politécnica de Madrid, Madrid, Spain
| | - Nish Mohith Kurukuti
- Legs & Walking AbilityLab, Shirley Ryan AbilityLab, Chicago, IL, United States of America.,Department of Biomedical Engineering and Mechanical Engineering, McCormick School of Engineering, Northwestern University, Chicago, IL, United States of America
| | - Cristina Montero-Pardo
- Neural Rehabilitation Group, Cajal Institute, Spanish National Research Council (CSIC), Madrid, Spain.,Universidad Carlos III de Madrid, Madrid, Spain
| | - Filipe Oliveira Barroso
- Neural Rehabilitation Group, Cajal Institute, Spanish National Research Council (CSIC), Madrid, Spain
| | - José Luis Pons
- Legs & Walking AbilityLab, Shirley Ryan AbilityLab, Chicago, IL, United States of America.,Department of PM&R, Feinberg School of Medicine, Northwestern University, Chicago, IL, United States of America.,Department of Biomedical Engineering and Mechanical Engineering, McCormick School of Engineering, Northwestern University, Chicago, IL, United States of America
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4
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Khatibi A, Vahdat S, Lungu O, Finsterbusch J, Büchel C, Cohen-Adad J, Marchand-Pauvert V, Doyon J. Brain-spinal cord interaction in long-term motor sequence learning in human: An fMRI study. Neuroimage 2022; 253:119111. [PMID: 35331873 DOI: 10.1016/j.neuroimage.2022.119111] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2021] [Revised: 03/03/2022] [Accepted: 03/16/2022] [Indexed: 10/18/2022] Open
Abstract
The spinal cord is important for sensory guidance and execution of skilled movements. Yet its role in human motor learning is not well understood. Despite evidence revealing an active involvement of spinal circuits in the early phase of motor learning, whether long-term learning engages similar changes in spinal cord activation and functional connectivity remains unknown. Here, we investigated spinal-cerebral functional plasticity associated with learning of a specific sequence of visually-guided joystick movements (sequence task) over six days of training. On the first and last training days, we acquired high-resolution functional images of the brain and cervical cord simultaneously, while participants practiced the sequence or a random task while electromyography was recorded from wrist muscles. After six days of training, the subjects' motor performance improved in the sequence compared to the control condition. These behavioral changes were associated with decreased co-contractions and increased reciprocal activations between antagonist wrist muscles. Importantly, early learning was characterized by activation in the C8 level, whereas a more rostral activation in the C6-C7 was found during the later learning phase. Motor sequence learning was also supported by increased spinal cord functional connectivity with distinct brain networks, including the motor cortex, superior parietal lobule, and the cerebellum at the early stage, and the angular gyrus and cerebellum at a later stage of learning. Our results suggest that the early vs. late shift in spinal activation from caudal to rostral cervical segments synchronized with distinct brain networks, including parietal and cerebellar regions, is related to progressive changes reflecting the increasing fine control of wrist muscles during motor sequence learning.
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Affiliation(s)
- Ali Khatibi
- McConnell Brain Imaging Center, Montreal Neurological Institute, McGill University, Montreal, QC, Canada; Centre de recherche de l'Institut Universitaire de Gériatrie de Montréal, Montréal, QC, Canada; Centre of Precision Rehabilitation for Spinal Pain (CPR Spine), University of Birmingham, UK; Centre for Human Brain Health, University of Birmingham, UK.
| | - Shahabeddin Vahdat
- McConnell Brain Imaging Center, Montreal Neurological Institute, McGill University, Montreal, QC, Canada; Centre de recherche de l'Institut Universitaire de Gériatrie de Montréal, Montréal, QC, Canada; Department of Applied Physiology and Kinesiology, University of Florida, Gainesville, FL, USA
| | - Ovidiu Lungu
- McConnell Brain Imaging Center, Montreal Neurological Institute, McGill University, Montreal, QC, Canada; Centre de recherche de l'Institut Universitaire de Gériatrie de Montréal, Montréal, QC, Canada; Department of psychiatry and addictology, University of Montreal, Montreal, QC, Canada
| | - Jurgen Finsterbusch
- Department of Systems Neuroscience, University Medical Center Hamburg-Eppendorf, Germany
| | - Christian Büchel
- Department of Systems Neuroscience, University Medical Center Hamburg-Eppendorf, Germany
| | - Julien Cohen-Adad
- NeuroPoly Lab, Institute of Biomedical Engineering, Polytechnique Montreal, Montreal, QC, Canada; Functional Neuroimaging Unit, CRIUGM, University of Montreal, Montreal, QC, Canada; Mila Quebec AI Institute, Montreal, QC, Canada
| | | | - Julien Doyon
- McConnell Brain Imaging Center, Montreal Neurological Institute, McGill University, Montreal, QC, Canada; Centre de recherche de l'Institut Universitaire de Gériatrie de Montréal, Montréal, QC, Canada
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Effects of paired stimulation with specific waveforms on cortical and spinal plasticity in subjects with a chronic spinal cord injury. J Formos Med Assoc 2022; 121:2044-2056. [DOI: 10.1016/j.jfma.2022.02.016] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2021] [Revised: 12/13/2021] [Accepted: 02/17/2022] [Indexed: 12/16/2022] Open
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Xu J, Lopez AJ, Hoque MM, Borich MR, Kesar TM. Temporal Profile of Descending Cortical Modulation of Spinal Excitability: Group and Individual-Specific Effects. Front Integr Neurosci 2022; 15:777741. [PMID: 35197831 PMCID: PMC8859157 DOI: 10.3389/fnint.2021.777741] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2021] [Accepted: 12/21/2021] [Indexed: 11/16/2022] Open
Abstract
Sensorimotor control is modulated through complex interactions between descending corticomotor pathways and ascending sensory inputs. Pairing sub-threshold transcranial magnetic stimulation (TMS) with peripheral nerve stimulation (PNS) modulates the Hoffmann’s reflex (H-reflex), providing a neurophysiologic probe into the influence of descending cortical drive on spinal segmental circuits. However, individual variability in the timing and magnitude of H-reflex modulation is poorly understood. Here, we varied the inter-stimulus interval (ISI) between TMS and PNS to systematically manipulate the relative timing of convergence of descending TMS-induced volleys with respect to ascending PNS-induced afferent volleys in the spinal cord to: (1) characterize effective connectivity between the primary motor cortex (M1) and spinal circuits, mediated by both direct, fastest-conducting, and indirect, slower-conducting descending pathways; and (2) compare the effect of individual-specific vs. standard ISIs. Unconditioned and TMS-conditioned H-reflexes (24 different ISIs ranging from −6 to 12 ms) were recorded from the soleus muscle in 10 able-bodied individuals. The magnitude of H-reflex modulation at individualized ISIs (earliest facilitation delay or EFD and individual-specific peak facilitation) was compared with standard ISIs. Our results revealed a significant effect of ISI on H-reflex modulation. ISIs eliciting earliest-onset facilitation (EFD 0 ms) ranged from −3 to −5 ms across individuals. No difference in the magnitude of facilitation was observed at EFD 0 ms vs. a standardized short-interval ISI of −1.5 ms. Peak facilitation occurred at longer ISIs, ranging from +3 to +11 ms. The magnitude of H-reflex facilitation derived using an individual-specific peak facilitation was significantly larger than facilitation observed at a standardized longer-interval ISI of +10 ms. Our results suggest that unique insights can be provided with individual-specific measures of top-down effective connectivity mediated by direct and/or fastest-conducting pathways (indicated by the magnitude of facilitation observed at EFD 0 ms) and other descending pathways that encompass relatively slower and/or indirect connections from M1 to spinal circuits (indicated by peak facilitation and facilitation at longer ISIs). By comprehensively characterizing the temporal profile and inter-individual variability of descending modulation of spinal reflexes, our findings provide methodological guidelines and normative reference values to inform future studies on neurophysiological correlates of the complex array of descending neural connections between M1 and spinal circuits.
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Affiliation(s)
- Jiang Xu
- Department of Rehabilitation Medicine, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
- Division of Physical Therapy, Department of Rehabilitation Medicine, Emory University, Atlanta, GA, United States
| | - Alejandro J. Lopez
- Division of Physical Therapy, Department of Rehabilitation Medicine, Emory University, Atlanta, GA, United States
- Neuroscience Graduate Program, Graduate Division of Biological and Biomedical Sciences, Emory University, Atlanta, GA, United States
| | - Maruf M. Hoque
- Division of Physical Therapy, Department of Rehabilitation Medicine, Emory University, Atlanta, GA, United States
| | - Michael R. Borich
- Division of Physical Therapy, Department of Rehabilitation Medicine, Emory University, Atlanta, GA, United States
| | - Trisha M. Kesar
- Division of Physical Therapy, Department of Rehabilitation Medicine, Emory University, Atlanta, GA, United States
- *Correspondence: Trisha M. Kesar
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Effect of Long-Term Classical Ballet Dance Training on Postactivation Depression of the Soleus Hoffmann-Reflex. Motor Control 2022; 26:169-180. [PMID: 34986460 DOI: 10.1123/mc.2021-0079] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2021] [Revised: 11/01/2021] [Accepted: 11/05/2021] [Indexed: 11/18/2022]
Abstract
Classical ballet dancing is a good model for studying the long-term activity-dependent plasticity of the central nervous system in humans, as it requires unique ankle movements to maintain ballet postures. The purpose of this study was to investigate whether postactivation depression is changed through long-term specific motor training. Eight ballet dancers and eight sedentary subjects participated in this study. The soleus Hoffmann reflexes were elicited at after the completion of a slow, passive dorsiflexion of the ankle. The results demonstrated that the depression of the soleus Hoffmann reflex (i.e., postactivation depression) was larger in classical ballet dancers than in sedentary subjects at two poststretch intervals. This suggests that the plastic change through long-term specific motor training is also expressed in postactivation depression of the soleus Hoffmann reflex. Increased postactivation depression would strengthen the supraspinal control of the plantarflexors and may contribute to fine ankle movements in classical ballet dancers.
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Bertschinger R, Giboin LS, Gruber M. Endurance Trained Athletes Do Not per se Have Higher Hoffmann Reflexes Than Recreationally Active Controls. Front Physiol 2021; 12:736067. [PMID: 34867445 PMCID: PMC8633408 DOI: 10.3389/fphys.2021.736067] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2021] [Accepted: 10/21/2021] [Indexed: 11/13/2022] Open
Abstract
The impact of endurance training on spinal neural circuitries remains largely unknown. Some studies have reported higher H-reflexes in endurance trained athletes and therefore, adaptations within the Ia afferent pathways after long term endurance training have been suggested. In the present study we tested the hypothesis that cyclists (n = 12) demonstrate higher Hoffmann reflexes (H-reflexes) compared to recreationally active controls (n = 10). Notwithstanding, highly significant differences in endurance performance (VO2peak: 60.6 for cyclists vs. 46.3 ml/min/kg for controls (p < 0.001) there was no difference in the size of the SOL H-reflex between cyclists and controls (Hmax/Mmax ratio 61.3 vs. 60.0%, respectively (p = 0.840). Further analyses of the H and M recruitment curves for SOL revealed a significant steeper slope of the M recruitment curve in the group of cyclists (76.2 ± 3.8° vs. 72.0 ± 4.4°, p = 0.046) without a difference in the H-recruitment curve (84.6 ± 3.0° vs. 85.0 ± 2.8°, p = 0.784) compared to the control group. Cycling is classified as an endurance sport and thus the findings of the present study do not further support the assumption that long-term aerobic training leads to a general increase of the H-reflex. Amongst methodological differences in assessing the H-reflex, the training-specific sensorimotor control of the endurance sport itself might differently affect the responsiveness of spinal motoneurons on Ia-afferent inputs.
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Affiliation(s)
- Raphael Bertschinger
- Human Performance Research Centre, Department of Sport Science, University of Konstanz, Konstanz, Germany
| | - Louis-Solal Giboin
- Human Performance Research Centre, Department of Sport Science, University of Konstanz, Konstanz, Germany
| | - Markus Gruber
- Human Performance Research Centre, Department of Sport Science, University of Konstanz, Konstanz, Germany
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9
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Mendonça T, Brito R, Luna P, Campêlo M, Shirahige L, Fontes L, Dias R, Piscitelli D, Monte-Silva K. Repetitive transcranial magnetic stimulation on the modulation of cortical and spinal cord excitability in individuals with spinal cord injury. Restor Neurol Neurosci 2021; 39:291-301. [PMID: 34334434 DOI: 10.3233/rnn-211167] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
BACKGROUND Repetitive transcranial magnetic stimulation (rTMS) has been applied for modulating cortical excitability and treating spasticity in neurological lesions. However, it is unclear which rTMS frequency is most effective in modulating cortical and spinal excitability in incomplete spinal cord injury (SCI). OBJECTIVE To evaluate electrophysiological and clinical repercussions of rTMS compared to sham stimulation when applied to the primary motor cortex (M1) in individuals with incomplete SCI. METHODS A total of 11 subjects (35±12 years) underwent three experimental sessions of rTMS (10 Hz, 1 Hz and sham stimulation) in a randomized order at 90%intensity of the resting motor threshold and interspersed by a seven-day interval between sessions. The following outcome measures were evaluated: M1 and spinal cord excitability and spasticity in the moments before (baseline), immediately after (T0), 30 (T30) and 60 (T60) minutes after rTMS. M1 excitability was obtained through the motor evoked potential (MEP); spinal cord excitability by the Hoffman reflex (H-reflex) and homosynaptic depression (HD); and spasticity by the modified Ashworth scale (MAS). RESULTS A significant increase in cortical excitability was observed in subjects submitted to 10 Hz rTMS at the T0 moment when compared to sham stimulation (p = 0.008); this increase was also significant at T0 (p = 0.009), T30 (p = 0.005) and T60 (p = 0.005) moments when compared to the baseline condition. No significant differences were observed after the 10 Hz rTMS on spinal excitability or on spasticity. No inter-group differences were detected, or in the time after application of 1 Hz rTMS, or after sham stimulation for any of the assessed outcomes. CONCLUSIONS High-frequency rTMS applied to M1 was able to promote increased cortical excitability in individuals with incomplete SCI for at least 60 minutes; however, it did not modify spinal excitability or spasticity.
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Affiliation(s)
- Thyciane Mendonça
- Applied Neuroscience Laboratory, Department of Physical Therapy, Universidade Federal de Pernambuco, UFPE, Recife -PE -Brazil
| | - Rodrigo Brito
- Applied Neuroscience Laboratory, Department of Physical Therapy, Universidade Federal de Pernambuco, UFPE, Recife -PE -Brazil.,NAPeN Network (Núcleo de Assistência e Pesquisa em Neuromodulação), Brazil
| | - Plínio Luna
- Applied Neuroscience Laboratory, Department of Physical Therapy, Universidade Federal de Pernambuco, UFPE, Recife -PE -Brazil
| | - Mayara Campêlo
- Applied Neuroscience Laboratory, Department of Physical Therapy, Universidade Federal de Pernambuco, UFPE, Recife -PE -Brazil
| | - Lívia Shirahige
- Applied Neuroscience Laboratory, Department of Physical Therapy, Universidade Federal de Pernambuco, UFPE, Recife -PE -Brazil.,NAPeN Network (Núcleo de Assistência e Pesquisa em Neuromodulação), Brazil
| | - Luís Fontes
- Applied Neuroscience Laboratory, Department of Physical Therapy, Universidade Federal de Pernambuco, UFPE, Recife -PE -Brazil
| | - Rebeca Dias
- Applied Neuroscience Laboratory, Department of Physical Therapy, Universidade Federal de Pernambuco, UFPE, Recife -PE -Brazil
| | - Daniele Piscitelli
- School of Medicine and Surgery, University of Milano-Bicocca, Milano, Italy.,School of Physical and Occupational Therapy, McGill University, Montreal, Canada
| | - Kátia Monte-Silva
- Applied Neuroscience Laboratory, Department of Physical Therapy, Universidade Federal de Pernambuco, UFPE, Recife -PE -Brazil.,NAPeN Network (Núcleo de Assistência e Pesquisa em Neuromodulação), Brazil
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Giboin L, Tokuno C, Kramer A, Henry M, Gruber M. Motor learning induces time‐dependent plasticity that is observable at the spinal cord level. J Physiol 2020; 598:1943-1963. [DOI: 10.1113/jp278890] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2019] [Accepted: 02/28/2020] [Indexed: 01/22/2023] Open
Affiliation(s)
- Louis‐Solal Giboin
- Sensorimotor Performance Lab Human Performance Research Centre Department of Sport Science University of Konstanz Kinstanz Germany
| | - Craig Tokuno
- Department of Kinesiology Brock University St Catharines ON Canada
| | - Andreas Kramer
- Sensorimotor Performance Lab Human Performance Research Centre Department of Sport Science University of Konstanz Kinstanz Germany
| | - Mélanie Henry
- Laboratory of Applied Biology and Research Unit in Applied Neurophysiology ULB Neuroscience Institute Université libre de Bruxelles Bruxelles Belgium
| | - Markus Gruber
- Sensorimotor Performance Lab Human Performance Research Centre Department of Sport Science University of Konstanz Kinstanz Germany
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11
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Exploiting cervicolumbar connections enhances short-term spinal cord plasticity induced by rhythmic movement. Exp Brain Res 2019; 237:2319-2329. [PMID: 31286172 DOI: 10.1007/s00221-019-05598-9] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2019] [Accepted: 07/04/2019] [Indexed: 01/08/2023]
Abstract
Arm cycling causes suppression of soleus (SOL) Hoffmann (H-) reflex that outlasts the activity period. Arm cycling presumably activates propriospinal networks that modulate Ia presynaptic inhibition. Interlimb pathways are thought to relate to the control of quadrupedal locomotion, allowing for smooth, coordinated movement of the arms and legs. We examined whether the number of active limb pairs affects the amount and duration of activity-dependent plasticity of the SOL H-reflex. On separate days, 14 participants completed 4 randomly ordered 30 min experimental sessions: (1) quiet sitting (CTRL); (2) arm cycling (ARM); (3) leg cycling (LEG); and (4) arm and leg cycling (A&L) on an ergometer. SOL H-reflex and M-wave were evoked via electrical stimulation of the tibial nerve. M-wave and H-reflex recruitment curves were recorded, while the participants sat quietly prior to, 10 and 20 min into, immediately after, and at 2.5, 5, 7.5, 10, 15, 20, 25, and 30 min after each experimental session. Normalized maximal H-reflexes were unchanged in CTRL, but were suppressed by > 30% during the ARM, LEG, and A&L. H-reflex suppression outlasted activity duration for ARM (≤ 2.5 mins), LEG (≤ 5 mins), and A&L (≤ 30 mins). The duration of reflex suppression after A&L was greater than the algebraic summation of ARM and LEG. This non-linear summation suggests that using the arms and legs simultaneously-as in typical locomotor synergies-amplifies networks responsible for the short-term plasticity of lumbar spinal cord excitability. Enhanced activity of spinal networks may have important implications for the implementation of locomotor training for targeted rehabilitation.
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12
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Mortaza N, Moussavi Z, Stecina K, Salter JE, Passmore SR, Gardiner PF, Glazebrook CM. Effects of training with a neuro-mechano stimulator rehabilitation bicycle on functional recovery and paired-reflex depression of the soleus in individuals with incomplete paralysis: a proof-of-principle study. Int J Neurosci 2019; 129:1066-1075. [PMID: 31220973 DOI: 10.1080/00207454.2019.1634068] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
Aim: The present study describes the training effects of a novel motorized bicycle-like device for individuals with incomplete spinal cord injury. Methods: Participants were five individuals with motor incomplete spinal cord injury (56 ± 7 years). Four of five participants received two 30-min sessions of training: one with, and one without, mechanical stimulation on the plantar surface of the foot; soleus paired H-reflex depression was examined before and after each session. Three of five participants received 24 sessions of 30-min of training (long-training). Following the long-training, balance, walking and spasticity improvements were assessed using validated clinical outcome measures, in addition to the H-reflex assessment. Results: One cycling session with mechanical stimulation yielded 14% and 32% more reflex depression in participants with moderate spasticity (n = 2/4). The same trend was not observed in non-spastic participants (n = 2/4). All participants who participated in the long-training had spasticity and showed reduced spasticity, improved walking speed, endurance and balance. Conclusions: Overall, participants with spasticity showed increased soleus H-reflex suppression after one training session with mechanical stimulation and reduced spasticity scores after long training. We interpret this as evidence that the training influenced both presynaptic and postsynaptic inhibitory mechanisms acting on soleus motoneurons. Therefore, this training has the potential to be a non-invasive complementary therapy to reduce spasticity after incomplete spinal cord injury.
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Affiliation(s)
- Niyousha Mortaza
- Program of Biomedical Engineering, Faculty of Engineering, University of Manitoba , Winnipeg , Manitoba , Canada.,Program of Applied Health Sciences, University of Manitoba , Winnipeg , Manitoba , Canada.,Faculty of Kinesiology and Recreation Management, University of Manitoba , Winnipeg , Manitoba , Canada
| | - Zahra Moussavi
- Program of Biomedical Engineering, Faculty of Engineering, University of Manitoba , Winnipeg , Manitoba , Canada
| | - Katinka Stecina
- Program of Biomedical Engineering, Faculty of Engineering, University of Manitoba , Winnipeg , Manitoba , Canada.,Department of Physiology & Pathophysiology, University of Manitoba , Winnipeg , Manitoba , Canada.,Spinal cord Research Center, University of Manitoba , Winnipeg , Manitoba , Canada
| | - Jennifer E Salter
- Faculty of Medicine, Physical Medicine and Rehabilitation, University of Manitoba , Winnipeg , Manitoba , Canada
| | - Steven R Passmore
- Program of Applied Health Sciences, University of Manitoba , Winnipeg , Manitoba , Canada.,Faculty of Kinesiology and Recreation Management, University of Manitoba , Winnipeg , Manitoba , Canada.,Health, Leisure, and Human Performance Research Institute, University of Manitoba , Winnipeg , Manitoba , Canada
| | - Phillip F Gardiner
- Faculty of Kinesiology and Recreation Management, University of Manitoba , Winnipeg , Manitoba , Canada.,Department of Physiology & Pathophysiology, University of Manitoba , Winnipeg , Manitoba , Canada.,Spinal cord Research Center, University of Manitoba , Winnipeg , Manitoba , Canada.,Health, Leisure, and Human Performance Research Institute, University of Manitoba , Winnipeg , Manitoba , Canada
| | - Cheryl M Glazebrook
- Program of Biomedical Engineering, Faculty of Engineering, University of Manitoba , Winnipeg , Manitoba , Canada.,Program of Applied Health Sciences, University of Manitoba , Winnipeg , Manitoba , Canada.,Faculty of Kinesiology and Recreation Management, University of Manitoba , Winnipeg , Manitoba , Canada.,Health, Leisure, and Human Performance Research Institute, University of Manitoba , Winnipeg , Manitoba , Canada
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13
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Fernández-Lago H, Bello O, Salgado AV, Fernandez-del-Olmo M. Acute kinematic and neurophysiological effects of treadmill and overground walking in Parkinson’s disease. NeuroRehabilitation 2019; 44:433-443. [DOI: 10.3233/nre-182638] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Affiliation(s)
- Helena Fernández-Lago
- Faculty of Nursing and Physical Therapy, University of Lleida, Lleida, Spain
- Research Group of Health Care (GRECS), IRBLleida, Spain
| | - Olalla Bello
- Department of Physical Therapy, Faculty of Physical Therapy, University of A Coruña, A Coruña, Spain
| | - Antía Vidal Salgado
- Department of Physical Education, Faculty of Sciences of Sport and Physical Education, University of A Coruña, A Coruña, Spain
| | - Miguel Fernandez-del-Olmo
- Department of Physical Education, Faculty of Sciences of Sport and Physical Education, University of A Coruña, A Coruña, Spain
- Physical Education and Sports Area, University of Rey Juan Carlos, Madrid, Spain
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14
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Quilgars C, Bertrand SS. Activity-dependent synaptic dynamics in motor circuits of the spinal cord. CURRENT OPINION IN PHYSIOLOGY 2019. [DOI: 10.1016/j.cophys.2018.12.011] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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15
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Rocchi L, Suppa A, Leodori G, Celletti C, Camerota F, Rothwell J, Berardelli A. Plasticity Induced in the Human Spinal Cord by Focal Muscle Vibration. Front Neurol 2018; 9:935. [PMID: 30450077 PMCID: PMC6225532 DOI: 10.3389/fneur.2018.00935] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2018] [Accepted: 10/16/2018] [Indexed: 12/18/2022] Open
Abstract
The spinal cord spinal cord has in the past been considered a hardwired system which responds to inputs in a stereotyped way. A growing body of data have instead demonstrated its ability to retain information and modify its effector capabilities, showing activity-dependent plasticity. Whereas, plasticity in the spinal cord is well documented after different forms of physical exercise, whether exogenous stimulation can induce similar changes is still a matter of debate. This issue is both of scientific and clinical relevance, since at least one form of stimulation, i.e., focal muscle vibration (fMV), is currently used as a treatment for spasticity. The aim of the present study was to assess whether fMV can induce plasticity at the SC level when applied to different muscles of the upper limb. Changes in different electrophysiological measures, such as H-reflex testing homonymous and heteronymous pathways, reciprocal inhibition and somatosensory evoked potentials were used as outcomes. We found that fMV was able to induce long-term depression-like plasticity in specific spinal cord circuits depending on the muscle vibrated. These findings helped understand the basic mechanisms underlying the effects of fMV and might help to develop more advanced stimulation protocols.
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Affiliation(s)
- Lorenzo Rocchi
- Department of Clinical and Movement Neurosciences, UCL Queen Square Institute of Neurology, University College London, London, United Kingdom.,Department of Human Neurosciences, Sapienza University of Rome, Rome, Italy
| | - Antonio Suppa
- Department of Human Neurosciences, Sapienza University of Rome, Rome, Italy.,Department of Clinical Neurophysiology, IRCCS Neuromed Institute, Pozzilli, Italy
| | - Giorgio Leodori
- Department of Human Neurosciences, Sapienza University of Rome, Rome, Italy.,Department of Clinical Neurophysiology, IRCCS Neuromed Institute, Pozzilli, Italy
| | - Claudia Celletti
- Physical Medicine and Rehabilitation Division, Sapienza University of Rome, Rome, Italy
| | - Filippo Camerota
- Physical Medicine and Rehabilitation Division, Sapienza University of Rome, Rome, Italy
| | - John Rothwell
- Department of Clinical and Movement Neurosciences, UCL Queen Square Institute of Neurology, University College London, London, United Kingdom
| | - Alfredo Berardelli
- Department of Human Neurosciences, Sapienza University of Rome, Rome, Italy.,Department of Clinical Neurophysiology, IRCCS Neuromed Institute, Pozzilli, Italy
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16
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Albuquerque PL, Campêlo M, Mendonça T, Fontes LAM, Brito RDM, Monte-Silva K. Effects of repetitive transcranial magnetic stimulation and trans-spinal direct current stimulation associated with treadmill exercise in spinal cord and cortical excitability of healthy subjects: A triple-blind, randomized and sham-controlled study. PLoS One 2018; 13:e0195276. [PMID: 29596524 PMCID: PMC5875883 DOI: 10.1371/journal.pone.0195276] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2017] [Accepted: 03/18/2018] [Indexed: 11/18/2022] Open
Abstract
Repetitive transcranial magnetic stimulation (rTMS) over motor cortex and trans-spinal direct current stimulation (tsDCS) modulate corticospinal circuits in healthy and injured subjects. However, their associated effects with physical exercise is still not defined. This study aimed to investigate the effect of three different settings of rTMS and tsDCS combined with treadmill exercise on spinal cord and cortical excitability of healthy subjects. We performed a triple blind, randomized, sham-controlled crossover study with 12 healthy volunteers who underwent single sessions of rTMS (1Hz, 20Hz and Sham) and tsDCS (anodal, cathodal and Sham) associated with 20 minutes of treadmill walking. Cortical excitability was assessed by motor evoked potential (MEP) and spinal cord excitability by the Hoffmann reflex (Hr), nociceptive flexion reflex (NFR) and homosynaptic depression (HD). All measures were assessed before, immediately, 30 and 60 minutes after the experimental procedures. Our results demonstrated that anodal tsDCS/treadmill exercise reduced MEP's amplitude and NFR's area compared to sham condition, conversely, cathodal tsDCS/treadmill exercise increased NFR's area. High-frequency rTMS increased MEP's amplitude and NFR's area compared to sham condition. Anodal tsDCS/treadmill exercise and 20Hz rTMS/treadmill exercise reduced Hr amplitude up to 30 minutes after stimulation offset and no changes were observed in HD measures. We demonstrated that tsDCS and rTMS combined with treadmill exercise modulated cortical and spinal cord excitability through different mechanisms. tsDCS modulated spinal reflexes in a polarity-dependent way acting at local spinal circuits while rTMS probably promoted changes in the presynaptic inhibition of spinal motoneurons. In addition, the association of two neuromodulatory techniques induced long-lasting changes.
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Affiliation(s)
- Plínio Luna Albuquerque
- Applied Neuroscience Laboratory, Department of Physical Therapy, Universidade Federal de Pernambuco, Recife, Pernambuco, Brazil
- Department of Physical Therapy, Centro Universitário Tabosa de Almeida, Caruaru, Pernambuco, Brazil
- Postgraduate Program in Neuropsychiatry and Behavioral Sciences, Universidade Federal de Pernambuco, Recife, Pernambuco, Brazil
| | - Mayara Campêlo
- Applied Neuroscience Laboratory, Department of Physical Therapy, Universidade Federal de Pernambuco, Recife, Pernambuco, Brazil
- Postgraduate Program in Neuropsychiatry and Behavioral Sciences, Universidade Federal de Pernambuco, Recife, Pernambuco, Brazil
| | - Thyciane Mendonça
- Applied Neuroscience Laboratory, Department of Physical Therapy, Universidade Federal de Pernambuco, Recife, Pernambuco, Brazil
| | - Luís Augusto Mendes Fontes
- Applied Neuroscience Laboratory, Department of Physical Therapy, Universidade Federal de Pernambuco, Recife, Pernambuco, Brazil
| | - Rodrigo de Mattos Brito
- Applied Neuroscience Laboratory, Department of Physical Therapy, Universidade Federal de Pernambuco, Recife, Pernambuco, Brazil
| | - Katia Monte-Silva
- Applied Neuroscience Laboratory, Department of Physical Therapy, Universidade Federal de Pernambuco, Recife, Pernambuco, Brazil
- Postgraduate Program in Neuropsychiatry and Behavioral Sciences, Universidade Federal de Pernambuco, Recife, Pernambuco, Brazil
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17
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Functional Electrical Stimulation and Its Use During Cycling for the Rehabilitation of Individuals with Stroke. ACTA ACUST UNITED AC 2018. [DOI: 10.1007/978-3-319-72736-3_21] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register]
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18
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Ceballos-Villegas ME, Saldaña Mena JJ, Gutierrez Lozano AL, Sepúlveda-Cañamar FJ, Huidobro N, Manjarrez E, Lomeli J. The Complexity of H-wave Amplitude Fluctuations and Their Bilateral Cross-Covariance Are Modified According to the Previous Fitness History of Young Subjects under Track Training. Front Hum Neurosci 2017; 11:530. [PMID: 29163107 PMCID: PMC5671983 DOI: 10.3389/fnhum.2017.00530] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2017] [Accepted: 10/18/2017] [Indexed: 12/28/2022] Open
Abstract
The Hoffmann reflex (H-wave) is produced by alpha-motoneuron activation in the spinal cord. A feature of this electromyography response is that it exhibits fluctuations in amplitude even during repetitive stimulation with the same intensity of current. We herein explore the hypothesis that physical training induces plastic changes in the motor system. Such changes are evaluated with the fractal dimension (FD) analysis of the H-wave amplitude-fluctuations (H-wave FD) and the cross-covariance (CCV) between the bilateral H-wave amplitudes. The aim of this study was to compare the H-wave FD as well as the CCV before and after track training in sedentary individuals and athletes. The training modality in all subjects consisted of running three times per week (for 13 weeks) in a concrete road of 5 km. Given the different physical condition of sedentary vs. athletes, the running time between sedentary and athletes was different. After training, the FD was significantly increased in sedentary individuals but significantly reduced in athletes, although there were no changes in spinal excitability in either group of subjects. Moreover, the CCV between bilateral H-waves exhibited a significant increase in athletes but not in sedentary individuals. These differential changes in the FD and CCV indicate that the plastic changes in the complexity of the H-wave amplitude fluctuations as well as the synaptic inputs to the Ia-motoneuron systems of both legs were correlated to the previous fitness history of the subjects. Furthermore, these findings demonstrate that the FD and CCV can be employed as indexes to study plastic changes in the human motor system.
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Affiliation(s)
- Maria E Ceballos-Villegas
- Sección de Posgrado e Investigación, Laboratorio de Neurofisiología Humana y Control Motor, Escuela Superior de Medicina, Instituto Politécnico Nacional, Mexico City, Mexico
| | - Juan J Saldaña Mena
- Escuela de Quiropráctica, Universidad Estatal del Valle de Ecatepec, Ecatepec de Morelos, Mexico
| | - Ana L Gutierrez Lozano
- Sección de Posgrado e Investigación, Laboratorio de Neurofisiología Humana y Control Motor, Escuela Superior de Medicina, Instituto Politécnico Nacional, Mexico City, Mexico
| | | | - Nayeli Huidobro
- Instituto de Fisiología, Benemérita Universidad Autónoma de Puebla, Puebla, Mexico
| | - Elias Manjarrez
- Instituto de Fisiología, Benemérita Universidad Autónoma de Puebla, Puebla, Mexico
| | - Joel Lomeli
- Sección de Posgrado e Investigación, Laboratorio de Neurofisiología Humana y Control Motor, Escuela Superior de Medicina, Instituto Politécnico Nacional, Mexico City, Mexico
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19
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Kawaishi Y, Matsumoto N, Nishiwaki T, Hirano T. Postactivation depression of soleus H-reflex increase with recovery of lower extremities motor functions in patients with subacute stroke. J Phys Ther Sci 2017; 29:1539-1542. [PMID: 28931983 PMCID: PMC5599816 DOI: 10.1589/jpts.29.1539] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2017] [Accepted: 06/05/2017] [Indexed: 11/24/2022] Open
Abstract
[Purpose] The soleus H-reflex is depressed at stimulation rates greater than 0.1 Hz. This
reflex depression is referred to as postactivation depression. Postactivation depression
reflects the reduced efficacy of the Ia-motoneurons synapses when they are evaluated after
a previous activation. The aim of this study was to determine whether the recovery of
motor functions in the lower extremities affects the PAD of the soleus H-reflex in
patients with subacute stroke undergoing rehabilitation. [Subjects and Methods] Eight
patients with subacute stroke patients were recruited. Postactivation depression,
Fugl-Meyer score (lower-limb portion), walking velocity, the Modified Ashworth Scale, and
center of pressure sway during standing were measured within three days of admission to
rehabilitation and 50 days later. [Results] After rehabilitation, Fugl-Meyer scores,
center of pressure path length, and walking velocity were significantly improved, and
postactivation depression had significantly increased. There was a significant positive
correlation between the rates of change of postactivation depression and center of
pressure path length. [Conclusion] The results demonstrated that postactivation depression
is partially normalized after rehabilitation in patients with subacute stroke, and
suggested that the recovery in lower extremity function after stroke particularly standing
stability is affected by spinal synaptic plasticity.
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Affiliation(s)
- Yu Kawaishi
- Department of Rehabilitation, Kobe Rehabilitation Hospital: 14-1 Nakaichiriyama, Shimotanigami-Aza, Ymada-cho, Kita-ku, Kobe-shi, Hyogo 651-1102, Japan
| | - Naoki Matsumoto
- Department of Rehabilitation, Kobe Rehabilitation Hospital: 14-1 Nakaichiriyama, Shimotanigami-Aza, Ymada-cho, Kita-ku, Kobe-shi, Hyogo 651-1102, Japan
| | - Toshiya Nishiwaki
- Department of Rehabilitation, Kobe Rehabilitation Hospital: 14-1 Nakaichiriyama, Shimotanigami-Aza, Ymada-cho, Kita-ku, Kobe-shi, Hyogo 651-1102, Japan
| | - Tatsuro Hirano
- Department of Rehabilitation, Kobe Rehabilitation Hospital: 14-1 Nakaichiriyama, Shimotanigami-Aza, Ymada-cho, Kita-ku, Kobe-shi, Hyogo 651-1102, Japan
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20
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How plastic are human spinal cord motor circuitries? Exp Brain Res 2017; 235:3243-3249. [PMID: 28776155 DOI: 10.1007/s00221-017-5037-x] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2016] [Accepted: 07/17/2017] [Indexed: 12/27/2022]
Abstract
Human and animal studies have documented that neural circuitries in the spinal cord show adaptive changes caused by altered supraspinal and/or afferent input to the spinal circuitry in relation to learning, immobilization, injury and neurorehabilitation. Reversible adaptations following, e.g. the acquisition or refinement of a motor skill rely heavily on the functional integration between supraspinal and sensory inputs to the spinal cord networks. Accordingly, what is frequently conceived as a change in the spinal circuitry may be a change in either descending or afferent input or in the relative integration of these, i.e. a change in the neuronal weighting. This is evident from findings documenting only task-specific functional changes after periods of altered inputs whereas resting responses remain unaffected. In fact, the proximity of the spinal circuitry to the outer world may demand a more rigid organization compared to the highly flexible cortical circuits. The understanding of all of this is important for the planning and execution of neurorehabilitation.
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Piazza S, Gómez-Soriano J, Bravo-Esteban E, Torricelli D, Avila-Martin G, Galan-Arriero I, Pons JL, Taylor J. Maintenance of cutaneomuscular neuronal excitability after leg-cycling predicts lower limb muscle strength after incomplete spinal cord injury. Clin Neurophysiol 2016; 127:2402-9. [PMID: 27178859 DOI: 10.1016/j.clinph.2016.03.007] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2015] [Revised: 02/15/2016] [Accepted: 03/04/2016] [Indexed: 01/01/2023]
Abstract
OBJECTIVE Controlled leg-cycling modulates H-reflex activity after spinal cord injury (SCI). Preserved cutaneomuscular reflex activity is also essential for recovery of residual motor function after SCI. Here the effect of a single leg-cycling session was assessed on cutaneomuscular-conditioned H-reflex excitability in relation to residual lower limb muscle function after incomplete SCI (iSCI). METHODS Modulation of Soleus H-reflex activity was evaluated following ipsilateral plantar electrical stimulation applied at 25-100ms inter-stimulus intervals (ISI's), before and after leg-cycling in ten healthy individuals and nine subjects with iSCI. RESULTS Leg-cycling in healthy subjects increased cutaneomuscular-conditioned H-reflex excitability between 25 and 75ms ISI (p<0.001), compared to a small loss of excitability at 75ms ISI after iSCI (p<0.05). In addition, change in cutaneomuscular-conditioned H-reflex excitability at 50ms and 75ms ISI in subjects with iSCI after leg-cycling predicted lower ankle joint hypertonia and higher Triceps Surae muscle strength, respectively. CONCLUSION Leg-cycling modulates cutaneomuscular-conditioned spinal neuronal excitability in healthy subjects and individuals with iSCI, and is related to residual lower limb muscle function. SIGNIFICANCE Cutaneomuscular-conditioned H reflex modulation could be used as a surrogate biomarker of both central neuroplasticity and lower limb muscle function, and could benchmark lower-limb rehabilitation programs in subjects with iSCI.
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Affiliation(s)
- Stefano Piazza
- Neural Rehabilitation Group, Cajal Institute, CSIC, Madrid 28002, Spain.
| | - Julio Gómez-Soriano
- Sensorimotor Function Group, Hospital Nacional de Parapléjicos, Toledo 45072, Spain; Toledo Physiotherapy Research Group (GIFTO), Nursing and Physiotherapy School, Castilla La Mancha University, Toledo 45072, Spain.
| | - Elisabeth Bravo-Esteban
- Neural Rehabilitation Group, Cajal Institute, CSIC, Madrid 28002, Spain; Sensorimotor Function Group, Hospital Nacional de Parapléjicos, Toledo 45072, Spain; iPhysio Research Group, San Jorge University Zaragoza, Spain.
| | - Diego Torricelli
- Neural Rehabilitation Group, Cajal Institute, CSIC, Madrid 28002, Spain.
| | - Gerardo Avila-Martin
- Sensorimotor Function Group, Hospital Nacional de Parapléjicos, Toledo 45072, Spain.
| | - Iriana Galan-Arriero
- Sensorimotor Function Group, Hospital Nacional de Parapléjicos, Toledo 45072, Spain.
| | - José Luis Pons
- Neural Rehabilitation Group, Cajal Institute, CSIC, Madrid 28002, Spain.
| | - Julian Taylor
- Sensorimotor Function Group, Hospital Nacional de Parapléjicos, Toledo 45072, Spain; Stoke Mandeville Spinal Research, National Spinal Injuries Centre, Aylesbury HP218AL, UK; Harris Manchester College, University of Oxford, Oxford OX1 3TD, UK.
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22
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Burke D. Clinical uses of H reflexes of upper and lower limb muscles. Clin Neurophysiol Pract 2016; 1:9-17. [PMID: 30214954 PMCID: PMC6123946 DOI: 10.1016/j.cnp.2016.02.003] [Citation(s) in RCA: 94] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2016] [Accepted: 02/10/2016] [Indexed: 10/25/2022] Open
Abstract
H reflexes can be recorded from virtually all muscles that have muscle spindles, but reflex reinforcement may be required for the reflex response to be demonstrable. This can allow conduction across proximal nerve segments and most nerve root segments commonly involved by pathology. Stimulus rate is critical in subjects who are at rest. However the reflex attenuation with higher rates is greatly reduced during a background contraction of the test muscle, with only minor changes in latency if any. In addition the contraction ensures that the reflex response occurs in the desired muscle. Reflex latencies should be corrected for height (or limb length) and age. Because the reflex discharge requires a synchronised volley in group Ia afferents, large increases in reflex latency occur rarely with purely sensory lesions. If the H reflex of soleus, quadriceps femoris or flexor carpi radialis is absent at rest but appears during a voluntary contraction at near-normal latency, there is either low central excitability or a predominantly sensory abnormality. With the former H reflexes will be difficult to elicit throughout the body. If H reflexes can be recorded at rest from muscles for which no reflex can normally be demonstrated, there is good evidence for hyperreflexia. In the context of possible ALS, this is an important finding when there is EMG evidence of chronic partial denervation in that muscle.
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Alexeeva N, Calancie B. Efficacy of QuadroPulse rTMS for improving motor function after spinal cord injury: Three case studies. J Spinal Cord Med 2016; 39:50-7. [PMID: 25437531 PMCID: PMC4725792 DOI: 10.1179/2045772314y.0000000279] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/31/2022] Open
Abstract
CONTEXT/OBJECTIVE To examine the effects of repetitive QuadroPulse transcranial magnetic stimulation (rTMS(QP)) on hand/leg function after spinal cord injury (SCI). DESIGN Interventional proof-of-concept study. SETTING University laboratory. PARTICIPANTS Three adult subjects with cervical SCI. Interventions Repeated trains of magnetic stimuli were applied to the motor cortical hand/leg area. Several exploratory single-day rTMS(QP) protocols were examined. Ultimately we settled on a protocol using three 5-day trials of (1) rTMS(QP) only; (2) exercise only (targeting hand or leg function); and (3) rTMS(QP) combined with exercise. OUTCOME MEASURES Hand motor function was assessed by Purdue Pegboard and Complete Minnesota Dexterity tests. Walking function was based on treadmill walking and the Timed Up and Go test. Electromyographic recordings were used for neurophysiological testing of cortical (by single- and double-pulse TMS) and spinal (via tendon taps and electrical nerve stimulation) excitability. RESULTS Single-day rTMS(QP) application had no clear effect in the 2 subjects whose hand function was targeted, but improved walking speed in the person targeted for walking, accompanied by increased cortical excitability and reduced spinal excitability. All 3 subjects showed functional improvement following the 5-day rTMS(QP) intervention, an effect being even more pronounced after the five-day combined rTMS(QP) + exercise sessions. There were no rTMS(QP)-associated adverse effects. CONCLUSION Our findings suggest a functional benefit of motor cortical rTMS(QP) after SCI. The effect of rTMS(QP) appears to be augmented when stimulation is accompanied by targeted exercises, warranting expansion of this pilot study to a larger subject population.
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Affiliation(s)
| | - Blair Calancie
- Correspondence to: Blair Calancie, Department of Neurosurgery, SUNY Upstate Medical University, 750 E. Adams St, IHP #1213, Syracuse, NY 13210, USA.
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24
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Kubota S, Hirano M, Koizume Y, Tanabe S, Funase K. Changes in the Spinal Neural Circuits are Dependent on the Movement Speed of the Visuomotor Task. Front Hum Neurosci 2015; 9:667. [PMID: 26696873 PMCID: PMC4678204 DOI: 10.3389/fnhum.2015.00667] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2015] [Accepted: 11/23/2015] [Indexed: 12/02/2022] Open
Abstract
Previous studies have shown that spinal neural circuits are modulated by motor skill training. However, the effects of task movement speed on changes in spinal neural circuits have not been clarified. The aim of this research was to investigate whether spinal neural circuits were affected by task movement speed. Thirty-eight healthy subjects participated in this study. In experiment 1, the effects of task movement speed on the spinal neural circuits were examined. Eighteen subjects performed a visuomotor task involving ankle muscle slow (nine subjects) or fast (nine subjects) movement speed. Another nine subjects performed a non-visuomotor task (controls) in fast movement speed. The motor task training lasted for 20 min. The amounts of D1 inhibition and reciprocal Ia inhibition were measured using H-relfex condition-test paradigm and recorded before, and at 5, 15, and 30 min after the training session. In experiment 2, using transcranial magnetic stimulation (TMS), the effects of corticospinal descending inputs on the presynaptic inhibitory pathway were examined before and after performing either a visuomotor (eight subjects) or a control task (eight subjects). All measurements were taken under resting conditions. The amount of D1 inhibition increased after the visuomotor task irrespective of movement speed (P < 0.01). The amount of reciprocal Ia inhibition increased with fast movement speed conditioning (P < 0.01), but was unchanged by slow movement speed conditioning. These changes lasted up to 15 min in D1 inhibition and 5 min in reciprocal Ia inhibition after the training session. The control task did not induce changes in D1 inhibition and reciprocal Ia inhibition. The TMS conditioned inhibitory effects of presynaptic inhibitory pathways decreased following visuomotor tasks (P < 0.01). The size of test H-reflex was almost the same size throughout experiments. The results suggest that supraspinal descending inputs for controlling joint movement are responsible for changes in the spinal neural circuits, and that task movement speed is one of the critical factors for inducing plastic changes in reciprocal Ia inhibition.
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Affiliation(s)
- Shinji Kubota
- Human Motor Control Laboratory, Department of Human Sciences, Graduate School of Integrated Arts and Sciences, Hiroshima University Hiroshima, Japan ; Research Fellow of the Japan Society for the Promotion of Science Tokyo, Japan
| | - Masato Hirano
- Human Motor Control Laboratory, Department of Human Sciences, Graduate School of Integrated Arts and Sciences, Hiroshima University Hiroshima, Japan ; Research Fellow of the Japan Society for the Promotion of Science Tokyo, Japan
| | - Yoshiki Koizume
- Human Motor Control Laboratory, Department of Human Sciences, Graduate School of Integrated Arts and Sciences, Hiroshima University Hiroshima, Japan
| | - Shigeo Tanabe
- Faculty of Rehabilitation, School of Health Sciences, Fujita Health University Aichi, Japan
| | - Kozo Funase
- Human Motor Control Laboratory, Department of Human Sciences, Graduate School of Integrated Arts and Sciences, Hiroshima University Hiroshima, Japan
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Vahdat S, Lungu O, Cohen-Adad J, Marchand-Pauvert V, Benali H, Doyon J. Simultaneous Brain-Cervical Cord fMRI Reveals Intrinsic Spinal Cord Plasticity during Motor Sequence Learning. PLoS Biol 2015; 13:e1002186. [PMID: 26125597 PMCID: PMC4488354 DOI: 10.1371/journal.pbio.1002186] [Citation(s) in RCA: 65] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2015] [Accepted: 05/22/2015] [Indexed: 12/16/2022] Open
Abstract
The spinal cord participates in the execution of skilled movements by translating high-level cerebral motor representations into musculotopic commands. Yet, the extent to which motor skill acquisition relies on intrinsic spinal cord processes remains unknown. To date, attempts to address this question were limited by difficulties in separating spinal local effects from supraspinal influences through traditional electrophysiological and neuroimaging methods. Here, for the first time, we provide evidence for local learning-induced plasticity in intact human spinal cord through simultaneous functional magnetic resonance imaging of the brain and spinal cord during motor sequence learning. Specifically, we show learning-related modulation of activity in the C6–C8 spinal region, which is independent from that of related supraspinal sensorimotor structures. Moreover, a brain–spinal cord functional connectivity analysis demonstrates that the initial linear relationship between the spinal cord and sensorimotor cortex gradually fades away over the course of motor sequence learning, while the connectivity between spinal activity and cerebellum gains strength. These data suggest that the spinal cord not only constitutes an active functional component of the human motor learning network but also contributes distinctively from the brain to the learning process. The present findings open new avenues for rehabilitation of patients with spinal cord injuries, as they demonstrate that this part of the central nervous system is much more plastic than assumed before. Yet, the neurophysiological mechanisms underlying this intrinsic functional plasticity in the spinal cord warrant further investigations. Simultaneous neuroimaging of brain and spinal cord reveals intrinsic plasticity in the spinal cord during motor sequence learning in humans, independent from that of related sensorimotor structures in the brain. When we acquire a new motor skill—for example, learning how to play a musical instrument—new synaptic connections are induced in a distributed network of brain areas. There is ample evidence from human neuroimaging studies for this high plasticity of the brain, but what about the spinal cord, the main link between the brain and the peripheral nervous system? Literature on animal models has recently hinted that spinal cord neurons can learn during various conditioning paradigms. However, human learning models by tradition assume that the spinal cord acts as a passive relay of information from the cortex to the muscles. In this study, we simultaneously acquired functional images of both the brain and the cervical spinal cord through functional magnetic resonance imaging, and we provide evidence for local spinal cord plasticity during a well-studied motor learning task in humans. We also demonstrate a dynamic change in the interaction of the brain and spinal cord regions over the course of motor learning. The present findings have important clinical implications for rehabilitation of patients with spinal cord injuries, as they demonstrate that this part of the central nervous system is much more plastic than it was assumed before.
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Affiliation(s)
- Shahabeddin Vahdat
- Functional Neuroimaging Unit, University of Montreal, Montreal, Quebec, Canada
- SensoriMotor Rehabilitation Research Team (CIHR), Montreal, Canada
| | - Ovidiu Lungu
- Functional Neuroimaging Unit, University of Montreal, Montreal, Quebec, Canada
- SensoriMotor Rehabilitation Research Team (CIHR), Montreal, Canada
| | - Julien Cohen-Adad
- SensoriMotor Rehabilitation Research Team (CIHR), Montreal, Canada
- École Polytechnique de Montréal, Montreal, Quebec, Canada
| | | | - Habib Benali
- SensoriMotor Rehabilitation Research Team (CIHR), Montreal, Canada
- INSERM/UPMC, Pitié-Salpêtrière Hospital, Paris, France
| | - Julien Doyon
- Functional Neuroimaging Unit, University of Montreal, Montreal, Quebec, Canada
- SensoriMotor Rehabilitation Research Team (CIHR), Montreal, Canada
- * E-mail:
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Chang YJ, Chou CC, Huang WT, Lu CS, Wong AM, Hsu MJ. Cycling Regimen Induces Spinal Circuitry Plasticity and Improves Leg Muscle Coordination in Individuals With Spinocerebellar Ataxia. Arch Phys Med Rehabil 2015; 96:1006-13. [DOI: 10.1016/j.apmr.2015.01.021] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2014] [Revised: 01/12/2015] [Accepted: 01/26/2015] [Indexed: 10/24/2022]
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Sabatier MJ, Wedewer W, Barton B, Henderson E, Murphy JT, Ou K. Slope walking causes short-term changes in soleus H-reflex excitability. Physiol Rep 2015; 3:3/3/e12308. [PMID: 25742955 PMCID: PMC4393150 DOI: 10.14814/phy2.12308] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
Abstract
The purpose of this study was to test the hypothesis that downslope treadmill walking decreases spinal excitability. Soleus H-reflexes were measured in sixteen adults on 3 days. Measurements were taken before and twice after 20 min of treadmill walking at 2.5 mph (starting at 10 and 45 min post). Participants walked on a different slope each day [level (Lv), upslope (Us) or downslope (Ds)]. The tibial nerve was electrically stimulated with a range of intensities to construct the M-response and H-reflex curves. Maximum evoked responses (Hmax and Mmax) and slopes of the ascending limbs (Hslp and Mslp) of the curves were evaluated. Rate-dependent depression (RDD) was measured as the % depression of the H-reflex when measured at a rate of 1.0 Hz versus 0.1 Hz. Heart rate (HR), blood pressure (BP), and ratings of perceived exertion (RPE) were measured during walking. Ds and Lv walking reduced the Hmax/Mmax ratio (P = 0.001 & P = 0.02), although the reduction was larger for Ds walking (29.3 ± 6.2% vs. 6.8 ± 5.2%, P = 0.02). The reduction associated with Ds walking was correlated with physical activity level as measured via questionnaire (r = -0.52, P = 0.04). Us walking caused an increase in the Hslp/Mslp ratio (P = 0.03) and a decrease in RDD (P = 0.04). These changes recovered by 45 min. Exercise HR and BP were highest during Us walking. RPE was greater during Ds and Us walking compared to Lv walking, but did not exceed "Fairly light" for Ds walking. In conclusion, in healthy adults treadmill walking has a short-term effect on soleus H-reflex excitability that is determined by the slope of the treadmill surface.
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Affiliation(s)
- Manning J Sabatier
- Department of Rehabilitation Medicine, Emory University School of Medicine, Atlanta, Georgia
| | - Wesley Wedewer
- Department of Rehabilitation Medicine, Emory University School of Medicine, Atlanta, Georgia
| | - Ben Barton
- Department of Rehabilitation Medicine, Emory University School of Medicine, Atlanta, Georgia
| | - Eric Henderson
- Department of Rehabilitation Medicine, Emory University School of Medicine, Atlanta, Georgia
| | - John T Murphy
- Department of Rehabilitation Medicine, Emory University School of Medicine, Atlanta, Georgia
| | - Kar Ou
- Department of Rehabilitation Medicine, Emory University School of Medicine, Atlanta, Georgia
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Pathophysiology of spasticity: implications for neurorehabilitation. BIOMED RESEARCH INTERNATIONAL 2014; 2014:354906. [PMID: 25530960 PMCID: PMC4229996 DOI: 10.1155/2014/354906] [Citation(s) in RCA: 175] [Impact Index Per Article: 17.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/23/2014] [Revised: 07/11/2014] [Accepted: 09/09/2014] [Indexed: 11/18/2022]
Abstract
Spasticity is the velocity-dependent increase in muscle tone due to the exaggeration of stretch reflex. It is only one of the several components of the upper motor neuron syndrome (UMNS). The central lesion causing the UMNS disrupts the balance of supraspinal inhibitory and excitatory inputs directed to the spinal cord, leading to a state of disinhibition of the stretch reflex. However, the delay between the acute neurological insult (trauma or stroke) and the appearance of spasticity argues against it simply being a release phenomenon and suggests some sort of plastic changes, occurring in the spinal cord and also in the brain. An important plastic change in the spinal cord could be the progressive reduction of postactivation depression due to limb immobilization. As well as hyperexcitable stretch reflexes, secondary soft tissue changes in the paretic limbs enhance muscle resistance to passive displacements. Therefore, in patients with UMNS, hypertonia can be divided into two components: hypertonia mediated by the stretch reflex, which corresponds to spasticity, and hypertonia due to soft tissue changes, which is often referred as nonreflex hypertonia or intrinsic hypertonia. Compelling evidences state that limb mobilisation in patients with UMNS is essential to prevent and treat both spasticity and intrinsic hypertonia.
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Boudarham J, Roche N, Teixeira M, Hameau S, Robertson J, Bensmail D, Zory R. Relationship between neuromuscular fatigue and spasticity in chronic stroke patients: A pilot study. J Electromyogr Kinesiol 2014; 24:292-9. [DOI: 10.1016/j.jelekin.2013.11.006] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2013] [Revised: 10/10/2013] [Accepted: 11/26/2013] [Indexed: 10/25/2022] Open
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Knikou M, Mummidisetty CK. Locomotor training improves premotoneuronal control after chronic spinal cord injury. J Neurophysiol 2014; 111:2264-75. [PMID: 24598526 DOI: 10.1152/jn.00871.2013] [Citation(s) in RCA: 51] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
Spinal inhibition is significantly reduced after spinal cord injury (SCI) in humans. In this work, we examined if locomotor training can improve spinal inhibition exerted at a presynaptic level. Sixteen people with chronic SCI received an average of 45 training sessions, 5 days/wk, 1 h/day. The soleus H-reflex depression in response to low-frequency stimulation, presynaptic inhibition of soleus Ia afferent terminals following stimulation of the common peroneal nerve, and bilateral EMG recovery patterns were assessed before and after locomotor training. The soleus H reflexes evoked at 1.0, 0.33, 0.20, 0.14, and 0.11 Hz were normalized to the H reflex evoked at 0.09 Hz. Conditioned H reflexes were normalized to the associated unconditioned H reflex evoked with subjects seated, while during stepping both H reflexes were normalized to the maximal M wave evoked after the test H reflex at each bin of the step cycle. Locomotor training potentiated homosynaptic depression in all participants regardless the type of the SCI. Presynaptic facilitation of soleus Ia afferents remained unaltered in motor complete SCI patients. In motor incomplete SCIs, locomotor training either reduced presynaptic facilitation or replaced presynaptic facilitation with presynaptic inhibition at rest. During stepping, presynaptic inhibition was modulated in a phase-dependent manner. Locomotor training changed the amplitude of locomotor EMG excitability, promoted intralimb and interlimb coordination, and altered cocontraction between knee and ankle antagonistic muscles differently in the more impaired leg compared with the less impaired leg. The results provide strong evidence that locomotor training improves premotoneuronal control after SCI in humans at rest and during walking.
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Affiliation(s)
- Maria Knikou
- Sensory Motor Performance Program, Rehabilitation Institute of Chicago, Chicago, Illinois; Department of Physical Medicine and Rehabilitation, Northwestern University Feinberg Medical School, Chicago, Illinois; Graduate Center/The City University of New York, New York, New York; and Department of Physical Therapy, College of Staten Island, Staten Island, New York
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Trompetto C, Marinelli L, Mori L, Canneva S, Colombano F, Traverso E, Currà A, Abbruzzese G. The effect of age on post-activation depression of the upper limb H-reflex. Eur J Appl Physiol 2013; 114:359-64. [PMID: 24292018 DOI: 10.1007/s00421-013-2778-5] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2013] [Accepted: 11/16/2013] [Indexed: 11/24/2022]
Abstract
PURPOSE Post-activation depression (PaD) refers to the inhibition of the H-reflex induced by a preceding conditioning stimulus able to activate the afferents mediating the H-reflex itself. PaD can be investigated assessing the frequency-related depression of the H-reflex. This parameter, which is highly correlated to the severity of spasticity, has been used in the longitudinal assessment of spastic patients, in particular to assess the effect of drugs and rehabilitation over the years. However, in such longitudinal assessment, changes observed might be age related and not only disease related. The aim of this study was to investigate the possible age effects on PaD. METHODS The frequency-related depression of the flexor carpi radialis (FCR) H-reflex was examined in two groups of young (20 subjects; 28 ± 3 years) and aged (18 subjects; 69 ± 6 years) healthy subjects. PaD was evaluated by comparing the H-reflex amplitudes obtained with a stimulation frequency of 0.1 Hz with those obtained using higher frequencies (0.33-0.5-1-2 Hz). RESULTS The results showed that frequency-related depression of the FCR H-reflex is similar in young and elderly subjects at all frequencies, with the exception of 2 Hz. CONCLUSION Our study shows that ageing does not affect the frequency-related depression of the FCR H-reflex at the frequencies of 1 Hz or lower, supporting the reliability of this method to assess PaD in the clinical practice, particularly for the longitudinal assessment of spasticity. A decrease of GABA-ergic presynaptic inhibition seems to be the more likely explanation for the age-related changes that we observed at the frequency of 2 Hz.
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Affiliation(s)
- Carlo Trompetto
- Department of Neurosciences, Rehabilitation, Ophthalmology, Genetics, Maternal and Child Health, Institute of Neurology, University of Genova, Largo Daneo 3, 16132, Genoa, Italy
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Trompetto C, Marinelli L, Mori L, Cossu E, Zilioli R, Simonini M, Abbruzzese G, Baratto L. Postactivation depression changes after robotic-assisted gait training in hemiplegic stroke patients. Gait Posture 2013; 38:729-33. [PMID: 23570893 DOI: 10.1016/j.gaitpost.2013.03.011] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/10/2012] [Revised: 02/11/2013] [Accepted: 03/10/2013] [Indexed: 02/02/2023]
Abstract
Postactivation depression is decreased in patients with spasticity and partially restored by physical exercise in spinal cord injured patients. Up until now, the possibility to modulate postactivation depression with motor training has never been explored in subjects with spasticity following brain lesions. Postactivation depression, assessed as frequency related depression of soleus H-reflex, was investigated before and after robotic-assisted gait training in a group of seven subjects with spastic hemiparesis following hemispheric stroke. Patients received three sessions per week of robotic-assisted gait training for a period of 4 weeks (12 sessions in total). Postactivation depression was measured before the treatment (T0), after the first session (T1) and after the last session (T2). Postactivation depression was quantified as the ratio between H-reflex amplitude at 1 Hz and at 0.1 Hz. The greater the 1 Hz/0.1 Hz ratio, the smaller the postactivation depression. Following robotic-assisted gait training, the 1 Hz/0.1 Hz ratio decreased from 0.79±0.26 at T0 to 0.56±0.18 at T1 and 0.58±0.13 at T2. Post hoc analysis showed a significant difference between T0 and T1 and between T0 and T2, stating an increase of postactivation depression. No significant differences were found between T1 and T2. This study provides the first demonstration that physical exercise can determine a partial normalization of postactivation depression in hemiparetic patients with spasticity following unilateral hemispheric stroke.
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Affiliation(s)
- Carlo Trompetto
- Institute of Neurology, Department of Neurosciences, Rehabilitation, Ophthalmology, Genetics, Maternal and Child Health, University of Genova, Largo Daneo 3, 16132 Genova, Italy
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Bagce HF, Saleh S, Adamovich SV, Krakauer JW, Tunik E. Corticospinal excitability is enhanced after visuomotor adaptation and depends on learning rather than performance or error. J Neurophysiol 2012. [PMID: 23197454 DOI: 10.1152/jn.00304.2012] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
We used adaptation to high and low gains in a virtual reality setup of the hand to test competing hypotheses about the excitability changes that accompany motor learning. Excitability was assayed through changes in amplitude of motor evoked potentials (MEPs) in relevant hand muscles elicited with single-pulse transcranial magnetic stimulation (TMS). One hypothesis is that MEPs will either increase or decrease, directly reflecting the effect of low or high gain on motor output. The alternative hypothesis is that MEP changes are not sign dependent but rather serve as a marker of visuomotor learning, independent of performance or visual-to-motor mismatch (i.e., error). Subjects were required to make flexion movements of a virtual forefinger to visual targets. A gain of 1 meant that the excursions of their real finger and virtual finger matched. A gain of 0.25 ("low gain") indicated a 75% reduction in visual versus real finger displacement, a gain of 1.75 ("high gain") the opposite. MEP increases (>40%) were noted in the tonically activated task-relevant agonist muscle for both high- and low-gain perturbations after adaptation reached asymptote with kinematics matched to veridical levels. Conversely, only small changes in excitability occurred in a control task of pseudorandom gains that required adjustments to large errors but in which learning could not accumulate. We conclude that changes in corticospinal excitability are related to learning rather than performance or error.
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Affiliation(s)
- Hamid F Bagce
- Department of Rehabilitation and Movement Science, School of Health Related Professions, University of Medicine and Dentistry of New Jersey, Newark, New Jersey 07107, USA
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Teo W, Rodrigues J, Mastaglia F, Thickbroom G. Breakdown in central motor control can be attenuated by motor practice and neuro-modulation of the primary motor cortex. Neuroscience 2012; 220:11-8. [DOI: 10.1016/j.neuroscience.2012.06.048] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2012] [Revised: 06/19/2012] [Accepted: 06/19/2012] [Indexed: 11/25/2022]
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Activity-dependent plasticity of spinal circuits in the developing and mature spinal cord. Neural Plast 2012; 2012:964843. [PMID: 22900208 PMCID: PMC3415235 DOI: 10.1155/2012/964843] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2012] [Accepted: 06/12/2012] [Indexed: 01/29/2023] Open
Abstract
Part of the development and maturation of the central nervous system (CNS) occurs through interactions with the environment. Through physical activities and interactions with the world, an animal receives considerable sensory information from various sources. These sources can be internally (proprioceptive) or externally (such as touch and pressure) generated senses. Ample evidence exists to demonstrate that the sensory information originating from large diameter afferents (Ia fibers) have an important role in inducing essential functional and morphological changes for the maturation of both the brain and the spinal cord. The Ia fibers transmit sensory information generated by muscle activity and movement. Such use or activity-dependent plastic changes occur throughout life and are one reason for the ability to acquire new skills and learn new movements. However, the extent and particularly the mechanisms of activity-dependent changes are markedly different between a developing nervous system and a mature nervous system. Understanding these mechanisms is an important step to develop strategies for regaining motor function after different injuries to the CNS. Plastic changes induced by activity occur both in the brain and spinal cord. This paper reviews the activity-dependent changes in the spinal cord neural circuits during both the developmental stages of the CNS and in adulthood.
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Jessop T, DePaola A, Casaletto L, Englard C, Knikou M. Short-term plasticity of human spinal inhibitory circuits after isometric and isotonic ankle training. Eur J Appl Physiol 2012; 113:273-84. [DOI: 10.1007/s00421-012-2438-1] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2012] [Accepted: 05/29/2012] [Indexed: 12/18/2022]
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Giesebrecht S, van Duinen H, Todd G, Gandevia SC, Taylor JL. Training in a ballistic task but not a visuomotor task increases responses to stimulation of human corticospinal axons. J Neurophysiol 2012; 107:2485-92. [DOI: 10.1152/jn.01117.2010] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
Short periods of training in motor tasks can increase motor cortical excitability. This study investigated whether changes also occur at a subcortical level. Subjects trained in ballistic finger abduction or visuomotor tracking. The right index finger rotated around the metacarpophalangeal (MCP) joint in a splint. Surface EMG was recorded from the first dorsal interosseous. Transcranial magnetic stimulation over the back of the head (double-cone coil) elicited cervicomedullary motor evoked potentials (CMEPs) by stimulation of corticospinal axons. Responses were recorded from the relaxed muscle before, between, and after two sets of training. In study 1 ( n = 7), training comprised two sets of 150 maximal finger abductions. Feedback of acceleration was provided. With training, acceleration increased significantly. CMEPs increased to 248 ± 152% (± SD) of baseline immediately after training ( P = 0.007) but returned to control level (155 ± 141%) 10 min later. In study 2 ( n = 7), subjects matched MCP joint angle to a target path on a computer screen. After ∼30 min of training, tracking improved as shown by increased correlation between joint angle and the target pathway, reduced time lag, and reduced EMGrms. However, CMEPs remained unchanged. These results show that transmission through the corticospinal pathway at a spinal level increased after repeated ballistic movements but not after training in a visuomotor task. Thus, changes at a spinal level may contribute to improved performance in some motor tasks.
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Affiliation(s)
| | | | - Gabrielle Todd
- School of Pharmacy and Medical Sciences and Sansom Institute, University of South Australia, Adelaide, Australia
| | - Simon C. Gandevia
- Neuroscience Research Australia, Randwick, and
- The University of New South Wales, Kensington, New South Wales; and
| | - Janet L. Taylor
- Neuroscience Research Australia, Randwick, and
- The University of New South Wales, Kensington, New South Wales; and
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Winkler T, Mergner B, Szecsi J, Bender A, Straube A. Spinal and cortical activity-dependent plasticity following learning of complex arm movements in humans. Exp Brain Res 2012; 219:267-74. [PMID: 22476217 DOI: 10.1007/s00221-012-3086-8] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2012] [Accepted: 03/23/2012] [Indexed: 11/24/2022]
Abstract
Activity-dependent plasticity is a fundamental requirement for human motor learning, which takes place at several stages of the motor system and involves various mechanisms in neuronal circuitry. Here, we investigate parameters of cortical and spinal excitability before and immediately after a single session of locomotion-like arm training (LMT) or sequential visuo-motor learning (VMT). Both training paradigms focused especially on mainly activating the flexor carpi radialis muscle (FCR). The activity-dependent change in the excitability of FCR-associated neurons was investigated using standard transcranial magnetic stimulation, including analysis of motor-evoked potentials (MEP) amplitude, short-interval intracortical inhibition and intracortical facilitation (ICF). Furthermore, spinal plasticity was also assessed by means of homosynaptic FCR H-reflex depression (HD). LMT decreased HD and ICF. In contrast, VMT had no significant effect on cortical and spinal parameters. There was a nonsignificant tendency of an increase in MEP amplitudes after both interventions. This implies that human locomotor-related learning involves spinal mechanisms. Despite the decreasing importance of quadrupedal coordination in the course of evolution, these changes in transsynaptic plasticity may reflect a persisting locomotor memory-encoding function in the spinal circuitry of the human upper extremities. Evaluating FCR HD might be helpful for the evaluation and development of locomotor rehabilitation strategies.
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Affiliation(s)
- T Winkler
- Department of Neurology, Klinikum der Ludwig-Maximilians Universität München, Marchioninistr. 15, 81377 Munich, Germany.
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Roche N, Bussel B, Maier MA, Katz R, Lindberg P. Impact of precision grip tasks on cervical spinal network excitability in humans. J Physiol 2011; 589:3545-58. [PMID: 21606115 DOI: 10.1113/jphysiol.2011.206268] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Abstract
Motor skill acquisition in the lower limb may induce modifications of spinal network excitability. We hypothesized that short-term motor adaptation in precision grip tasks would also induce modifications of cervical spinal network excitability. In a first series of experiments, we studied the impact of two different precision grip force control tasks (a visuomotor force-tracking task and a control force task without visual feedback) on cervical spinal network excitability in healthy subjects. We separately tested the efficacy of two key components of the spinal circuitry: (i) presynaptic inhibition on flexor carpi radialis (FCR) Ia terminals, and (ii) disynaptic inhibition directed from extensor carpi radialis (ECR) to FCR. We found that disynaptic inhibition decreased temporarily after both force control tasks, independently of the presence of visual feedback. In contrast, the amount of presynaptic inhibition on FCR Ia terminals decreased only after the visuomotor force tracking task. This temporary decrease was correlated with improved tracking accuracy during the task (i.e. short-term motor adaptation). A second series of experiments confirmed these results and showed that the visuomotor force-tracking task resulted also in an increase of the Hmax/Mmax ratio and the slope of the ascending part of the H-reflex recruitment curve. In order to address the role of presynaptic inhibition in the motor adaptation process, we conducted a third series of experiments during which presynaptic inhibition was recorded before and after two consecutive sessions of visuomotor force tracking. The results showed that (i) improved tracking accuracy occurred during both sessions, and (ii) presynaptic inhibition decreased only after the first session of visuomotor force tracking. Taken together, these results suggest thus that the nature of the motor task performed has a specific impact on the excitability of these cervical spinal circuits. These findings also suggest that early motor adaptation is associated with a modulation of presynaptic Ia inhibition in the upper limb.
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Affiliation(s)
- N Roche
- ER-6 UPMC: Physiologie et physiopathologie de la motricité chez l'Homme-Médecine Physique et Réadaptation, Hôpital Pitié Salpêtrière, 75013 Paris, France.
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Abstract
The work of recent decades has shown that the nervous system changes continually throughout life. Activity-dependent central nervous system (CNS) plasticity has many different mechanisms and involves essentially every region, from the cortex to the spinal cord. This new knowledge radically changes the challenge of explaining learning and memory and greatly increases the relevance of the spinal cord. The challenge is now to explain how continual and ubiquitous plasticity accounts for the initial acquisition and subsequent stability of many different learned behaviors. The spinal cord has a key role because it is the final common pathway for all behavior and is a site of substantial plasticity. Furthermore, because it is simple, accessible, distant from the rest of the CNS, and directly connected to behavior, the spinal cord is uniquely suited for identifying sites and mechanisms of plasticity and for determining how they account for behavioral change. Experimental models based on spinal cord reflexes facilitate study of the gradual plasticity that makes possible most rapid learning phenomena. These models reveal principles and generate concepts that are likely to apply to learning and memory throughout the CNS. In addition, they offer new approaches to guiding activity-dependent plasticity so as to restore functions lost to injury or disease.
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Affiliation(s)
- Jonathan R Wolpaw
- Laboratory of Neural Injury and Repair, Wadsworth Center, New York State Department of Health, Albany, NY 12201-0509, USA.
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Neural control of locomotion and training-induced plasticity after spinal and cerebral lesions. Clin Neurophysiol 2010; 121:1655-68. [DOI: 10.1016/j.clinph.2010.01.039] [Citation(s) in RCA: 76] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2009] [Revised: 01/15/2010] [Accepted: 01/19/2010] [Indexed: 12/21/2022]
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Spinal DC stimulation in humans modulates post-activation depression of the H-reflex depending on current polarity. Clin Neurophysiol 2010; 121:957-61. [DOI: 10.1016/j.clinph.2010.01.014] [Citation(s) in RCA: 89] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2009] [Revised: 01/11/2010] [Accepted: 01/15/2010] [Indexed: 11/24/2022]
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White matter organization in cervical spinal cord relates differently to age and control of grip force in healthy subjects. J Neurosci 2010; 30:4102-9. [PMID: 20237280 DOI: 10.1523/jneurosci.5529-09.2010] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Diffusion tensor imaging (DTI) can be used to elucidate relations between CNS structure and function. We hypothesized that the degree of spinal white matter organization relates to the accuracy of control of grip force. Healthy subjects of different age were studied using DTI and visuomotor tracking of precision grip force. The latter is a prime component of manual dexterity. A regional analysis of spinal white matter [fractional anisotropy (FA)] across multiple cervical levels (C2-C3, C4-C5, and C6-C7) and in different regions of interest (left and right lateral or medial spinal cord) was performed. FA was highest at the C2-C3 level, higher on the right than the left side, and higher in the lateral than in the medial spinal cord (p < 0.001). FA of whole cervical spinal cord (C2-C7) was lower in subjects with high tracking error (r = -0.56, p = 0.004) and decreased with age (r = -0.63, p = 0.001). A multiple regression analysis revealed an independent contribution of each predictor (semipartial correlations: age, r = -0.55, p < 0.001; tracking error, r = -0.49, p = 0.003). The closest relation between FA and tracking error was found at the C6-C7 level in the lateral spinal cord, in which the corticospinal tract innervates spinal circuitry controlling hand and digit muscles. FA of the medial spinal cord correlated consistently with age across all cervical levels, whereas FA of the lateral spinal cord did not. The results suggest (1) a functionally relevant specialization of lateral spinal cord white matter and (2) an increased sensitivity to age-related decline in medial spinal cord white matter in healthy subjects.
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Lungu O, Frigon A, Piché M, Rainville P, Rossignol S, Doyon J. Changes in spinal reflex excitability associated with motor sequence learning. J Neurophysiol 2010; 103:2675-83. [PMID: 20237314 DOI: 10.1152/jn.00006.2010] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
There is ample evidence that motor sequence learning is mediated by changes in brain activity. Yet the question of whether this form of learning elicits changes detectable at the spinal cord level has not been addressed. To date, studies in humans have revealed that spinal reflex activity may be altered during the acquisition of various motor skills, but a link between motor sequence learning and changes in spinal excitability has not been demonstrated. To address this issue, we studied the modulation of H-reflex amplitude evoked in the flexor carpi radialis muscle of 14 healthy individuals between blocks of movements that involved the implicit acquisition of a sequence versus other movements that did not require learning. Each participant performed the task in three conditions: "sequence"-externally triggered, repeating and sequential movements, "random"-similar movements, but performed in an arbitrary order, and "simple"- involving alternating movements in a left-right or up-down direction only. When controlling for background muscular activity, H-reflex amplitude was significantly more reduced in the sequence (43.8 +/- 1.47%. mean +/- SE) compared with the random (38.2 +/- 1.60%) and simple (31.5 +/- 1.82%) conditions, while the M-response was not different across conditions. Furthermore, H-reflex changes were observed from the beginning of the learning process up to when subjects reached asymptotic performance on the motor task. Changes also persisted for >60 s after motor activity ceased. Such findings suggest that the excitability in some spinal reflex circuits is altered during the implicit learning process of a new motor sequence.
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Affiliation(s)
- Ovidiu Lungu
- Unité de Neuroimagerie Fonctionelle, Centre de Recherche de l'Institut Universitaire de Gériatrie de Montréal, Montréal, Quebec, Canada.
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Comparison of Single Bout Effects of Bicycle Training Versus Locomotor Training on Paired Reflex Depression of the Soleus H-Reflex After Motor Incomplete Spinal Cord Injury. Arch Phys Med Rehabil 2009; 90:1218-28. [DOI: 10.1016/j.apmr.2009.01.022] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2008] [Revised: 01/28/2009] [Accepted: 01/28/2009] [Indexed: 11/17/2022]
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McNulty PA, Jankelowitz SK, Wiendels TM, Burke D. Postactivation Depression of the Soleus H Reflex Measured Using Threshold Tracking. J Neurophysiol 2008; 100:3275-84. [PMID: 18922951 DOI: 10.1152/jn.90435.2008] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The interpretation of changes in the soleus H reflex is problematic in the face of reflex gain changes, a nonlinear input/output relationship for the motoneuron pool, and a nonhomogeneous response of different motoneurons to afferent inputs. By altering the stimulus intensity to maintain a constant reflex output, threshold tracking allows a relatively constant population of α-motoneurons to be studied. This approach was used to examine postactivation (“homosynaptic”) depression of the H reflex (HD) in 23 neurologically healthy subjects. The H reflex was elicited by tibial nerve stimulation at 0.05, 0.1, 0.3, 1, and 2 Hz at rest and during voluntary plantar flexion at 2.5, 5, and 10% of maximum. A computerized threshold tracking procedure was used to set the current needed to generate a target H reflex 10% of Mmax. The current needed to produce the target reflex increased with stimulus rate but not significantly beyond 1 Hz. In three subjects, the current needed to produce H reflexes of 5, 10, 15, and 20% Mmax at 0.3, 1, and 2 Hz increased with rate and with the size of the test H reflex. HD was significantly reduced during voluntary contractions. Using threshold tracking, HD was maximal at lower frequencies than previously emphasized, probably because HD is greater the larger the test H reflex. This would reinforce the greater sensitivity of small motoneurons to reflex inputs.
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Blicher JU, Nielsen JF. Cortical and spinal excitability changes after robotic gait training in healthy participants. Neurorehabil Neural Repair 2008; 23:143-9. [PMID: 19047360 DOI: 10.1177/1545968308317973] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
BACKGROUND Recent studies have proposed a role for robotic gait training in participants with acquired brain injury, but the effects on the excitability of cortical and spinal neurons even in healthy participants are uncertain. OBJECTIVE To investigate changes in corticospinal excitability in healthy participants after active and passive robotic gait training in a driven gait orthosis (DGO), the Lokomat. METHODS Thirteen healthy participants took part in 2 experiments. Each participant performed 20 minutes of active and passive gait training in a DGO. Motor evoked potentials (MEP), short-interval intracortical inhibition (SICI), intracortical facilitation (ICF), F-wave frequency, and Mmax were measured in the right tibialis anterior muscle before and after training. RESULTS Active training led to a decline in MEP amplitude and F-wave frequency. The MEP decline was associated with subjective muscle fatigue. Passive training induced a decrease in SICI lasting for 20 minutes after training. CONCLUSIONS The decline in MEP after active training is most likely because of central fatigue, whereas the decreased F-wave frequency might represent short-term plastic changes in the spinal cord. The decrease in SICI after passive training probably reflects a decrease in intracortical GABA activity, which could benefit the acquisition of new motor skills.
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Affiliation(s)
- Jakob U Blicher
- Hammel Neurorehabilitation and Research Centre, Aarhus University Hospital, Denmark.
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Impaired efficacy of spinal presynaptic mechanisms in spastic stroke patients. Brain 2008; 132:734-48. [DOI: 10.1093/brain/awn310] [Citation(s) in RCA: 79] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
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Suppression of soleus H-reflex amplitude is graded with frequency of rhythmic arm cycling. Exp Brain Res 2008; 193:297-306. [PMID: 19011847 DOI: 10.1007/s00221-008-1625-0] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2008] [Accepted: 10/14/2008] [Indexed: 10/21/2022]
Abstract
In humans, rhythmic arm cycling has been shown to significantly suppress the soleus H-reflex amplitude in stationary legs. The specific nature of the relationship between frequency of arm cycling and H-reflex modulation in the legs has not been explored. We speculated that the effect of arm cycling on reflexes in leg muscles is related to the neural control of arm movement; therefore, we hypothesized that a graded increase in arm cycling frequency would produce a graded suppression of the soleus H-reflex amplitude. We also hypothesized that a threshold frequency of arm cycling would be identified at which the H-reflex amplitude significantly differed from static control trials (i.e., the arms were stationary). Soleus H-reflexes were evoked in stationary legs with tibial nerve stimulation during both control and rhythmic arm cycling (0.03-2.0 Hz) trials. The results show a significant inverse linear relation between arm cycling frequency and soleus H-reflex amplitude (P<0.05). Soleus H-reflex amplitude significantly differed from control at an average threshold cycling frequency of 0.8 Hz. The results demonstrate that increased frequency of upper limb movement increases the intensity of interlimb influences on the neural activity in stationary legs. Further, a minimum threshold frequency of arm cycling is required to produce a significant effect. This suggests that achieving a threshold frequency of rhythmic arm movement may be important to incorporate in rehabilitation strategies to engage the appropriate interlimb neural pathways.
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