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Dai Y, Cheng Y, Ge R, Chen K, Yang L. Exercise-induced adaptation of neurons in the vertebrate locomotor system. JOURNAL OF SPORT AND HEALTH SCIENCE 2024; 13:160-171. [PMID: 37914153 PMCID: PMC10980905 DOI: 10.1016/j.jshs.2023.10.006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/20/2023] [Revised: 09/20/2023] [Accepted: 10/07/2023] [Indexed: 11/03/2023]
Abstract
Vertebrate neurons are highly dynamic cells that undergo several alterations in their functioning and physiologies in adaptation to various external stimuli. In particular, how these neurons respond to physical exercise has long been an area of active research. Studies of the vertebrate locomotor system's adaptability suggest multiple mechanisms are involved in the regulation of neuronal activity and properties during exercise. In this brief review, we highlight recent results and insights from the field with a focus on the following mechanisms: (a) alterations in neuronal excitability during acute exercise; (b) alterations in neuronal excitability after chronic exercise; (c) exercise-induced changes in neuronal membrane properties via modulation of ion channel activity; (d) exercise-enhanced dendritic plasticity; and (e) exercise-induced alterations in neuronal gene expression and protein synthesis. Our hope is to update the community with a cellular and molecular understanding of the recent mechanisms underlying the adaptability of the vertebrate locomotor system in response to both acute and chronic physical exercise.
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Affiliation(s)
- Yue Dai
- Key Lab of Adolescent Health Assessment and Exercise Intervention of Ministry of Education, College of Physical Education and Health Care, East China Normal University, Shanghai 200241, China; Shanghai Key Laboratory of Multidimensional Information Processing, School of Communication and Electronic Engineering, East China Normal University, Shanghai 200241, China.
| | - Yi Cheng
- Key Lab of Adolescent Health Assessment and Exercise Intervention of Ministry of Education, College of Physical Education and Health Care, East China Normal University, Shanghai 200241, China
| | - Renkai Ge
- School of Physical Education and Health Care, East China Jiaotong University, Nanchang 330013, China
| | - Ke Chen
- Key Laboratory of High Confidence Software Technologies of Ministry of Education, School of Computer Science, Peking University, Beijing 100871, China
| | - Liming Yang
- Key Lab of Adolescent Health Assessment and Exercise Intervention of Ministry of Education, College of Physical Education and Health Care, East China Normal University, Shanghai 200241, China
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2
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Power KE, Lockyer EJ, Botter A, Vieira T, Button DC. Endurance-exercise training adaptations in spinal motoneurones: potential functional relevance to locomotor output and assessment in humans. Eur J Appl Physiol 2022; 122:1367-1381. [PMID: 35226169 DOI: 10.1007/s00421-022-04918-2] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2021] [Accepted: 02/11/2022] [Indexed: 12/14/2022]
Abstract
It is clear from non-human animal work that spinal motoneurones undergo endurance training (chronic) and locomotor (acute) related changes in their electrical properties and thus their ability to fire action potentials in response to synaptic input. The functional implications of these changes, however, are speculative. In humans, data suggests that similar chronic and acute changes in motoneurone excitability may occur, though the work is limited due to technical constraints. To examine the potential influence of chronic changes in human motoneurone excitability on the acute changes that occur during locomotor output, we must develop more sophisticated recording techniques or adapt our current methods. In this review, we briefly discuss chronic and acute changes in motoneurone excitability arising from non-human and human work. We then discuss the potential interaction effects of chronic and acute changes in motoneurone excitability and the potential impact on locomotor output. Finally, we discuss the use of high-density surface electromyogram recordings to examine human motor unit firing patterns and thus, indirectly, motoneurone excitability. The assessment of single motor units from high-density recording is mainly limited to tonic motor outputs and minimally dynamic motor output such as postural sway. Adapting this technology for use during locomotor outputs would allow us to gain a better understanding of the potential functional implications of endurance training-induced changes in human motoneurone excitability on motor output.
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Affiliation(s)
- Kevin E Power
- Human Neurophysiology Lab, School of Human Kinetics and Recreation, Memorial University of Newfoundland, St. John's, NL, A1C 5S7, Canada. .,Faculty of Medicine, Memorial University of Newfoundland, St. John's, NL, Canada.
| | - Evan J Lockyer
- Human Neurophysiology Lab, School of Human Kinetics and Recreation, Memorial University of Newfoundland, St. John's, NL, A1C 5S7, Canada.,Faculty of Medicine, Memorial University of Newfoundland, St. John's, NL, Canada
| | - Alberto Botter
- Laboratory for Engineering of the Neuromuscular System (LISiN), Department of Electronics and Telecommunication, Politecnico di Torino, Turin, Italy.,PoliToBIOMed Lab, Politecnico di Torino, Turin, Italy
| | - Taian Vieira
- Laboratory for Engineering of the Neuromuscular System (LISiN), Department of Electronics and Telecommunication, Politecnico di Torino, Turin, Italy.,PoliToBIOMed Lab, Politecnico di Torino, Turin, Italy
| | - Duane C Button
- Human Neurophysiology Lab, School of Human Kinetics and Recreation, Memorial University of Newfoundland, St. John's, NL, A1C 5S7, Canada.,Faculty of Medicine, Memorial University of Newfoundland, St. John's, NL, Canada
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3
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Lockyer EJ, Compton CT, Forman DA, Pearcey GE, Button DC, Power KE. Moving forward: methodological considerations for assessing corticospinal excitability during rhythmic motor output in humans. J Neurophysiol 2021; 126:181-194. [PMID: 34133230 DOI: 10.1152/jn.00027.2021] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
The use of transcranial magnetic stimulation to assess the excitability of the central nervous system to further understand the neural control of human movement is expansive. The majority of the work performed to-date has assessed corticospinal excitability either at rest or during relatively simple isometric contractions. The results from this work are not easily extrapolated to rhythmic, dynamic motor outputs, given that corticospinal excitability is task-, phase-, intensity-, direction-, and muscle-dependent (Power KE, Lockyer EJ, Forman DA, Button DC. Appl Physiol Nutr Metab 43: 1176-1185, 2018). Assessing corticospinal excitability during rhythmic motor output, however, involves technical challenges that are to be overcome, or at the minimum considered, when attempting to design experiments and interpret the physiological relevance of the results. The purpose of this narrative review is to highlight the research examining corticospinal excitability during a rhythmic motor output and, importantly, to provide recommendations regarding the many factors that must be considered when designing and interpreting findings from studies that involve limb movement. To do so, the majority of work described herein refers to work performed using arm cycling (arm pedaling or arm cranking) as a model of a rhythmic motor output used to examine the neural control of human locomotion.
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Affiliation(s)
- Evan J Lockyer
- Human Neurophysiology Lab, School of Human Kinetics and Recreation, Memorial University of Newfoundland, St. John's, Newfoundland, Canada.,Faculty of Medicine, Memorial University of Newfoundland, St. John's, Newfoundland, Canada
| | - Chris T Compton
- Human Neurophysiology Lab, School of Human Kinetics and Recreation, Memorial University of Newfoundland, St. John's, Newfoundland, Canada.,Faculty of Medicine, Memorial University of Newfoundland, St. John's, Newfoundland, Canada
| | - Davis A Forman
- Department of Human Health and Nutritional Sciences, University of Guelph, Guelph, Ontario, Canada
| | - Gregory E Pearcey
- Department of Physical Medicine and Rehabilitation, Feinberg School of Medicine, Northwestern University, Chicago, Illinois.,Department of Physiology, Feinberg School of Medicine, Northwestern University, Chicago, Illinois.,Shirley Ryan Ability Lab, Chicago, Illinois
| | - Duane C Button
- Human Neurophysiology Lab, School of Human Kinetics and Recreation, Memorial University of Newfoundland, St. John's, Newfoundland, Canada.,Faculty of Medicine, Memorial University of Newfoundland, St. John's, Newfoundland, Canada
| | - Kevin E Power
- Human Neurophysiology Lab, School of Human Kinetics and Recreation, Memorial University of Newfoundland, St. John's, Newfoundland, Canada.,Faculty of Medicine, Memorial University of Newfoundland, St. John's, Newfoundland, Canada
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Chaytor CP, Forman D, Byrne J, Loucks-Atkinson A, Power KE. Changes in muscle activity during the flexion and extension phases of arm cycling as an effect of power output are muscle-specific. PeerJ 2020; 8:e9759. [PMID: 32983635 PMCID: PMC7500348 DOI: 10.7717/peerj.9759] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2020] [Accepted: 07/28/2020] [Indexed: 01/08/2023] Open
Abstract
Arm cycling is commonly used in rehabilitation settings for individuals with motor impairments in an attempt to facilitate neural plasticity, potentially leading to enhanced motor function in the affected limb(s). Studies examining the neural control of arm cycling, however, typically cycle using a set cadence and power output. Given the importance of motor output intensity, typically represented by the amplitude of electromyographic (EMG) activity, on neural excitability, surprisingly little is known about how arm muscle activity is modulated using relative workloads. Thus, the objective of this study was to characterize arm muscle activity during arm cycling at different relative workloads. Participants (n = 11) first completed a 10-second maximal arm ergometry sprint to determine peak power output (PPO) followed by 11 randomized trials of 20-second arm cycling bouts ranging from 5–50% of PPO (5% increments) and a standard 25 W workload. All submaximal trials were completed at 60 rpm. Integrated EMG amplitude (iEMG) was assessed from the biceps brachii, brachioradialis, triceps brachii, flexor carpi radialis, extensor carpi radialis and anterior deltoid of the dominant arm. Arm cycling was separated into two phases, flexion and extension, relative to the elbow joint for all comparisons. As expected, iEMG amplitude increased during both phases of cycling for all muscles examined. With the exception of the triceps brachii and extensor carpi radialis, iEMG amplitudes differed between the flexion and extension phases. Finally, there was a linear relationship between iEMG amplitude and the %PPO for all muscles during both elbow flexion and extension.
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Affiliation(s)
- Carla P Chaytor
- Human Kinetics and Recreation, Memorial University of Newfoundland, St. John's, Newfoundland, Canada
| | - Davis Forman
- Human Kinetics and Recreation, Memorial University of Newfoundland, St. John's, Newfoundland, Canada
| | - Jeannette Byrne
- Human Kinetics and Recreation, Memorial University of Newfoundland, St. John's, Newfoundland, Canada
| | - Angela Loucks-Atkinson
- Human Kinetics and Recreation, Memorial University of Newfoundland, St. John's, Newfoundland, Canada
| | - Kevin E Power
- Human Kinetics and Recreation, Memorial University of Newfoundland, St. John's, Newfoundland, Canada
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Forman DA, Forman GN, Murphy BA, Holmes MWR. Sustained Isometric Wrist Flexion and Extension Maximal Voluntary Contractions on Corticospinal Excitability to Forearm Muscles during Low-Intensity Hand-Gripping. Brain Sci 2020; 10:E445. [PMID: 32668568 PMCID: PMC7408559 DOI: 10.3390/brainsci10070445] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2020] [Revised: 07/06/2020] [Accepted: 07/07/2020] [Indexed: 02/02/2023] Open
Abstract
The wrist extensors demonstrate an earlier fatigue onset than the wrist flexors. However, it is currently unclear whether fatigue induces unique changes in muscle activity or corticospinal excitability between these muscle groups. The purpose of this study was to examine how sustained isometric wrist extension/flexion maximal voluntary contractions (MVCs) influence muscle activity and corticospinal excitability of the forearm. Corticospinal excitability to three wrist flexors and three wrist extensors were measured using motor evoked potentials (MEPs) elicited via transcranial magnetic stimulation. Responses were elicited while participants exerted 10% of their maximal handgrip force, before and after a sustained wrist flexion or extension MVC (performed on separate sessions). Post-fatigue measures were collected up to 10-min post-fatigue. Immediately post-fatigue, extensor muscle activity was significantly greater following the wrist flexion fatigue session, although corticospinal excitability (normalized to muscle activity) was greater on the wrist extension day. Responses were largely unchanged in the wrist flexors. However, for the flexor carpi ulnaris, normalized MEP amplitudes were significantly larger following wrist extension fatigue. These findings demonstrate that sustained isometric flexion/extension MVCs result in a complex reorganization of forearm muscle recruitment strategies during hand-gripping. Based on these findings, previously observed corticospinal behaviour following fatigue may not apply when the fatiguing task and measurement task are different.
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Affiliation(s)
- Davis A. Forman
- Faculty of Science, Ontario Tech University, Oshawa, ON L1G 0C5, Canada;
| | - Garrick N. Forman
- Faculty of Applied Health Sciences, Brock University, St. Catharines, ON L2S 3A1, Canada;
| | - Bernadette A. Murphy
- Faculty of Health Sciences, Ontario Tech University, Oshawa, ON L1G 0C5, Canada;
| | - Michael W. R. Holmes
- Faculty of Applied Health Sciences, Brock University, St. Catharines, ON L2S 3A1, Canada;
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Emanuelsen A, Voigt M, Madeleine P, Hansen EA. Effect of Tapping Bout Duration During Freely Chosen and Passive Finger Tapping on Rate Enhancement. J Mot Behav 2020; 53:351-363. [PMID: 32525455 DOI: 10.1080/00222895.2020.1779021] [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: 10/24/2022]
Abstract
The present study investigated whether the duration of the first tapping bout, which could also be considered 'the priming', would play a role for the occurrence of the behavioral phenomenon termed repeated bout rate enhancement. Eighty-eight healthy individuals were recruited. Sixty-three of these demonstrated repeated bout rate enhancement and they were assigned to two different groups, which performed either active or passive tapping as priming. The durations of the first tapping bouts, which acted as priming, were 20, 60, 120, and 180 s. Following the first bout there was a 10 min rest and a subsequent 180 s tapping bout performed at freely chosen tapping rate. Vertical displacement and tapping force data were recorded. Rate enhancement was elicited independently of the duration of the first bout in both groups. Rate enhancement occurred without concurrent changes of the magnitude of vertical displacement, time to peak force, and duration of finger contact phase. The peak force was reduced when 180 s of tapping had been performed as priming. The increased tapping rate following priming by as little as 20 s active or passive tapping, as observed here, is suggested to be a result of increased net excitability of the nervous system.
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Affiliation(s)
- Anders Emanuelsen
- Department of Health Science and Technology, Sport Sciences - Performance and Technology, Aalborg University, Aalborg, Denmark
| | - Michael Voigt
- Department of Health Science and Technology, Sport Sciences - Performance and Technology, Aalborg University, Aalborg, Denmark
| | - Pascal Madeleine
- Department of Health Science and Technology, Sport Sciences - Performance and Technology, Aalborg University, Aalborg, Denmark
| | - Ernst Albin Hansen
- Department of Health Science and Technology, Sport Sciences - Performance and Technology, Aalborg University, Aalborg, Denmark
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Power KE, Lockyer EJ, Forman DA, Button DC. Modulation of motoneurone excitability during rhythmic motor outputs. Appl Physiol Nutr Metab 2018. [DOI: 10.1139/apnm-2018-0077] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
In quadrupeds, special circuity located within the spinal cord, referred to as central pattern generators (CPGs), is capable of producing complex patterns of activity such as locomotion in the absence of descending input. During these motor outputs, the electrical properties of spinal motoneurones are modulated such that the motoneurone is more easily activated. Indirect evidence suggests that like quadrupeds, humans also have spinally located CPGs capable of producing locomotor outputs, albeit descending input is considered to be of greater importance. Whether motoneurone properties are reconfigured in a similar manner to those of quadrupeds is unclear. The purpose of this review is to summarize our current state of knowledge regarding the modulation of motoneurone excitability during CPG-mediated motor outputs using animal models. This will be followed by more recent work initially aimed at understanding changes in motoneurone excitability during CPG-mediated motor outputs in humans, which quickly expanded to also include supraspinal excitability.
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Affiliation(s)
- Kevin E. Power
- School of Human Kinetics and Recreation, Memorial University of Newfoundland, St. John’s, NL A1C 5S7, Canada
- Faculty of Medicine, Memorial University of Newfoundland, St. John’s, NL A1C 5S7, Canada
| | - Evan J. Lockyer
- School of Human Kinetics and Recreation, Memorial University of Newfoundland, St. John’s, NL A1C 5S7, Canada
| | - Davis A. Forman
- School of Human Kinetics and Recreation, Memorial University of Newfoundland, St. John’s, NL A1C 5S7, Canada
- Faculty of Science, University of Ontario Institute of Technology, Oshawa, ON L1H 7K4, Canada
| | - Duane C. Button
- School of Human Kinetics and Recreation, Memorial University of Newfoundland, St. John’s, NL A1C 5S7, Canada
- Faculty of Medicine, Memorial University of Newfoundland, St. John’s, NL A1C 5S7, Canada
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Spence AJ, Alcock LR, Lockyer EJ, Button DC, Power KE. Phase- and Workload-Dependent Changes in Corticospinal Excitability to the Biceps and Triceps Brachii during Arm Cycling. Brain Sci 2016; 6:brainsci6040060. [PMID: 27983685 PMCID: PMC5187574 DOI: 10.3390/brainsci6040060] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2016] [Revised: 12/10/2016] [Accepted: 12/12/2016] [Indexed: 11/16/2022] Open
Abstract
This is the first study to examine corticospinal excitability (CSE) to antagonistic muscle groups during arm cycling. Transcranial magnetic stimulation (TMS) of the motor cortex and transmastoid electrical stimulation (TMES) of the corticospinal tract were used to assess changes in supraspinal and spinal excitability, respectively. TMS induced motor evoked potentials (MEPs) and TMES induced cervicomedullary evoked potentials (CMEPs) were recorded from the biceps and triceps brachii at two positions, mid-elbow flexion and extension, while cycling at 5% and 15% of peak power output. While phase-dependent modulation of MEP and CMEP amplitudes occurred in the biceps brachii, there was no difference between flexion and extension for MEP amplitudes in the triceps brachii and CMEP amplitudes were higher during flexion than extension. Furthermore, MEP amplitudes in both biceps and triceps brachii increased with increased workload. CMEP amplitudes increased with higher workloads in the triceps brachii, but not biceps brachii, though the pattern of change in CMEPs was similar to MEPs. Differences between changes in CSE between the biceps and triceps brachii suggest that these antagonistic muscles may be under different neural control during arm cycling. Putative mechanisms are discussed.
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Affiliation(s)
- Alyssa-Joy Spence
- School of Human Kinetics and Recreation Memorial University of Newfoundland, St. John's, NL A1B 3X9, Canada.
| | - Lynsey R Alcock
- School of Human Kinetics and Recreation Memorial University of Newfoundland, St. John's, NL A1B 3X9, Canada.
| | - Evan J Lockyer
- School of Human Kinetics and Recreation Memorial University of Newfoundland, St. John's, NL A1B 3X9, Canada.
| | - Duane C Button
- School of Human Kinetics and Recreation Memorial University of Newfoundland, St. John's, NL A1B 3X9, Canada.
- Faculty of Medicine, Memorial University of Newfoundland, St. John's, NL A1B 3X9, Canada.
| | - Kevin E Power
- School of Human Kinetics and Recreation Memorial University of Newfoundland, St. John's, NL A1B 3X9, Canada.
- Faculty of Medicine, Memorial University of Newfoundland, St. John's, NL A1B 3X9, Canada.
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Differences in corticospinal excitability to the biceps brachii between arm cycling and tonic contraction are not evident at the immediate onset of movement. Exp Brain Res 2016; 234:2339-49. [DOI: 10.1007/s00221-016-4639-z] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2016] [Accepted: 03/23/2016] [Indexed: 10/22/2022]
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10
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Aboodarda SJ, Copithorne DB, Pearcey GE, Button DC, Power KE. Changes in supraspinal and spinal excitability of the biceps brachii following brief, non-fatiguing submaximal contractions of the elbow flexors in resistance-trained males. Neurosci Lett 2015; 607:66-71. [DOI: 10.1016/j.neulet.2015.09.028] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2015] [Revised: 08/28/2015] [Accepted: 09/23/2015] [Indexed: 11/28/2022]
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Forman DA, Philpott DTG, Button DC, Power KE. Cadence-dependent changes in corticospinal excitability of the biceps brachii during arm cycling. J Neurophysiol 2015; 114:2285-94. [PMID: 26289462 DOI: 10.1152/jn.00418.2015] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2015] [Accepted: 08/19/2015] [Indexed: 11/22/2022] Open
Abstract
This is the first study to report the influence of different cadences on the modulation of supraspinal and spinal excitability during arm cycling. Supraspinal and spinal excitability were assessed using transcranial magnetic stimulation of the motor cortex and transmastoid electrical stimulation of the corticospinal tract, respectively. Transcranial magnetic stimulation-induced motor evoked potentials and transmastoid electrical stimulation-induced cervicomedullary evoked potentials (CMEPs) were recorded from the biceps brachii at two separate positions corresponding to elbow flexion and extension (6 and 12 o'clock relative to a clock face, respectively) while arm cycling at 30, 60 and 90 rpm. Motor evoked potential amplitudes increased significantly as cadence increased during both elbow flexion (P < 0.001) and extension (P = 0.027). CMEP amplitudes also increased with cadence during elbow flexion (P < 0.01); however, the opposite occurred during elbow extension (i.e., decreased CMEP amplitude; P = 0.01). The data indicate an overall increase in the excitability of corticospinal neurons which ultimately project to biceps brachii throughout arm cycling as cadence increased. Conversely, changes in spinal excitability as cadence increased were phase dependent (i.e., increased during elbow flexion and decreased during elbow extension). Phase- and cadence-dependent changes in spinal excitability are suggested to be mediated via changes in the balance of excitatory and inhibitory synaptic input to the motor pool, as opposed to changes in the intrinsic properties of spinal motoneurons.
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Affiliation(s)
- Davis A Forman
- School of Human Kinetics and Recreation, Memorial University of Newfoundland, St. John's, Newfoundland, Canada; and
| | - Devin T G Philpott
- School of Human Kinetics and Recreation, Memorial University of Newfoundland, St. John's, Newfoundland, Canada; and
| | - Duane C Button
- School of Human Kinetics and Recreation, Memorial University of Newfoundland, St. John's, Newfoundland, Canada; and Faculty of Medicine, Memorial University of Newfoundland, St. John's, Newfoundland, Canada
| | - Kevin E Power
- School of Human Kinetics and Recreation, Memorial University of Newfoundland, St. John's, Newfoundland, Canada; and Faculty of Medicine, Memorial University of Newfoundland, St. John's, Newfoundland, Canada
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12
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Chen CC, Chuang YF, Yang HC, Hsu MJ, Huang YZ, Chang YJ. Neuromuscular electrical stimulation of the median nerve facilitates low motor cortex excitability in patients with spinocerebellar ataxia. J Electromyogr Kinesiol 2014; 25:143-50. [PMID: 25434572 DOI: 10.1016/j.jelekin.2014.10.009] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2014] [Revised: 08/26/2014] [Accepted: 10/17/2014] [Indexed: 11/26/2022] Open
Abstract
The neuromodulation of motor excitability has been shown to improve functional movement in people with central nervous system damage. This study aimed to investigate the mechanism of peripheral neuromuscular electrical stimulation (NMES) in motor excitability and its effects in people with spinocerebellar ataxia (SCA). This single-blind case-control study was conducted on young control (n=9), age-matched control (n=9), and SCA participants (n=9; 7 SCAIII and 2 sporadic). All participants received an accumulated 30 min of NMES (25 Hz, 800 ms on/800 ms off) of the median nerve. The central motor excitability, measured by motor evoked potential (MEP) and silent period, and the peripheral motor excitability, measured by the H-reflex and M-wave, were recorded in flexor carpi radialis (FCR) muscle before, during, and after the NMES was applied. The results showed that NMES significantly enhanced the MEP in all 3 groups. The silent period, H-reflex and maximum M-wave were not changed by NMES. We conclude that NMES enhances low motor excitability in patients with SCA and that the mechanism of the neuromodulation was supra-segmental. These findings are potentially relevant to the utilization of NMES for preparation of motor excitability. The protocol was registered at Clinicaltrials.gov (NCT02103075).
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Affiliation(s)
- Chih-Chung Chen
- Department of Physical Therapy and Graduate Institute of Rehabilitation Science, College of Medicine and Healthy Aging Research Center, Chang Gung University, 259, Wen-Hwa 1st Rd, Kweishan, Taoyuan 333, Taiwan
| | - Yu-Fen Chuang
- Department of Physical Therapy and Graduate Institute of Rehabilitation Science, College of Medicine and Healthy Aging Research Center, Chang Gung University, 259, Wen-Hwa 1st Rd, Kweishan, Taoyuan 333, Taiwan
| | - Hsiao-Chu Yang
- Department of Physical Therapy and Graduate Institute of Rehabilitation Science, College of Medicine and Healthy Aging Research Center, Chang Gung University, 259, Wen-Hwa 1st Rd, Kweishan, Taoyuan 333, Taiwan
| | - Miao-Ju Hsu
- Department of Physical Therapy, College of Health Science, Kaohsiung Medical University, 100, Shih-Chuan 1st Road, Kaohsiung 807, Taiwan; Department of Physical Medicine and Rehabilitation, Kaohsiung Medical University Hospital, 100, Tzyou 1st Road, Kaohsiung 807, Taiwan
| | - Ying-Zu Huang
- Department of Neurology, Chang Gung Memorial Hospital 5, Fusing St., Kweishan, Taoyuan 333, Taiwan; College of Medicine, Chang Gung University, 259, Wen-Hwa 1st Rd, Kweishan, Taoyuan 333, Taiwan
| | - Ya-Ju Chang
- Department of Physical Therapy and Graduate Institute of Rehabilitation Science, College of Medicine and Healthy Aging Research Center, Chang Gung University, 259, Wen-Hwa 1st Rd, Kweishan, Taoyuan 333, Taiwan.
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13
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Forman D, Raj A, Button DC, Power KE. Corticospinal excitability of the biceps brachii is higher during arm cycling than an intensity-matched tonic contraction. J Neurophysiol 2014; 112:1142-51. [PMID: 24899677 DOI: 10.1152/jn.00210.2014] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Human studies have not assessed corticospinal excitability of an upper-limb prime mover during arm cycling. The purpose of the present study was to determine whether supraspinal and/or spinal motoneuron excitability of the biceps brachii was different between arm cycling and an intensity-matched tonic contraction. We hypothesized that spinal motoneuron excitability would be higher during arm cycling than an intensity-matched tonic contraction. Supraspinal and spinal motoneuron excitability were assessed using transcranial magnetic stimulation (TMS) of the motor cortex and transmastoid electrical stimulation (TMES) of the corticospinal tract, respectively. TMS-induced motor-evoked potentials (MEPs) and TMES-induced cervicomedullary-evoked potentials (CMEPs) were assessed at three separate positions (3, 6, and 12 o'clock relative to a clock face) during arm cycling and an intensity-matched tonic contraction. MEP amplitudes were 7.2 and 8.8% maximum amplitude of the compound muscle action potential (Mmax) larger during arm cycling compared with a tonic contraction at the 3 (P < 0.001) and 6 o'clock (P < 0.001) positions, respectively. There was no difference between tasks during elbow extension (12 o'clock). CMEP amplitudes were 5.2% Mmax larger during arm cycling compared with a tonic contraction at the 3 o'clock position (P < 0.001) with no differences seen at midflexion (6 o'clock) or extension (12 o'clock). The data indicate an increase in the excitability of corticospinal neurons, which ultimately project to biceps brachii during the elbow flexion portion of arm cycling, and increased spinal motoneuron excitability at the onset of elbow flexion during arm cycling. We conclude that supraspinal and spinal motoneuron excitability are phase- and task-dependent.
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Affiliation(s)
- Davis Forman
- School of Human Kinetics and Recreation, Memorial University of Newfoundland, St. John's, Newfoundland, Canada
| | - Amita Raj
- Faculty of Health Sciences, University of Ontario Institute of Technology, Oshawa, Ontario, Canada; and
| | - Duane C Button
- School of Human Kinetics and Recreation, Memorial University of Newfoundland, St. John's, Newfoundland, Canada; Faculty of Medicine, Memorial University of Newfoundland, St. John's, Newfoundland, Canada
| | - Kevin E Power
- School of Human Kinetics and Recreation, Memorial University of Newfoundland, St. John's, Newfoundland, Canada;
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