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Dietmann A, Blanquet M, Rösler KM, Scheidegger O. Effects of high resistance muscle training on corticospinal output during motor fatigue assessed by transcranial magnetic stimulation. Front Physiol 2023; 14:1125974. [PMID: 36969602 PMCID: PMC10036808 DOI: 10.3389/fphys.2023.1125974] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2022] [Accepted: 02/27/2023] [Indexed: 03/12/2023] Open
Abstract
Introduction: Central fatigue refers to a reduced drive of motor cortical output during exercise, and performance can be enhanced after training. However, the effects of training on central fatigue remain unclear. Changes in cortical output can be addressed non-invasively using transcranial magnetic stimulation (TMS). The aim of the study was to compare responses to TMS during a fatiguing exercise before and after a 3 weeks lasting resistance training, in healthy subjects.Methods: The triple stimulation technique (TST) was used to quantify a central conduction index (CCI = amplitude ratio of central conduction response and peripheral nerve response) to the abductor digiti minimi muscle (ADM) in 15 subjects. The training consisted of repetitive isometric maximal voluntary contractions (MVC) of ADM for 2 min twice a day. Before and after this training, TST recordings were obtained every 15 s during an 2 min exercise of MVC of the ADM, where subjects performed repetitive contractions of the ADM, and repeatedly during a recovery period of 7 min.Results: There was a consistent decrease of force to approximately 40% of MVC in all experiments and in all subjects, both before and after training. In all subjects, CCI decreased during exercise. While before training, theCCI decreased to 49% (SD 23.7%) after 2 min of exercise, it decreased after training onlyto 79% (SD 26.4%) after exercise (p < 0.01).Discussion: The training regimen increased the proportion of target motor units that could be activated by TMS during a fatiguing exercise. The results point to a reduced intracortical inhibition, which may be a transient physiological response to facilitate the motor task. Possible underlying mechanisms at spinal and supraspinal sites are discussed.
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Affiliation(s)
- Anelia Dietmann
- Department of Neurology, Inselspital, Bern University Hospital, University of Bern, Switzerland, Bern, Switzerland
| | - Marisa Blanquet
- Department of Neurology, Inselspital, Bern University Hospital, University of Bern, Switzerland, Bern, Switzerland
| | - Kai Michael Rösler
- Department of Neurology, Inselspital, Bern University Hospital, University of Bern, Switzerland, Bern, Switzerland
- Neurozentrum Basel, Bellevue Medical Group, Basel, Switzerland
| | - Olivier Scheidegger
- Department of Neurology, Inselspital, Bern University Hospital, University of Bern, Switzerland, Bern, Switzerland
- Institute for Diagnostic and Interventional Neuroradiology, Inselspital, Bern University Hospital, University of Bern, Bern, Switzerland
- *Correspondence: Olivier Scheidegger ,
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Nakashima A, Moriuchi T, Matsuda D, Nakamura J, Fujiwara K, Ikio Y, Hasegawa T, Mitunaga W, Higashi T. Continuous Repetition Motor Imagery Training and Physical Practice Training Exert the Growth of Fatigue and Its Effect on Performance. Brain Sci 2022; 12:brainsci12081087. [PMID: 36009150 PMCID: PMC9405920 DOI: 10.3390/brainsci12081087] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2022] [Revised: 08/11/2022] [Accepted: 08/12/2022] [Indexed: 11/23/2022] Open
Abstract
Continuous repetition of motor imagery leads to mental fatigue. This study aimed to examine whether fatigue caused by motor imagery training affects improvement in performance and the change in corticospinal excitability. The participants were divided into “physical practice training” and “motor imagery training” groups, and a visuomotor task (set at 50% of maximal voluntary contraction in participants) was performed to assess the training effect on fatigue. The measurements were recorded before and after training. Corticospinal excitability at rest was measured by transcranial magnetic stimulation according to the Neurophysiological Index. Subjective mental fatigue and muscle fatigue were assessed by using the visual analog scale and by measuring the pinch force, respectively. Additionally, the error area was evaluated and calculated at pre-, mid-, and post-terms after training, using a visuomotor task. After training, muscle fatigue, subjective mental fatigue, and decreased corticospinal excitability were noted in both of the groups. Moreover, the visuomotor task decreased the error area by training; however, there was no difference in the error area between the mid- and post-terms. In conclusion, motor imagery training resulted in central fatigue by continuous repetition, which influenced the improvement in performance in the same manner as physical practice training.
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Affiliation(s)
- Akira Nakashima
- Department of Rehabilitation, Juzenkai Hospital, Nagasaki 852-8012, Japan
- Graduate School of Biomedical Sciences, Nagasaki University, Nagasaki 852-8012, Japan
| | - Takefumi Moriuchi
- Graduate School of Biomedical Sciences, Nagasaki University, Nagasaki 852-8012, Japan
| | - Daiki Matsuda
- Graduate School of Biomedical Sciences, Nagasaki University, Nagasaki 852-8012, Japan
| | - Jirou Nakamura
- Graduate School of Biomedical Sciences, Nagasaki University, Nagasaki 852-8012, Japan
| | - Kengo Fujiwara
- Graduate School of Biomedical Sciences, Nagasaki University, Nagasaki 852-8012, Japan
| | - Yuta Ikio
- Graduate School of Biomedical Sciences, Nagasaki University, Nagasaki 852-8012, Japan
| | - Takashi Hasegawa
- Graduate School of Biomedical Sciences, Nagasaki University, Nagasaki 852-8012, Japan
| | - Wataru Mitunaga
- Graduate School of Biomedical Sciences, Nagasaki University, Nagasaki 852-8012, Japan
| | - Toshio Higashi
- Graduate School of Biomedical Sciences, Nagasaki University, Nagasaki 852-8012, Japan
- Correspondence:
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Serajian A, Nourshahi M, LaVoy E, Eliaspour D, Rajabi H, Kondalaji RZ. Effect of a 4-week fish oil supplementation on neuromuscular performance after exhaustive exercise in young healthy men. COMPARATIVE EXERCISE PHYSIOLOGY 2021. [DOI: 10.3920/cep200011] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Neuromuscular function is one of the important factors affecting athletic performance. Previous studies have shown that fish oil supplementation can improve performance. This study investigated the effect of fish oil on neuromuscular performance after exhausting exercise. Eighteen healthy men (mean ± standard deviation; age 26.9±2.6 years; weight 78.33±10.42 kg; height 175.8±4.9 cm; body fat percentage 18.40±5.46%) voluntarily participated and were randomly assigned to fish and corn oil groups in a double blind manner. Participants received 6 g/day of oil for 4 weeks, while maintaining baseline diet and training status during the study. Changes in maximal voluntary contraction (MVC) of the tibialis anterior muscle, neuromuscular propagation of tibialis anterior muscle (M-wave), corticospinal excitability (MEP: motor evoked potential), and the rate of perceived exertion (RPE) were evaluated before and after supplementation in response to a modified Bruce exhausting protocol. Group differences in changes in each variable following supplementation were assessed by two-way analysis of variances (ANOVA). Compared to corn oil, fish oil demonstrated less perceived exertion at the end of exhaustive exercise (F=9.72, P=0.001) after supplementation, and normalised MEP to M-wave showed a trend (F=3.83, P=0.071). However, M-wave peak to peak amplitudes changes were not significant between the groups (P>0.05). In addition, significant differences were observed between baseline MVC values of the group following supplementation. Thus, it seems that fish oil can improve corticospinal excitability, thereby improving neuromuscular function in exhausting activities. Therefore, fish oil supplementation may be recommended to increase performance in activities otherwise limited. However, the mechanism underlying this effect remains to be elucidated.
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Affiliation(s)
- A. Serajian
- Department of Exercise physiology, Shahid-Beheshti University, Tehran, 19839-63112, Iran
| | - M. Nourshahi
- Department of Exercise physiology, Shahid-Beheshti University, Tehran, 19839-63112, Iran
| | - E. LaVoy
- Department of Health and Human Performance, University of Houston, 3875 Holman St., Houston, TX 77204-6015, USA
| | - D. Eliaspour
- Department of physical medicine and rehabilitation, Shahid-Beheshti university of medical sciences, Tehran, 1989934147, Iran
| | - H. Rajabi
- Department of exercise physiology, Kharazmi University, Tehran, 37551-31979, Iran
| | - R. Zekri Kondalaji
- Department of exercise physiology, Tabriz University, 29 Bahman Boulevard, Tabriz, 5166616471, Iran
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Mirifar A, Cross-Villasana F, Beckmann J, Ehrlenspiel F. Effects of the unilateral dynamic handgrip on resting cortical activity levels: A replication and extension. Int J Psychophysiol 2020; 156:40-48. [PMID: 32702385 DOI: 10.1016/j.ijpsycho.2020.07.003] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2019] [Revised: 05/28/2020] [Accepted: 07/07/2020] [Indexed: 10/23/2022]
Abstract
Previous studies have linked unilateral hand contractions to subsequent changes in hemispheric asymmetric activity, as reflected in the electroencephalographic alpha (8-12 Hz) range in each hemisphere. However, debate continues regarding the state of asymmetry induced by unilateral contractions. We have previously found a bilateral enhancement of alpha amplitude that occurs after contractions, reflecting cortical downregulation instead of changes in asymmetric activity. To corroborate our observations, we examined the effects of 45 s of unilateral dynamic handgrip contractions on subsequent resting alpha activity. Twenty-two right-handed participants were recruited (M = 25 years, 17 female). The study used a within-subjects design consisting of a pre- and post-test (2 min resting; eyes open) for the intervention (dynamic handgrip; at a self-determined pace of approximately twice a second for 45 s for each hand). Following the handgrip task, an increase in alpha amplitude above the baseline was observed over the entire cortex, which was greater after left-hand squeezing. This observation confirms our previous findings and we have extended them by adding more electrodes to gain further insights into the handgrip exercise as an external brain stimulator. Moreover, we grouped electrodes according to scalp regions to facilitate the visualization of the effects on the frequency spectrum. Our findings can be used to develop targeted interventions aimed at modifying behavioral outcomes affected by alpha activity.
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Affiliation(s)
- Arash Mirifar
- Department of Sport and Health Sciences, Chair of Sport Psychology, Technische Universität München, Germany.
| | - Fernando Cross-Villasana
- Department of Sport and Health Sciences, Chair of Sport Psychology, Technische Universität München, Germany
| | - Jürgen Beckmann
- School of Human Movement and Nutrition Sciences, University of Queensland, Australia
| | - Felix Ehrlenspiel
- Department of Sport and Health Sciences, Chair of Sport Psychology, Technische Universität München, Germany
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Latella C, van der Groen O, Ruas CV, Taylor JL. Effect of fatigue-related group III/IV afferent firing on intracortical inhibition and facilitation in hand muscles. J Appl Physiol (1985) 2019; 128:149-158. [PMID: 31725359 DOI: 10.1152/japplphysiol.00595.2019] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Fatiguing exercise causes a reduction in motor drive to the muscle. Group III/IV muscle afferent firing is thought to contribute to this process; however, the effect on corticospinal and intracortical networks is poorly understood. In two experiments, participants performed sustained maximal isometric finger abductions of the first dorsal interosseous (FDI) muscle, with postexercise blood flow occlusion (OCC) to maintain the firing of group III/IV afferents or without occlusion (control; CON). Before and after exercise, single- and paired-pulse transcranial magnetic stimulation (TMS) tested motor evoked potentials (MEPs), intracortical facilitation [ICF (12 ms)], and short-interval intracortical inhibition [SICI2 (2 ms), SICI3 (3 ms)]. Ulnar nerve stimulation elicited maximal M waves (MMAX). For experiment 1 (n = 16 participants), TMS intensities were 70% and 120% of resting motor threshold (RMT) for the conditioning and MEP stimuli, respectively. For experiment 2 (n = 16 participants), the MEP was maintained at 1 mV before and after exercise and the conditioning stimulus individualized. In experiment 1, MEP/MMAX was reduced after exercise (~48%, P = 0.007) but was not different between conditions. No changes occurred in ICF or SICI. In experiment 2, MEP/MMAX increased (~27%, P = 0.027) and less inhibition (SICI2: ~21%, P = 0.021) occurred after exercise for both conditions, whereas ICF decreased for CON only (~28%, P = 0.006). MEPs and SICI2 were modulated by fatiguing contractions but not by group III/IV afferent firing, whereas sustained afferent firing appeared to counteract postexercise reductions in ICF in FDI. The findings do not support the idea that actions of group III/IV afferents on motor cortical networks contribute to the reduction in voluntary activation observed in other studies.NEW & NOTEWORTHY This is the first study to investigate, in human hand muscles, the action of fatigue-related group III/IV muscle afferent firing on intracortical facilitation and inhibition. In fatigued and nonexercised hand muscles, intracortical inhibition is reduced after exercise but is not modulated differently by the firing of group III/IV afferents. However, facilitation is maintained for the fatigued muscle when group III/IV afferents fire, but these results are unlikely to explain the reduction in voluntary activation observed in other studies.
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Affiliation(s)
- Christopher Latella
- Centre for Exercise and Sports Science Research, School of Medical and Health Sciences, Edith Cowan University, Joondalup, Perth, Western Australia, Australia.,Neurophysiology Research Laboratory, Edith Cowan University, Joondalup, Perth, Western Australia, Australia
| | - Onno van der Groen
- Centre for Exercise and Sports Science Research, School of Medical and Health Sciences, Edith Cowan University, Joondalup, Perth, Western Australia, Australia.,Neurorehabilitation and Robotics Laboratory, Edith Cowan University, Joondalup, Perth, Western Australia, Australia
| | - Cassio V Ruas
- Centre for Exercise and Sports Science Research, School of Medical and Health Sciences, Edith Cowan University, Joondalup, Perth, Western Australia, Australia
| | - Janet L Taylor
- Centre for Exercise and Sports Science Research, School of Medical and Health Sciences, Edith Cowan University, Joondalup, Perth, Western Australia, Australia.,Neurophysiology Research Laboratory, Edith Cowan University, Joondalup, Perth, Western Australia, Australia.,Neuroscience Research Australia, Randwick, New South Wales, Australia
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Kjeldsen SS, Næss-Schmidt ET, Hansen GM, Nielsen JF, Stubbs PW. Neuromuscular effects of dorsiflexor training with and without blood flow restriction. Heliyon 2019; 5:e02341. [PMID: 31467996 PMCID: PMC6710534 DOI: 10.1016/j.heliyon.2019.e02341] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2019] [Revised: 03/26/2019] [Accepted: 08/15/2019] [Indexed: 10/27/2022] Open
Abstract
Blood flow restriction training (BFRT) has been proposed for elderly and clinical populations with weakness. Before being used in these populations it is important to understand the neurological effects of, and subject perceptions to, BFRT. Seventeen healthy subjects were recruited and performed 2 experimental sessions, BFRT and training without blood flow restriction (TR-only), on separate days. Four sets of concentric/eccentric dorsiflexion contractions against theraband resistance were performed. Surface electromyography of the tibialis anterior was recorded during exercise and for the electrophysiological measures. At baseline, immediately-post, 10-min-post and 20-min-post exercise, motor evoked potentials (MEPs) from single pulse transcranial magnetic stimulation (TMS), paired-pulse TMS with interstimulus intervals of 2-ms (SICI) and 15-ms (ICF), and the M-max amplitude were recorded in the resting TA. Following training, subjects provided a numerical rating of the levels of pain, discomfort, fatigue, focus and difficulty during training. Muscle activation was higher in the last 20 contractions during BFRT compared to TR. There was no difference (time × condition interaction) between BFRT and TR for single-pulse MEP, SICI, ICF or M-max amplitude. There was a significant main effect of timepoint for single-pulse MEP and M-max amplitudes with both significantly reduced for 20-min-post exercise. No reductions were observed for SICI and ICF amplitudes. Taken together, BFRT and TR-only were only different during exercise and both regimes induced similar significant reductions in M-Max and MEP-amplitude post-training. Due to the lack of changes in SICI and ICF, it is unlikely that changes occurred in cortical sites related to these pathways. The increased surface electromyography activity in the last 20 contractions, indicate that the training regimes are different and that BFRT possibly induces more fatigue than TR. As such, BFRT could be used as an adjunct to conventional training. However, as subjects perceived BFRT as more painful, difficult and uncomfortable than TR-only, people should be selected carefully to undertake BFRT.
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Affiliation(s)
- Simon Svanborg Kjeldsen
- Research Department, Hammel Neurorehabilitation and Research Center, Aarhus University, Hammel, Denmark
| | | | - Gunhild Mo Hansen
- Research Department, Hammel Neurorehabilitation and Research Center, Aarhus University, Hammel, Denmark
| | - Jørgen Feldbæk Nielsen
- Research Department, Hammel Neurorehabilitation and Research Center, Aarhus University, Hammel, Denmark
| | - Peter William Stubbs
- Research Department, Hammel Neurorehabilitation and Research Center, Aarhus University, Hammel, Denmark.,University of Technology Sydney, Graduate School of Health, Discipline of Physiotherapy, Sydney, Australia
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7
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Onishi H. Cortical excitability following passive movement. Phys Ther Res 2018; 21:23-32. [PMID: 30697506 DOI: 10.1298/ptr.r0001] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2018] [Accepted: 09/12/2018] [Indexed: 12/15/2022]
Abstract
In brain injury rehabilitation, passive movement exercises are frequently used to maintain or improve mobility and range of motion. They can also induce beneficial and sustained neuroplastic changes. Neuroimaging studies have revealed that passive movements without motor commands activate not only the primary somatosensory cortex but also the primary motor cortex, supplementary motor area, and posterior parietal cortex as well as the secondary somatosensory cortex (S2) in healthy subjects. Repetitive passive movement has also been reported to induce increases or decreases in cortical excitability. In this review, we focused on the following: cortical activity following passive movement; cortical excitability during passive movement; and changes in cortical excitability after repetitive passive movement.
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Affiliation(s)
- Hideaki Onishi
- Institute for Human Movement and Medical Sciences, Niigata University of Health and Welfare.,Department of Physical Therapy, Niigata University of Health and Welfare
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Kalmar JM. On task: Considerations and future directions for studies of corticospinal excitability in exercise neuroscience and related disciplines. Appl Physiol Nutr Metab 2018; 43:1113-1121. [DOI: 10.1139/apnm-2018-0123] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Over the last few decades, transcranial magnetic stimulation (TMS) has emerged as a conventional laboratory technique in human neurophysiological research. Exercise neuroscientists have used TMS to study central nervous system contributions to fatigue, training, and performance in health, injury, and disease. In such studies, corticospinal excitability is often assessed at rest or during simple isometric tasks with the implication that the results may be extrapolated to more functional and complex movement outside of the laboratory. However, the neural mechanisms that influence corticospinal excitability are both state- and task-dependent. Furthermore, there are many sites of modulation along the pathway from the motor cortex to the muscle; a fact that is somewhat obscured by the all-encompassing and poorly defined term “corticospinal excitability”. Therefore, the tasks we use to assess corticospinal excitability and the conclusions that we draw from such a global measure of the motor pathway must be taken into consideration. The overall objective of this review is to highlight the task-dependent nature of corticospinal excitability and the tools used to assess modulation at cortical and spinal sites of modulation. By weighing the advantages and constraints of conventional approaches to studying corticospinal excitability, and considering some new and novel approaches, we will continue to advance our understanding of the neural control of movement during exercise.
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Affiliation(s)
- Jayne M. Kalmar
- Wilfrid Laurier University, Department of Kinesiology and Physical Education, Waterloo, ON N2L 3C5, Canada
- Wilfrid Laurier University, Department of Kinesiology and Physical Education, Waterloo, ON N2L 3C5, Canada
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9
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Ishikawa N, Miyao R, Tsuiki S, Sasaki R, Miyaguchi S, Onishi H. Corticospinal excitability following repetitive voluntary movement. J Clin Neurosci 2018; 57:93-98. [DOI: 10.1016/j.jocn.2018.08.026] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2018] [Accepted: 08/12/2018] [Indexed: 10/28/2022]
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Abstract
Fatigue brought about by intense muscular contraction typically is accompanied by a reduction in motor-unit firing rate. The decrease in motor-unit output with fatigue appears to be caused by two interacting processes: 1) a decline in the net excitatory drive to motoneurons and 2) adaptation in the responsiveness of motoneurons to synaptic input. Whether a reduction in motor-unit firing rate in itself contributes to force loss associated with fatigue, however, is an unresolved question. The neuromuscular wisdom hypothesis suggests that decreases in firing rate help to maintain force by optimizing the input to motor units as their contractile properties change. On the other hand, recent work indicates that mechanical function of some motor units is altered during prolonged activity such that diminished firing rate would augment force loss and, thereby, contribute to fatigue. Neural adaptations, therefore, may serve to limit the extent of muscular activity. NEUROSCIENTIST 2:203-206, 1996
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Miyaguchi S, Kojima S, Kirimoto H, Tamaki H, Onishi H. Do Differences in Levels, Types, and Duration of Muscle Contraction Have an Effect on the Degree of Post-exercise Depression? Front Hum Neurosci 2016; 10:159. [PMID: 27199696 PMCID: PMC4850151 DOI: 10.3389/fnhum.2016.00159] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2015] [Accepted: 03/31/2016] [Indexed: 12/04/2022] Open
Abstract
We conducted two experiments to determine how differences in muscle contraction levels, muscle contraction types, and movement duration affect degree of post-exercise depression (PED) after non-exhaustive, repetitive finger movement. Twelve healthy participants performed repetitive abduction movements of the right index finger at 2 Hz. In experiment 1, we examined the effects of muscle contraction levels at 10, 20, and 30% maximum voluntary contraction and the effects of muscle contraction types at isotonic and isometric contraction. In experiment 2, we examined the effects of movement duration at 2 and 6 min. Motor-evoked potentials (MEPs) were recorded from the right first dorsal interosseous muscle before movement tasks and 1–10 min after movement tasks. MEP amplitudes after isotonic contraction tasks were significantly smaller than those after isometric contraction tasks and decreased with increasing contraction levels, but were independent of movement duration. This study demonstrated that the degree of PED after non-exhaustive repetitive finger movement depended on muscle contraction levels and types. Thus, the degree of PED may depend on the levels of activity in the motor cortex during a movement task. This knowledge will aid in the design of rehabilitation protocols.
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Affiliation(s)
- Shota Miyaguchi
- Institute for Human Movement and Medical Sciences, Niigata University of Health and Welfare Niigata, Japan
| | - Sho Kojima
- Institute for Human Movement and Medical Sciences, Niigata University of Health and Welfare Niigata, Japan
| | - Hikari Kirimoto
- Institute for Human Movement and Medical Sciences, Niigata University of Health and Welfare Niigata, Japan
| | - Hiroyuki Tamaki
- Institute for Human Movement and Medical Sciences, Niigata University of Health and Welfare Niigata, Japan
| | - Hideaki Onishi
- Institute for Human Movement and Medical Sciences, Niigata University of Health and Welfare Niigata, Japan
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Cunningham DA, Janini D, Wyant A, Bonnett C, Varnerin N, Sankarasubramanian V, Potter-Baker KA, Roelle S, Wang X, Siemionow V, Yue GH, Plow EB. Post-exercise depression following submaximal and maximal isometric voluntary contraction. Neuroscience 2016; 326:95-104. [PMID: 27058145 DOI: 10.1016/j.neuroscience.2016.03.060] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2015] [Revised: 03/25/2016] [Accepted: 03/28/2016] [Indexed: 11/29/2022]
Abstract
It is well known that corticomotor excitability is altered during the post-exercise depression following fatigue within the primary motor cortex (M1). However, it is currently unknown whether corticomotor reorganization following muscle fatigue differs between magnitudes of force and whether corticomotor reorganization occurs measured with transcranial magnetic stimulation (TMS). Fifteen young healthy adults (age 23.8±1.4, 8 females) participated in a within-subjects, repeated measures design study, where they underwent three testing sessions separated by one-week each. Subjects performed separate sessions of each: low-force isometric contraction (30% maximal voluntary contraction [MVC]), high-force isometric contraction (95% MVC) of the first dorsal interosseous (FDI) muscle until self-perceived exhaustion, as well as one session of a 30-min rest as a control. We examined changes in corticomotor map area, excitability and location of the FDI representation in and around M1 using TMS. The main finding was that following low-force, but not high-force fatigue (HFF) corticomotor map area and excitability reduced [by 3cm(2) (t(14)=-2.94, p=0.01) and 56% respectively t(14)=-4.01, p<0.001)]. Additionally, the region of corticomotor excitability shifted posteriorly (6.4±2.5mm) (t(14)=-6.33, p=.019). Corticomotor output became less excitable particularly in regions adjoining M1. Overall, post-exercise depression is present in low-force, but not for HFF. Further, low-force fatigue (LFF) results in a posterior shift in corticomotor output. These changes may be indicative of increased sensory feedback from the somatosensory cortex during the recovery phase of fatigue.
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Affiliation(s)
- David A Cunningham
- Department of Biomedical Engineering, Lerner Research Institute, Cleveland Clinic, Cleveland, OH, United States; School of Biomedical Sciences, Kent State University, Kent, OH, United States
| | - Daniel Janini
- Department of Biomedical Engineering, Lerner Research Institute, Cleveland Clinic, Cleveland, OH, United States
| | - Alexandria Wyant
- Department of Biomedical Engineering, Lerner Research Institute, Cleveland Clinic, Cleveland, OH, United States; Center for Neurological Restoration, Neurosurgery, Neurological Institute, Cleveland Clinic, Cleveland, OH, United States
| | - Corin Bonnett
- Department of Biomedical Engineering, Lerner Research Institute, Cleveland Clinic, Cleveland, OH, United States
| | - Nicole Varnerin
- Department of Biomedical Engineering, Lerner Research Institute, Cleveland Clinic, Cleveland, OH, United States
| | | | - Kelsey A Potter-Baker
- Department of Biomedical Engineering, Lerner Research Institute, Cleveland Clinic, Cleveland, OH, United States
| | - Sarah Roelle
- Department of Biomedical Engineering, Lerner Research Institute, Cleveland Clinic, Cleveland, OH, United States
| | - Xiaofeng Wang
- Department of Quantitative Health Sciences, Cleveland Clinic, Cleveland, OH, United States
| | - Vlodek Siemionow
- Department of Biomedical Engineering, Lerner Research Institute, Cleveland Clinic, Cleveland, OH, United States
| | - Guang H Yue
- Human Performance & Engineering Research, Kessler Foundation, West Orange, NJ, United States; Department of Physical Medicine & Rehab, Rutgers New Jersey Medical School, Rutgers University, Newark, NJ, United States.
| | - Ela B Plow
- Department of Biomedical Engineering, Lerner Research Institute, Cleveland Clinic, Cleveland, OH, United States; Center for Neurological Restoration, Neurosurgery, Neurological Institute, Cleveland Clinic, Cleveland, OH, United States; Department of Physical Medicine & Rehab, Neurological Institute, Cleveland Clinic, Cleveland, OH, United States.
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Kotan S, Kojima S, Miyaguchi S, Sugawara K, Onishi H. Depression of corticomotor excitability after muscle fatigue induced by electrical stimulation and voluntary contraction. Front Hum Neurosci 2015; 9:363. [PMID: 26150781 PMCID: PMC4472998 DOI: 10.3389/fnhum.2015.00363] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2015] [Accepted: 06/08/2015] [Indexed: 11/13/2022] Open
Abstract
In this study, we examined the effect of muscle fatigue induced by tetanic electrical stimulation (ES) and submaximal isometric contraction on corticomotor excitability. Experiments were performed in a cross-over design. Motor-evoked potentials (MEPs) were elicited by transcranial magnetic stimulation (TMS). Corticomotor excitability was recorded before and after thumb opposition muscle fatigue tasks, in which 10% of the maximal tension intensity was induced by tetanic ES or voluntary contraction (VC). The participants were 10 healthy individuals who performed each task for 10 min. Surface electrodes placed over the abductor pollicis brevis (APB) muscle recorded MEPs. F- and M-waves were elicited from APB by supramaximal ES of the median nerve. After the tetanic ES- and VC tasks, MEP amplitudes were significantly lower than before the task. However, F- and M-wave amplitudes remained unchanged. These findings suggest that corticospinal excitability is reduced by muscle fatigue as a result of intracortical inhibitory mechanisms. Our results also suggest that corticomotor excitability is reduced by muscle fatigue caused by both VC and tetanic ES.
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Affiliation(s)
- Shinichi Kotan
- Institute for Human Movement and Medical Sciences, Niigata University of Health and Welfare Niigata, Japan
| | - Sho Kojima
- Institute for Human Movement and Medical Sciences, Niigata University of Health and Welfare Niigata, Japan
| | - Shota Miyaguchi
- Institute for Human Movement and Medical Sciences, Niigata University of Health and Welfare Niigata, Japan
| | - Kazuhiro Sugawara
- Institute for Human Movement and Medical Sciences, Niigata University of Health and Welfare Niigata, Japan
| | - Hideaki Onishi
- Institute for Human Movement and Medical Sciences, Niigata University of Health and Welfare Niigata, Japan
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Gruet M, Temesi J, Brisswalter J, Millet G, Vergès S. Stimulation magnétique transcrânienne : application à la physiologie de l’exercice. Sci Sports 2014. [DOI: 10.1016/j.scispo.2014.04.002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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Temesi J, Gruet M, Rupp T, Verges S, Millet GY. Resting and active motor thresholds versus stimulus-response curves to determine transcranial magnetic stimulation intensity in quadriceps femoris. J Neuroeng Rehabil 2014; 11:40. [PMID: 24655366 PMCID: PMC3976163 DOI: 10.1186/1743-0003-11-40] [Citation(s) in RCA: 63] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2013] [Accepted: 03/04/2014] [Indexed: 01/07/2023] Open
Abstract
Background Transcranial magnetic stimulation (TMS) is a widely-used investigative technique in motor cortical evaluation. Recently, there has been a surge in TMS studies evaluating lower-limb fatigue. TMS intensity of 120-130% resting motor threshold (RMT) and 120% active motor threshold (AMT) and TMS intensity determined using stimulus–response curves during muscular contraction have been used in these studies. With the expansion of fatigue research in locomotion, the quadriceps femoris is increasingly of interest. It is important to select a stimulus intensity appropriate to evaluate the variables, including voluntary activation, being measured in this functionally important muscle group. This study assessed whether selected quadriceps TMS stimulus intensity determined by frequently employed methods is similar between methods and muscles. Methods Stimulus intensity in vastus lateralis, rectus femoris and vastus medialis muscles was determined by RMT, AMT (i.e. during brief voluntary contractions at 10% maximal voluntary force, MVC) and maximal motor-evoked potential (MEP) amplitude from stimulus–response curves during brief voluntary contractions at 10, 20 and 50% MVC at different stimulus intensities. Results Stimulus intensity determined from a 10% MVC stimulus–response curve and at 120 and 130% RMT was higher than stimulus intensity at 120% AMT (lowest) and from a 50% MVC stimulus–response curve (p < 0.05). Stimulus intensity from a 20% MVC stimulus–response curve was similar to 120% RMT and 50% MVC stimulus–response curve. Mean stimulus intensity for stimulus–response curves at 10, 20 and 50% MVC corresponded to approximately 135, 115 and 100% RMT and 180, 155 and 130% AMT, respectively. Selected stimulus intensity was similar between muscles for all methods (p > 0.05). Conclusions Similar optimal stimulus intensity and maximal MEP amplitudes at 20 and 50% MVC and the minimal risk of residual fatigue at 20% MVC suggest that a 20% MVC stimulus–response curve is appropriate for determining TMS stimulus intensity in the quadriceps femoris. The higher selected stimulus intensities at 120-130% RMT have the potential to cause increased coactivation and discomfort and the lower stimulus intensity at 120% AMT may underestimate evoked responses. One muscle may also act as a surrogate in determining optimal quadriceps femoris stimulation intensity.
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Affiliation(s)
| | | | | | | | - Guillaume Y Millet
- Laboratoire de Physiologie de l'Exercice, Université de Lyon, Saint-Etienne F-42023, France.
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Miyaguchi S, Onishi H, Kojima S, Sugawara K, Tsubaki A, Kirimoto H, Tamaki H, Yamamoto N. Corticomotor excitability induced by anodal transcranial direct current stimulation with and without non-exhaustive movement. Brain Res 2013; 1529:83-91. [DOI: 10.1016/j.brainres.2013.07.026] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2013] [Revised: 07/13/2013] [Accepted: 07/18/2013] [Indexed: 12/01/2022]
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Amann M, Venturelli M, Ives SJ, McDaniel J, Layec G, Rossman MJ, Richardson RS. Peripheral fatigue limits endurance exercise via a sensory feedback-mediated reduction in spinal motoneuronal output. J Appl Physiol (1985) 2013; 115:355-64. [PMID: 23722705 DOI: 10.1152/japplphysiol.00049.2013] [Citation(s) in RCA: 148] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023] Open
Abstract
This study sought to determine whether afferent feedback associated with peripheral muscle fatigue inhibits central motor drive (CMD) and thereby limits endurance exercise performance. On two separate days, eight men performed constant-load, single-leg knee extensor exercise to exhaustion (85% of peak power) with each leg (Leg1 and Leg2). On another day, the performance test was repeated with one leg (Leg1) and consecutively (within 10 s) with the other/contralateral leg (Leg2-post). Exercise-induced quadriceps fatigue was assessed by reductions in potentiated quadriceps twitch-force from pre- to postexercise (ΔQtw,pot) in response to supramaximal magnetic femoral nerve stimulation. The output from spinal motoneurons, estimated from quadriceps electromyography (iEMG), was used to reflect changes in CMD. Rating of perceived exertion (RPE) was recorded during exercise. Time to exhaustion (∼9.3 min) and exercise-induced ΔQtw,pot (∼51%) were similar in Leg1 and Leg2 (P > 0.5). In the consecutive leg trial, endurance performance of the first leg was similar to that observed during the initial trial (∼9.3 min; P = 0.8); however, time to exhaustion of the consecutively exercising contralateral leg (Leg2-post) was shorter than the initial Leg2 trial (4.7 ± 0.6 vs. 9.2 ± 0.4 min; P < 0.01). Additionally, ΔQtw,pot following Leg2-post was less than Leg2 (33 ± 3 vs 52 ± 3%; P < 0.01). Although the slope of iEMG was similar during Leg2 and Leg2-post, end-exercise iEMG following Leg2-post was 26% lower compared with Leg2 (P < 0.05). Despite a similar rate of rise, RPE was consistently ∼28% higher throughout Leg2-post vs. Leg2 (P < 0.05). In conclusion, this study provides evidence that peripheral fatigue and associated afferent feedback limits the development of peripheral fatigue and compromises endurance exercise performance by inhibiting CMD.
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Affiliation(s)
- Markus Amann
- Department of Medicine, University of Utah, Salt Lake City, Utah, USA.
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Corticospinal Responses to Sustained Locomotor Exercises: Moving Beyond Single-Joint Studies of Central Fatigue. Sports Med 2013; 43:437-49. [DOI: 10.1007/s40279-013-0020-6] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
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20
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Gruet M, Temesi J, Rupp T, Levy P, Millet G, Verges S. Stimulation of the motor cortex and corticospinal tract to assess human muscle fatigue. Neuroscience 2013; 231:384-99. [DOI: 10.1016/j.neuroscience.2012.10.058] [Citation(s) in RCA: 73] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2012] [Revised: 10/10/2012] [Accepted: 10/29/2012] [Indexed: 10/27/2022]
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21
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Hopkinson NS, Dayer MJ, Antoine-Jonville S, Swallow EB, Porcher R, Vazir A, Poole-Wilson P, Polkey MI. Central and peripheral quadriceps fatigue in congestive heart failure. Int J Cardiol 2012; 167:2594-9. [PMID: 22795722 PMCID: PMC3776927 DOI: 10.1016/j.ijcard.2012.06.064] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/01/2012] [Revised: 06/11/2012] [Accepted: 06/17/2012] [Indexed: 11/03/2022]
Abstract
AIMS The clinical syndrome of heart failure includes exercise limitation that is not directly linked to measures of cardiac function. Quadriceps fatigability may be an important component of this and this may arise from peripheral or central factors. METHODS AND RESULTS We studied 10 men with CHF and 10 healthy age-matched controls. Compared with a rest condition, 10 min after incremental maximal cycle exercise, twitch quadriceps force in response to supramaximal magnetic femoral nerve stimulation fell in both groups (CHF 14.1% ± 18.1%, p=0.037; CONTROL 20.8 ± 11.0%, p<0.001; no significant difference between groups). There was no significant change in quadriceps maximum voluntary contraction voluntary force. The difference in the motor evoked potential (MEP) response to transcranial magnetic stimulation of the motor cortex between rest and exercise conditions at 10 min, normalised to the peripheral action potential, also fell significantly in both groups (CHF: 27.3 ± 38.7%, p=0.037; CONTROL 41.1 ± 47.7%, p=0.024). However, the fall in MEP was sustained for a longer period in controls than in patients (p=0.048). CONCLUSIONS The quadriceps is more susceptible to fatigue, with a similar fall in TwQ occurring in CHF patients at lower levels of exercise. This is associated with no change in voluntary activation but a lesser degree of depression of quadriceps motor evoked potential.
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Affiliation(s)
- Nicholas S Hopkinson
- NIHR Respiratory Biomedical Research Unit at Royal Brompton and Harefield NHS Foundation Trust and Imperial College London, Royal Brompton Hospital, London, UK.
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Mileva KN, Sumners DP, Bowtell JL. Decline in voluntary activation contributes to reduced maximal performance of fatigued human lower limb muscles. Eur J Appl Physiol 2012; 112:3959-70. [DOI: 10.1007/s00421-012-2381-1] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2011] [Accepted: 03/06/2012] [Indexed: 11/24/2022]
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Scheidegger O, Kamm CP, Humpert SJ, Rösler KM. Corticospinal output during muscular fatigue differs in multiple sclerosis patients compared to healthy controls. Mult Scler 2012; 18:1500-6. [DOI: 10.1177/1352458512438722] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Background: In multiple sclerosis (MS), fatigue is a common and often disabling symptom. It has multiple causes with central motor fatigue playing an important role. Objective: The objective of this study was to analyse the central motor conduction changes in relation to muscle contraction force during muscle fatigue and recovery in MS patients compared to healthy controls. Methods: A total of 23 MS patients with fatigue and 13 healthy subjects were assessed during 2 minutes of fatiguing exercise of the abductor digiti minimi muscle of the hand and the subsequent 7 minutes of recovery. Central motor conduction was quantified by transcranial magnetic stimulation using the triple stimulation protocol and calculating a central conduction index (CCI). Results: Force declined to 36% of the pre-exercise level (SD 16%; p < 0.01) in MS patients and to 44% (SD 9%, p < 0.01) in healthy subjects (group differences, not statistically significant). The decline of the CCI was significantly less marked in patients (–20%, SD 26%, p < 0.05) than in healthy subjects (–57%, SD 15%, p < 0.05; group differences, p < 0.05). The decline of force and CCI were not correlated in either group. Conclusions: During a fatiguing exercise, the decline in central motor conduction is significantly less pronounced in MS patients than healthy subjects, although the reduction of force is similar.
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Affiliation(s)
- O Scheidegger
- Inselspital, Bern University Hospital and University of Bern, Switzerland
| | - CP Kamm
- Inselspital, Bern University Hospital and University of Bern, Switzerland
| | - SJ Humpert
- Inselspital, Bern University Hospital and University of Bern, Switzerland
| | - KM Rösler
- Inselspital, Bern University Hospital and University of Bern, Switzerland
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Boërio D, Lefaucheur JP, Bassez G, Hogrel JY. Central and peripheral components of exercise-related fatigability in myotonic dystrophy type 1. Acta Neurol Scand 2012; 125:38-46. [PMID: 22188374 DOI: 10.1111/j.1600-0404.2011.01497.x] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
BACKGROUND Fatigue frequently occurs in myotonic dystrophy type 1 (DM1), but its pathophysiology remains unclear. This study assessed central and peripheral components of exercise-related fatigability in patients with DM1, compared to controls. METHODS Examinations were performed before and after a contraction of the abductor digiti minimi (ADM) muscle sustained for 45 s at 60% of maximal voluntary contraction (MVC). Myoelectric activity was recorded using high spatial resolution surface EMG during twitch stimulations and MVC and was characterized by root mean square, mean power frequency (MPF), and muscle fiber conduction velocity (MFCV). Peripheral nerve excitability was assessed by stimulating the ulnar nerve at the wrist with ADM recordings. Motor cortex excitability testing to transcranial magnetic stimulation included measures of intracortical facilitation and inhibition of motor evoked potentials (MEPs) in ADM muscle. RESULTS At baseline, patients with DM1 showed altered peripheral nerve and cortical excitability (reduced intracortical facilitation) associated with impaired myoelectric properties. During the fatiguing exercise, the force remained stable, while MPF and MFCV decreased in both DM1 and control groups. After exercise, only refractoriness was reduced in patients with DM1, whereas controls showed marked neuromuscular and cortical changes. CONCLUSION Patients with DM1 showed altered excitability of various cortical and neuromuscular components at baseline. However, most of excitability parameters did not vary after exercise in patients with DM1, in contrast to controls. This suggests that excitability properties, frankly altered at baseline, were not prone to be affected further after exercise in patients with DM1.
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Affiliation(s)
- D Boërio
- Institut de Myologie, UPMC UMR S, INSERM U, CNRS UMR, GH Pitié-Salpêtrière, Paris, France
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25
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Andersen B, Felding UA, Krarup C. Increased probability of repetitive spinal motoneuron activation by transcranial magnetic stimulation after muscle fatigue in healthy subjects. J Appl Physiol (1985) 2011; 112:832-40. [PMID: 22174399 DOI: 10.1152/japplphysiol.00917.2009] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Triple stimulation technique (TST) has previously shown that transcranial magnetic stimulation (TMS) fails to activate a proportion of spinal motoneurons (MNs) during motor fatigue. The depression in size of the TST response, but no attenuation of the conventional motor-evoked potential, suggested increased probability of repetitive spinal MN activation during exercise, even if some MNs failed to discharge by the brain stimulus. Here we used a modified TST [quadruple stimulation (QuadS) and quintuple stimulation (QuintS)] to examine the influence of fatiguing exercise on second and third MN discharges after a single TMS in healthy subjects. This method allows an estimation of the percentage of double and triple discharging MNs. Following a sustained contraction of the abductor digiti minimi muscle at 50% maximal force maintained to exhaustion, the size of QuadS and QuintS responses increased markedly, reflecting that a greater proportion of spinal MNs was activated two or three times by the transcranial stimulus. The size of QuadS responses did not return to precontraction levels during 10-min observation time, indicating long-lasting increase in excitatory input to spinal MNs. In addition, the postexercise behavior of QuadS responses was related to the duration of the contraction, pointing to a correlation between repeated activation of MNs and the subject's ability to maintain force. In conclusion, the study confirmed that an increased fraction of spinal MNs fire more than once in response to TMS when the muscle is fatigued. Repetitive MN firing may provide an adaptive mechanism to maintain motor unit activation and task performance during sustained voluntary activity.
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Affiliation(s)
- Birgit Andersen
- Department of Clinical Neurophysiology, Copenhagen University Hospital, Rigshospitalet, Copenhagen, Denmark.
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26
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Post-exercise depression in corticomotor excitability after dynamic movement: a general property of fatiguing and non-fatiguing exercise. Exp Brain Res 2011; 216:41-9. [DOI: 10.1007/s00221-011-2906-6] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2011] [Accepted: 10/06/2011] [Indexed: 10/15/2022]
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Milanović S, Filipović S, Blesić S, Ilić T, Dhanasekaran S, Ljubisavljević M. Paired-associative stimulation can modulate muscle fatigue induced motor cortex excitability changes. Behav Brain Res 2011; 223:30-5. [DOI: 10.1016/j.bbr.2011.04.013] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2010] [Revised: 04/01/2011] [Accepted: 04/10/2011] [Indexed: 11/25/2022]
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Hilty L, Lutz K, Maurer K, Rodenkirch T, Spengler CM, Boutellier U, Jäncke L, Amann M. Spinal opioid receptor-sensitive muscle afferents contribute to the fatigue-induced increase in intracortical inhibition in healthy humans. Exp Physiol 2011; 96:505-17. [PMID: 21317218 DOI: 10.1113/expphysiol.2010.056226] [Citation(s) in RCA: 58] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
We investigated the influence of spinal opioid receptor-sensitive muscle afferents on cortical changes following fatiguing unilateral knee-extensor exercise. On separate days, seven subjects performed an identical five sets of intermittent isometric right-quadriceps contractions, each consisting of eight submaximal contractions [63 ± 7% maximal voluntary contraction (MVC)] and one MVC. The exercise was performed following either lumbar interspinous saline injection or lumbar intrathecal fentanyl injection blocking the central projection of spinal opioid receptor-sensitive lower limb muscle afferents. To quantify exercise-induced peripheral fatigue, quadriceps twitch force (Q(tw,pot)) was assessed via supramaximal magnetic femoral nerve stimulation before and after exercise. Motor evoked potentials and cortical silent periods (CSPs) were evaluated via transcranial magnetic stimulation of the motor cortex during a 3% MVC pre-activation period immediately following exercise. End-exercise quadriceps fatigue was significant and similar in both conditions (Q(tw,pot) -35 and -39% for placebo and fentanyl, respectively; P = 0.38). Immediately following exercise on both days, motor evoked potentials were similar to those obtained prior to exercise. Compared with pre-exercise baseline, CSP in the placebo trial was 21 ± 5% longer postexercise (P < 0.01). In contrast, CSP following the fentanyl trial was not significantly prolonged compared with the pre-exercise baseline (6 ± 4%). Our findings suggest that the central effects of spinal opioid receptor-sensitive muscle afferents might facilitate the fatigue-induced increase in CSP. Furthermore, since the CSP is thought to reflect inhibitory intracortical interneuron activity, which may contribute to central fatigue, our findings imply that spinal opioid receptor-sensitive muscle afferents might influence central fatigue by facilitating intracortical inhibition.
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Affiliation(s)
- Lea Hilty
- Exercise Physiology, ETH Zurich and Institute of Physiology, University of Zurich, Switzerland
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Rossi A, Biasella A, Scarselli C, Piu P, Ginanneschi F. Influence of activity-induced axonal hypoexcitability on transmission of descending and segmental signals. Brain Res 2009; 1320:47-59. [PMID: 20026312 DOI: 10.1016/j.brainres.2009.12.023] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2009] [Revised: 12/04/2009] [Accepted: 12/07/2009] [Indexed: 01/21/2023]
Abstract
In this experiment, the changes in excitability of motor axons produced after natural activity were measured in nine healthy subjects using 1 min of maximal voluntary contractions (MVC) of the abductor digiti minimi (ADM) by studying the relationship between stimulus intensity applied to the ulnar nerve and the size of the ADM compound muscle action potential (CMAP). On cessation of the contraction, there was a prominent right-shift of the input-output curve: the intensity required to produce a control CMAP approximately 60% of maximum, generated a post-contraction response approximately 25% of maximum. Similar changes occurred in the input-output curves obtained by recording the ulnar nerve volley evoked by same test stimulus for CMAP. Motor-evoked potential (MEP) and F-waves (and H-reflex in one subject) were recorded from ADM before and after 1 min of MVC. On cessation of contraction, the MEP input-output curves exhibited a significant right-shift: the stimulus required to evoke a pre-contraction maximum MEP ( approximately 60% of maximum CMAP) generated a post-contraction response approximately 65% of initial values. One minute of MVC produced similar decreases of F ( approximately 35%)- and H ( approximately 30%)-ADM responses. All responses recovered their control value in 15-20 min after the end of contraction. The almost identical depressive effect produced by 1 min of MVC on peripherally and centrally generated muscle responses suggests a common conditioning factor. These findings are discussed within the context of activity-induced motor axonal hyperpolarizion.
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Affiliation(s)
- Alessandro Rossi
- Clinical Neurophysiology, Department of Neurological Neurosurgical and Behavioural Sciences, University of Siena, Viale Bracci 1, 53100 Siena, Italy.
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30
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Execution-dependent modulation of corticospinal excitability during action observation. Exp Brain Res 2009; 199:17-25. [DOI: 10.1007/s00221-009-1962-7] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2009] [Accepted: 07/22/2009] [Indexed: 10/20/2022]
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31
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Rösler KM, Scheidegger O, Magistris MR. Corticospinal output and loss of force during motor fatigue. Exp Brain Res 2009; 197:111-23. [DOI: 10.1007/s00221-009-1897-z] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2008] [Accepted: 06/05/2009] [Indexed: 11/28/2022]
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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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Takahashi K, Maruyama A, Maeda M, Etoh S, Hirakoba K, Kawahira K, Rothwell JC. Unilateral grip fatigue reduces short interval intracortical inhibition in ipsilateral primary motor cortex. Clin Neurophysiol 2008; 120:198-203. [PMID: 19028439 DOI: 10.1016/j.clinph.2008.10.003] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2008] [Revised: 09/16/2008] [Accepted: 10/02/2008] [Indexed: 11/26/2022]
Abstract
OBJECTIVE This study was designed to examine whether exhaustive grip exercise of the left hand affected intracortical excitability in ipsilateral motor cortex. METHODS Ten healthy male subjects (aged 21-24 years) participated in experiment 1 in which paired-pulse transcranial magnetic stimulation (TMS) was used to test corticospinal and corticocortical excitability in right (relaxed) first dorsal interosseous (FDI) muscle during the recovery period after exhaustive forceful grip exercise of the left hand. Seven of the same subjects participated in experiment 2, in which the intensity of the test stimulus was adjusted so that the amplitude of motor evoked potential (MEP(TEST)) was kept constant throughout the measurement. RESULTS In experiment 1, MEP(TEST) was slightly reduced from 5 to 15min after exercise whilst short interval intracortical inhibition (SICI) at interstimulus interval (ISI) of 2 and 3ms became less effective. Intracortical facilitation (ICF) was unchanged. In experiment 2 when the MEP(TEST) was maintained at a constant size there was again no change in ICF, and the reduction in SICI was still present at the same intervals. CONCLUSIONS We conclude that unilateral exhaustive grip exercise reduced the excitability of the corticospinal output of the ipsilateral motor cortex whilst simultaneously reducing the excitability of SICI. These results would be compatible with the idea that fatigue increases the tonic level of interhemispheric inhibition from the fatigued to the non-fatigued cortex. SIGNIFICANCE Muscle fatigue to the point of exhaustion has lasting effects on the excitability of intracortical circuits in the non-exercised hemisphere, perhaps via changes in the tonic levels of activity in transcallosal pathways.
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Affiliation(s)
- Kyohei Takahashi
- Biological Functions and Engineering, Kyushu Institute of Technology, Kitakyushu, Japan
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Triscott S, Gordon J, Kuppuswamy A, King N, Davey N, Ellaway P. Differential effects of endurance and resistance training on central fatigue. J Sports Sci 2008; 26:941-51. [DOI: 10.1080/02640410701885439] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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Post M, Bayrak S, Kernell D, Zijdewind I. Contralateral muscle activity and fatigue in the human first dorsal interosseous muscle. J Appl Physiol (1985) 2008; 105:70-82. [DOI: 10.1152/japplphysiol.01298.2007] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
During effortful unilateral contractions, muscle activation is not limited to the target muscles but activity is also observed in contralateral muscles. The amount of this associated activity is depressed in a fatigued muscle, even after correction for fatigue-related changes in maximal force. In the present experiments, we aimed to compare fatigue-related changes in associated activity vs. parameters that are used as markers for changes in central nervous system (CNS) excitability. Subjects performed brief maximal voluntary contractions (MVCs) with the index finger in abduction direction before and after fatiguing protocols. We followed changes in MVCs, associated activity, motor-evoked potentials (MEP; transcranial magnetic stimulation), maximal compound muscle potentials (M waves), and superimposed twitches (double pulse) for 20 min after the fatiguing protocols. During the fatiguing protocols, associated activity increased in contralateral muscles, whereas afterwards the associated force was reduced in the fatigued muscle. This force reduction was significantly larger than the decline in MVC. However, associated activity (force and electromyography) remained depressed for only 5–10 min, whereas the MVCs stayed depressed for over 20 min. These decreases were accompanied by a reduction in MEP, MVC electromyography activity, and voluntary activation in the fatigued muscle. According to these latter markers, the decrease in CNS motor excitability lasted much longer than the depression in associated activity. Differential effects of fatigue on (associated) submaximal vs. maximal contractions might contribute to these differences in postfatigue behavior. However, we cannot exclude differences in processes that are specific to either voluntary or to associated contractions.
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Deshpande G, LaConte S, Peltier S, Hu X. Directed transfer function analysis of fMRI data to investigate network dynamics. CONFERENCE PROCEEDINGS : ... ANNUAL INTERNATIONAL CONFERENCE OF THE IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. ANNUAL CONFERENCE 2008; 2006:671-4. [PMID: 17946850 DOI: 10.1109/iembs.2006.259969] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
In this work, we have adapted the directed transfer function (DTF) to fMRI for the analysis of cortical network dynamics. While modern fMRI sequences are capable of sampling at second or sub-second rates, the underlying hemodynamic response limits the true temporal resolution to the order of 6-12 seconds. Therefore, DTF analysis of fMRI is appropriate for characterizing dynamics in brain response which evolves more slowly than the fMRI response, such as those during learning, fatigue and habituation. In such cases, the response to repeated trials will change with time and a summary measure from each trial can be used as input to the DTF analysis because these summary measures are of appropriate sampling rates and are not affected by the sluggishness of the hemodynamic response. As an example, we investigated the dynamic effects of muscle fatigue on the motor network. Specifically, DTF was used as a multivariate measure of the strength and direction of information flow between the various nodes of the network. We found that the primary motor area had a causal influence on the supplementary motor area, pre-motor area and cerebellum, and this influence initially increased with time and diminished towards the end of the experiment, probably as a result of fatigue.
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Affiliation(s)
- Gopikrishna Deshpande
- Dept. of Biomedical Engineering, Georgia Institute of Technology, Atlanta, GA 30322, USA
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Antal A, Terney D, Poreisz C, Paulus W. Towards unravelling task-related modulations of neuroplastic changes induced in the human motor cortex. Eur J Neurosci 2007; 26:2687-91. [DOI: 10.1111/j.1460-9568.2007.05896.x] [Citation(s) in RCA: 203] [Impact Index Per Article: 11.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Ross EZ, Nowicky AV, McConnell AK. Influence of acute inspiratory loading upon diaphragm motor-evoked potentials in healthy humans. J Appl Physiol (1985) 2007; 102:1883-90. [PMID: 17234806 DOI: 10.1152/japplphysiol.00694.2006] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Acute prior activity of the inspiratory muscles can enhance inspiratory muscle strength and reduce effort perception during subsequent inspiratory efforts. However, the mechanisms subserving these changes are poorly understood. Responses to magnetic stimulation in 10 subjects were studied after an acute bout of nonfatiguing inspiratory muscle loading (IML), corresponding to 40% of subjects’ initial maximal inspiratory pressure (MIP), and after an acute bout of nonloaded, forced inspiration (NLF). Motor-evoked potentials elicited by cortical stimulation (MEPc) and by phrenic nerve stimulation (MEPp) were recorded transcutaneously from the diaphragm before, immediately after, and 15 min after two sets of 30 inspiratory efforts, at rest and during an MIP effort. After IML, MIP increased to 113 ± 3% (SE) of baseline and diaphragm MEPp (during MIP) significantly increased (129 ± 10% of baseline). Diaphragmatic MEPc (during MIP), expressed as a percentage of maximal MEPp, decreased after IML (from 29 ± 9% to 20 ± 6%; P = 0.017) and after NLF (from 43 ± 5% to 31 ± 5%; P = 0.032). Observations from the biceps brachi demonstrated that changes after IML and NLF were specific to the inspiratory muscle, since no significant changes were observed in biceps force generation or in MEPp or MEPc amplitudes. These data indicate that after IML increased global inspiratory strength is accompanied by increased peripheral excitability and by a dampening of corticospinal excitability of the diaphragm.
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Affiliation(s)
- Emma Z Ross
- Centre for Sports Medicine and Human Performance, Brunel University, Uxbridge, Middlesex UB8 3PH, UK.
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Taube W, Gruber M, Beck S, Faist M, Gollhofer A, Schubert M. Cortical and spinal adaptations induced by balance training: correlation between stance stability and corticospinal activation. Acta Physiol (Oxf) 2007; 189:347-58. [PMID: 17263693 DOI: 10.1111/j.1748-1716.2007.01665.x] [Citation(s) in RCA: 133] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
AIM To determine the sites of adaptation responsible for improved stance stability after balance (=sensorimotor) training, changes in corticospinal and spinal excitability were investigated in 23 healthy subjects. METHODS Neural adaptations were assessed by means of H-reflex stimulation, transcranial magnetic stimulation (TMS) and conditioning of the H-reflex by TMS (Hcond) before and after 4 weeks of balance training. All measurements were performed during stance perturbation on a treadmill. Fast posterior translations induced short- (SLR), medium- and long-latency responses (LLR) in the soleus muscle. Motor-evoked potential- (MEP) and Hcond-amplitudes as well as Hmax/Mmax ratios were determined at SLR and LLR. Postural stability was measured during perturbation on the treadmill. RESULTS Balance training improved postural stability. Hmax/Mmax ratios were significantly decreased at LLR. MEPs and Hcond revealed significantly reduced facilitation at LLR following training. A negative correlation between adaptations of Hcond and changes in stance stability was observed (r = -0.87; P < 0.01) while no correlation was found between stance stability and changes in Hmax/Mmax ratio. No changes in any parameter occurred at the spinally organized SLR and in the control group. CONCLUSION The decrease in MEP- and Hcond-facilitation implies reduced corticospinal and cortical excitability at the transcortically mediated LLR. Changes in cortical excitability were directly related to improvements in stance stability as shown by correlation of these parameters. The absence of such a correlation between Hmax/Mmax ratios and stance stability suggests that mainly supraspinal adaptations contributed to improved balance performance following training.
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Affiliation(s)
- W Taube
- Department of Sport Science, University of Freiburg, Freiburg, Germany.
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Dayer MJ, Jonville S, Chatwin M, Swallow EB, Porcher R, Sharshar T, Ross ET, Hopkinson NS, Moxham J, Polkey MI. Exercise-induced depression of the diaphragm motor evoked potential is not affected by non-invasive ventilation. Respir Physiol Neurobiol 2007; 155:243-54. [PMID: 16914394 DOI: 10.1016/j.resp.2006.06.007] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2005] [Revised: 06/19/2006] [Accepted: 06/20/2006] [Indexed: 10/24/2022]
Abstract
Whole body exercise is followed by a depression of the diaphragm motor evoked potential (MEP). It is unknown whether the change is due to diaphragm activity or whole body exercise. To test the hypothesis that exercise-induced MEP depression was related to diaphragm activity, we performed two experiments. The first examined the effect of whole body exercise, performed with and without the use of non-invasive ventilation (NIV). NIV resulted in significant unloading of the diaphragm (pressure time product 101+/-68 cm H(2)O/s/min versus 278+/-95 cm H(2)O/s/min, p<0.001). Both conditions produced significant MEP depression compared to the control condition (% drop at 5 min, after exercise and exercise with NIV: 29 and 34%, p=0.77). Study 2 compared exercise with isocapnic hyperventilation. At 20 min the MEP had fallen by 29% in the exercise session versus 5% with hyperventilation (p=0.098). We conclude that the work of breathing during whole body exercise is not the primary driver of exercise-induced diaphragm MEP depression.
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Affiliation(s)
- Mark J Dayer
- Respiratory Muscle Laboratory, Royal Brompton Hospital, London SW3 6NP, United Kingdom
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41
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Taube W, Gruber M, Beck S, Faist M, Gollhofer A, Schubert M. Cortical and spinal adaptations induced by balance training: correlation between stance stability and corticospinal activation. Acta Physiol (Oxf) 2007. [DOI: 10.1111/j.1365-201x.2007.01665.x] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Paine PA, Aziz Q, Gardener E, Hobson A, Mistry S, Thompson DG, Hamdy S. Assessing the temporal reproducibility of human esophageal motor-evoked potentials to transcranial magnetic stimulation. J Clin Neurophysiol 2006; 23:374-80. [PMID: 16885712 DOI: 10.1097/01.wnp.0000209578.08391.e2] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
Abstract
BACKGROUND Although the electrophysiological properties and reproducibility of somatic limb motor evoked potentials (MEPs) to transcranial magnetic stimulation (TMS) are well characterized, little is known about the reproducibility of MEPs for viscerosomatic structures such as the esophagus. AIM To determine the temporal reproducibility of esophageal MEPs to TMS. METHODS MEPs to TMS were recorded from the proximal esophagus, using a swallowed catheter housing a pair of electrodes, in eight healthy subjects at five stimulus intensities (SI) (motor threshold [MT] to 20% above MT). For each SI, 20 consecutive TMS stimuli at 5-second intervals were delivered over a single scalp site (dominant hemisphere at site exhibiting MT at lowest SI) and repeated 40 and 80 minutes thereafter. MEP amplitudes and latencies were measured, and means were sequentially calculated for each SI and then log-transformed. The repeatability coefficients (RC) for the three time points were calculated across each set of 20 stimuli and presented as an exponential ratio. RESULTS Best RC (amplitude/latency) were achieved at 120% SI relative to MT, being 1.8/1.2 (optimal = 1.0). For lower intensities of 115%, 110%, 105%, and 100% SI, the RC were 2.1/1.2, 2.1/1.1, 2.4/1.2, and 2.6/1.4, respectively. For all SI, the greatest reductions in RC occurred over the first 10 stimuli, with little additional gain beyond this number. CONCLUSIONS Latencies of esophageal MEP to TMS across intensities are highly reproducible, whereas amplitudes are more stimulus intensity-dependent, being most reliable and reproducible at the highest stimulus strengths. SIGNIFICANCE Using careful parameters, TMS can be used reliably in future studies of viscerosomatic structures, although the size of the response variability needs to be taken into account when assessing changes in cortico-fugal activity.
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Affiliation(s)
- P A Paine
- Department of Gastrointestinal Sciences and Statistics, Hope Hospital, Salford, University of Manchester, United Kingdom
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Kalmar JM, Cafarelli E. Central excitability does not limit postfatigue voluntary activation of quadriceps femoris. J Appl Physiol (1985) 2006; 100:1757-64. [PMID: 16424071 DOI: 10.1152/japplphysiol.01347.2005] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Abstract
After fatigue, motor evoked potentials (MEP) elicited by transcranial magnetic stimulation and cervicomedullary evoked potentials elicited by stimulation of the corticospinal tract are depressed. These reductions in corticomotor excitability and corticospinal transmission are accompanied by voluntary activation failure, but this may not reflect a causal relationship. Our purpose was to determine whether a decline in central excitability contributes to central fatigue. We hypothesized that, if central excitability limits voluntary activation, then a caffeine-induced increase in central excitability should offset voluntary activation failure. In this repeated-measures study, eight men each attended two sessions. Baseline measures of knee extension torque, maximal voluntary activation, peripheral transmission, contractile properties, and central excitability were made before administration of caffeine (6 mg/kg) or placebo. The amplitude of vastus lateralis MEPs elicited during minimal muscle activation provided a measure of central excitability. After a 1-h rest, baseline measures were repeated before, during, and after a fatigue protocol that ended when maximal voluntary torque declined by 35% (Tlim). Increased prefatigue MEP amplitude ( P = 0.055) and cortically evoked twitch ( P < 0.05) in the caffeine trial indicate that the drug increased central excitability. In the caffeine trial, increased MEP amplitude was correlated with time to task failure ( r = 0.74, P < 0.05). Caffeine potentiated the MEP early in the fatigue protocol ( P < 0.05) and offset the 40% decline in placebo MEP ( P < 0.05) at Tlim. However, this was not associated with enhanced maximal voluntary activation during fatigue or recovery, demonstrating that voluntary activation is not limited by central excitability.
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Affiliation(s)
- J M Kalmar
- Department of Biology, Rm. 346, Bethune College, York University, 4700 Keele St., Toronto, ON, Canada M3J 1P3
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Maruyama A, Matsunaga K, Tanaka N, Rothwell JC. Muscle fatigue decreases short-interval intracortical inhibition after exhaustive intermittent tasks. Clin Neurophysiol 2006; 117:864-70. [PMID: 16495147 DOI: 10.1016/j.clinph.2005.12.019] [Citation(s) in RCA: 63] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2005] [Revised: 11/15/2005] [Accepted: 12/20/2005] [Indexed: 11/29/2022]
Abstract
OBJECTIVE Central fatigue is the inability of central commands to recruit maximum evocable muscle force during voluntary contraction. Here, we investigate how fatigue affects the inhibitory circuits of the motor cortex. METHODS MEPs, short interval intracortical inhibition (SICI) and intracortical facilitation (ICF) were evaluated using a paired pulse transcranial magnetic stimulation (TMS) paradigm before, during and after a series of 5 isometric contractions of the FDI muscle to 50% maximal voluntary contraction (MVC). Each contraction lasted 2 min and was separated from the next by a pause of 2 min 40 s. Twelve male healthy subjects (range from 22 to 51 years) participated in experiment 1, in which the intensity of test stimulus was constant throughout the experiment. Eight of the same subjects (range from 26 to 51 years) participated in experiment 2, in which the intensity of test stimulus was adjusted so that the amplitude of the test MEP was kept constant throughout the measurement. RESULTS As expected, test MEPs gradually decreased with progressive fatigue and recovered to control values with 5-10 min of rest. Because of the change in MEP amplitude, changes in percent SICI (reduced inhibition) and percent ICF (increased facilitation) in experiment 1 are difficult to interpret. When the test MEP was maintained at a constant size in experiment 2 there was no change in percent ICF, but the reduction in SICI was still present although it recovered to control values within the first 5-10 min of rest. CONCLUSIONS SICI in FDI decreases transiently after a series of fatiguing isometric contractions. This decrease may compensate to some extent for reduced cortical excitability after muscle fatigue.
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Affiliation(s)
- Atsuo Maruyama
- Sobell Department of Motor Neuroscience and Movement Disorders, Institute of Neurology, University College London, London, UK.
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Liu JZ, Yao B, Siemionow V, Sahgal V, Wang X, Sun J, Yue GH. Fatigue induces greater brain signal reduction during sustained than preparation phase of maximal voluntary contraction. Brain Res 2006; 1057:113-26. [PMID: 16129419 DOI: 10.1016/j.brainres.2005.07.064] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2005] [Revised: 07/19/2005] [Accepted: 07/21/2005] [Indexed: 11/22/2022]
Abstract
Animal studies have shown that there are cell populations only discharging phasically before a motor task and others only active tonically during holding phase of the task. How muscle fatigue influences these two types of cell populations, however, is unknown. Because the phasic neurons are only active briefly before the task but the tonic ones are active continuously throughout the task, we hypothesized that fatigue would have a less effect on cortical signals during the preparation phase (representing phasic discharge) than that during the sustained phase (representing tonic discharge). Eight participants performed 200 handgrip maximal voluntary contractions (MVCs) with simultaneous recordings of scalp electroencephalographic (EEG), handgrip force, and finger flexor surface electromyographic (EMG) signals. Power spectrograms of the EEG during the preparation and sustained phases were analyzed in each of the five 40-trial blocks, with data from the first block representing a condition of moderate fatigue and the last, severe fatigue. Movement-related cortical potential (MRCP) was derived by trigger-averaging 40 EEG epochs in each block. The power of all EEG frequencies did not alter significantly during the preparation phase but decreased significantly during the sustained phase of the contraction. The MRCP negative potential (NP) related to motor task preparation only showed minimal changes. These results suggest that MVC-induced fatigue has differential effects on cortical signals during motor task preparation compared to its execution and maintenance. The signals of the two phases may represent activities of the two cortical cell populations previously found by animal studies.
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Affiliation(s)
- Jing Z Liu
- Department of Biomedical Engineering, Lerner Research Institute, The Cleveland Clinic Foundation, Cleveland, OH 44195, USA
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Peltier SJ, LaConte SM, Niyazov DM, Liu JZ, Sahgal V, Yue GH, Hu XP. Reductions in interhemispheric motor cortex functional connectivity after muscle fatigue. Brain Res 2005; 1057:10-6. [PMID: 16140287 DOI: 10.1016/j.brainres.2005.06.078] [Citation(s) in RCA: 65] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2004] [Revised: 06/23/2005] [Accepted: 06/25/2005] [Indexed: 11/19/2022]
Abstract
Muscle fatigue has been known to differentially affect the activation level of the primary motor cortices (MIs) of the brain's two hemispheres. Whether this fatigue-related decoupling influence on the motor cortical signals extends beyond the motor action to the after-fatigue-task resting state is unknown. This question can be addressed by analyzing functional connectivity (FC) of low-frequency oscillations of resting-state functional MRI (fMRI) signals of the MIs. Low-frequency oscillations (<0.08 Hz) have been detected in many fMRI studies and appear to be synchronized between functionally related areas. These patterns of FC have been shown to differ between normal and various pathological states. The purpose of this study was to examine muscle fatigue-induced resting-state interhemispheric motor cortex FC changes in healthy subjects. We hypothesized that muscle fatigue would create a temporary "disrupted state" in the brain, and would decrease resting state interhemispheric motor cortical FC. Ten healthy subjects performed repetitive unilateral handgrip contractions that induced significant muscle fatigue, with resting state fMRI data collected before and after the task. After excluding two subjects due to gross head motion, interhemispheric motor cortex FC was assessed by cross-correlating the MI fMRI signal time courses. We found that the number of significant interhemispheric correlations in the MI fMRI signals decreased significantly after the performance of the fatigue task. These results suggest that resting state interhemispheric motor cortex FC may be used as an index of recovery from fatigue.
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Affiliation(s)
- Scott J Peltier
- Biomedical Engineering, Emory University/Georgia Tech, Hospital Annex, 531 Asbury Circle, Suite N305, Atlanta, GA 30322-4600, USA.
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Liu JZ, Zhang L, Yao B, Sahgal V, Yue GH. Fatigue induced by intermittent maximal voluntary contractions is associated with significant losses in muscle output but limited reductions in functional MRI-measured brain activation level. Brain Res 2005; 1040:44-54. [PMID: 15804425 DOI: 10.1016/j.brainres.2005.01.059] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2004] [Revised: 01/12/2005] [Accepted: 01/13/2005] [Indexed: 11/24/2022]
Abstract
The main purpose of this study was to characterize brain activation patterns during a fatigue task involving repetitive maximal voluntary contractions (MVC) of finger flexor muscles. Fourteen young, healthy human participants performed approximately 100 handgrip MVCs (each 2-s contraction was followed by a 1-s rest) while their brain was imaged by functional MRI (fMRI). The handgrip force and electromyograms (EMG) of the finger flexors declined progressively to about 40% of the initial values at the end of the fatigue task, suggesting that significant muscle fatigue had occurred. In contrast, the level of the fMRI signal in the primary (sensorimotor), secondary (supplementary motor), and association (prefrontal and cingulate) motor-function cortices did not change significantly throughout the fatigue task (although the signal of the primary sensorimotor cortex showed a clear trend of decline). The fMRI data from the task of intermittent handgrip MVCs differed dramatically from those obtained in a 2-min sustained handgrip MVC published in a recent report, in which the overall fMRI-measured brain activation level was substantially lower and followed an increase-then-decrease pattern compared to the linear decreases in force and EMG. These results support the notion that the motor cortical centers control the tasks of repetitive and continuous muscle contractions differently and that there is a decoupling in the signal changes of the brain and muscles during muscle fatigue processes induced by maximal voluntary contractions.
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Affiliation(s)
- Jing Z Liu
- Department of Biomedical Engineering, Lerner Research Institute, The Cleveland Clinic Foundation, Cleveland, OH 44195, USA
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Pitcher JB, Robertson AL, Clover EC, Jaberzadeh S. Facilitation of cortically evoked potentials with motor imagery during post-exercise depression of corticospinal excitability. Exp Brain Res 2004; 160:409-17. [PMID: 15502993 DOI: 10.1007/s00221-004-2021-z] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2003] [Accepted: 05/14/2004] [Indexed: 11/28/2022]
Abstract
This study examined whether muscle fatigue alters the facilitatory effect of motor imagery on corticospinal excitability. We aimed to determine if post-exercise depression of potentials evoked magnetically from the motor cortex is associated with alterations in internally generated movement plans. In experiment 1, motor-evoked potentials (MEPs) were recorded from two right hand and two right forearm muscles, at rest and during motor imagery of a maximal handgrip contraction, in eight neurologically normal subjects, before and after a 2-min maximal voluntary handgrip contraction. Resting MEP amplitude was facilitated by motor imagery in three of the four muscles, but consistently only in two. Motor imagery also reduced the trial-to-trial variability of resting MEPs. Following the exercise, resting MEP amplitude was depressed reliably in only one muscle engaged in the task, although two other muscles exhibited some depression. Motor imagery MEPs were smaller after exercise, but the degree of facilitation compared to the rest MEP was unchanged. In experiment 2, TMS intensity was increased after exercise-induced MEP depression so that the MEP amplitude matched the pre-exercise baseline. The amplitude of the MEP facilitated with motor imagery was not altered by MEP depression, nor was it increased when the TMS intensity was increased. These results suggest, at least with a simple motor task, that while post-exercise depression reduces corticospinal excitability, it does not appear to significantly affect the strength of the input to the motor cortex from those areas of the brain responsible for the storage and generation of internal representations of movement.
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Affiliation(s)
- Julia B Pitcher
- Discipline of Physiology, School of Molecular and Biomedical Sciences, The University of Adelaide, 5005, Adelaide, South Australia, Australia.
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Kalmar JM, Cafarelli E. Central fatigue and transcranial magnetic stimulation: effect of caffeine and the confound of peripheral transmission failure. J Neurosci Methods 2004; 138:15-26. [PMID: 15325107 DOI: 10.1016/j.jneumeth.2004.03.006] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2003] [Revised: 02/27/2004] [Accepted: 03/04/2004] [Indexed: 10/26/2022]
Abstract
In this experiment, we attempt to replicate the fatigue-induced decline in voluntary surface electromyography (EMG) and motor evoked potentials (MEPs) observed in previous studies and determine: (1) if this decline can be attributed to central failure, and (2) whether this failure is offset by caffeine. Seven subjects each attended two sessions (caffeine and placebo). Central excitability was estimated using transcranial magnetic stimulation (TMS), and surface EMG and twitch interpolation were used to estimate voluntary activation before, during and after fatigue of the first dorsal interosseous (FDI). Mass action potentials (M waves) were evoked to assess peripheral transmission throughout the experiment. We observed an increase in post-activation potentiation of the motor evoked potential in the caffeine trial and a fatigue-induced decline in the MEP and maximal EMG in both the placebo and caffeine trials. However, there was also a fatigue-induced decline in peripheral transmission, and estimates of central failure were considerably reduced when normalized to the M wave. A review of central fatigue literature revealed many studies that attribute the decline in voluntary EMG or MEPs wholly to central failure and fail to consider peripheral transmission. Thus, we conclude by stressing the importance of reporting peripheral transmission when surface recordings are used to estimate central mechanisms.
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Affiliation(s)
- Jayne M Kalmar
- Department of Biology, York University, Toronto, Ont., Canada
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Humphry AT, Lloyd-Davies EJ, Teare RJ, Williams KE, Strutton PH, Davey NJ. Specificity and functional impact of post-exercise depression of cortically evoked motor potentials in man. Eur J Appl Physiol 2004; 92:211-8. [PMID: 15045505 DOI: 10.1007/s00421-004-1082-9] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/10/2004] [Indexed: 10/26/2022]
Abstract
Magnetic stimulation of the motor cortex with electromyographic recordings from exercising muscles has shown corticospinal excitability to be depressed following exercise. We now investigate whether this depression spreads to non-exercising muscles and its influence on performance. Healthy volunteers made unilateral biceps curls to exhaustion and, in another later session, for 25% of the time to exhaustion. Bilateral motor-evoked potentials (MEPs) in biceps brachii and first dorsal interosseus muscles were measured at 2-min intervals before and after exercise. In another experiment, subjects performed exhaustive curls and, in addition to MEP areas, force production in biceps, hand-grip force, simple reaction times and movement times were measured bilaterally. MEPs were depressed after exhaustive exercise in the exercising biceps for over 60 min; depression was also observed 10-15 min after exercise in the non-exercising biceps but not in the first dorsal interosseus of either hand. The shorter exercise period produced depression of MEPs only in the exercising muscle. After exhaustive exercise maximum voluntary contraction fell in the exercising biceps and this correlated with MEP areas. No reduction in force was seen in the non-exercising biceps but hand-grip force fell slightly in both arms. There was no change in reaction times or movement times. Depression of MEPs can occur in non-exercising homonymous muscles but not in heteronymous muscles and only when exercise levels are high. There was no measurable functional deficit in the non-exercising limb, so we conclude that the reduced corticospinal excitability observed in this limb has little or no consequence on the performance parameters measured.
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Affiliation(s)
- A T Humphry
- Department of Sensorimotor Systems, Division of Neuroscience and Psychological Medicine, Imperial College London, Charing Cross Hospital, London, W6 8RF, UK
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