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Kuhn YA, Egger S, Bugnon M, Lehmann N, Taubert M, Taube W. Age-related decline in GABAergic intracortical inhibition can be counteracted by long-term learning of balance skills. J Physiol 2024; 602:3737-3753. [PMID: 38949035 DOI: 10.1113/jp285706] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2023] [Accepted: 06/11/2024] [Indexed: 07/02/2024] Open
Abstract
Ageing induces a decline in GABAergic intracortical inhibition, which seems to be associated not only with decremental changes in well-being, sleep quality, cognition and pain management but also with impaired motor control. So far, little is known regarding whether targeted interventions can prevent the decline of intracortical inhibition in the primary motor cortex in the elderly. Therefore, the present study investigated whether age-related cortical dis-inhibition could be reversed after 6 months of balance learning and whether improvements in postural control correlated with the extent of reversed dis-inhibition. The results demonstrated that intracortical inhibition can be upregulated in elderly subjects after long-term balance learning and revealed a correlation between changes in balance performance and intracortical inhibition. This is the first study to show physical activity-related upregulation of GABAergic inhibition in a population with chronic dis-inhibition and may therefore be seminal for many pathologies in which the equilibrium between inhibitory and excitatory neurotransmitters is disturbed. KEY POINTS: Ageing induces a decline in GABAergic intracortical inhibition. So far, little is known regarding whether targeted interventions can prevent the decline of intracortical inhibition in the primary motor cortex in the elderly. After 6 months of balance learning, intracortical inhibition can be upregulated in elderly subjects. The results of this study also revealed a correlation between changes in balance performance and intracortical inhibition. This is the first study to show physical activity-related upregulation of GABAergic inhibition in a population with chronic dis-inhibition.
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Affiliation(s)
- Yves-Alain Kuhn
- Department of Neurosciences and Movement Science, Faculty of Science and Medicine, University of Fribourg, Fribourg, Switzerland
| | - Sven Egger
- Department of Neurosciences and Movement Science, Faculty of Science and Medicine, University of Fribourg, Fribourg, Switzerland
| | - Matteo Bugnon
- Department of Neurosciences and Movement Science, Faculty of Science and Medicine, University of Fribourg, Fribourg, Switzerland
| | - Nico Lehmann
- Department of Neurosciences and Movement Science, Faculty of Science and Medicine, University of Fribourg, Fribourg, Switzerland
- Department of Sport Science, Institute III, Faculty of Humanities, Otto von Guericke University, Magdeburg, Germany
- Department of Neurology, Max Planck Institute for Human Cognitive and Brain Sciences, Leipzig, Germany
- Collaborative Research Center 1436 Neural Resources of Cognition, Otto von Guericke University, Magdeburg, Germany
| | - Marco Taubert
- Department of Sport Science, Institute III, Faculty of Humanities, Otto von Guericke University, Magdeburg, Germany
- Collaborative Research Center 1436 Neural Resources of Cognition, Otto von Guericke University, Magdeburg, Germany
- Center for Behavioral and Brain Science (CBBS), Otto von Guericke University, Universitätsplatz 2, Magdeburg, Germany
| | - Wolfgang Taube
- Department of Neurosciences and Movement Science, Faculty of Science and Medicine, University of Fribourg, Fribourg, Switzerland
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Gomez-Guerrero G, Avela J, Jussila I, Pihlajamäki E, Deng FY, Kidgell DJ, Ahtiainen JP, Walker S. Cortical and spinal responses to short-term strength training and detraining in young and older adults in rectus femoris muscle. Eur J Appl Physiol 2024; 124:2209-2223. [PMID: 38441691 PMCID: PMC11199260 DOI: 10.1007/s00421-024-05443-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2023] [Accepted: 02/14/2024] [Indexed: 06/27/2024]
Abstract
INTRODUCTION Strength training mitigates the age-related decline in strength and muscle activation but limited evidence exists on specific motor pathway adaptations. METHODS Eleven young (22-34 years) and ten older (66-80 years) adults underwent five testing sessions where lumbar-evoked potentials (LEPs) and motor-evoked potentials (MEPs) were measured during 20 and 60% of maximum voluntary contraction (MVC). Ten stimulations, randomly delivered, targeted 25% of maximum compound action potential for LEPs and 120, 140, and 160% of active motor threshold (aMT) for MEPs. The 7-week whole-body resistance training intervention included five exercises, e.g., knee extension (5 sets) and leg press (3 sets), performed twice weekly and was followed by 4 weeks of detraining. RESULTS Young had higher MVC (~ 63 N·m, p = 0.006), 1-RM (~ 50 kg, p = 0.002), and lower aMT (~ 9%, p = 0.030) than older adults at baseline. Young increased 1-RM (+ 18 kg, p < 0.001), skeletal muscle mass (SMM) (+ 0.9 kg, p = 0.009), and LEP amplitude (+ 0.174, p < 0.001) during 20% MVC. Older adults increased MVC (+ 13 N·m, p = 0.014), however, they experienced decreased LEP amplitude (- 0.241, p < 0.001) during 20% MVC and MEP amplitude reductions at 120% (- 0.157, p = 0.034), 140% (- 0.196, p = 0.026), and 160% (- 0.210, p = 0.006) aMT during 60% MVC trials. After detraining, young and older adults decreased 1-RM, while young adults decreased SMM. CONCLUSION Higher aMT and MEP amplitude in older adults were concomitant with lower baseline strength. Training increased strength in both groups, but divergent modifications in cortico-spinal activity occurred. Results suggest that the primary locus of adaptation occurs at the spinal level.
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Affiliation(s)
- Gonzalo Gomez-Guerrero
- Faculty of Sport and Health Sciences, NeuroMuscular Research Center, Viveca, VIV221, University of Jyväskylä, 40700, Jyväskylä, Finland.
| | - Janne Avela
- Faculty of Sport and Health Sciences, NeuroMuscular Research Center, Viveca, VIV221, University of Jyväskylä, 40700, Jyväskylä, Finland
| | - Ilkka Jussila
- Faculty of Sport and Health Sciences, NeuroMuscular Research Center, Viveca, VIV221, University of Jyväskylä, 40700, Jyväskylä, Finland
| | - Esa Pihlajamäki
- Faculty of Sport and Health Sciences, NeuroMuscular Research Center, Viveca, VIV221, University of Jyväskylä, 40700, Jyväskylä, Finland
| | - Fu-Yu Deng
- Faculty of Sport and Health Sciences, NeuroMuscular Research Center, Viveca, VIV221, University of Jyväskylä, 40700, Jyväskylä, Finland
| | - Dawson J Kidgell
- Monash Exercise Neuroplasticity Research Unit, School of Primary and Allied Health Care, Faculty of Medicine, Nursing and Health Sciences, Monash University, Melbourne, Australia
| | - Juha P Ahtiainen
- Faculty of Sport and Health Sciences, NeuroMuscular Research Center, Viveca, VIV221, University of Jyväskylä, 40700, Jyväskylä, Finland
| | - Simon Walker
- Faculty of Sport and Health Sciences, NeuroMuscular Research Center, Viveca, VIV221, University of Jyväskylä, 40700, Jyväskylä, Finland
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Nùñez-Lisboa M, Valero-Breton M, Dewolf AH. Unraveling age-related impairment of the neuromuscular system: exploring biomechanical and neurophysiological perspectives. Front Physiol 2023; 14:1194889. [PMID: 37427405 PMCID: PMC10323685 DOI: 10.3389/fphys.2023.1194889] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2023] [Accepted: 06/14/2023] [Indexed: 07/11/2023] Open
Abstract
With extended life expectancy, the quality of life of elders is a priority. Loss of mobility, increased morbidity and risks of falls have dramatic individual and societal impacts. Here we consider the age-related modifications of gait, from a biomechanical and neurophysiological perspective. Among the many factors of frailty involved (e.g., metabolic, hormonal, immunological), loss of muscle strength and neurodegenerative changes inducing slower muscle contraction may play a key role. We highlight that the impact of the multifactorial age-related changes in the neuromuscular systems results in common features of gait in the immature gait of infants and older adults. Besides, we also consider the reversibility of age-related neuromuscular deterioration by, on the one hand, exercise training, and the other hand, novel techniques such as direct spinal stimulation (tsDCS).
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Affiliation(s)
- M. Nùñez-Lisboa
- Laboratoire de Biomécanique et Physiologie et la Locomotion, Institute of Neuroscience, Louvain-la-Neuve, Belgium
- Exercise Science Laboratory, School of Kinesiology, Faculty of Medicine, Universidad Finis Terrae, Santiago, Chile
| | - M. Valero-Breton
- Exercise Science Laboratory, School of Kinesiology, Faculty of Medicine, Universidad Finis Terrae, Santiago, Chile
| | - A. H. Dewolf
- Laboratoire de Biomécanique et Physiologie et la Locomotion, Institute of Neuroscience, Louvain-la-Neuve, Belgium
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Theodosiadou A, Henry M, Duchateau J, Baudry S. Revisiting the use of Hoffmann reflex in motor control research on humans. Eur J Appl Physiol 2023; 123:695-710. [PMID: 36571622 DOI: 10.1007/s00421-022-05119-7] [Citation(s) in RCA: 9] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2022] [Accepted: 12/17/2022] [Indexed: 12/27/2022]
Abstract
Research in movement science aims at unravelling mechanisms and designing methods for restoring and maximizing human functional capacity, and many techniques provide access to neural adjustments (acute changes) or long-term adaptations (chronic changes) underlying changes in movement capabilities. First described by Paul Hoffmann over a century ago, when an electrical stimulus is applied to a peripheral nerve, this causes action potentials in afferent axons, primarily the Ia afferents of the muscle spindles, which recruit homonymous motor neurons, thereby causing an electromyographic response known as the Hoffmann (H) reflex. This technique is a valuable tool in the study of the neuromuscular function in humans and has provided relevant information in the neural control of movement. The large use of the H reflex in motor control research on humans relies in part to its relative simplicity. However, such simplicity masks subtleties that require rigorous experimental protocols and careful data interpretation. After highlighting basic properties and methodological aspects that should be considered for the correct use of the H-reflex technique, this brief narrative review discusses the purpose of the H reflex and emphasizes its use as a tool to assess the effectiveness of Ia afferents in discharging motor neurones. The review also aims to reconsider the link between H-reflex modulation and Ia presynaptic inhibition, the use of the H-reflex technique in motor control studies, and the effects of ageing. These aspects are summarized as recommendations for the use of the H reflex in motor control research on humans.
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Affiliation(s)
- Anastasia Theodosiadou
- Laboratory of Applied Biology, Research Unit in Applied Neurophysiology (LABNeuro), Faculty of Motor Sciences, ULB-Neurosciences Institute (UNI), Université Libre de Bruxelles (ULB), 808 Route de Lennik, CP 640, 1070, Brussels, Belgium
| | - Mélanie Henry
- Laboratory of Applied Biology, Research Unit in Applied Neurophysiology (LABNeuro), Faculty of Motor Sciences, ULB-Neurosciences Institute (UNI), Université Libre de Bruxelles (ULB), 808 Route de Lennik, CP 640, 1070, Brussels, Belgium
| | - Jacques Duchateau
- Laboratory of Applied Biology, Research Unit in Applied Neurophysiology (LABNeuro), Faculty of Motor Sciences, ULB-Neurosciences Institute (UNI), Université Libre de Bruxelles (ULB), 808 Route de Lennik, CP 640, 1070, Brussels, Belgium
| | - Stéphane Baudry
- Laboratory of Applied Biology, Research Unit in Applied Neurophysiology (LABNeuro), Faculty of Motor Sciences, ULB-Neurosciences Institute (UNI), Université Libre de Bruxelles (ULB), 808 Route de Lennik, CP 640, 1070, Brussels, Belgium.
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Batista-Ferreira L, Rabelo NF, da Cruz GM, Costa JNDA, Elias LA, Mezzarane RA. Effects of voluntary contraction on the soleus H-reflex of different amplitudes in healthy young adults and in the elderly. Front Hum Neurosci 2022; 16:1039242. [PMID: 36590063 PMCID: PMC9797586 DOI: 10.3389/fnhum.2022.1039242] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2022] [Accepted: 11/30/2022] [Indexed: 12/23/2022] Open
Abstract
A number of H-reflex studies used a moderate steady voluntary contraction in an attempt to keep the motoneuron pool excitability relatively constant. However, it is not clear whether the voluntary muscle activation itself represents a confounding factor for the elderly, as a few ongoing mechanisms of reflex modulation might be compromised. Further, it is well-known that the amount of either inhibition or facilitation from a given conditioning depends on the size of the test H-reflex. The present study aimed at evaluating the effects of voluntary contraction over a wide range of reflex amplitudes. A significant reflex facilitation during an isometric voluntary contraction of the soleus muscle (15% of the maximal voluntary isometric contraction-MVC) was found for both young adults and the elderly (p < 0.05), regardless of their test reflex amplitudes (considering the ascending limb of the H-reflex recruitment curve-RC). No significant difference was detected in the level of reflex facilitation between groups for all the amplitude parameters extracted from the RC. Simulations with a computational model of the motoneuron pool driven by stationary descending commands yielded qualitatively similar amount of reflex facilitation, as compared to human experiments. Both the experimental and modeling results suggest that possible age-related differences in spinal cord mechanisms do not significantly influence the reflex modulation during a moderate voluntary muscle activation. Therefore, a background voluntary contraction of the ankle extensors (e.g., similar to the one necessary to maintain upright stance) can be used in experiments designed to compare the RCs of both populations. Finally, in an attempt to elucidate the controversy around changes in the direct motor response (M-wave) during contraction, the maximum M-wave (Mmax) was compared between groups and conditions. It was found that the Mmax significantly increases (p < 0.05) during contraction and decreases (p < 0.05) with age arguably due to muscle fiber shortening and motoneuron loss, respectively.
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Affiliation(s)
- Leandra Batista-Ferreira
- Laboratory of Signal Processing and Motor Control, Faculty of Physical Education, University of Brasília, Brasília, Goiás, Brazil
| | - Natielle Ferreira Rabelo
- Neural Engineering Research Laboratory, Center for Biomedical Engineering, University of Campinas, Campinas, São Paulo, Brazil,Department of Electronics and Biomedical Engineering, School of Electrical and Computer Engineering, University of Campinas, Campinas, São Paulo, Brazil
| | - Gabriel Menezes da Cruz
- Laboratory of Signal Processing and Motor Control, Faculty of Physical Education, University of Brasília, Brasília, Goiás, Brazil
| | | | - Leonardo Abdala Elias
- Neural Engineering Research Laboratory, Center for Biomedical Engineering, University of Campinas, Campinas, São Paulo, Brazil,Department of Electronics and Biomedical Engineering, School of Electrical and Computer Engineering, University of Campinas, Campinas, São Paulo, Brazil
| | - Rinaldo André Mezzarane
- Laboratory of Signal Processing and Motor Control, Faculty of Physical Education, University of Brasília, Brasília, Goiás, Brazil,Postgraduate Program in Biomedical Engineering, University of Brasília, Brasília, Goiás, Brazil,*Correspondence: Rinaldo André Mezzarane,
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Epiu I, Gandevia SC, Boswell‐Ruys CL, Carter SG, Finn HT, Nguyen DAT, Butler JE, Hudson AL. Respiratory-related evoked potentials in chronic obstructive pulmonary disease and healthy aging. Physiol Rep 2022; 10:e15519. [PMID: 36461659 PMCID: PMC9718949 DOI: 10.14814/phy2.15519] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2022] [Accepted: 11/02/2022] [Indexed: 06/17/2023] Open
Abstract
Altered neural processing and increased respiratory sensations have been reported in chronic obstructive pulmonary disease (COPD) as larger respiratory-related evoked potentials (RREPs), but the effect of healthy-aging has not been considered adequately. We tested RREPs evoked by brief airway occlusions in 10 participants with moderate-to-severe COPD, 11 age-matched controls (AMC) and 14 young controls (YC), with similar airway occlusion pressure stimuli across groups. Mean age was 76 years for COPD and AMC groups, and 30 years for the YC group. Occlusion intensity and unpleasantness was rated using the modified Borg scale, and anxiety rated using the Hospital Anxiety and Depression Scale. There was no difference in RREP peak amplitudes across groups, except for the N1 peak, which was significantly greater in the YC group than the COPD and AMC groups (p = 0.011). The latencies of P1, P2 and P3 occurred later in COPD versus YC (p < 0.05). P3 latency occurred later in AMC than YC (p = 0.024). COPD and AMC groups had similar Borg ratings for occlusion intensity (3.0 (0.5, 3.5) [Median (IQR)] and 3.0 (3.0, 3.0), respectively; p = 0.476) and occlusion unpleasantness (1.3 (0.1, 3.4) and 1.0 (0.75, 2.0), respectively; p = 0.702). The COPD group had a higher anxiety score than AMC group (p = 0.013). A higher N1 amplitude suggests the YC group had higher cognitive processing of respiratory inputs than the COPD and AMC groups. Both COPD and AMC groups showed delayed neural responses to the airway occlusion, which may indicate impaired processing of respiratory sensory inputs in COPD and healthy aging.
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Affiliation(s)
- Isabella Epiu
- Neuroscience Research AustraliaRandwickNew South WalesAustralia
- University of New South WalesSydneyNew South WalesAustralia
- Prince of Wales HospitalSydneyNew South WalesAustralia
| | - Simon C. Gandevia
- Neuroscience Research AustraliaRandwickNew South WalesAustralia
- University of New South WalesSydneyNew South WalesAustralia
- Prince of Wales HospitalSydneyNew South WalesAustralia
| | - Claire L. Boswell‐Ruys
- Neuroscience Research AustraliaRandwickNew South WalesAustralia
- University of New South WalesSydneyNew South WalesAustralia
- Prince of Wales HospitalSydneyNew South WalesAustralia
| | - Sophie G. Carter
- Neuroscience Research AustraliaRandwickNew South WalesAustralia
- University of New South WalesSydneyNew South WalesAustralia
| | - Harrison T. Finn
- Neuroscience Research AustraliaRandwickNew South WalesAustralia
- University of New South WalesSydneyNew South WalesAustralia
| | - David A. T. Nguyen
- Neuroscience Research AustraliaRandwickNew South WalesAustralia
- University of New South WalesSydneyNew South WalesAustralia
| | - Jane E. Butler
- Neuroscience Research AustraliaRandwickNew South WalesAustralia
- University of New South WalesSydneyNew South WalesAustralia
| | - Anna L. Hudson
- Neuroscience Research AustraliaRandwickNew South WalesAustralia
- University of New South WalesSydneyNew South WalesAustralia
- College of Medicine and Public HealthFlinders UniversityBedford ParkSouth AustraliaAustralia
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Russell C, Difford N, Stamenkovic A, Stapley P, McAndrew D, Arpel C, MacKinnon C, Shemmell J. Postural support requirements preferentially modulate late components of the gastrocnemius response to transcranial magnetic stimulation. Exp Brain Res 2022; 240:2647-2657. [PMID: 36006434 PMCID: PMC9510120 DOI: 10.1007/s00221-022-06440-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2022] [Accepted: 08/05/2022] [Indexed: 11/27/2022]
Abstract
Mounting evidence suggests that motor evoked potentials (MEPs) recorded in upper limb muscles with postural support roles following transcranial magnetic stimulation receive contributions from both corticospinal and non-corticospinal descending pathways. We tested the hypothesis that neural structures responsible for regulating upright balance are involved in transmitting late portions of TMS-induced MEPs in a lower limb muscle. MEPs were recorded in the medial gastrocnemius muscles of each leg, while participants supported their upright posture in five postural conditions that required different levels of support from the target muscles. We observed that early and late portions of the MEP were modulated independently, with early MEP amplitude being reduced when high levels of postural support were required from a target muscle. Independent modulation of early and late MEPs by altered postural demand suggests largely separable transmission of each part of the MEP. The early component of the MEP is likely generated by fast-conducting corticospinal pathways, whereas the later component may be primarily transmitted along a polysynaptic cortico-reticulospinal pathway.
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Affiliation(s)
- Cassandra Russell
- School of Medical, Indigenous and Health Sciences, Faculty of Science, Medicine and Health, University of Wollongong, Building 41, Northfields Avenue, Wollongong, NSW, 2522, Australia
| | - Nathan Difford
- School of Medical, Indigenous and Health Sciences, Faculty of Science, Medicine and Health, University of Wollongong, Building 41, Northfields Avenue, Wollongong, NSW, 2522, Australia
| | - Alexander Stamenkovic
- Department of Physical Therapy, College of Health Professions, Virgina Commonwealth University, Richmond, USA
| | - Paul Stapley
- School of Medical, Indigenous and Health Sciences, Faculty of Science, Medicine and Health, University of Wollongong, Building 41, Northfields Avenue, Wollongong, NSW, 2522, Australia
| | - Darryl McAndrew
- School of Medical, Indigenous and Health Sciences, Faculty of Science, Medicine and Health, University of Wollongong, Building 41, Northfields Avenue, Wollongong, NSW, 2522, Australia
| | - Caitlin Arpel
- School of Medical, Indigenous and Health Sciences, Faculty of Science, Medicine and Health, University of Wollongong, Building 41, Northfields Avenue, Wollongong, NSW, 2522, Australia
| | - Colum MacKinnon
- Department of Neurology, University of Minnesota, Minneapolis, USA
| | - Jonathan Shemmell
- School of Medical, Indigenous and Health Sciences, Faculty of Science, Medicine and Health, University of Wollongong, Building 41, Northfields Avenue, Wollongong, NSW, 2522, Australia.
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Sun Y, Hurd CL, Barnes MM, Yang JF. Neural Plasticity in Spinal and Corticospinal Pathways Induced by Balance Training in Neurologically Intact Adults: A Systematic Review. Front Hum Neurosci 2022; 16:921490. [PMID: 36061497 PMCID: PMC9428930 DOI: 10.3389/fnhum.2022.921490] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2022] [Accepted: 06/20/2022] [Indexed: 12/02/2022] Open
Abstract
Balance training, defined here as training of postural equilibrium, improves postural control and reduces the rate of falls especially in older adults. This systematic review aimed to determine the neuroplasticity induced by such training in younger (18–30 years old) and older adults (≥65 years old). We focused on spinal and corticospinal pathways, as studied with electrophysiology, in people without neurological or other systemic disorders. We were specifically interested in the change in the excitability of these pathways before and after training. Searches were conducted in four databases: MEDLINE, CINAHL, Scopus, and Embase. A total of 1,172 abstracts were screened, and 14 articles were included. Quality of the studies was evaluated with the Downs and Black checklist. Twelve of the studies measured spinal reflexes, with ten measuring the soleus H-reflex. The H-reflex amplitude was consistently reduced in younger adults after balance training, while mixed results were found in older adults, with many showing an increase in the H-reflex after training. The differences in results between studies of younger vs. older adults may be related to the differences in their H-reflexes at baseline, with older adults showing much smaller H-reflexes than younger adults. Five studies measured corticospinal and intracortical excitability using transcranial magnetic stimulation. Younger adults showed reduced corticospinal excitability and enhanced intracortical inhibition after balance training. Two studies on older adults reported mixed results after training. No conclusions could be drawn for corticospinal and intracortical plasticity given the small number of studies. Overall, balance training induced measurable change in spinal excitability, with different changes seen in younger compared to older adults.
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Affiliation(s)
- Yao Sun
- Department of Physical Therapy, Faculty of Rehabilitation Medicine, University of Alberta, Edmonton, AB, Canada
| | - Caitlin L. Hurd
- Department of Physical Therapy, Faculty of Rehabilitation Medicine, University of Alberta, Edmonton, AB, Canada
| | - Michelle M. Barnes
- Department of Physical Therapy, Faculty of Rehabilitation Medicine, University of Alberta, Edmonton, AB, Canada
| | - Jaynie F. Yang
- Department of Physical Therapy, Faculty of Rehabilitation Medicine, University of Alberta, Edmonton, AB, Canada
- Neuroscience & Mental Health Institute, University of Alberta, Edmonton, AB, Canada
- *Correspondence: Jaynie F. Yang
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Papavasileiou A, Mademli L, Hatzitaki V, Patikas DA. Electromyographic responses to unexpected Achilles tendon vibration-induced perturbations during standing in young and older people. Exp Brain Res 2022; 240:1017-1027. [PMID: 35171309 DOI: 10.1007/s00221-022-06309-7] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2021] [Accepted: 01/16/2022] [Indexed: 02/04/2023]
Abstract
This study aimed to investigate age-related differences in electromyographic (EMG) responses to unexpected Achilles tendon vibration (ATV) perturbations while standing blindfold. ATV with variable and random duration (12-15 s) and rest periods (20-24 s) was applied on 18 young and 16 older volunteers. The anterior/posterior center of pressure (CoP) and the soleus (SOL) and tibialis anterior (TA) EMG were analyzed for 1 s before and 8 s after the ATV onset and offset. ATV induced a posterior shift of CoP in both groups, with more pronounced shift in the older group. During ATV onset, the older group demonstrated less SOL and more TA EMG increase compared to the young group. During the first 0.5 s of ATV offset, SOL EMG was decreased in both age groups, while TA showed a burst of EMG activity that was greater in the older group. No difference in the latencies of EMG peaks or valleys was observed between the groups. It is concluded that ATV induces greater posterior CoP shift in older adults, and they adopt a recovery strategy, characterized by a decreased SOL activation and an increased TA activation. These differences are possibly attributed to the increased fear of falling, decreased limits of stability and reduced capacity of older people to reweight their sensory inflow when proprioception is distorted.
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Affiliation(s)
- Anastasia Papavasileiou
- School of Physical Education and Sport Science at Serres, Aristotle University of Thessaloniki, 62110, Ag. Ioannis, Serres, Greece
| | - Lida Mademli
- School of Physical Education and Sport Science at Serres, Aristotle University of Thessaloniki, 62110, Ag. Ioannis, Serres, Greece
| | - Vassilia Hatzitaki
- School of Physical Education and Sport Science, Aristotle University of Thessaloniki, Thessaloniki, Greece
| | - Dimitrios A Patikas
- School of Physical Education and Sport Science at Serres, Aristotle University of Thessaloniki, 62110, Ag. Ioannis, Serres, Greece.
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Xu J, Lopez AJ, Hoque MM, Borich MR, Kesar TM. Temporal Profile of Descending Cortical Modulation of Spinal Excitability: Group and Individual-Specific Effects. Front Integr Neurosci 2022; 15:777741. [PMID: 35197831 PMCID: PMC8859157 DOI: 10.3389/fnint.2021.777741] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2021] [Accepted: 12/21/2021] [Indexed: 11/16/2022] Open
Abstract
Sensorimotor control is modulated through complex interactions between descending corticomotor pathways and ascending sensory inputs. Pairing sub-threshold transcranial magnetic stimulation (TMS) with peripheral nerve stimulation (PNS) modulates the Hoffmann’s reflex (H-reflex), providing a neurophysiologic probe into the influence of descending cortical drive on spinal segmental circuits. However, individual variability in the timing and magnitude of H-reflex modulation is poorly understood. Here, we varied the inter-stimulus interval (ISI) between TMS and PNS to systematically manipulate the relative timing of convergence of descending TMS-induced volleys with respect to ascending PNS-induced afferent volleys in the spinal cord to: (1) characterize effective connectivity between the primary motor cortex (M1) and spinal circuits, mediated by both direct, fastest-conducting, and indirect, slower-conducting descending pathways; and (2) compare the effect of individual-specific vs. standard ISIs. Unconditioned and TMS-conditioned H-reflexes (24 different ISIs ranging from −6 to 12 ms) were recorded from the soleus muscle in 10 able-bodied individuals. The magnitude of H-reflex modulation at individualized ISIs (earliest facilitation delay or EFD and individual-specific peak facilitation) was compared with standard ISIs. Our results revealed a significant effect of ISI on H-reflex modulation. ISIs eliciting earliest-onset facilitation (EFD 0 ms) ranged from −3 to −5 ms across individuals. No difference in the magnitude of facilitation was observed at EFD 0 ms vs. a standardized short-interval ISI of −1.5 ms. Peak facilitation occurred at longer ISIs, ranging from +3 to +11 ms. The magnitude of H-reflex facilitation derived using an individual-specific peak facilitation was significantly larger than facilitation observed at a standardized longer-interval ISI of +10 ms. Our results suggest that unique insights can be provided with individual-specific measures of top-down effective connectivity mediated by direct and/or fastest-conducting pathways (indicated by the magnitude of facilitation observed at EFD 0 ms) and other descending pathways that encompass relatively slower and/or indirect connections from M1 to spinal circuits (indicated by peak facilitation and facilitation at longer ISIs). By comprehensively characterizing the temporal profile and inter-individual variability of descending modulation of spinal reflexes, our findings provide methodological guidelines and normative reference values to inform future studies on neurophysiological correlates of the complex array of descending neural connections between M1 and spinal circuits.
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Affiliation(s)
- Jiang Xu
- Department of Rehabilitation Medicine, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
- Division of Physical Therapy, Department of Rehabilitation Medicine, Emory University, Atlanta, GA, United States
| | - Alejandro J. Lopez
- Division of Physical Therapy, Department of Rehabilitation Medicine, Emory University, Atlanta, GA, United States
- Neuroscience Graduate Program, Graduate Division of Biological and Biomedical Sciences, Emory University, Atlanta, GA, United States
| | - Maruf M. Hoque
- Division of Physical Therapy, Department of Rehabilitation Medicine, Emory University, Atlanta, GA, United States
| | - Michael R. Borich
- Division of Physical Therapy, Department of Rehabilitation Medicine, Emory University, Atlanta, GA, United States
| | - Trisha M. Kesar
- Division of Physical Therapy, Department of Rehabilitation Medicine, Emory University, Atlanta, GA, United States
- *Correspondence: Trisha M. Kesar
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11
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Alizadehsaravi L, Koster RAJ, Muijres W, Maas H, Bruijn SM, van Dieën JH. The underlying mechanisms of improved balance after one and ten sessions of balance training in older adults. Hum Mov Sci 2021; 81:102910. [PMID: 34864610 DOI: 10.1016/j.humov.2021.102910] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2021] [Revised: 11/17/2021] [Accepted: 11/22/2021] [Indexed: 11/16/2022]
Abstract
Training improves balance control in older adults, but the time course and neural mechanisms underlying these improvements are unclear. We studied balance robustness and performance, H-reflex gains, paired reflex depression, and co-contraction duration in ankle muscles after one and ten training sessions in 22 older adults (+65 yrs). Mediolateral balance robustness, time to balance loss in unipedal standing on a platform with decreasing rotational stiffness, improved (33%) after one session, with no further improvement after ten sessions. Balance performance, absolute mediolateral center of mass velocity, improved (18.75%) after one session in perturbed unipedal standing and (18.18%) after ten sessions in unperturbed unipedal standing. Co-contraction duration of soleus/tibialis anterior increased (16%) after ten sessions. H-reflex gain and paired reflex depression excitability did not change. H-reflex gains were lower, and soleus/tibialis anterior co-contraction duration was higher in participants with more robust balance after ten sessions, and co-contraction duration was higher in participants with better balance performance at several time-points. Changes in robustness and performance were uncorrelated with changes in co-contraction duration, H-reflex gain, or paired reflex depression. In older adults, balance robustness improved over a single session, while performance improved gradually over multiple sessions. Changes in co-contraction and excitability of ankle muscles were not exclusive causes of improved balance.
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Affiliation(s)
- Leila Alizadehsaravi
- Department of Human Movement Sciences, Faculty of Behavioural and Movement Sciences, Vrije Universiteit Amsterdam, Amsterdam, the Netherlands; Department of BioMechanical Engineering, Faculty of Mechanical, Maritime and Materials Engineering, Delft University of Technology, Delft, The Netherlands
| | - Ruud A J Koster
- Department of Human Movement Sciences, Faculty of Behavioural and Movement Sciences, Vrije Universiteit Amsterdam, Amsterdam, the Netherlands
| | - Wouter Muijres
- Department of Human Movement Sciences, Faculty of Behavioural and Movement Sciences, Vrije Universiteit Amsterdam, Amsterdam, the Netherlands; Department of Movement Sciences, Katholieke Universiteit Leuven, Leuven, Belgium
| | - Huub Maas
- Department of Human Movement Sciences, Faculty of Behavioural and Movement Sciences, Vrije Universiteit Amsterdam, Amsterdam, the Netherlands
| | - Sjoerd M Bruijn
- Department of Human Movement Sciences, Faculty of Behavioural and Movement Sciences, Vrije Universiteit Amsterdam, Amsterdam, the Netherlands
| | - Jaap H van Dieën
- Department of Human Movement Sciences, Faculty of Behavioural and Movement Sciences, Vrije Universiteit Amsterdam, Amsterdam, the Netherlands.
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12
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Epiu I, Gandevia SC, Boswell-Ruys CL, Basha C, Archer SNJ, Butler JE, Hudson AL. Inspiratory muscle responses to sudden airway occlusion in chronic obstructive pulmonary disease. J Appl Physiol (1985) 2021; 131:36-44. [PMID: 33955264 DOI: 10.1152/japplphysiol.00017.2021] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Brief airway occlusion produces a potent reflex inhibition of inspiratory muscles that is thought to protect against aspiration. Its duration is prolonged in asthma and obstructive sleep apnea. We assessed this inhibitory reflex (IR) in chronic obstructive pulmonary disease (COPD). Reflex responses to brief (250 ms) inspiratory occlusions were measured in 18 participants with moderate to severe COPD (age 73 ± 11 yr) and 17 healthy age-matched controls (age 72 ± 6 yr). We compared the incidence and properties of the IR between groups. Median eupneic preocclusion electromyographic activity was higher in the COPD group than controls (9.4 μV vs. 5.2 μV, P = 0.001). Incidence of the short-latency IR was higher in the COPD group compared with controls (15 participants vs. 7 participants, P = 0.010). IR duration for scalenes was similar for the COPD and control groups [73 ± 37 ms (means ± SD) and 90 ± 50 ms, respectively] as was the magnitude of inhibition. IRs in the diaphragm were not detected in the controls but were present in 9 participants of the COPD group (P = 0.001). The higher incidence of the IR in the COPD group than in the age-matched controls may reflect the increased inspiratory neural drive in the COPD group. This higher drive counteracts changes in chest wall and lung mechanics. However, when present, the reflex was similar in size and duration in the two groups. The relation between the IR in COPD and swallowing function could be assessed.NEW & NOTEWORTHY A potent short-latency reflex inhibition of inspiratory muscles produced by airway occlusion was tested in people with COPD and age-matched controls. The reflex was more prevalent in COPD, presumably due to an increased neural drive to breathe. When present, the reflex was similar in duration in the two groups, longer than historical data for younger control groups. The work reveals novel differences in reflex control of inspiratory muscles due to aging as well as COPD.
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Affiliation(s)
- Isabella Epiu
- Neuroscience Research Australia, Sydney, New South Wales, Australia.,Faculty of Medicine, University of New South Wales, Sydney, New South Wales, Australia.,Prince of Wales Hospital, Sydney, New South Wales, Australia
| | - Simon C Gandevia
- Neuroscience Research Australia, Sydney, New South Wales, Australia.,Faculty of Medicine, University of New South Wales, Sydney, New South Wales, Australia.,Prince of Wales Hospital, Sydney, New South Wales, Australia
| | - Claire L Boswell-Ruys
- Neuroscience Research Australia, Sydney, New South Wales, Australia.,Faculty of Medicine, University of New South Wales, Sydney, New South Wales, Australia.,Prince of Wales Hospital, Sydney, New South Wales, Australia
| | - Chanelle Basha
- Neuroscience Research Australia, Sydney, New South Wales, Australia.,Department of Physiotherapy, Macquarie University, Sydney, New South Wales, Australia
| | - Sean N J Archer
- Neuroscience Research Australia, Sydney, New South Wales, Australia.,Department of Physiotherapy, Macquarie University, Sydney, New South Wales, Australia
| | - Jane E Butler
- Neuroscience Research Australia, Sydney, New South Wales, Australia.,Faculty of Medicine, University of New South Wales, Sydney, New South Wales, Australia
| | - Anna L Hudson
- Neuroscience Research Australia, Sydney, New South Wales, Australia.,Faculty of Medicine, University of New South Wales, Sydney, New South Wales, Australia
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13
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Dewolf AH, Sylos-Labini F, Cappellini G, Ivanenko Y, Lacquaniti F. Age-related changes in the neuromuscular control of forward and backward locomotion. PLoS One 2021; 16:e0246372. [PMID: 33596223 PMCID: PMC7888655 DOI: 10.1371/journal.pone.0246372] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2020] [Accepted: 01/18/2021] [Indexed: 01/14/2023] Open
Abstract
Previous studies found significant modification in spatiotemporal parameters of backward walking in healthy older adults, but the age-related changes in the neuromuscular control have been considered to a lesser extent. The present study compared the intersegmental coordination, muscle activity and corresponding modifications of spinal montoneuronal output during both forward and backward walking in young and older adults. Ten older and ten young adults walked forward and backward on a treadmill at different speeds. Gait kinematics and EMG activity of 14 unilateral lower-limb muscles were recorded. As compared to young adults, the older ones used shorter steps, a more in-phase shank and foot motion, and the activity profiles of muscles innervated from the sacral segments were significantly wider in each walking condition. These findings highlight age-related changes in the neuromuscular control of both forward and backward walking. A striking feature of backward walking was the differential organization of the spinal output as compared to forward gait. In addition, the resulting spatiotemporal map patterns also characterized age-related changes of gait. Finally, modifications of the intersegmental coordination with aging were greater during backward walking. On the whole, the assessment of backward walk in addition to routine forward walk may help identifying or unmasking neuromuscular adjustments of gait to aging.
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Affiliation(s)
- Arthur H. Dewolf
- Department of Systems Medicine and Center of Space Biomedicine, University of Rome Tor Vergata, Rome, Italy
- * E-mail:
| | | | - Germana Cappellini
- Laboratory of Neuromotor Physiology, IRCCS Santa Lucia Foundation, Rome, Italy
- Department of Pediatric Neurorehabilitation, IRCCS Santa Lucia Foundation, Rome, Italy
| | - Yury Ivanenko
- Laboratory of Neuromotor Physiology, IRCCS Santa Lucia Foundation, Rome, Italy
| | - Francesco Lacquaniti
- Department of Systems Medicine and Center of Space Biomedicine, University of Rome Tor Vergata, Rome, Italy
- Laboratory of Neuromotor Physiology, IRCCS Santa Lucia Foundation, Rome, Italy
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14
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Debenham MIB, Smuin JN, Grantham TDA, Ainslie PN, Dalton BH. Hypoxia and standing balance. Eur J Appl Physiol 2021; 121:993-1008. [PMID: 33484334 DOI: 10.1007/s00421-020-04581-5] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2020] [Accepted: 12/10/2020] [Indexed: 11/24/2022]
Abstract
PURPOSE Standing balance control is important for everyday function and often goes unnoticed until impairments appear. Presently, more than 200 million people live at altitudes > 2500 m above sea level, and many others work at or travel to these elevations. Thus, it is important to understand how hypoxia alters balance owing to implications for occupations and travelers. Herein, the influence of normobaric and hypobaric hypoxia on standing balance control is reviewed and summarized. As postural control relies on the integration of sensorimotor signals, the potential hypoxic-sensitive neurophysiological factors that contribute to balance impairments are also reviewed. Specifically, we examine how hypoxia impairs visual, vestibular, and proprioceptive cues, and their integration within subcortical or cortical areas. METHODS This systematic review included a literature search conducted via multiple databases with keywords related to postural balance, hypoxia, and altitude. Articles (n = 13) were included if they met distinct criteria. RESULTS Compared to normoxia, normobaric hypoxia worsened parameters of standing balance by 2-10% and up to 83 and 240% in hypobaric hypoxia (high-altitude and lab-based, respectively). Although balance was only disrupted during normobaric hypoxia at FIO2 < ~ 0.15, impairments consistently occurred during hypobaric hypoxia at altitudes > 1524 m (~ FIO2 < 0.18). CONCLUSION Hypoxia, especially hypobaric, impairs standing balance. The mechanisms underpinning postural decrements likely involve alterations to processing and integration of sensorimotor signals within subcortical or cortical structures involving visual, vestibular, and proprioceptive pathways and subsequent motor commands that direct postural adjustments. Future studies are required to determine the sensorimotor factors that may influence balance control in hypoxia.
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Affiliation(s)
- Mathew I B Debenham
- School of Health and Exercise Sciences, Faculty of Health and Social Development, University of British Columbia Okanagan, Kelowna, Canada
| | - Janelle N Smuin
- School of Health and Exercise Sciences, Faculty of Health and Social Development, University of British Columbia Okanagan, Kelowna, Canada
| | - Tess D A Grantham
- School of Health and Exercise Sciences, Faculty of Health and Social Development, University of British Columbia Okanagan, Kelowna, Canada
| | - Philip N Ainslie
- School of Health and Exercise Sciences, Faculty of Health and Social Development, University of British Columbia Okanagan, Kelowna, Canada
| | - Brian H Dalton
- School of Health and Exercise Sciences, Faculty of Health and Social Development, University of British Columbia Okanagan, Kelowna, Canada.
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15
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Mildren RL, Schmidt ME, Eschelmuller G, Carpenter MG, Blouin JS, Inglis JT. Influence of age on the frequency characteristics of the soleus muscle response to Achilles tendon vibration during standing. J Physiol 2020; 598:5231-5243. [PMID: 32822066 DOI: 10.1113/jp280324] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2020] [Accepted: 08/19/2020] [Indexed: 12/17/2022] Open
Abstract
KEY POINTS Proprioceptive sensory information from the ankle joint is critical for the control of upright posture and balance. We examined the influence of age (n = 54 healthy adults, 20-82 years old) on lower limb muscle responses to proprioceptive perturbations evoked by Achilles tendon vibration during standing. The frequency bandwidth of the muscle response became narrower, and the gain (the muscle response relative to the stimulus) and scaling (increases in response amplitude with increases in stimulus amplitude) decreased with age. Mechanics of the muscle-tendon unit (mechanical admittance) did not differ with age during standing, and thus probably did not mediate the age-related changes observed in soleus muscle responses to vibration. These findings add to our understanding of how altered proprioceptive responses may contribute to impaired mobility and falls with ageing. ABSTRACT Proprioceptive information from the ankle joint plays an important role in the control of upright posture and balance. Ageing influences many components of the sensorimotor system, which leads to poor mobility and falls. However, little is known about the influence of age on the characteristics of short latency muscle responses to proprioceptive stimuli during standing across frequencies that are encoded by muscle spindles. We examined the frequency characteristics of the soleus muscle response to noisy (10-115 Hz) Achilles tendon vibration during standing in 54 healthy adults across a broad age range (20-82 years). The results showed the frequency bandwidth of the soleus response (vibration-electromyography coherence) became progressively narrower with ageing. Coherence was significantly lower in middle-aged relative to young adults between ∼7-11 and 28-62 Hz, lower in older relative to middle-aged adults between ∼30-50 Hz and lower in older relative to young adults between ∼7-64 Hz. Muscle response gain was similar between age groups at low frequencies, although gain was lower in older relative to young adults between ∼28-54 Hz. Across the age range, the response amplitude (peak-to-peak cross-covariance) and the scaling of the response with stimulus amplitude were both negatively correlated with age. Muscle-tendon mechanics (admittance) did not differ with age, suggesting this did not mediate differences in soleus responses. Our findings suggest there is a progressive change in the soleus response to proprioceptive stimuli with ageing during standing, which could contribute to poorer mobility and falls.
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Affiliation(s)
- Robyn L Mildren
- School of Kinesiology, University of British Columbia, Vancouver, BC, Canada
| | - Margot E Schmidt
- School of Kinesiology, University of British Columbia, Vancouver, BC, Canada
| | - Gregg Eschelmuller
- School of Kinesiology, University of British Columbia, Vancouver, BC, Canada
| | - Mark G Carpenter
- School of Kinesiology, University of British Columbia, Vancouver, BC, Canada.,Djavad Mowafaghian Centre for Brain Health, University of British Columbia, Vancouver, BC, Canada.,International Collaboration on Repair Discoveries, Vancouver, BC, Canada
| | - Jean-Sébastien Blouin
- School of Kinesiology, University of British Columbia, Vancouver, BC, Canada.,Djavad Mowafaghian Centre for Brain Health, University of British Columbia, Vancouver, BC, Canada.,Institute for Computing, Information and Cognitive Systems, University of British Columbia, Vancouver, BC, Canada
| | - J Timothy Inglis
- School of Kinesiology, University of British Columbia, Vancouver, BC, Canada.,Djavad Mowafaghian Centre for Brain Health, University of British Columbia, Vancouver, BC, Canada.,International Collaboration on Repair Discoveries, Vancouver, BC, Canada
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16
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Paulauskas H, Baranauskiene N, Wang J, Mikucioniene D, Eimantas N, Brazaitis M. Local knee heating increases spinal and supraspinal excitability and enhances plantar flexion and dorsiflexion torque production of the ankle in older adults. Eur J Appl Physiol 2020; 120:2259-2271. [PMID: 32776256 DOI: 10.1007/s00421-020-04449-8] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2020] [Accepted: 07/25/2020] [Indexed: 12/28/2022]
Abstract
PURPOSE Aging is associated with progressive loss of active muscle mass and consequent decreases in resting metabolic rate and body temperature, and slowing of nerve conduction velocities and muscle contractility. These effectors compromise the ability of the elderly to maintain an upright posture during sudden balance perturbation, increase the risk of falls, and lead to self-imposed reduction in physical activity. Short-term superficial acute heating can modulate the neural drive transmission to exercising muscles without any marked change in deep-muscle temperature. METHODS To determine whether the short-term (5 min) application of local passive knee-surface heating (next-to-skin temperature, ~ 44 °C) in healthy older subjects of both sexes (64-74 years; eight men/eight women) enhances reflex excitability, we compared the voluntarily and electrically induced ankle muscle torque production and contractile properties with those of healthy younger subjects of both sexes (21-35 years, 10 men/10 women). RESULTS The application of local heating (vs. control) increased the maximal Hoffman reflex (Hmax), the maximal volitional wave (Vsup) amplitude, and the Hmax/Mmax amplitude ratio, and decreased Vsup latency only in older adults. In the older adults (vs. younger adults), the application of local heating (vs. control trial) was accompanied by a significant increase in maximal voluntary peak torque, rate of torque development, and isokinetic peak torque of plantar flexion/dorsiflexion muscle contraction. CONCLUSION The spinal and supraspinal reflex excitability of older adults increased during local knee-heating application. The improved motor drive transmission observed in older adults was accompanied by increased voluntarily induced torque production of the ankle muscles during isometric/isokinetic contractions.
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Affiliation(s)
- Henrikas Paulauskas
- Institute of Sports Science and Innovation, Lithuanian Sports University, Sporto 6, 44221, Kaunas, Lithuania
| | - Neringa Baranauskiene
- Institute of Sports Science and Innovation, Lithuanian Sports University, Sporto 6, 44221, Kaunas, Lithuania
| | - Junli Wang
- Institute of Sports Science and Innovation, Lithuanian Sports University, Sporto 6, 44221, Kaunas, Lithuania
| | - Daiva Mikucioniene
- Faculty of Mechanical Engineering and Design, Kaunas University of Technology, Studentu 56, 51424, Kaunas, Lithuania
| | - Nerijus Eimantas
- Institute of Sports Science and Innovation, Lithuanian Sports University, Sporto 6, 44221, Kaunas, Lithuania.
| | - Marius Brazaitis
- Institute of Sports Science and Innovation, Lithuanian Sports University, Sporto 6, 44221, Kaunas, Lithuania.
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17
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Walker S, Monto S, Piirainen JM, Avela J, Tarkka IM, Parviainen TM, Piitulainen H. Older Age Increases the Amplitude of Muscle Stretch-Induced Cortical Beta-Band Suppression But Does not Affect Rebound Strength. Front Aging Neurosci 2020; 12:117. [PMID: 32508626 PMCID: PMC7248310 DOI: 10.3389/fnagi.2020.00117] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2019] [Accepted: 04/07/2020] [Indexed: 12/11/2022] Open
Abstract
Healthy aging is associated with deterioration of the sensorimotor system, which impairs balance and somatosensation. However, the exact age-related changes in the cortical processing of sensorimotor integration are unclear. This study investigated primary sensorimotor cortex (SM1) oscillations in the 15-30 Hz beta band at rest and following (involuntary) rapid stretches to the triceps surae muscles (i.e., proprioceptive stimulation) of young and older adults. A custom-built, magnetoencephalography (MEG)-compatible device was used to deliver rapid (190°·s-1) ankle rotations as subjects sat passively in a magnetically-shielded room while MEG recorded their cortical signals. Eleven young (age 25 ± 3 years) and 12 older (age 70 ± 3 years) adults matched for physical activity level demonstrated clear 15-30 Hz beta band suppression and rebound in response to the stretches. A sub-sample (10 young and nine older) were tested for dynamic balance control on a sliding platform. Older adults had greater cortical beta power pre-stretch (e.g., right leg: 4.0 ± 1.6 fT vs. 5.6 ± 1.7 fT, P = 0.044) and, subsequently, greater normalized movement-related cortical beta suppression post-proprioceptive stimulation (e.g., right leg: -5.8 ± 1.3 vs. -7.6 ± 1.7, P = 0.01) than young adults. Furthermore, poorer balance was associated with stronger cortical beta suppression following proprioceptive stimulation (r = -0.478, P = 0.038, n = 19). These results provide further support that cortical processing of proprioception is hindered in older adults, potentially (adversely) influencing sensorimotor integration. This was demonstrated by the impairment of prompt motor action control, i.e., regaining perturbed balance. Finally, SM1 cortex beta suppression to a proprioceptive stimulus seems to indicate poorer sensorimotor functioning in older adults.
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Affiliation(s)
- Simon Walker
- NeuroMuscular Research Center, Faculty of Sport and Health Sciences, University of Jyväskylä, Jyväskylä, Finland
| | - Simo Monto
- Department of Psychology, Centre for Interdisciplinary Brain Research, University of Jyväskylä, Jyväskylä, Finland
| | - Jarmo M Piirainen
- NeuroMuscular Research Center, Faculty of Sport and Health Sciences, University of Jyväskylä, Jyväskylä, Finland
| | - Janne Avela
- NeuroMuscular Research Center, Faculty of Sport and Health Sciences, University of Jyväskylä, Jyväskylä, Finland
| | - Ina M Tarkka
- Faculty of Sport and Health Sciences and Centre for Interdisciplinary Brain Research, University of Jyväskylä, Jyväskylä, Finland
| | - Tiina M Parviainen
- Department of Psychology, Centre for Interdisciplinary Brain Research, University of Jyväskylä, Jyväskylä, Finland
| | - Harri Piitulainen
- NeuroMuscular Research Center, Faculty of Sport and Health Sciences, University of Jyväskylä, Jyväskylä, Finland.,Department of Neuroscience and Biomedical Engineering, Aalto University School of Science, Espoo, Finland
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18
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Walker S, Piitulainen H, Manlangit T, Avela J, Baker SN. Older adults show elevated intermuscular coherence in eyes‐open standing but only young adults increase coherence in response to closing the eyes. Exp Physiol 2020; 105:1000-1011. [DOI: 10.1113/ep088468] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2020] [Accepted: 04/01/2020] [Indexed: 11/08/2022]
Affiliation(s)
- S. Walker
- NeuroMuscular Research Center Faculty of Sport and Health Sciences University of Jyväskylä Jyväskylä FI‐40014 Finland
| | - H. Piitulainen
- NeuroMuscular Research Center Faculty of Sport and Health Sciences University of Jyväskylä Jyväskylä FI‐40014 Finland
- Department of Neuroscience and Biomedical Engineering School of Science Aalto University Espoo Finland
| | - T. Manlangit
- NeuroMuscular Research Center Faculty of Sport and Health Sciences University of Jyväskylä Jyväskylä FI‐40014 Finland
| | - J. Avela
- NeuroMuscular Research Center Faculty of Sport and Health Sciences University of Jyväskylä Jyväskylä FI‐40014 Finland
| | - S. N. Baker
- Institute of Neuroscience, Medical School Newcastle University Newcastle upon Tyne UK
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19
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Howells J, Sangari S, Matamala JM, Kiernan MC, Marchand-Pauvert V, Burke D. Interrogating interneurone function using threshold tracking of the H reflex in healthy subjects and patients with motor neurone disease. Clin Neurophysiol 2020; 131:1986-1996. [PMID: 32336595 DOI: 10.1016/j.clinph.2020.03.028] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2020] [Revised: 02/21/2020] [Accepted: 03/15/2020] [Indexed: 11/18/2022]
Abstract
OBJECTIVE The excitability of the lower motoneurone pool is traditionally tested using the H reflex and a constant-stimulus paradigm, which measures changes in the amplitude of the reflex response. This technique has limitations because reflex responses of different size must involve the recruitment or inhibition of different motoneurones. The threshold-tracking technique ensures that the changes in excitability occur for an identical population of motoneurones. We aimed to assess this technique and then apply it in patients with motor neurone disease (MND). METHODS The threshold-tracking approach was assessed in 17 healthy subjects and 11 patients with MND. The soleus H reflex was conditioned by deep peroneal nerve stimulation producing reciprocal Ia and so-called D1 and D2 inhibitions, which are believed to reflect presynaptic inhibition of soleus Ia afferents. RESULTS Threshold tracking was quicker than the constant-stimulus technique and reliable, properties that may be advantageous for clinical studies. D1 inhibition was significantly reduced in patients with MND. CONCLUSIONS Threshold tracking is useful and may be preferable under some conditions for studying the excitability of the motoneurone pool. The decreased D1 inhibition in the patients suggests that presynaptic inhibition may be reduced in MND. SIGNIFICANCE Reduced presynaptic inhibition could be evidence of an interneuronopathy in MND. It is possible that the hyperreflexia is a spinal pre-motoneuronal disorder, and not definitive evidence of corticospinal involvement in MND.
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Affiliation(s)
- James Howells
- Brain & Mind Centre, The University of Sydney, N.S.W. 2006, Australia
| | - Sina Sangari
- Sorbonne Université, INSERM, CNRS, Laboratoire d'Imagerie Biomédicale, LIB, F-75006 Paris, France
| | - José Manuel Matamala
- Department of Neurological Science and Biomedical Neuroscience Institute, Faculty of Medicine, University of Chile, Santiago, Chile
| | - Matthew C Kiernan
- Brain & Mind Centre, The University of Sydney, N.S.W. 2006, Australia; Department of Neurology, Royal Prince Alfred Hospital and The University of Sydney, N.S.W. 2006, Australia
| | | | - David Burke
- Department of Neurology, Royal Prince Alfred Hospital and The University of Sydney, N.S.W. 2006, Australia.
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Hali K, Dalton BH, Harwood B, Fessler AF, Power GA, Rice CL. Differential Modulation of Motor Unit Properties from the Separate Components of the Triceps Surae in Humans. Neuroscience 2020; 428:192-198. [PMID: 31917353 DOI: 10.1016/j.neuroscience.2019.12.023] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2019] [Revised: 12/11/2019] [Accepted: 12/12/2019] [Indexed: 10/25/2022]
Abstract
The triceps surae is comprised of the soleus, and medial (MG) and lateral (LG) gastrocnemii. Modulation of triceps surae motor units (MUs) is context- and muscle-dependent, yet it is unknown how the disparate components of the triceps surae work together to achieve the common goal of high-intensity voluntary isometric plantar flexion torque gradation. Thus, the purpose was to assess the interrelationships between MU recruitment thresholds (MURTs) and MU discharge rates (MUDRs) among these three muscles during contractions from low to high intensities. We sampled 157 MU action potential trains from the MG (68), LG (38) and soleus (51) using fine-wire intramuscular electromyography (EMG) during voluntary ramp isometric contractions up to 100% maximal voluntary contraction (MVC). The soleus exhibited 41% and 54% lower MURTs compared to the MG (p < 0.0001) and LG (p < 0.0001), respectively, whereas MG MURTs were 22% lower than the LG (p < 0.0001). Initial MUDRs were 35% and 26% greater for the LG compared with the MG (p < 0.0001) and soleus (p < 0.0001), but no difference was detected between the MG and soleus (p = 0.28). Finally, initial MUDRs displayed a positive relationship with MURTs for each independent triceps surae component (p ≤ 0.002). The relative differences in MU properties of each muscle in this synergistic group illustrate that MU control strategies are likely optimized with respect to the relative contribution of each muscle to plantar flexion torque or functional roles.
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Affiliation(s)
- Kalter Hali
- School of Kinesiology, Faculty of Health Sciences, The University of Western Ontario, London, Ontario, Canada
| | - Brian H Dalton
- School of Health and Exercise Sciences, The University of British Columbia Okanagan, Kelowna, British Columbia, Canada.
| | - Brad Harwood
- School of Kinesiology, Faculty of Health Sciences, The University of Western Ontario, London, Ontario, Canada
| | - Andrew F Fessler
- Department of Human Physiology, University of Oregon, Eugene, OR, United States
| | - Geoffrey A Power
- Department of Human Health and Nutritional Sciences, College of Biological Sciences, University of Guelph, Guelph, Ontario, Canada
| | - Charles L Rice
- School of Kinesiology, Faculty of Health Sciences, The University of Western Ontario, London, Ontario, Canada; Department of Anatomy and Cell Biology, Schulich School of Medicine and Dentistry, The University of Western Ontario, London, Ontario, Canada
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Baudry S, Duchateau J. Aftereffects of prolonged Achilles tendon vibration on postural control are reduced in older adults. Exp Gerontol 2020; 131:110822. [PMID: 31899339 DOI: 10.1016/j.exger.2019.110822] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2019] [Revised: 12/21/2019] [Accepted: 12/26/2019] [Indexed: 11/16/2022]
Abstract
AIM To assess the change in the contribution of proprioceptive signal from leg muscles in postural control with ageing. METHODS Fifteen young (~23 yr) and fifteen older adults (~68 yr) participated in Experiment 1, which consisted of recording the mean position of the centre of pressure (CoP), CoP path length, CoP velocity, and the amplitude of the Hoffmann (H) reflex and maximal M wave (MMAX) in the soleus muscle during upright standing, before and after 1 h of bilateral Achilles tendon vibration applied in seated posture. Eight young (~24 yr) and eight older adults (~67 yr) participated in Experiment 2 consisting of recording H-reflex and MMAX in seated posture before and after the 1-h vibration procedure used in Experiment 1. RESULTS Immediately after the 1-h vibration, the mean CoP position shifted forward in both groups (p < 0.05), with a greater magnitude of change (% pre-vibration) in young [mean(SD); 74(41)%] than older adults [44(40)%; p < 0.05]. The CoP path length and velocity only increased in young adults after vibration (p < 0.05). The H-reflex amplitude decreased only in young adults after vibration [before: 35(12); after: 16(13)% Mmax, p < 0.05] during upright standing (Experiment 1), whereas it decreased similarly (p > 0.05) in young [before: 47(12)% Mmax; after: 28(17)% Mmax] and older adults [before: 34(13)% Mmax; after: 21(14)% Mmax] in seated posture (Experiment 2). CONCLUSION Prolonged Achilles tendon vibrations lead to lesser postural perturbation in older than in young adults, supporting the assumption of a decreased reliance on leg muscle proprioception in postural control with ageing.
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Affiliation(s)
- Stéphane Baudry
- Laboratory of Applied Biology, Research Unit in Applied Neurophysiology, ULB-Neurosciences Institute (UNI), Université Libre de Bruxelles (ULB), 808 route de Lennik, 1070 Brussels, Belgium.
| | - Jacques Duchateau
- Laboratory of Applied Biology, Research Unit in Applied Neurophysiology, ULB-Neurosciences Institute (UNI), Université Libre de Bruxelles (ULB), 808 route de Lennik, 1070 Brussels, Belgium
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Systematic Balance Exercises Influence Cortical Activation and Serum BDNF Levels in Older Adults. J Clin Med 2019; 8:jcm8111910. [PMID: 31703409 PMCID: PMC6912622 DOI: 10.3390/jcm8111910] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2019] [Revised: 10/23/2019] [Accepted: 11/05/2019] [Indexed: 11/17/2022] Open
Abstract
We sought to investigate whether systematic balance training modulates brain area activity responsible for postural control and influence brain-derived neurotrophic factor (BDNF) mRNA protein expression. Seventy-four older adults were randomly divided into three groups (mean age 65.34 ± 3.79 years, 30 females): Classic balance exercises (CBT), virtual reality balance exercises (VBT), and control (CON). Neuroimaging studies were performed at inclusion and after completion of the training or 12 weeks later (CON). Blood samples were obtained to measure BDNF expression. The study revealed significant interaction of sessions and groups: In the motor imagery (MI) condition for supplementary motor area (SMA) activity (Fat peak = 5.25, p < 0.05); in the action observation (AO) condition for left and right supramarginal gyrus/posterior insula (left: Fat peak = 6.48, p < 0.05; right: Fat peak = 6.92, p < 0.05); in the action observation together with motor imagery (AOMI) condition for the middle occipital gyrus (laterally)/area V5 (left: Fat peak = 6.26, p < 0.05; right: Fat peak = 8.37, p < 0.05), and in the cerebellum–inferior semilunar lobule/tonsil (Fat peak = 5.47, p < 0.05). After the training serum BDNF level has increased in CBT (p < 0.001) and in CBT compared to CON (p < 0.05). Systematic balance training may reverse the age-related cortical over-activations and appear to be a factor mediating neuroplasticity in older adults.
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Henry M, Baudry S. Age-related changes in leg proprioception: implications for postural control. J Neurophysiol 2019; 122:525-538. [PMID: 31166819 DOI: 10.1152/jn.00067.2019] [Citation(s) in RCA: 113] [Impact Index Per Article: 22.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023] Open
Abstract
In addition to being a prerequisite for many activities of daily living, the ability to maintain steady upright standing is a relevant model to study sensorimotor integrative function. Upright standing requires managing multimodal sensory inputs to produce finely tuned motor output that can be adjusted to accommodate changes in standing conditions and environment. The sensory information used for postural control mainly arises from the vestibular system of the inner ear, vision, and proprioception. Proprioception (sense of body position and movement) encompasses signals from mechanoreceptors (proprioceptors) located in muscles, tendons, and joint capsules. There is general agreement that proprioception signals from leg muscles provide the primary source of information for postural control. This is because of their exquisite sensitivity to detect body sway during unperturbed upright standing that mainly results from variations in leg muscle length induced by rotations around the ankle joint. However, aging is associated with alterations of muscle spindles and their neural pathways, which induce a decrease in the sensitivity, acuity, and integration of the proprioceptive signal. These alterations promote changes in postural control that reduce its efficiency and thereby may have deleterious consequences for the functional independence of an individual. This narrative review provides an overview of how aging alters the proprioceptive signal from the legs and presents compelling evidence that these changes modify the neural control of upright standing.
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Affiliation(s)
- Mélanie Henry
- Laboratory of Applied Biology and Research Unit in Applied Neurophysiology, ULB Neuroscience Institute, Université libre de Bruxelles, Brussels, Belgium
| | - Stéphane Baudry
- Laboratory of Applied Biology and Research Unit in Applied Neurophysiology, ULB Neuroscience Institute, Université libre de Bruxelles, Brussels, Belgium
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24
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Charalambous CC, Liang JN, Kautz SA, George MS, Bowden MG. Bilateral Assessment of the Corticospinal Pathways of the Ankle Muscles Using Navigated Transcranial Magnetic Stimulation. J Vis Exp 2019. [PMID: 30855569 DOI: 10.3791/58944] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Distal leg muscles receive neural input from motor cortical areas via the corticospinal tract, which is one of the main motor descending pathway in humans and can be assessed using transcranial magnetic stimulation (TMS). Given the role of distal leg muscles in upright postural and dynamic tasks, such as walking, a growing research interest in the assessment and modulation of the corticospinal tracts relative to the function of these muscles has emerged in the last decade. However, methodological parameters used in previous work have varied across studies making the interpretation of results from cross-sectional and longitudinal studies less robust. Therefore, use of a standardized TMS protocol specific to the assessment of leg muscles' corticomotor response (CMR) will allow for direct comparison of results across studies and cohorts. The objective of this paper is to present a protocol that provides the flexibility to simultaneously assess the bilateral CMR of two main ankle antagonistic muscles, the tibialis anterior and soleus, using single pulse TMS with a neuronavigation system. The present protocol is applicable while the examined muscle is either fully relaxed or isometrically contracted at a defined percentage of maximum isometric voluntary contraction. Using each subject's structural MRI with the neuronavigation system ensures accurate and precise positioning of the coil over the leg cortical representations during assessment. Given the inconsistency in CMR derived measures, this protocol also describes a standardized calculation of these measures using automated algorithms. Though this protocol is not conducted during upright postural or dynamic tasks, it can be used to assess bilaterally any pair of leg muscles, either antagonistic or synergistic, in both neurologically intact and impaired subjects.
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Affiliation(s)
- Charalambos C Charalambous
- Department of Neurology, New York University School of Medicine; Department of Health Sciences and Research, Medical University of South Carolina;
| | - Jing Nong Liang
- Department of Physical Therapy, University of Nevada Las Vegas; Department of Health Professions, Medical University of South Carolina
| | - Steve A Kautz
- Department of Health Sciences and Research, Medical University of South Carolina; Ralph H. Johnson VA Medical Center
| | - Mark S George
- Ralph H. Johnson VA Medical Center; Department of Psychiatry, Medical University of South Carolina
| | - Mark G Bowden
- Department of Health Sciences and Research, Medical University of South Carolina; Ralph H. Johnson VA Medical Center; Division of Physical Therapy, Medical University of South Carolina
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25
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Fujio K, Obata H, Kawashima N, Nakazawa K. Presetting of the Corticospinal Excitability in the Tibialis Anterior Muscle in Relation to Prediction of the Magnitude and Direction of Postural Perturbations. Front Hum Neurosci 2019; 13:4. [PMID: 30705626 PMCID: PMC6344449 DOI: 10.3389/fnhum.2019.00004] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2018] [Accepted: 01/04/2019] [Indexed: 11/13/2022] Open
Abstract
The prediction of upcoming perturbation modulates postural responses in the ankle muscles. The effects of this prediction on postural responses vary according to predictable factors. When the amplitude of perturbation can be predicted, the long-latency response is set at an appropriate size for the required response, whereas when the direction of perturbation can be predicted, there is no effect. The neural mechanisms underlying these phenomena are poorly understood. Here, we examined how the corticospinal excitability of the ankle muscles [i.e., the tibialis anterior (TA), the soleus (SOL), and the medial gastrocnemius (MG), with a focus on the TA], would be modulated in five experimental conditions: (1) No-perturbation; (2) Low (anterior translation with small amplitude); (3) High (anterior translation with large amplitude); (4) Posterior (posterior translation with large amplitude); and (5) Random (Low, High, and Posterior in randomized order). We measured the motor-evoked potentials (MEPs) induced by transcranial magnetic stimulation (TMS) at 50 ms before surface-translation in each condition. The electromyographic (EMG) responses evoked by surface-translations were also measured. The results showed that the TA-MEP amplitude was greater in the High condition (where the largest TA-EMG response was evoked among the five conditions) compared to that in the No-perturbation, Low, and Posterior conditions (High vs. No-perturbation, p < 0.001; High vs. Low, p = 0.001; High vs. Posterior, p = 0.001). In addition, the MEP amplitude in the Random condition was significantly greater than that in the No-perturbation and Low conditions (Random vs. No-perturbation, p = 0.002; Random vs. Low, p = 0.002). The EMG response in the TA evoked by perturbation was significantly smaller when a perturbation can be predicted (predictable vs. unpredictable, p < 0.001). In the SOL and MG muscles, no prominent modulations of the MEP amplitude or EMG response were observed, suggesting that the effects of prediction on corticospinal excitability differ between the dorsiflexor and plantar flexor muscles. These findings suggest that the corticospinal excitability in the TA is scaled in parallel with the prediction of the direction and magnitude of an upcoming perturbation in advance.
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Affiliation(s)
- Kimiya Fujio
- Department of Rehabilitation Science, Faculty of Health Care Science, Chiba Prefectural University of Health Sciences, Chiba, Japan.,Department of Rehabilitation for the Movement Functions, Research Institute of the National Rehabilitation Center for Persons with Disabilities, Saitama, Japan
| | - Hiroki Obata
- Department of Humanities and Social Sciences, Institute of Liberal Arts, Kyushu Institute of Technology, Fukuoka, Japan
| | - Noritaka Kawashima
- Department of Rehabilitation for the Movement Functions, Research Institute of the National Rehabilitation Center for Persons with Disabilities, Saitama, Japan
| | - Kimitaka Nakazawa
- Sports Science Laboratory, Department of Life Sciences, Graduate School of Arts and Sciences, University of Tokyo, Tokyo, Japan
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26
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Johannsson J, Duchateau J, Baudry S. Modulation of the Hoffmann reflex in soleus and medial gastrocnemius during stair ascent and descent in young and older adults. Gait Posture 2019; 68:115-121. [PMID: 30472523 DOI: 10.1016/j.gaitpost.2018.11.018] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/01/2018] [Revised: 09/09/2018] [Accepted: 11/15/2018] [Indexed: 02/02/2023]
Abstract
BACKGROUND The Hoffmann (H) reflex can provide relevant information on spinal control of leg muscles during locomotor tasks in young and older adults. RESEARCH QUESTION Is the H reflex in the leg muscles differently modulated during stair gait in young and older adults? METHOD The H reflex in soleus (SOL) and medial gastrocnemius (MG) (normalized to the maximal M-wave amplitude obtained during upright standing; Mmax) was recorded in 19 young and 18 older adults during upright standing, and stair ascent and descent of a 3-step staircase. RESULTS H-reflex amplitude during upright standing was greater in young than older adults for SOL (48% vs. 26% Mmax; p = 0.001) and MG (23% vs. 14% Mmax; p = 0.02). When data were averaged across groups during stair ascent, H-reflex amplitude in SOL increased from 15% Mmax at the beginning of the stance phase to 29% Mmax at mid-stance, then decreased to be 4% Mmax in the swing phase. During stair descent, H-reflex amplitude was maximal (20% Mmax) at the beginning of the stance phase, decreased to 5% Mmax at the end of stance, and increased to 11% Mmax in the swing phase. Similar adjustments were observed for the H reflex in MG for both ascent and descent. H-reflex modulation during gait cycle (relative to upright standing) is less pronounced in older adults (p < 0.05). However, no difference was observed between subgroups of young and older adults matched for H-reflex amplitude in upright standing. In both groups, H-reflex modulation was not associated with changes in background electromyographic activity. SIGNIFICANCE This study indicates that the H reflex is modulated within the stair gait cycle during ascent and descent. Although its magnitude was slightly reduced, the overall modulation of the H reflex is not affected in healthy older adults.
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Affiliation(s)
- Johanna Johannsson
- Laboratory of Applied Neurophysiology and Biology, ULB Neuroscience Institute (UNI), Université libre de Bruxelles (ULB), 808 route de Lennik, 1070 Brussels, Belgium
| | - Jacques Duchateau
- Laboratory of Applied Neurophysiology and Biology, ULB Neuroscience Institute (UNI), Université libre de Bruxelles (ULB), 808 route de Lennik, 1070 Brussels, Belgium
| | - Stéphane Baudry
- Laboratory of Applied Neurophysiology and Biology, ULB Neuroscience Institute (UNI), Université libre de Bruxelles (ULB), 808 route de Lennik, 1070 Brussels, Belgium.
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Kesar TM, Stinear JW, Wolf SL. The use of transcranial magnetic stimulation to evaluate cortical excitability of lower limb musculature: Challenges and opportunities. Restor Neurol Neurosci 2018; 36:333-348. [PMID: 29758954 DOI: 10.3233/rnn-170801] [Citation(s) in RCA: 41] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
Neuroplasticity is a fundamental yet relatively unexplored process that can impact rehabilitation of lower extremity (LE) movements. Transcranial magnetic stimulation (TMS) has gained widespread application as a non-invasive brain stimulation technique for evaluating neuroplasticity of the corticospinal pathway. However, a majority of TMS studies have been performed on hand muscles, with a paucity of TMS investigations focused on LE muscles. This perspective review paper proposes that there are unique methodological challenges associated with using TMS to evaluate corticospinal excitability of lower limb muscles. The challenges include: (1) the deeper location of the LE motor homunculus; (2) difficulty with targeting individual LE muscles during TMS; and (3) differences in corticospinal circuity controlling upper and lower limb muscles. We encourage future investigations that modify traditional methodological approaches to help address these challenges. Systematic TMS investigations are needed to determine the extent of overlap in corticomotor maps for different LE muscles. A simple, yet informative methodological solution involves simultaneous recordings from multiple LE muscles, which will provide the added benefit of observing how other relevant muscles co-vary in their responses during targeted TMS assessment directed toward a specific muscle. Furthermore, conventionally used TMS methods (e.g., determination of hot spot location and motor threshold) may need to be modified for TMS studies involving LE muscles. Additional investigations are necessary to determine the influence of testing posture as well as activation state of adjacent and distant LE muscles on TMS-elicited responses. An understanding of these challenges and solutions specific to LE TMS will improve the ability of neurorehabilitation clinicians to interpret TMS literature, and forge novel future directions for neuroscience research focused on elucidating neuroplasticity processes underlying locomotion and gait training.
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Affiliation(s)
- Trisha M Kesar
- Department of Rehabilitation Medicine, Division of Physical Therapy, Emory University, Atlanta, GA, USA
| | - James W Stinear
- Exercise Sciences, The University of Auckland, Auckland, New Zealand
| | - Steven L Wolf
- Department of Rehabilitation Medicine, Division of Physical Therapy, Emory University, Atlanta, GA, USA.,Center for Visual and Neurocognitive Rehabilitation, Atlanta Veterans Affair Medical Center, Decatur, GA, USA
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28
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Hortobágyi T, van de Waardt LE, Tokuno CD, Taube W, Papegaaij S. Age-related reversal of spinal excitability during anticipatory postural control. Eur J Appl Physiol 2018; 118:2577-2585. [PMID: 30182185 PMCID: PMC6244700 DOI: 10.1007/s00421-018-3982-0] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2018] [Accepted: 08/29/2018] [Indexed: 11/25/2022]
Abstract
Introduction An internal perturbation of standing balance activates muscles critical for maintaining balance and is preceded by anticipatory postural adjustments (APAs). In healthy younger adults, a measure of spinal excitability in the form of the Hoffmann (H) reflex becomes depressed during APAs but how aging affects the reflex control of APAs is unknown. Methods We compared H reflex excitability profiles in the right soleus muscle, indirectly indicating APA, between younger (n = 11, age 19–24 years), middle-aged (n = 10, age 37–56 years), and older healthy adults (n = 11, age 63–78 years). Subjects rapidly raised the right-dominant arm in response to an auditory cue. The H reflex was evoked 120 ms, 100 ms, 80 ms, 60 ms, 40 ms, 20 ms, and 0 ms before as well as 20 ms after the onset of the right anterior deltoid muscle activation. For data processing, each trial was controlled for the corresponding background EMG activity before normalizing the standing data to the data in sitting in the 8 time bins. Results All subjects showed a silent period in the soleus background electromyographic activity, suggesting the presence of APA. We found that the stereotypical H reflex depression associated with APAs in younger adults was reduced in middle-aged adults and reversed to facilitation in older adults. The depression occurred in 10 out of 11 younger adults, whereas all 11 older adults exhibited facilitation. Conclusion Because APAs are organized at the supraspinal level, we speculate a supraspinal origin of the age-related reflex facilitation during APAs.
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Affiliation(s)
- Tibor Hortobágyi
- Center for Human Movement Sciences, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands.
| | - Lajenda E van de Waardt
- Center for Human Movement Sciences, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands
| | - Craig D Tokuno
- Department of Kinesiology, Brock University, St. Catharines, Canada
| | - Wolfgang Taube
- Sport and Movement Sciences, Department of Medicine, University of Fribourg, Fribourg, Switzerland
| | - Selma Papegaaij
- Center for Human Movement Sciences, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands
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Brownstein CG, Ansdell P, Škarabot J, Frazer A, Kidgell D, Howatson G, Goodall S, Thomas K. Motor cortical and corticospinal function differ during an isometric squat compared with isometric knee extension. Exp Physiol 2018; 103:1251-1263. [DOI: 10.1113/ep086982] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2018] [Accepted: 06/19/2018] [Indexed: 02/01/2023]
Affiliation(s)
- Callum G. Brownstein
- Faculty of Health and Life Sciences, Department of Sport, Exercise & Rehabilitation; Northumbria University; Newcastle UK
| | - Paul Ansdell
- Faculty of Health and Life Sciences, Department of Sport, Exercise & Rehabilitation; Northumbria University; Newcastle UK
| | - Jakob Škarabot
- Faculty of Health and Life Sciences, Department of Sport, Exercise & Rehabilitation; Northumbria University; Newcastle UK
| | - Ash Frazer
- Department of Physiotherapy, Faculty of Medicine, Nursing and Health Sciences, School of Primary and Allied Health Care; Monash University; Melbourne Victoria Australia
| | - Dawson Kidgell
- Department of Physiotherapy, Faculty of Medicine, Nursing and Health Sciences, School of Primary and Allied Health Care; Monash University; Melbourne Victoria Australia
| | - Glyn Howatson
- Faculty of Health and Life Sciences, Department of Sport, Exercise & Rehabilitation; Northumbria University; Newcastle UK
- Water Research Group, School of Environmental Sciences and Development; Northwest University; Potchefstroom South Africa
| | - Stuart Goodall
- Faculty of Health and Life Sciences, Department of Sport, Exercise & Rehabilitation; Northumbria University; Newcastle UK
| | - Kevin Thomas
- Faculty of Health and Life Sciences, Department of Sport, Exercise & Rehabilitation; Northumbria University; Newcastle UK
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Piitulainen H, Seipäjärvi S, Avela J, Parviainen T, Walker S. Cortical Proprioceptive Processing Is Altered by Aging. Front Aging Neurosci 2018; 10:147. [PMID: 29962945 PMCID: PMC6010536 DOI: 10.3389/fnagi.2018.00147] [Citation(s) in RCA: 42] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2018] [Accepted: 05/01/2018] [Indexed: 11/13/2022] Open
Abstract
Proprioceptive perception is impaired with aging, but little is known about aging-related deterioration of proprioception at the cortical level. Corticokinematic coherence (CKC) between limb kinematic and magnetoencephalographic (MEG) signals reflects cortical processing of proprioceptive afference. We, thus, compared CKC strength to ankle movements between younger and older subjects, and examined whether CKC predicts postural stability. Fifteen younger (range 18–31 years) and eight older (66–73 years) sedentary volunteers were seated in MEG, while their right and left ankle joints were moved separately at 2 Hz (for 4 min each) using a novel MEG-compatible ankle-movement actuator. Coherence was computed between foot acceleration and MEG signals. CKC strength at the movement frequency (F0) and its first harmonic (F1) was quantified. In addition, postural sway was quantified during standing eyes-open and eyes-closed tasks to estimate motor performance. CKC peaked in the gradiometers over the vertex, and was significantly stronger (~76%) at F0 for the older than younger subjects. At F1, only the dominant-leg CKC was significantly stronger (~15%) for the older than younger subjects. In addition, CKC (at F1) was significantly stronger in the non-dominant than dominant leg, but only in the younger subjects. Postural sway was significantly (~64%) higher in the older than younger subjects when standing with eyes closed. Regression models indicated that CKC strength at F1 in the dominant leg and age were the only significant predictors for postural sway. Our results indicated that aging-related cortical-proprioceptive processing is altered by aging. Stronger CKC may reflect poorer cortical proprioceptive processing, and not solely the amount of proprioceptive afference as suggested earlier. In combination with ankle-movement actuator, CKC can be efficiently used to unravel proprioception-related-neuronal mechanisms and the related plastic changes in aging, rehabilitation, motor-skill acquisition, motor disorders etc.
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Affiliation(s)
- Harri Piitulainen
- Sensorimotor Systems Group, Department of Neuroscience and Biomedical Engineering, Aalto University School of Science, Espoo, Finland.,Biology of Physical Activity and Neuromuscular Research Center, Faculty of Sport and Health Sciences, University of Jyväskylä, Jyväskylä, Finland
| | - Santtu Seipäjärvi
- Biology of Physical Activity and Neuromuscular Research Center, Faculty of Sport and Health Sciences, University of Jyväskylä, Jyväskylä, Finland
| | - Janne Avela
- Biology of Physical Activity and Neuromuscular Research Center, Faculty of Sport and Health Sciences, University of Jyväskylä, Jyväskylä, Finland
| | - Tiina Parviainen
- Centre for Interdisciplinary Brain Research, Department of Psychology, University of Jyväskylä, Jyväskylä, Finland
| | - Simon Walker
- Biology of Physical Activity and Neuromuscular Research Center, Faculty of Sport and Health Sciences, University of Jyväskylä, Jyväskylä, Finland
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31
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Seeing action simulation as it unfolds: The implicit effects of action scenes on muscle contraction evidenced through the use of a grip-force sensor. Neuropsychologia 2018; 114:231-242. [DOI: 10.1016/j.neuropsychologia.2018.04.026] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2017] [Revised: 04/18/2018] [Accepted: 04/23/2018] [Indexed: 11/20/2022]
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32
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Kim KM, Best TM, Aiyer A. How Do Athletes with Chronic Ankle Instability Suffer from Impaired Balance? An Update on Neurophysiological Mechanisms. Curr Sports Med Rep 2018; 16:309-311. [PMID: 28902750 DOI: 10.1249/jsr.0000000000000407] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Affiliation(s)
- Kyung-Min Kim
- 1Department of Kinesiology and Sport Sciences, University of Miami, Coral Gables, FL; 2Family Medicine, Kinesiology, UHealth Sports Medicine Institute, University of Miami/Miller School of Medicine, Miami, FL; and 3Department of Orthopaedics, University of Miami/Miller School of Medicine, Miami, FL
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Merlet AN, Cattagni T, Cornu C, Jubeau M. Effect of knee angle on neuromuscular assessment of plantar flexor muscles: A reliability study. PLoS One 2018; 13:e0195220. [PMID: 29596480 PMCID: PMC5875874 DOI: 10.1371/journal.pone.0195220] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2017] [Accepted: 02/25/2018] [Indexed: 11/18/2022] Open
Abstract
INTRODUCTION This study aimed to determine the intra- and inter-session reliability of neuromuscular assessment of plantar flexor (PF) muscles at three knee angles. METHODS Twelve young adults were tested for three knee angles (90°, 30° and 0°) and at three time points separated by 1 hour (intra-session) and 7 days (inter-session). Electrical (H reflex, M wave) and mechanical (evoked and maximal voluntary torque, activation level) parameters were measured on the PF muscles. Intraclass correlation coefficients (ICC) and coefficients of variation were calculated to determine intra- and inter-session reliability. RESULTS The mechanical measurements presented excellent (ICC>0.75) intra- and inter-session reliabilities regardless of the knee angle considered. The reliability of electrical measurements was better for the 90° knee angle compared to the 0° and 30° angles. CONCLUSIONS Changes in the knee angle may influence the reliability of neuromuscular assessments, which indicates the importance of considering the knee angle to collect consistent outcomes on the PF muscles.
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Affiliation(s)
- Angèle N. Merlet
- Laboratory Movement, Interactions, Performance, Faculty of Sport Sciences, University of Nantes, Nantes, France
| | - Thomas Cattagni
- Laboratory Movement, Interactions, Performance, Faculty of Sport Sciences, University of Nantes, Nantes, France
- Inserm Unit 1179, Team 3: Technologies and Innovative Therapies Applied to Neuromuscular diseases, UVSQ. CIC 805, Physiology-Functional Testing Ward, AP-HP, Raymond Poincaré Teaching Hospital, Garches, France
- * E-mail:
| | - Christophe Cornu
- Laboratory Movement, Interactions, Performance, Faculty of Sport Sciences, University of Nantes, Nantes, France
| | - Marc Jubeau
- Laboratory Movement, Interactions, Performance, Faculty of Sport Sciences, University of Nantes, Nantes, France
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Age-Related Differences in Cortical and Subcortical Activities during Observation and Motor Imagery of Dynamic Postural Tasks: An fMRI Study. Neural Plast 2018; 2018:1598178. [PMID: 29675037 PMCID: PMC5872650 DOI: 10.1155/2018/1598178] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2017] [Revised: 12/01/2017] [Accepted: 12/21/2017] [Indexed: 11/18/2022] Open
Abstract
Age-related changes in brain activation other than in the primary motor cortex are not well known with respect to dynamic balance control. Therefore, the current study aimed to explore age-related differences in the control of static and dynamic postural tasks using fMRI during mental simulation of balance tasks. For this purpose, 16 elderly (72 ± 5 years) and 16 young adults (27 ± 5 years) were asked to mentally simulate a static and a dynamic balance task by motor imagery (MI), action observation (AO), or the combination of AO and MI (AO + MI). Age-related differences were detected in the form of larger brain activations in elderly compared to young participants, especially in the challenging dynamic task when applying AO + MI. Interestingly, when MI (no visual input) was contrasted to AO (visual input), elderly participants revealed deactivation of subcortical areas. The finding that the elderly demonstrated overactivation in mostly cortical areas in challenging postural conditions with visual input (AO + MI and AO) but deactivation in subcortical areas during MI (no vision) may indicate that elderly individuals allocate more cortical resources to the internal representation of dynamic postural tasks. Furthermore, it might be assumed that they depend more strongly on visual input to activate subcortical internal representations.
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Fujio K, Obata H, Kitamura T, Kawashima N, Nakazawa K. Corticospinal Excitability Is Modulated as a Function of Postural Perturbation Predictability. Front Hum Neurosci 2018. [PMID: 29535618 PMCID: PMC5835041 DOI: 10.3389/fnhum.2018.00068] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Recent studies demonstrated that the corticospinal pathway is one of the key nodes for the feedback control of human standing and that the excitability is flexibly changed according to the current state of posture. However, it has been unclear whether this pathway is also involved in a predictive control of human standing. Here, we investigated whether the corticospinal excitability of the soleus (SOL) and tibialis anterior (TA) muscles during standing would be modulated anticipatorily when perturbation was impending. We measured the motor-evoked potential (MEP) induced by transcranial magnetic stimulation over the motor cortex at six stimulus intensities. Three experimental conditions were set depending on predictabilities about perturbation occurrence and onset: No perturbation, No Cue, and Cue conditions. In the Cue condition, an acoustic signal was given as timing information of perturbation. The slope of the stimulus-response relation curve revealed that the TA-MEP was enhanced when postural perturbation was expected compared to when the perturbation was not expected (No Perturbation vs. No Cue, 0.023 ± 0.004 vs. 0.042 ± 0.007; No Perturbation vs. Cue, 0.023 ± 0.004 vs. 0.050 ± 0.009; Bonferroni correction, p = 0.01, respectively). In addition, two-way analysis of variance (intensity × condition) revealed the main effect of condition (F(1,13) = 6.31, p = 0.03) but not intensity and interaction when the MEP amplitude of the Cue and No Cue conditions was normalized by that in No Perturbation, suggesting the enhancement more apparent when timing information was given. The SOL-MEP was not modulated even when perturbation was expected, but it slightly reduced due to the timing information. The results of an additional experiment confirmed that the acoustic cue by itself did not affect the TA- and SOL-MEPs. Our findings suggest that a prediction of a future state of standing balance modulates the corticospinal excitability in the TA, and that the additional timing information facilitates this modulation. The corticospinal pathway thus appears to be involved in mechanisms of the predictive control as well as feedback control of standing posture.
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Affiliation(s)
- Kimiya Fujio
- Department of Rehabilitation Science, Faculty of Health Care Science, Chiba Prefectural University of Health Sciences, Chiba, Japan.,Department of Rehabilitation for Movement Functions, Research Institute of National Rehabilitation Center for Persons with Disabilities, Saitama, Japan
| | - Hiroki Obata
- Department of Humanities and Social Sciences, Institute of Liberal Arts, Kyushu Institute of Technology, Fukuoka, Japan
| | - Taku Kitamura
- Department of Rehabilitation for Movement Functions, Research Institute of National Rehabilitation Center for Persons with Disabilities, Saitama, Japan
| | - Noritaka Kawashima
- Department of Rehabilitation for Movement Functions, Research Institute of National Rehabilitation Center for Persons with Disabilities, Saitama, Japan
| | - Kimitaka Nakazawa
- Sports Science Laboratory, Department of Life Sciences, Graduate School of Arts and Sciences, University of Tokyo, Tokyo, Japan
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Increasing mediolateral standing sway is associated with increasing corticospinal excitability, and decreasing M1 inhibition and facilitation. Gait Posture 2018; 60:135-140. [PMID: 29202358 DOI: 10.1016/j.gaitpost.2017.11.021] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/09/2017] [Revised: 11/22/2017] [Accepted: 11/27/2017] [Indexed: 02/02/2023]
Abstract
In standing, corticospinal excitability increases and primary motor cortex (M1) inhibition decreases in response to anterior posterior or direction unspecific manipulations that increase task difficulty. However, mediolateral (ML) sway control requires greater active neural involvement. Therefore, the primary purpose of this study was to determine the pattern of change in neural excitability when ML postural task difficulty is manipulated and to test whether the neural excitability is proportional to ML sway magnitude across conditions. Tibialis anterior corticospinal excitability was quantified using motor evoked potential (MEP) and postural sway was indexed using ML center of pressure (COP) velocity. Additionally, we examined inhibition and facilitation processes in the primary motor cortex using the paired pulse short interval intracortical inhibition (SICI) and intracortical facilitation (ICF) techniques respectively. Measurements were repeated in four conditions with quiet stance as a control. Differences between conditions were tested using one-way repeated measures ANOVAs, on log transformed data. Associations were quantified using Spearman's Rank Correlation Coefficient. There was a significant main effect of condition on all the neural excitability measures with MEP (p<0.001) being highest in the most difficult condition, and SICI (p=0.01), ICF (p<0.001) being lowest in the most difficult condition. Increasing ML COP velocity was significantly associated with increasing MEP amplitude (r=0.68, p<0.001), but decreasing SICI (r=0.24, p=0.03) and ICF (r=-0.54, p<0.001). Our results show that both corticospinal and M1 excitability in standing are scaled in proportion to ML task difficulty.
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Terada M, Kosik K, Johnson N, Gribble P. Altered postural control variability in older-aged individuals with a history of lateral ankle sprain. Gait Posture 2018; 60:88-92. [PMID: 29169097 DOI: 10.1016/j.gaitpost.2017.11.009] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/27/2017] [Revised: 10/27/2017] [Accepted: 11/10/2017] [Indexed: 02/02/2023]
Abstract
The current study aimed to examine postural control performance during a single-leg balance task in elderly individuals with and without a previous history of lateral ankle sprain (LAS). Eighteen adults with a previous history of LAS (mean age = 66 years old) and 12 healthy controls (mean age = 65 years old) were included in the study. Participants performed three trials of a single-leg balance task during an eyes-opened condition for 20-s. Center of pressure (COP) trajectories in the anteroposterior (AP) and mediolateral (ML) directions were collected with a force plate. The following postural control measures were calculated in the AP and ML directions: 1) Sample Entropy (SampEn); 2) Approximate Entropy (ApEn); 3) mean of Time-to-Boundary minima (mean TTB); and 4) COP velocity (COPV). Older-age participants with a history LAS exhibited lower ApEn-AP, SampEn-AP, and SampEn-ML values compared to healthy controls (p < 0.05). The information gained from this investigation indicates more rigid postural control patterns, less adaptability, and more difficulty maintaining COP during a single-leg balance task in adults with a previous history of LAS. Our data suggest that there is a need to consider history of musculoskeletal injury when evaluating factors for postural control and fall risk in the elderly. Future investigations are needed to assess the effect of LAS on age-related declines in postural control and discern associations between potential risk factors of fall-related injuries and LAS in an elderly population.
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Affiliation(s)
- Masafumi Terada
- College of Sport and Health Science, Ritsumeikan University, Shiga, Japan.
| | - Kyle Kosik
- Department of Rehabilitation Science, University of Kentucky, Lexington, KY, United States
| | - Nathan Johnson
- Department of Rehabilitation Science, University of Kentucky, Lexington, KY, United States
| | - Phillip Gribble
- Department of Rehabilitation Science, University of Kentucky, Lexington, KY, United States
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Ruffieux J, Mouthon A, Keller M, Mouthon M, Annoni JM, Taube W. Balance Training Reduces Brain Activity during Motor Simulation of a Challenging Balance Task in Older Adults: An fMRI Study. Front Behav Neurosci 2018; 12:10. [PMID: 29472847 PMCID: PMC5810285 DOI: 10.3389/fnbeh.2018.00010] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2017] [Accepted: 01/15/2018] [Indexed: 12/05/2022] Open
Abstract
Aging is associated with a shift from an automatic to a more cortical postural control strategy, which goes along with deteriorations in postural stability. Although balance training has been shown to effectively counteract these behavioral deteriorations, little is known about the effect of balance training on brain activity during postural tasks in older adults. We, therefore, assessed postural stability and brain activity using fMRI during motor imagery alone (MI) and in combination with action observation (AO; i.e., AO+MI) of a challenging balance task in older adults before and after 5 weeks of balance training. Results showed a nonsignificant trend toward improvements in postural stability after balance training, accompanied by reductions in brain activity during AO+MI of the balance task in areas relevant for postural control, which have been shown to be over-activated in older adults during (simulation of) motor performance, including motor, premotor, and multisensory vestibular areas. This suggests that balance training may reverse the age-related cortical over-activations and lead to changes in the control of upright posture toward the one observed in young adults.
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Affiliation(s)
- Jan Ruffieux
- Movement and Sport Sciences, Department of Medicine, University of Fribourg, Fribourg, Switzerland
| | - Audrey Mouthon
- Movement and Sport Sciences, Department of Medicine, University of Fribourg, Fribourg, Switzerland
| | - Martin Keller
- Movement and Sport Sciences, Department of Medicine, University of Fribourg, Fribourg, Switzerland
| | - Michaël Mouthon
- Neurology Laboratory, Department of Medicine, University of Fribourg, Fribourg, Switzerland
| | - Jean-Marie Annoni
- Neurology Laboratory, Department of Medicine, University of Fribourg, Fribourg, Switzerland
| | - Wolfgang Taube
- Movement and Sport Sciences, Department of Medicine, University of Fribourg, Fribourg, Switzerland
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Beaudette SM, Smith SGVS, Bent LR, Brown SHM. Spine Posture Influences Tactile Perceptual Sensitivity of the Trunk Dorsum. Ann Biomed Eng 2017; 45:2804-2812. [PMID: 28924674 DOI: 10.1007/s10439-017-1924-3] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2017] [Accepted: 09/12/2017] [Indexed: 11/27/2022]
Abstract
The purpose of the current work was to quantify the influence of posture-mediated skin deformation on trunk dorsum tactile perceptual sensitivity. Twelve young and healthy individuals were assessed while adopting three different spine postures (extension, neutral and flexion). Tactile sensitivity threshold tests (T10 and L4 vertebral levels) included measures of touch sensitivity, spatial acuity and stretch sensitivity. The results demonstrate that tactile sensitivity can differ due to changes in body posture. The skin of the trunk dorsum had increased thresholds for touch sensitivity, longitudinal spatial acuity and transverse stretch sensitivity in spine flexion. Furthermore, spine flexion also resulted in a reduced sensory threshold to stretching stimuli in the longitudinal direction. The opposite trends occurred when participants adopted spine extension. It is suggested that posture-mediated skin deformation generates changes in the amount of strain experienced by individual skin mechanoreceptors, and the relative spacing between mechanoreceptors. Furthermore, it is suggested that "pre-stretch" of the skin brings mechanoreceptors closer to their stretch activation thresholds, thereby increasing an individual's sensitivity to skin stretch when in spine flexion.
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Affiliation(s)
- Shawn M Beaudette
- Department of Human Health and Nutritional Sciences, University of Guelph, Guelph, ON, Canada
| | - Simone G V S Smith
- Department of Human Health and Nutritional Sciences, University of Guelph, Guelph, ON, Canada
| | - Leah R Bent
- Department of Human Health and Nutritional Sciences, University of Guelph, Guelph, ON, Canada
| | - Stephen H M Brown
- Department of Human Health and Nutritional Sciences, University of Guelph, Guelph, ON, Canada.
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Exploratory Study of the Influence of Posture and Hand Task on Corticomotor Excitability of Upper Extremity Muscles After Stroke. Arch Phys Med Rehabil 2017; 98:1771-1781. [DOI: 10.1016/j.apmr.2016.12.019] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2016] [Revised: 12/23/2016] [Accepted: 12/23/2016] [Indexed: 11/20/2022]
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Ruffieux J, Mouthon A, Keller M, Wälchli M, Taube W. Behavioral and neural adaptations in response to five weeks of balance training in older adults: a randomized controlled trial. J Negat Results Biomed 2017; 16:11. [PMID: 28610582 PMCID: PMC5470269 DOI: 10.1186/s12952-017-0076-1] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2017] [Accepted: 06/08/2017] [Indexed: 11/11/2022] Open
Abstract
Background While the positive effect of balance training on age-related impairments in postural stability is well-documented, the neural correlates of such training adaptations in older adults remain poorly understood. This study therefore aimed to shed more light on neural adaptations in response to balance training in older adults. Methods Postural stability as well as spinal reflex and cortical excitability was measured in older adults (65–80 years) before and after 5 weeks of balance training (n = 15) or habitual activity (n = 13). Postural stability was assessed during one- and two-legged quiet standing on a force plate (static task) and a free-swinging platform (dynamic task). The total sway path was calculated for all tasks. Additionally, the number of errors was counted for the one-legged tasks. To investigate changes in spinal reflex excitability, the H-reflex was assessed in the soleus muscle during quiet upright stance. Cortical excitability was assessed during an antero-posterior perturbation by conditioning the H-reflex with single-pulse transcranial magnetic stimulation. Results A significant training effect in favor of the training group was found for the number of errors conducted during one-legged standing (p = .050 for the static and p = .042 for the dynamic task) but not for the sway parameters in any task. In contrast, no significant effect was found for cortical excitability (p = 0.703). For spinal excitability, an effect of session (p < .001) as well as an interaction of session and group (p = .009) was found; however, these effects were mainly due to a reduced excitability in the control group. Conclusions In line with previous results, older adults’ postural stability was improved after balance training. However, these improvements were not accompanied by significant neural adaptations. Since almost identical studies in young adults found significant behavioral and neural adaptations after four weeks of training, we assume that age has an influence on the time course of such adaptations to balance training and/or the ability to transfer them from a trained to an untrained task. Electronic supplementary material The online version of this article (doi:10.1186/s12952-017-0076-1) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Jan Ruffieux
- Movement and Sport Sciences, Department of Medicine, University of Fribourg, Boulevard de Pérolles 90, 1700, Fribourg, Switzerland.
| | - Audrey Mouthon
- Movement and Sport Sciences, Department of Medicine, University of Fribourg, Boulevard de Pérolles 90, 1700, Fribourg, Switzerland
| | - Martin Keller
- Movement and Sport Sciences, Department of Medicine, University of Fribourg, Boulevard de Pérolles 90, 1700, Fribourg, Switzerland
| | - Michael Wälchli
- Movement and Sport Sciences, Department of Medicine, University of Fribourg, Boulevard de Pérolles 90, 1700, Fribourg, Switzerland
| | - Wolfgang Taube
- Movement and Sport Sciences, Department of Medicine, University of Fribourg, Boulevard de Pérolles 90, 1700, Fribourg, Switzerland
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Cattagni T, Merlet AN, Cornu C, Jubeau M. H-reflex and M-wave recordings: effect of pressure application to the stimulation electrode on the assessment of evoked potentials and subject's discomfort. Clin Physiol Funct Imaging 2017; 38:416-424. [PMID: 28444940 DOI: 10.1111/cpf.12431] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2016] [Accepted: 03/03/2017] [Indexed: 11/26/2022]
Abstract
This study aimed to compare the effect of different types of pressure applied to the stimulation electrode on assessing the efficiency of Ia-α-motoneuron transmission of the soleus muscle and the associated discomfort using electrical nerve stimulation. Twelve healthy young adults participated in three experimental sessions (one for each knee angle). The amplitudes of the maximal Hoffmann reflex (Hmax ) and motor potential (Mmax ) were recorded from the soleus muscle at 0°, 30° and 90° knee angles (0° full extension) through three pressure applications to the stimulation electrode: no pressure, pressure with manual application and pressure using adhesive tape. The soleus Hmax /Mmax were calculated to assess the efficiency of Ia-α-motoneuron transmission during varied knee angles and pressure application to the stimulation electrode. At the stimulation intensity evoking soleus Hmax and Mmax , subjects were asked to orally provide a value between 'no discomfort' (0) and 'worst possible discomfort' (10). The application of pressure on the stimulation electrode, particularly using adhesive tape, decreased both the stimulation intensity needed to evoke an electrophysiological response and the associated self-reported discomfort (P<0·05), while the Hmax /Mmax remained constant. At the stimulation intensity evoking Mmax , the electrical stimulation appeared to be more painful at 0° knee angle compared with 30° and 90° angles (P<0·01). To conclude, this study showed that a knee flexion and a pressure application to the stimulation electrode, especially using tape pressure, are recommended in the objective to reduce the patient/subjects' discomfort when eliciting evoked potentials on soleus muscle.
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Affiliation(s)
- Thomas Cattagni
- Laboratory "Movement, Interactions, Performance" (EA 4334), Faculty of Sport Sciences, University of Nantes, Nantes, France
| | - Angèle N Merlet
- Laboratory "Movement, Interactions, Performance" (EA 4334), Faculty of Sport Sciences, University of Nantes, Nantes, France
| | - Christophe Cornu
- Laboratory "Movement, Interactions, Performance" (EA 4334), Faculty of Sport Sciences, University of Nantes, Nantes, France
| | - Marc Jubeau
- Laboratory "Movement, Interactions, Performance" (EA 4334), Faculty of Sport Sciences, University of Nantes, Nantes, France
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Spinal and corticospinal pathways are differently modulated when standing at the bottom and the top of a three-step staircase in young and older adults. Eur J Appl Physiol 2017; 117:1165-1174. [PMID: 28409395 DOI: 10.1007/s00421-017-3603-3] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2016] [Accepted: 03/29/2017] [Indexed: 12/29/2022]
Abstract
PURPOSE This study investigated the modulation of spinal (group Ia afferents) and corticospinal pathways when young (22.7 ± 1.3 years) and older adults (72.2 ± 7.9 years) stood at the bottom and at the top of a three-step staircase equipped with force platforms. METHOD Changes in submaximal H-reflex amplitude (H 50) and slope of the H-reflex input-output relation (spinal pathway), and in amplitude of motor-evoked potentials (MEP) triggered by transcranial magnetic stimulation (corticospinal pathway) at two intensities (1.1× and 1.2× motor threshold) were recorded in soleus when subjects stood as steady as possible downstairs and upstairs. The centre of pressure (CoP) excursion was analyzed in the time and frequency domains in both conditions. RESULTS Regardless of age, the mean CoP velocity was greater when standing upstairs (11.1 ± 3.5 mm s-1) than downstairs (9.0 ± 2.3 mm s-1; p = 0.002). The CoP power spectral density (PSD) in the 0-0.5 Hz band was greater upstairs than downstairs (+18.4%; p = 0.03) whereas PSD in the 2-20Hz frequency band was lesser (-41%) upstairs than downstairs (p < 0.001), regardless of age. In both groups, the H 50 amplitude (-30.6%; p < 0.001) and slope of H-reflex input-output relation (-10.2%; p = 0.002) were lesser when standing upstairs than downstairs, whereas no significant difference was observed in MEP amplitude and silent period between balance conditions (p > 0.05). CONCLUSION These results indicate a lower dependence on spinal pathway to control soleus motor neurones when standing upstairs than downstairs accompanied by a change in postural control. This suggests that healthy older adults preserved their ability to adjust postural control to environmental demands.
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Mouthon AA, Ruffieux J, Keller M, Taube W. Age-Related Differences in Corticospinal Excitability during Observation and Motor Imagery of Balance Tasks. Front Aging Neurosci 2016; 8:317. [PMID: 28066238 PMCID: PMC5179536 DOI: 10.3389/fnagi.2016.00317] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2016] [Accepted: 12/08/2016] [Indexed: 12/30/2022] Open
Abstract
Postural control declines across adult lifespan. Non-physical balance training has been suggested as an alternative to improve postural control in frail/immobilized elderly people. Previous studies showed that this kind of training can improve balance control in young and older adults. However, it is unclear whether the brain of young and older adults is activated differently during mental simulations of balance tasks. For this purpose, soleus (SOL) and tibialis motor evoked potentials (MEPs) and SOL H-reflexes were elicited while 15 elderly (mean ± SD = 71 ± 4.6 years) and 15 young participants (mean ± SD = 27 ± 4.6 years) mentally simulated static and dynamic balance tasks using motor imagery (MI), action observation (AO) or the combination of AO and MI (AO + MI). Young subjects displayed significant modulations of MEPs that depended on the kind of mental simulation and the postural task. Elderly adults also revealed differences between tasks, but not between mental simulation conditions. Furthermore, the elderly displayed larger MEP facilitation during mental simulation (AGE-GROUP; F(1,28) = 5.9; p = 0.02) in the SOL muscle compared to the young and a task-dependent modulation of the tibialis background electromyography (bEMG) activity. H-reflex amplitudes and bEMG in the SOL showed neither task- nor age-dependent modulation. As neither mental simulation nor balance tasks modulated H-reflexes and bEMG in the SOL muscle, despite large variations in the MEP-amplitudes, there seems to be an age-related change in the internal cortical representation of balance tasks. Moreover, the modulation of the tibialis bEMG in the elderly suggests that aging partially affects the ability to inhibit motor output.
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Affiliation(s)
- Audrey A. Mouthon
- Movement and Sport Science, Department of Medicine, University of FribourgFribourg, Switzerland
- *Correspondence: Audrey A. Mouthon
| | - Jan Ruffieux
- Movement and Sport Science, Department of Medicine, University of FribourgFribourg, Switzerland
| | - Martin Keller
- Movement and Sport Science, Department of Medicine, University of FribourgFribourg, Switzerland
| | - Wolfgang Taube
- Movement and Sport Science, Department of Medicine, University of FribourgFribourg, Switzerland
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Bonnet CT, Baudry S. A functional synergistic model to explain postural control during precise visual tasks. Gait Posture 2016; 50:120-125. [PMID: 27597272 DOI: 10.1016/j.gaitpost.2016.08.030] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/05/2016] [Revised: 08/06/2016] [Accepted: 08/29/2016] [Indexed: 02/02/2023]
Abstract
In everyday life, individuals sometimes have to perform precise, or challenging, visual tasks in upright standing. Upright, one problem to perform precise saccades and fixations is that the body oscillates continuously in a mainly unpredictable way. Current cognitive models assume that the central nervous system should divide its attention to perform these 'dual tasks' because of limited attentional resources (keeping balance and performing the precise visual task). The problem with the concept of duality is that individuals (need to) succeed in precise visual tasks upright and should not be more unstable and inefficient - because of a division of attention - in these tasks. In our opinion, the central nervous system should work adaptively in a way that enables success in these tasks. Hence, instead of assuming 'duality' in cognitive processes, we suggest that i) a 'synergy' - or unification - between visual and postural processes may be required to succeed in precise visual tasks. Success in precise visual tasks upright would also require ii) the synergy to be based on two feedforward processes with the visual process being the leader; iii) individuals to reduce their postural sway to facilitate successful synergies; iiii) additional cognitive resources to link visual and postural processes. We discuss some literature findings consistent with these assumptions and summarize a recent validation of the synergistic model. In summary, both models of duality and synergy could be complementary and the present manuscript shows how they could be included in a higher-order, two directional, cognitive model of postural control.
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Affiliation(s)
- Cédrick T Bonnet
- Cognitive Science and Affective Science Laboratory (SCALab), Universities of Lille, CNRS, France.
| | - Stéphane Baudry
- Laboratory of Applied Biology and Neurophysiology, Université Libre de Bruxelles, FNRS, Belgium
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Baudry S. Aging Changes the Contribution of Spinal and Corticospinal Pathways to Control Balance. Exerc Sport Sci Rev 2016; 44:104-9. [DOI: 10.1249/jes.0000000000000080] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Arellano CJ, Caha D, Hennessey JE, Amiridis IG, Baudry S, Enoka RM. Fatigue-induced adjustment in antagonist coactivation by old adults during a steadiness task. J Appl Physiol (1985) 2016; 120:1039-46. [PMID: 26846553 DOI: 10.1152/japplphysiol.00908.2015] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2015] [Accepted: 01/22/2016] [Indexed: 11/22/2022] Open
Abstract
The purpose of this study was to determine the adjustments in the level of coactivation during a steadiness task performed by young and old adults after the torque-generating capacity of the antagonist muscles was reduced by a fatiguing contraction. Torque steadiness (coefficient of variation) and electromyographic activity of the extensor and flexor carpi radialis muscles were measured as participants matched a wrist extensor target torque (10% maximum) before and after sustaining an isometric contraction (30% maximum) with wrist flexors to task failure. Time to failure was similar (P = 0.631) for young (417 ± 121 s) and old (452 ± 174 s) adults. The reduction in maximal voluntary contraction torque (%initial) for the wrist flexors after the fatiguing contraction was greater (P = 0.006) for young (32.5 ± 13.7%) than old (21.8 ± 6.6%) adults. Moreover, maximal voluntary contraction torque for the wrist extensors declined for old (-13.7 ± 12.7%; P = 0.030), but not young (-5.4 ± 13.8%; P = 0.167), adults. Torque steadiness during the matching task with the wrist extensors was similar before and after the fatiguing contraction for both groups, but the level of coactivation increased after the fatiguing contraction for old (P = 0.049) but not young (P = 0.137) adults and was twice the amplitude for old adults (P = 0.002). These data reveal that old adults are able to adjust the amount of antagonist muscle activity independent of the agonist muscle during steady submaximal contractions.
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Affiliation(s)
- Christopher J Arellano
- Department of Ecology and Evolutionary Biology, Brown University, Providence, Rhode Island; Department of Integrative Physiology, University of Colorado, Boulder, Colorado
| | - David Caha
- Department of Integrative Physiology, University of Colorado, Boulder, Colorado
| | - Joseph E Hennessey
- Department of Integrative Physiology, University of Colorado, Boulder, Colorado
| | - Ioannis G Amiridis
- Department of Physical Education and Sport Sciences, Aristotle University of Thessaloniki, Serres, Greece; and
| | - Stéphane Baudry
- Laboratory of Applied Biology, Neurosciences Institute, Université Libre de Bruxelles, Brussels, Belgium
| | - Roger M Enoka
- Department of Integrative Physiology, University of Colorado, Boulder, Colorado
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Papegaaij S, Taube W, van Keeken HG, Otten E, Baudry S, Hortobágyi T. Postural challenge affects motor cortical activity in young and old adults. Exp Gerontol 2015; 73:78-85. [PMID: 26615878 DOI: 10.1016/j.exger.2015.11.015] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2015] [Revised: 10/27/2015] [Accepted: 11/23/2015] [Indexed: 11/18/2022]
Abstract
When humans voluntarily activate a muscle, intracortical inhibition decreases. Such a decrease also occurs in the presence of a postural challenge and more so with increasing age. Here, we examined age-related changes in motor cortical activity during postural and non-postural contractions with varying levels of postural challenge. Fourteen young (age 22) and twelve old adults (age 70) performed three conditions: (1) voluntary contraction of the soleus muscle in sitting and (2) leaning forward while standing with and (3) without being supported. Subthreshold transcranial magnetic stimulation was applied to the soleus motor area suppressing ongoing EMG, as an index of motor cortical activity. The area of EMG suppression was ~60% smaller (p<0.05) in unsupported vs. supported leaning and sitting, with no difference between these latter two conditions (p>0.05). Even though in absolute terms young compared with old adults leaned farther (p=0.018), there was no age effect or an age by condition interaction in EMG suppression. Leaning closer to the maximum without support correlated with less EMG suppression (rho=-0.44, p=0.034). We conclude that the critical factor in modulating motor cortical activity was postural challenge and not contraction aim or posture. Age did not affect the motor control strategy as quantified by the modulation of motor cortical activity, but the modulation appeared at a lower task difficulty with increasing age.
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Affiliation(s)
- Selma Papegaaij
- University of Groningen, University Medical Center Groningen, Center for Human Movement Sciences, Antonius Deusinglaan 1, 9713AV, Groningen, The Netherlands.
| | - Wolfgang Taube
- University of Fribourg, Department of Medicine, Ch. du Musée 8, CH-1700, Fribourg, Switzerland
| | - Helco G van Keeken
- University of Groningen, University Medical Center Groningen, Center for Human Movement Sciences, Antonius Deusinglaan 1, 9713AV, Groningen, The Netherlands
| | - Egbert Otten
- University of Groningen, University Medical Center Groningen, Center for Human Movement Sciences, Antonius Deusinglaan 1, 9713AV, Groningen, The Netherlands
| | - Stéphane Baudry
- Université Libre de Bruxelles, Faculty for Motor Sciences, Laboratory of Applied Biology, CP 640, Route de Lennik 808, 1070 Brussels, Belgium
| | - Tibor Hortobágyi
- University of Groningen, University Medical Center Groningen, Center for Human Movement Sciences, Antonius Deusinglaan 1, 9713AV, Groningen, The Netherlands; Department of Sport, Exercise and Rehabilitation, Northumbria University, Newcastle-upon-Tyne NE1 8ST, United Kingdom
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