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Milbocker KA, Smith IF, Klintsova AY. Maintaining a Dynamic Brain: A Review of Empirical Findings Describing the Roles of Exercise, Learning, and Environmental Enrichment in Neuroplasticity from 2017-2023. Brain Plast 2024; 9:75-95. [PMID: 38993580 PMCID: PMC11234674 DOI: 10.3233/bpl-230151] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/19/2023] [Indexed: 07/13/2024] Open
Abstract
Brain plasticity, also termed neuroplasticity, refers to the brain's life-long ability to reorganize itself in response to various changes in the environment, experiences, and learning. The brain is a dynamic organ capable of responding to stimulating or depriving environments, activities, and circumstances from changes in gene expression, release of neurotransmitters and neurotrophic factors, to cellular reorganization and reprogrammed functional connectivity. The rate of neuroplastic alteration varies across the lifespan, creating further challenges for understanding and manipulating these processes to benefit motor control, learning, memory, and neural remodeling after injury. Neuroplasticity-related research spans several decades, and hundreds of reviews have been written and published since its inception. Here we present an overview of the empirical papers published between 2017 and 2023 that address the unique effects of exercise, plasticity-stimulating activities, and the depriving effect of social isolation on brain plasticity and behavior.
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Affiliation(s)
| | - Ian F. Smith
- Department of Psychological and Brain Sciences, University of Delaware, University of Delaware, Newark, USA
| | - Anna Y. Klintsova
- Department of Psychological and Brain Sciences, University of Delaware, University of Delaware, Newark, USA
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2
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Romare M, Elcadi GH, Johansson E, Tsaklis P. Relative Neuroadaptive Effect of Resistance Training along the Descending Neuroaxis in Older Adults. Brain Sci 2023; 13:brainsci13040679. [PMID: 37190644 DOI: 10.3390/brainsci13040679] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2023] [Revised: 04/01/2023] [Accepted: 04/16/2023] [Indexed: 05/17/2023] Open
Abstract
Age-related decline in voluntary force production represents one of the main contributors to the onset of physical disability in older adults and is argued to stem from adverse musculoskeletal alterations and changes along the descending neuroaxis. The neural contribution of the above is possibly indicated by disproportionate losses in voluntary activation (VA) compared to muscle mass. For young adults, resistance training (RT) induces muscular and neural adaptations over several levels of the central nervous system, contributing to increased physical performance. However, less is known about the relative neuroadaptive contribution of RT in older adults. The aim of this review was to outline the current state of the literature regarding where and to what extent neural adaptations occur along the descending neuroaxis in response to RT in older adults. We performed a literature search in PubMed, Google Scholar and Scopus. A total of 63 articles met the primary inclusion criteria and following quality analysis (PEDro) 23 articles were included. Overall, neuroadaptations in older adults seemingly favor top-down adaptations, where the preceding changes of neural drive from superior levels affect the neural output of lower levels, following RT. Moreover, older adults appear more predisposed to neural rather than morphological adaptations compared to young adults, a potentially important implication for the improved maintenance of neuromuscular function during aging.
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Affiliation(s)
- Mattias Romare
- ErgoMech-Lab, Department of Physical Education and Sport Science, University of Thessaly, 42100 Trikala, Greece
| | - Guilherme H Elcadi
- ErgoMech-Lab, Department of Physical Education and Sport Science, University of Thessaly, 42100 Trikala, Greece
- Division of Ergonomics, School of Engineering Sciences in Chemistry, Biotechnology and Health, KTH Royal Institute of Technology, 14157 Huddinge, Sweden
| | - Elin Johansson
- Pain in Motion Research Group, Departments of Human Physiology and Rehabilitation Sciences, Faculty of Physical Education and Physiotherapy, Vrije Universiteit Brussel, PC 1050 Brussel, Belgium
| | - Panagiotis Tsaklis
- ErgoMech-Lab, Department of Physical Education and Sport Science, University of Thessaly, 42100 Trikala, Greece
- Centre of Orthopaedics and Regenerative Medicine, C.O.R.E.-C.I.R.I., Aristotle University of Thessaloniki, 541 24 Thessaloniki, Greece
- Department of Molecular Medicine and Surgery, Karolinska Institute, SE-171 76 Solna, Sweden
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Bilateral Improvements Following Unilateral Home-Based Training in Plantar Flexors: A Potential for Cross-Education in Rehabilitation. J Sport Rehabil 2023; 32:14-23. [PMID: 35894916 DOI: 10.1123/jsr.2021-0383] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2021] [Revised: 05/03/2022] [Accepted: 05/09/2022] [Indexed: 01/03/2023]
Abstract
CONTEXT Cross-education (CE) refers to neuromuscular gains in the untrained limb upon contralateral limb training. To date, only laboratory-based exercise programs have demonstrated CE. Home-based exercise prescription eliciting CE could have greater clinical applicability. OBJECTIVE To determine the effect of an 8-week, home-based unilateral strength training intervention on isokinetic muscle strength, muscular excitation, and power in trained and untrained plantar flexors. DESIGN Randomized controlled trial. METHODS Thirty-four healthy participants were randomized to intervention (n = 20) or control (n = 14). The intervention group completed 3 sets of 12 repetitions of progressively loaded unilateral calf raises 3 days per week. Concentric and eccentric peak torque were measured using isokinetic dynamometry at 30°/s and 120°/s. Maximal electromyogram amplitude was simultaneously measured. Power was measured using a jump mat. All variables were measured at preintervention, midintervention, and postintervention. RESULTS Strength significantly increased bilaterally pre-post at both velocities concentrically and eccentrically in intervention group participants. Maximal electromyogram amplitude significantly increased pre-post bilaterally at both velocities in the medial gastrocnemii of the intervention group. Power significantly increased bilaterally pre-post in the intervention group, with a dose-response effect demonstrated in the untrained plantar flexors. The CE effects of strength, power, and electromyogram activation were 23.4%, 14.6%, and 25.3%, respectively. All control group values were unchanged pre-post. CONCLUSION This study shows that a simple at-home unilateral plantar flexor exercise protocol induces significant increases in contralateral strength, muscular excitation, and power. These results suggest the applicability of CE in home rehabilitation programs aiming to restore or maintain neuromuscular function in inactive individuals or immobilized ankles.
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Macaulay TR, Hegarty A, Yan L, Duncan D, Pa J, Kutch JJ, La Rocca M, Lane CJ, Schroeder ET. Effects of a 12-Week Periodized Resistance Training Program on Resting Brain Activity and Cerebrovascular Function: A Nonrandomized Pilot Trial. Neurosci Insights 2022; 17:26331055221119441. [PMID: 35983377 PMCID: PMC9379950 DOI: 10.1177/26331055221119441] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2022] [Accepted: 07/27/2022] [Indexed: 01/26/2023] Open
Abstract
Resistance training is a promising strategy to promote healthy cognitive aging; however, the brain mechanisms by which resistance training benefits cognition have yet to be determined. Here, we examined the effects of a 12-week resistance training program on resting brain activity and cerebrovascular function in 20 healthy older adults (14 females, mean age 69.1 years). In this single group clinical trial, multimodal 3 T magnetic resonance imaging was performed at 3 time points: baseline (preceding a 12-week control period), pre-intervention, and post-intervention. Along with significant improvements in fluid cognition (d = 1.27), 4 significant voxelwise clusters were identified for decreases in resting brain activity after the intervention (Cerebellum, Right Middle Temporal Gyrus, Left Inferior Parietal Lobule, and Right Inferior Parietal Lobule), but none were identified for changes in resting cerebral blood flow. Using a separate region of interest approach, we provide estimates for improved cerebral blood flow, compared with declines over the initial control period, in regions associated with cognitive impairment, such as hippocampal blood flow (d = 0.40), and posterior cingulate blood flow (d = 0.61). Finally, resistance training had a small countermeasure effect on the age-related progression of white matter lesion volume (rank-biserial = -0.22), a biomarker of cerebrovascular disease. These proof-of-concept data support larger trials to determine whether resistance training can attenuate or even reverse salient neurodegenerative processes.
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Affiliation(s)
- Timothy R Macaulay
- Division of Biokinesiology and Physical
Therapy, Ostrow School of Dentistry, University of Southern California, Los Angeles,
CA, USA,Timothy R Macaulay, Division of
Biokinesiology and Physical Therapy, Ostrow School of Dentistry, University of
Southern California, 1540 E. Alcazar Street, CHP149, Los Angeles, CA 90089, USA.
| | - Amy Hegarty
- Division of Biokinesiology and Physical
Therapy, Ostrow School of Dentistry, University of Southern California, Los Angeles,
CA, USA
| | - Lirong Yan
- Mark and Mary Stevens Neuroimaging and
Informatics Institute, Department of Neurology, Keck School of Medicine, University
of Southern California, Los Angeles, CA, USA
| | - Dominique Duncan
- Mark and Mary Stevens Neuroimaging and
Informatics Institute, Department of Neurology, Keck School of Medicine, University
of Southern California, Los Angeles, CA, USA
| | - Judy Pa
- Mark and Mary Stevens Neuroimaging and
Informatics Institute, Department of Neurology, Keck School of Medicine, University
of Southern California, Los Angeles, CA, USA
| | - Jason J Kutch
- Division of Biokinesiology and Physical
Therapy, Ostrow School of Dentistry, University of Southern California, Los Angeles,
CA, USA
| | - Marianna La Rocca
- Mark and Mary Stevens Neuroimaging and
Informatics Institute, Department of Neurology, Keck School of Medicine, University
of Southern California, Los Angeles, CA, USA,Department of Preventive Medicine, Keck
School of Medicine, University of Southern California, Los Angeles, CA, USA
| | - Christianne J Lane
- Dipartimento Interateneo di Fisica,
Università degli Studi di Bari Aldo Moro, Bari, Italy
| | - E Todd Schroeder
- Division of Biokinesiology and Physical
Therapy, Ostrow School of Dentistry, University of Southern California, Los Angeles,
CA, USA
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Lim H, Madhavan S. Effects of Cross-Education on Neural Adaptations Following Non-Paretic Limb Training in Stroke: A Scoping Review with Implications for Neurorehabilitation. J Mot Behav 2022; 55:111-124. [PMID: 35940590 DOI: 10.1080/00222895.2022.2106935] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
Current stroke rehabilitation interventions focus on intensive task specific training of the paretic limb, which may not be feasible for individuals with higher levels of impairment or in the early phase of stroke. Cross-education, a mechanism that improves strength or skill of the untrained limb following unilateral motor training, has high clinical relevance for stroke rehabilitation. Despite its potential benefits, our knowledge on the application and efficacy of cross-education in stroke is limited. We performed a scoping review to synthesize the current evidence regarding neurophysiological and motor effects of cross-education training in stroke. Low to strong evidence from five studies demonstrated strength gains ranging from 31-200% in the untrained paretic limb following non-paretic muscle training. Neurophysiological mechanisms underlying cross-education were unclear as the three studies that used transcranial magnetic stimulation to probe functional connectivity demonstrated mixed results in low sample size. Our review suggests that cross-education is a promising clinical approach in stroke, however high quality studies focusing on neurophysiological mechanisms are required to establish the efficacy and underlying mechanisms of cross-education in stroke. Recommendations regarding future directions and clinical utility are provided.
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Affiliation(s)
- Hyosok Lim
- Brain Plasticity Laboratory, Department of Physical Therapy, University of Illinois at Chicago, Chicago, IL, USA.,Graduate Program in Rehabilitation Sciences, College of Applied Health Sciences, University of Illinois at Chicago, Chicago, IL, USA
| | - Sangeetha Madhavan
- Brain Plasticity Laboratory, Department of Physical Therapy, University of Illinois at Chicago, Chicago, IL, USA
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Pani J, Eikenes L, Reitlo LS, Stensvold D, Wisløff U, Håberg AK. Effects of a 5-Year Exercise Intervention on White Matter Microstructural Organization in Older Adults. A Generation 100 Substudy. Front Aging Neurosci 2022; 14:859383. [PMID: 35847676 PMCID: PMC9278017 DOI: 10.3389/fnagi.2022.859383] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2022] [Accepted: 05/25/2022] [Indexed: 12/13/2022] Open
Abstract
Aerobic fitness and exercise could preserve white matter (WM) integrity in older adults. This study investigated the effect on WM microstructural organization of 5 years of exercise intervention with either supervised moderate-intensity continuous training (MICT), high-intensity interval training (HIIT), or following the national physical activity guidelines. A total of 105 participants (70–77 years at baseline), participating in the randomized controlled trial Generation 100 Study, volunteered to take part in this longitudinal 3T magnetic resonance imaging (MRI) study. The HIIT group (n = 33) exercised for four intervals of 4 min at 90% of peak heart rate two times a week, the MICT group (n = 24) exercised continuously for 50 min at 70% peak heart rate two times a week, and the control group (n = 48) followed the national guidelines of ≥30 min of physical activity almost every day. At baseline and at 1-, 3-, and 5-year follow-ups, diffusion tensor imaging (DTI) scans were performed, cardiorespiratory fitness (CRF) was measured as peak oxygen uptake (VO2peak) with ergospirometry, and information on exercise habits was collected. There was no group*time or group effect on any of the DTI indices at any time point during the intervention. Across all groups, CRF was positively associated with fractional anisotropy (FA) and axial diffusivity (AxD) at the follow-ups, and the effect became smaller with time. Exercise intensity was associated with mean diffusivity (MD)/FA, with the greatest effect at 1-year and no effect at 5-year follow-up. There was an association between exercise duration and FA and radial diffusivity (RD) only after 1 year. Despite the lack of group*time interaction or group effect, both higher CRF and exercise intensity was associated with better WM microstructural organization throughout the intervention, but the effect became attenuated over time. Different aspects of exercising affected the WM metrics and WM tracts differently with the greatest and most overlapping effects in the corpus callosum. The current study indicates not only that high CRF and exercise intensity are associated with WM microstructural organization in aging but also that exercise’s positive effects on WM may decline with increasing age.
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Affiliation(s)
- Jasmine Pani
- Department of Neuromedicine and Movement Science, Faculty of Medicine and Health Sciences, Norwegian University of Science and Technology, Trondheim, Norway.,Department of Radiology and Nuclear Medicine, St Olav's University Hospital, Trondheim, Norway
| | - Live Eikenes
- Department of Circulation and Medical Imaging, Faculty of Medicine and Health Sciences, Norwegian University of Science and Technology, Trondheim, Norway
| | - Line S Reitlo
- Department of Neuromedicine and Movement Science, Faculty of Medicine and Health Sciences, Norwegian University of Science and Technology, Trondheim, Norway
| | - Dorthe Stensvold
- Department of Circulation and Medical Imaging, Faculty of Medicine and Health Sciences, Norwegian University of Science and Technology, Trondheim, Norway
| | - Ulrik Wisløff
- Department of Circulation and Medical Imaging, Faculty of Medicine and Health Sciences, Norwegian University of Science and Technology, Trondheim, Norway.,School of Human Movement and Nutrition Sciences, Faculty of Health and Behavioural Sciences, The University of Queensland, Brisbane, QLD, Australia
| | - Asta Kristine Håberg
- Department of Neuromedicine and Movement Science, Faculty of Medicine and Health Sciences, Norwegian University of Science and Technology, Trondheim, Norway.,Department of Radiology and Nuclear Medicine, St Olav's University Hospital, Trondheim, Norway
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7
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Atkinson E, Škarabot J, Ansdell P, Goodall S, Howatson G, Thomas K. Does the reticulospinal tract mediate adaptation to resistance training in humans? J Appl Physiol (1985) 2022; 133:689-696. [PMID: 35834623 PMCID: PMC9467470 DOI: 10.1152/japplphysiol.00264.2021] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
Abstract
Resistance training increases volitional force-producing capacity, and it is widely accepted that such an increase is partly underpinned by adaptations in the central nervous system, particularly in the early phases of training. Despite this, the neural substrate(s) responsible for mediating adaptation remains largely unknown. Most studies have focused on the corticospinal tract, the main descending pathway controlling movement in humans, with equivocal findings. It is possible that neural adaptation to resistance training is mediated by other structures; one such candidate is the reticulospinal tract. The aim of this narrative mini-review is to articulate the potential of the reticulospinal tract to underpin adaptations in muscle strength. Specifically, we 1) discuss why the structure and function of the reticulospinal tract implicate it as a potential site for adaptation; 2) review the animal and human literature that supports the idea of the reticulospinal tract as an important neural substrate underpinning adaptation to resistance training; and 3) examine the potential methodological options to assess the reticulospinal tract in humans.
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Affiliation(s)
- Elliott Atkinson
- Department of Sport, Exercise and Rehabilitation, grid.42629.3bNorthumbria University, Newcastle-upon-Tyne, United Kingdom
| | - Jakob Škarabot
- School of Sport, Exercise and Health Sciences, grid.6571.5Loughborough University, Loughborough, United Kingdom
| | - Paul Ansdell
- Department of Sport, Exercise and Rehabilitation, grid.42629.3bNorthumbria University, Newcastle-upon-Tyne, United Kingdom
| | - Stuart Goodall
- Department of Sport, Exercise and Rehabilitation, grid.42629.3bNorthumbria University, Newcastle-upon-Tyne, United Kingdom
| | - Glyn Howatson
- Department of Sport, Exercise and Rehabilitation, grid.42629.3bNorthumbria University, Newcastle-upon-Tyne, United Kingdom
| | - Kevin Thomas
- Department of Sport, Exercise and Rehabilitation, grid.42629.3bNorthumbria University, Newcastle-upon-Tyne, United Kingdom
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8
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Maleki S, Hendrikse J, Chye Y, Caeyenberghs K, Coxon JP, Oldham S, Suo C, Yücel M. Associations of cardiorespiratory fitness and exercise with brain white matter in healthy adults: A systematic review and meta-analysis. Brain Imaging Behav 2022; 16:2402-2425. [PMID: 35773556 PMCID: PMC9581839 DOI: 10.1007/s11682-022-00693-y] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/31/2022] [Indexed: 11/25/2022]
Abstract
Magnetic resonance imaging (MRI) studies have revealed positive associations between brain structure and physical activity, cardiorespiratory fitness, and exercise (referred to here as PACE). While a considerable body of research has investigated the effects of PACE on grey matter, much less is known about effects on white matter (WM). Hence, we conducted a systematic review of peer-reviewed literature published prior to 5th July 2021 using online databases (PubMed and Scopus) and PRISMA guidelines to synthesise what is currently known about the relationship between PACE and WM in healthy adults. A total of 60 studies met inclusion criteria and were included in the review. Heterogeneity across studies was calculated using Qochran's q test, and publication bias was assessed for each meta-analysis using Begg and Mazumdar rank correlation test. A meta-regression was also conducted to explore factors contributing to any observed heterogeneity. Overall, we observed evidence of positive associations between PACE and global WM volume (effect size (Hedges's g) = 0.137, p < 0.001), global WM anomalies (effect size = 0.182, p < 0.001), and local microstructure integrity (i.e., corpus callosum: effect size = 0.345, p < 0.001, and anterior limb of internal capsule: effect size = 0.198, p < 0.001). These findings suggest that higher levels of PACE are associated with improved global WM volume and local integrity. We appraise the quality of evidence, and discuss the implications of these findings for the preservation of WM across the lifespan. We conclude by providing recommendations for future research in order to advance our understanding of the specific PACE parameters and neurobiological mechanisms underlying these effects.
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Affiliation(s)
- Suzan Maleki
- BrainPark, Turner Institute for Brain and Mental Health, School of Psychological Sciences and Monash Biomedical Imaging Facility, Monash University, 770 Blackburn RD, Clayton, VIC, 3168, Australia
| | - Joshua Hendrikse
- Movement and Exercise Neuroscience Laboratory, Turner Institute for Brain and Mental Health, School of Psychological Sciences and Monash Biomedical Imaging Facility, Monash University, Clayton, Australia
| | - Yann Chye
- BrainPark, Turner Institute for Brain and Mental Health, School of Psychological Sciences and Monash Biomedical Imaging Facility, Monash University, 770 Blackburn RD, Clayton, VIC, 3168, Australia
| | - Karen Caeyenberghs
- Cognitive Neuroscience Unit, School of Psychology, Deakin University, Geelong, Australia
| | - James P Coxon
- Movement and Exercise Neuroscience Laboratory, Turner Institute for Brain and Mental Health, School of Psychological Sciences and Monash Biomedical Imaging Facility, Monash University, Clayton, Australia
| | - Stuart Oldham
- Neural Systems and Behaviour, Turner Institute for Brain and Mental Health, School of Psychological Sciences and Monash Biomedical Imaging Facility, Monash University, Clayton, Australia.,Developmental Imaging, Murdoch Children's Research Institute, Melbourne, Australia
| | - Chao Suo
- BrainPark, Turner Institute for Brain and Mental Health, School of Psychological Sciences and Monash Biomedical Imaging Facility, Monash University, 770 Blackburn RD, Clayton, VIC, 3168, Australia.
| | - Murat Yücel
- BrainPark, Turner Institute for Brain and Mental Health, School of Psychological Sciences and Monash Biomedical Imaging Facility, Monash University, 770 Blackburn RD, Clayton, VIC, 3168, Australia.
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9
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Chronic resistance training: is it time to rethink the time course of neural contributions to strength gain? Eur J Appl Physiol 2021; 121:2413-2422. [PMID: 34052876 DOI: 10.1007/s00421-021-04730-4] [Citation(s) in RCA: 27] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2021] [Accepted: 05/22/2021] [Indexed: 10/20/2022]
Abstract
Resistance training enhances muscular force due to a combination of neural plasticity and muscle hypertrophy. It has been well documented that the increase in strength over the first few weeks of resistance training (i.e. acute) has a strong underlying neural component and further enhancement in strength with long-term (i.e. chronic) resistance training is due to muscle hypertrophy. For obvious reasons, collecting long-term data on how chronic-resistance training affects the nervous system not feasible. As a result, the effect of chronic-resistance training on neural plasticity is less understood and has not received systematic exploration. Thus, the aim of this review is to provide rationale for investigating neural plasticity beyond acute-resistance training. We use cross-sectional work to highlight neural plasticity that occurs with chronic-resistance training at sites from the brain to spinal cord. Specifically, intra-cortical circuitry and the spinal motoneuron seem to be key sites for this plasticity. We then urge the need to further investigate the differential effects of acute versus chronic-resistance training on neural plasticity, and the role of this plasticity in increased strength. Such investigations may help in providing a clearer definition of the continuum of acute and chronic-resistance training, how the nervous system is altered during this continuum and the causative role of neural plasticity in changes in strength over the continuum of resistance training.
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Manca A, Hortobágyi T, Carroll TJ, Enoka RM, Farthing JP, Gandevia SC, Kidgell DJ, Taylor JL, Deriu F. Contralateral Effects of Unilateral Strength and Skill Training: Modified Delphi Consensus to Establish Key Aspects of Cross-Education. Sports Med 2021; 51:11-20. [PMID: 33175329 PMCID: PMC7806569 DOI: 10.1007/s40279-020-01377-7] [Citation(s) in RCA: 22] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/10/2022]
Abstract
Background Cross-education refers to increased motor output (i.e., force generation, skill) of the opposite, untrained limb following a period of unilateral exercise training. Despite extensive research, several aspects of the transfer phenomenon remain controversial. Methods A modified two-round Delphi online survey was conducted among international experts to reach consensus on terminology, methodology, mechanisms of action, and translational potential of cross-education, and to provide a framework for future research. Results Through purposive sampling of the literature, we identified 56 noted experts in the field, of whom 32 completed the survey, and reached consensus (75% threshold) on 17 out of 27 items. Conclusion Our consensus-based recommendations for future studies are that (1) the term ‘cross-education’ should be adopted to refer to the transfer phenomenon, also specifying if transfer of strength or skill is meant; (2) functional magnetic resonance imaging, short-interval intracortical inhibition and interhemispheric inhibition appear to be promising tools to study the mechanisms of transfer; (3) strategies which maximize cross-education, such as high-intensity training, eccentric contractions, and mirror illusion, seem worth being included in the intervention plan; (4) study protocols should be designed to include at least 13–18 sessions or 4–6 weeks to produce functionally meaningful transfer of strength, and (5) cross-education could be considered as an adjuvant treatment particularly for unilateral orthopedic conditions and sports injuries. Additionally, a clear gap in views emerged between the research field and the purely clinical field. The present consensus statement clarifies relevant aspects of cross-education including neurophysiological, neuroanatomical, and methodological characteristics of the transfer phenomenon, and provides guidance on how to improve the quality and usability of future cross-education studies. Electronic supplementary material The online version of this article (10.1007/s40279-020-01377-7) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- A Manca
- Department of Biomedical Sciences, University of Sassari, Viale San Pietro 43/b, 07100, Sassari, Italy
| | - T Hortobágyi
- Center for Human Movement Sciences, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands
| | - T J Carroll
- Centre for Sensorimotor Performance, School of Human Movement and Nutrition Sciences, The University of Queensland, Brisbane, QLD, Australia
| | - R M Enoka
- Department of Integrative Physiology, University of Colorado Boulder, Boulder, USA
| | - J P Farthing
- University of Saskatchewan College of Kinesiology, Saskatoon, SK, Canada
| | - S C Gandevia
- Neuroscience Research Australia (NeuRA), The University of New South Wales, Sydney, Australia
| | - D J Kidgell
- Department of Physiotherapy, School of Primary and Allied Health Care, Faculty of Medicine, Nursing and Health Science, Monash University, Melbourne, Australia
| | - J L Taylor
- School of Medical and Health Sciences, Edit Cowan University, Joondalup, Australia
| | - F Deriu
- Department of Biomedical Sciences, University of Sassari, Viale San Pietro 43/b, 07100, Sassari, Italy.
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11
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Hortobágyi T, Granacher U, Fernandez-Del-Olmo M, Howatson G, Manca A, Deriu F, Taube W, Gruber M, Márquez G, Lundbye-Jensen J, Colomer-Poveda D. Functional relevance of resistance training-induced neuroplasticity in health and disease. Neurosci Biobehav Rev 2020; 122:79-91. [PMID: 33383071 DOI: 10.1016/j.neubiorev.2020.12.019] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2020] [Revised: 12/18/2020] [Accepted: 12/19/2020] [Indexed: 01/13/2023]
Abstract
Repetitive, monotonic, and effortful voluntary muscle contractions performed for just a few weeks, i.e., resistance training, can substantially increase maximal voluntary force in the practiced task and can also increase gross motor performance. The increase in motor performance is often accompanied by neuroplastic adaptations in the central nervous system. While historical data assigned functional relevance to such adaptations induced by resistance training, this claim has not yet been systematically and critically examined in the context of motor performance across the lifespan in health and disease. A review of muscle activation, brain and peripheral nerve stimulation, and imaging data revealed that increases in motor performance and neuroplasticity tend to be uncoupled, making a mechanistic link between neuroplasticity and motor performance inconclusive. We recommend new approaches, including causal mediation analytical and hypothesis-driven models to substantiate the functional relevance of resistance training-induced neuroplasticity in the improvements of gross motor function across the lifespan in health and disease.
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Affiliation(s)
- Tibor Hortobágyi
- Center for Human Movement Sciences, University of Groningen, University Medical CenterGroningen, Groningen, Netherlands.
| | - Urs Granacher
- Division of Training and Movement Sciences, Research Focus Cognition Sciences, University of Potsdam, Potsdam, Germany
| | - Miguel Fernandez-Del-Olmo
- Area of Sport Sciences, Faculty of Sports Sciences and Physical Education, Center for Sport Studies, King Juan Carlos University, Madrid, Spain
| | - Glyn Howatson
- Department of Sport, Exercise and Rehabilitation, Northumbria University, Newcastle, UK; Water Research Group, North West University, Potchefstroom, South Africa
| | - Andrea Manca
- Department of Biomedical Sciences, University of Sassari, Sassari, Italy
| | - Franca Deriu
- Department of Biomedical Sciences, University of Sassari, Sassari, Italy
| | - Wolfgang Taube
- Department of Neurosciences and Movement Sciences, University of Fribourg, Fribourg, Switzerland
| | - Markus Gruber
- Human Performance Research Centre, Department of Sport Science, University of Konstanz, Konstanz, Germany
| | - Gonzalo Márquez
- Department of Physical Education and Sport, Faculty of Sports Sciences and Physical Education, University of A Coruña, A Coruña, Spain
| | - Jesper Lundbye-Jensen
- Movement & Neuroscience, Department of Nutrition, Exercise & Sports Department of Neuroscience, University of Copenhagenk, Faculty of Health Science, Universidad Isabel I, Burgos, Spain
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12
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Aagaard P, Bojsen-Møller J, Lundbye-Jensen J. Assessment of Neuroplasticity With Strength Training. Exerc Sport Sci Rev 2020; 48:151-162. [DOI: 10.1249/jes.0000000000000229] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
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13
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Macaulay TR, Fisher BE, Schroeder ET. Potential Indirect Mechanisms of Cognitive Enhancement After Long-Term Resistance Training in Older Adults. Phys Ther 2020; 100:907-916. [PMID: 31944253 PMCID: PMC7530578 DOI: 10.1093/ptj/pzaa013] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/16/2020] [Revised: 09/27/2019] [Accepted: 11/24/2019] [Indexed: 01/01/2023]
Abstract
The prevalence of dementia and other age-associated cognitive disorders is steadily increasing worldwide. With no cure after diagnosis, successful treatment likely requires maximum adherence to preventative countermeasures. Many potential risk factors are modifiable through exercise. Specifically, mounting evidence suggests that long-term resistance training (RT) can help maintain cognitive abilities with aging and have additional benefits to overall brain health. Physical therapists are uniquely positioned to administer such clinical interventions designed to slow disease progression. However, a neuroscientific foundation for these benefits must be established to justify the integration of RT for brain health into practice. The mechanisms of cognitive decline are commonly linked to fundamental processes of aging. Even healthy older adults experience decreases in physical capacity, vascular function, brain structure and function, glucose regulation, inflammation, mood, and sleep quality. Yet, clinical trials involving RT in older adults have consistently demonstrated improvements in each of these systems with concomitant enhancement of cognitive performance. Beneficial adaptations may indirectly or directly mediate benefits to brain function, and understanding this relationship can help us develop optimal intervention strategies for the aging population.
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Affiliation(s)
- Timothy R Macaulay
- Clinical Exercise Research Center, Division of Biokinesiology and Physical Therapy, University of Southern California, 1540 East Alcazar St, CHP 149, Los Angeles, CA 90089 (USA). Address all correspondence to Mr Macaulay at:
| | - Beth E Fisher
- Clinical Exercise Research Center, Division of Biokinesiology and Physical Therapy, University of Southern California
| | - E Todd Schroeder
- Clinical Exercise Research Center, Division of Biokinesiology and Physical Therapy, University of Southern California
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14
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Norman JE, Rutkowsky J, Bodine S, Rutledge JC. The Potential Mechanisms of Exercise-induced Cognitive Protection: A Literature Review. Curr Pharm Des 2019; 24:1827-1831. [PMID: 29623829 DOI: 10.2174/1381612824666180406105149] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2018] [Revised: 03/27/2018] [Accepted: 03/29/2018] [Indexed: 12/12/2022]
Abstract
Dementia has become a major health concern for the aging population of the United States. Studies indicate that participation in moderate exercise, with training, has been shown to have a beneficial impact on cognition. Thus, exercise and its effects on cognitive function has become an important area of research. This review summarizes the current literature on the potential mechanisms of the benefits of exercise for cognitive function.
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Affiliation(s)
- Jennifer E Norman
- Department of Internal Medicine, Division of Cardiovascular Medicine, University of California, Davis, CA, United States
| | - Jennifer Rutkowsky
- Department of Molecular Biosciences, School of Veterinary Medicine, University of California, Davis, CA, United States
| | - Sue Bodine
- Department of Internal Medicine, Division of Endocrinology and Metabolism, University of Iowa, Iowa City, IA, United States
| | - John C Rutledge
- Department of Internal Medicine, Division of Cardiovascular Medicine, University of California, Davis, CA, United States
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15
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Mason J, Frazer AK, Jaberzadeh S, Ahtiainen JP, Avela J, Rantalainen T, Leung M, Kidgell DJ. Determining the Corticospinal Responses to Single Bouts of Skill and Strength Training. J Strength Cond Res 2019; 33:2299-2307. [PMID: 31343552 DOI: 10.1519/jsc.0000000000003266] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Mason, J, Frazer, AK, Jaberzadeh, S, Ahtiainen, JP, Avela, J, Rantalainen, T, Leung, M, and Kidgell, DJ. Determining the corticospinal responses to single bouts of skill and strength training. J Strength Cond Res 33(9): 2299-2307, 2019-Neuroplastic changes in the primary motor cortex accompany performance improvements following motor practice. Recent evidence suggests that the corticospinal responses to strength and skill training are similar, following both a single session and repeated bouts of training, promoting discussion that strength training is a form of motor learning. However, these findings are limited by the lack of a light-load strength training group. Therefore, the aim of the current study was to determine whether a single session of heavy-load strength training, light-load strength training or skill training differentially modulates the corticospinal pathway. Transcranial magnetic stimulation was used to assess the excitatory and inhibitory circuitry of the motor cortex following a single session of skill training, and following a single session of light-load and heavy-load strength training. Following a single session of training, participants in all groups experienced comparable increases in corticospinal excitability (ranging from 38 to 46%, all p < 0.05); however, disparity was observed in the inhibitory responses. Corticospinal inhibition was reduced in all 3 single-sessions, although to a greater magnitude in the heavy-load and skill-training sessions (22 and 18% respectively, compared with 11% following light-load training, all p < 0.05). Short-interval intracortical inhibition was reduced immediately following single sessions of heavy-load strength training (40% p < 0.05) and skill training (47% p < 0.05), but remained unchanged the following light-load strength training session. It appears that the corticospinal responses to single sessions of different types of strength and skill training are task-dependent. These findings reinforce the notion that strength training, at least when heavily-loaded, can be considered a form of motor learning, potentially because of the sensory feedback involved.
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Affiliation(s)
- Joel Mason
- Department of Physiotherapy, School of Primary Health Care, Faculty of Medicine, Nursing and Health Sciences, Monash University, Melbourne, Australia
| | - Ashlyn K Frazer
- Department of Physiotherapy, School of Primary Health Care, Faculty of Medicine, Nursing and Health Sciences, Monash University, Melbourne, Australia
| | - Shapour Jaberzadeh
- Department of Physiotherapy, School of Primary 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, University of Jyväskylä, Jyväskylä, Finland
| | - Janne Avela
- Faculty of Sport and Health Sciences, Neuromuscular Research Center, University of Jyväskylä, Jyväskylä, Finland
| | - Timo Rantalainen
- Faculty of Sport and Health Sciences, Neuromuscular Research Center, University of Jyväskylä, Jyväskylä, Finland
| | - Michael Leung
- Department of Physiology, School of Biomedical Sciences, Faculty of Medicine, Nursing and Health Sciences, Monash University, Melbourne, Australia
| | - Dawson J Kidgell
- Department of Physiotherapy, School of Primary Health Care, Faculty of Medicine, Nursing and Health Sciences, Monash University, Melbourne, Australia
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16
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Herold F, Törpel A, Schega L, Müller NG. Functional and/or structural brain changes in response to resistance exercises and resistance training lead to cognitive improvements - a systematic review. Eur Rev Aging Phys Act 2019; 16:10. [PMID: 31333805 PMCID: PMC6617693 DOI: 10.1186/s11556-019-0217-2] [Citation(s) in RCA: 130] [Impact Index Per Article: 26.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2019] [Accepted: 06/26/2019] [Indexed: 02/16/2023] Open
Abstract
BACKGROUND During the aging process, physical capabilities (e.g., muscular strength) and cognitive functions (e.g., memory) gradually decrease. Regarding cognitive functions, substantial functional (e.g., compensatory brain activity) and structural changes (e.g., shrinking of the hippocampus) in the brain cause this decline. Notably, growing evidence points towards a relationship between cognition and measures of muscular strength and muscle mass. Based on this emerging evidence, resistance exercises and/or resistance training, which contributes to the preservation and augmentation of muscular strength and muscle mass, may trigger beneficial neurobiological processes and could be crucial for healthy aging that includes preservation of the brain and cognition. Compared with the multitude of studies that have investigated the influence of endurance exercises and/or endurance training on cognitive performance and brain structure, considerably less work has focused on the effects of resistance exercises and/or resistance training. While the available evidence regarding resistance exercise-induced changes in cognitive functions is pooled, the underlying neurobiological processes, such as functional and structural brain changes, have yet to be summarized. Hence, the purpose of this systematic review is to provide an overview of resistance exercise-induced functional and/or structural brain changes that are related to cognitive functions. METHODS AND RESULTS A systematic literature search was conducted by two independent researchers across six electronic databases; 5957 records were returned, of which 18 were considered relevant and were analyzed. SHORT CONCLUSION Based on our analyses, resistance exercises and resistance training evoked substantial functional brain changes, especially in the frontal lobe, which were accompanied by improvements in executive functions. Furthermore, resistance training led to lower white matter atrophy and smaller white matter lesion volumes. However, based on the relatively small number of studies available, the findings should be interpreted cautiously. Hence, future studies are required to investigate the underlying neurobiological mechanisms and to verify whether the positive findings can be confirmed and transferred to other needy cohorts, such as older adults with dementia, sarcopenia and/or dynapenia.
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Affiliation(s)
- Fabian Herold
- Research Group Neuroprotection, German Center for Neurodegenerative Diseases (DZNE), Leipziger Str. 44, 39120 Magdeburg, Germany
| | - Alexander Törpel
- Institute III, Department of Sport Science, Otto von Guericke University Magdeburg, Zschokkestr. 32, 39104 Magdeburg, Germany
| | - Lutz Schega
- Institute III, Department of Sport Science, Otto von Guericke University Magdeburg, Zschokkestr. 32, 39104 Magdeburg, Germany
| | - Notger G. Müller
- Research Group Neuroprotection, German Center for Neurodegenerative Diseases (DZNE), Leipziger Str. 44, 39120 Magdeburg, Germany
- Center for Behavioral Brain Sciences (CBBS), Brenneckestraße 6, 39118 Magdeburg, Germany
- Department of Neurology, Medical Faculty, Otto von Guericke University, Leipziger Str. 44, 39120 Magdeburg, Germany
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17
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Baird JF, Hubbard EA, Sutton BP, Motl RW. The relationship between corticospinal tract integrity and lower-extremity strength is attenuated when controlling for age and sex in multiple sclerosis. Brain Res 2018; 1701:171-176. [PMID: 30213666 PMCID: PMC7906425 DOI: 10.1016/j.brainres.2018.09.013] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2018] [Revised: 09/07/2018] [Accepted: 09/08/2018] [Indexed: 11/25/2022]
Abstract
Muscle weakness, particularly in the lower-extremities, is common in multiple sclerosis (MS) and seemingly results from damage along white matter pathways in the central nervous system including the corticospinal tract (CST). This study examined CST structural integrity indicated by diffusion tensor imaging (DTI) related metrics (fractional anisotropy [FA], mean diffusivity [MD], radial diffusivity [RD], and axial diffusivity [AD]) as correlates of knee flexor (KF) and knee extensor (KE) muscle strength in MS. We included 36 persons with MS who underwent MRI and measurements of peak KE and KF strength using an isokinetic dynamometer. We examined associations using bivariate Spearman (rs) and partial Spearman correlation (prs) analyses controlling for age and sex. Peak KF strength was significantly associated with FA (rs = 0.42) and RD (rs = -0.36) and peak KE strength was significantly associated with MD (rs = -0.47) and RD (rs = -0.36). The correlations were attenuated after controlling for age and sex, but the relationship between KF strength and FA demonstrated a trend towards significance (prs = 0.33, p = 0.056). We provide evidence that the anatomical integrity of the CST may be associated with lower-extremity strength in MS. The attenuated correlations when controlling for age and sex suggest these factors, rather than MS per se, may be important contributors toward an association between CST DTI-metrics and KF and KE strength. Future rehabilitation trials of resistance training should consider including CST integrity as an outcome and/or predictor of strength adaptations.
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Affiliation(s)
- Jessica F Baird
- Department of Physical Therapy, University of Alabama at Birmingham, Birmingham, AL, USA.
| | - Elizabeth A Hubbard
- Department of Kinesiology and Community Health, University of Illinois at Urbana-Champaign, Urbana, IL, USA
| | - Bradley P Sutton
- Bioengineering and Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign, Urbana, IL, USA
| | - Robert W Motl
- Department of Physical Therapy, University of Alabama at Birmingham, Birmingham, AL, USA.
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18
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Green LA, Gabriel DA. The effect of unilateral training on contralateral limb strength in young, older, and patient populations: a meta-analysis of cross education. PHYSICAL THERAPY REVIEWS 2018. [DOI: 10.1080/10833196.2018.1499272] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Affiliation(s)
- Lara A. Green
- Department of Kinesiology, Brock University, St. Catharines, ON, Canada
| | - David A. Gabriel
- Department of Kinesiology, Brock University, St. Catharines, ON, Canada
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19
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Toh Z, Gu Q, Seah T, Wong W, McNab J, Chuang K, Hong X, Tang P. Increased white matter connectivity seen in young judo athletes with MRI. Clin Radiol 2018. [DOI: 10.1016/j.crad.2018.06.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
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20
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Frazer AK, Pearce AJ, Howatson G, Thomas K, Goodall S, Kidgell DJ. Determining the potential sites of neural adaptation to cross-education: implications for the cross-education of muscle strength. Eur J Appl Physiol 2018; 118:1751-1772. [PMID: 29995227 DOI: 10.1007/s00421-018-3937-5] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2018] [Accepted: 07/05/2018] [Indexed: 12/11/2022]
Abstract
Cross-education describes the strength gain in the opposite, untrained limb following a unilateral strength training program. Since its discovery in 1894, several studies now confirm the existence of cross-education in contexts that involve voluntary dynamic contractions, eccentric contraction, electrical stimulation, whole-body vibration and, more recently, following mirror feedback training. Although many aspects of cross-education have been established, the mediating neural mechanisms remain unclear. Overall, the findings of this review show that the neural adaptations to cross-education of muscle strength most likely represent a continuum of change within the central nervous system that involves both structural and functional changes within cortical motor and non-motor regions. Such changes are likely to be the result of more subtle changes along the entire neuroaxis which include, increased corticospinal excitability, reduced cortical inhibition, reduced interhemispheric inhibition, changes in voluntary activation and new regions of cortical activation. However, there is a need to widen the breadth of research by employing several neurophysiological techniques (together) to better understand the potential mechanisms mediating cross-education. This fundamental step is required in order to better prescribe targeted and effective guidelines for the clinical practice of cross-education. There is a need to determine whether similar cortical responses also occur in clinical populations where, perhaps, the benefits of cross-education could be best observed.
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Affiliation(s)
- Ashlyn K Frazer
- Department of Physiotherapy, Faculty of Medicine, Nursing and Health Sciences, School of Primary and Allied Health Care, Monash University, PO Box 527, Frankston, Melbourne, VIC, 3199, Australia.
| | - Alan J Pearce
- Discipline of Exercise Science, School of Allied Health, La Trobe University, Melbourne, Australia
| | - Glyn Howatson
- Department of Sport, Exercise and Rehabilitation, Northumbria University, Newcastle-upon-Tyne, UK.,Water Research Group, School of Biological Sciences, North West University, Potchefstroom, South Africa
| | - Kevin Thomas
- Department of Sport, Exercise and Rehabilitation, Northumbria University, Newcastle-upon-Tyne, UK
| | - Stuart Goodall
- Department of Sport, Exercise and Rehabilitation, Northumbria University, Newcastle-upon-Tyne, UK
| | - Dawson J Kidgell
- Department of Physiotherapy, Faculty of Medicine, Nursing and Health Sciences, School of Primary and Allied Health Care, Monash University, PO Box 527, Frankston, Melbourne, VIC, 3199, Australia
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21
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Manca A, Hortobágyi T, Rothwell J, Deriu F. Neurophysiological adaptations in the untrained side in conjunction with cross-education of muscle strength: a systematic review and meta-analysis. J Appl Physiol (1985) 2018; 124:1502-1518. [DOI: 10.1152/japplphysiol.01016.2017] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
We reviewed the evidence from randomized controlled trials (RCTs) focusing on the neurophysiological adaptations in the untrained side associated with cross-education of strength (CE) and pooled data into definite effect estimates for neurophysiological variables assessed in chronic CE studies. Furthermore, scoping directions for future research were provided to enhance the homogeneity and comparability of studies investigating the neural responses to CE. The magnitude of CE was 21.1 ± 18.2% (mean ± SD; P < 0.0001) in 22 RCTs ( n = 467 subjects) that measured at least 1 neurophysiological variable in the untrained side, including the following: electromyography (EMG; 14 studies); motor evoked potential (MEP; 8 studies); short-interval intracortical inhibition (SICI), recruitment curve, and M wave (6 studies); cortical silent period (cSP; 5 studies); interhemispheric inhibition, intracortical facilitation (ICF), and H reflex (2 studies); and V wave, short-interval ICF, short-latency afferent inhibition, and long-latency afferent inhibition (1 study). Only EMG, MEP, ICF, cSP, and SICI could be included in the meta-analysis (18 studies, n = 387). EMG ( P = 0.26, n = 235) and MEP amplitude ( P = 0.11, n = 145) did not change in the untrained limb after CE. cSP duration ( P = 0.02, n = 114) and SICI ( P = 0.001, n = 95) decreased in the untrained hemisphere according to body region and type and intensity of training. The magnitude of CE did not correlate with changes in these transcranial magnetic stimulation (TMS) measures. The design of this meta-analytical study and the lack of correlations prevented the ability to link mechanistically the observed neurophysiological changes to CE. Notwithstanding the limited amount of data available for pooling, the use of TMS to assess the ipsilateral neurophysiological responses to unilateral training still confirms the central neural origin hypothesis of chronic CE induced by strength training. However, how these neural adaptations contribute to CE remains unclear.
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Affiliation(s)
- Andrea Manca
- Department of Biomedical Sciences, University of Sassari, Sassari, Italy
| | - Tibor Hortobágyi
- Center for Human Movement Sciences, University Medical Centre Groningen, University of Groningen, Groningen, The Netherlands
| | - John Rothwell
- Sobell Department of Motor Neuroscience and Movement Disorders, Institute of Neurology, University College London, London, United Kingdom
| | - Franca Deriu
- Department of Biomedical Sciences, University of Sassari, Sassari, Italy
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22
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Kristensen TD, Mandl RC, Jepsen JR, Rostrup E, Glenthøj LB, Nordentoft M, Glenthøj BY, Ebdrup BH. Non-pharmacological modulation of cerebral white matter organization: A systematic review of non-psychiatric and psychiatric studies. Neurosci Biobehav Rev 2018; 88:84-97. [DOI: 10.1016/j.neubiorev.2018.03.013] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2017] [Revised: 03/11/2018] [Accepted: 03/12/2018] [Indexed: 10/17/2022]
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23
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Kumar A, Kothari M, Grigoriadis A, Trulsson M, Svensson P. Bite or brain: Implication of sensorimotor regulation and neuroplasticity in oral rehabilitation procedures. J Oral Rehabil 2018; 45:323-333. [DOI: 10.1111/joor.12603] [Citation(s) in RCA: 39] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/28/2017] [Indexed: 02/04/2023]
Affiliation(s)
- A. Kumar
- Division of Oral Diagnostics and Rehabilitation; Department of Dental Medicine; Karolinska Institutet; Huddinge Sweden
- Scandinavian Center for Orofacial Neurosciences (SCON); Huddinge Sweden
| | - M. Kothari
- Hammel Neurorehabilitation Centre and University Research Clinic; Aarhus University; Hammel Denmark
| | - A. Grigoriadis
- Division of Oral Diagnostics and Rehabilitation; Department of Dental Medicine; Karolinska Institutet; Huddinge Sweden
- Scandinavian Center for Orofacial Neurosciences (SCON); Huddinge Sweden
| | - M. Trulsson
- Division of Oral Diagnostics and Rehabilitation; Department of Dental Medicine; Karolinska Institutet; Huddinge Sweden
- Scandinavian Center for Orofacial Neurosciences (SCON); Huddinge Sweden
| | - P. Svensson
- Division of Oral Diagnostics and Rehabilitation; Department of Dental Medicine; Karolinska Institutet; Huddinge Sweden
- Scandinavian Center for Orofacial Neurosciences (SCON); Huddinge Sweden
- Section of Orofacial Pain and Jaw Function; Institute for Odontology and Oral Health; Aarhus University; Aarhus Denmark
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24
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Tøien T, Unhjem R, Øren TS, Kvellestad ACG, Hoff J, Wang E. Neural Plasticity with Age: Unilateral Maximal Strength Training Augments Efferent Neural Drive to the Contralateral Limb in Older Adults. J Gerontol A Biol Sci Med Sci 2017; 73:596-602. [DOI: 10.1093/gerona/glx218] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2017] [Accepted: 10/31/2017] [Indexed: 11/13/2022] Open
Affiliation(s)
- Tiril Tøien
- Department of Circulation and Medical Imaging, Faculty of Medicine, Norwegian University of Science and Technology, Trondheim, Norway
| | - Runar Unhjem
- Faculty of Professional Studies, Nord University, Bodø, Norway
| | - Thomas Storehaug Øren
- Department of Circulation and Medical Imaging, Faculty of Medicine, Norwegian University of Science and Technology, Trondheim, Norway
| | - Ann Charlotte Gjertsen Kvellestad
- Department of Circulation and Medical Imaging, Faculty of Medicine, Norwegian University of Science and Technology, Trondheim, Norway
| | - Jan Hoff
- Department of Circulation and Medical Imaging, Faculty of Medicine, Norwegian University of Science and Technology, Trondheim, Norway
- Department of Østmarka, Division of Mental Healthcare, St. Olav’s Hospital, Trondheim University Hospital, Norway
| | - Eivind Wang
- Department of Circulation and Medical Imaging, Faculty of Medicine, Norwegian University of Science and Technology, Trondheim, Norway
- Department of Research and Development, St. Olav’s University Hospital, Trondheim, Norway
- Department of Medicine, University of Utah, Salt Lake City, Utah
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25
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Manca A, Dragone D, Dvir Z, Deriu F. Cross-education of muscular strength following unilateral resistance training: a meta-analysis. Eur J Appl Physiol 2017; 117:2335-2354. [PMID: 28936703 DOI: 10.1007/s00421-017-3720-z] [Citation(s) in RCA: 69] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2017] [Accepted: 09/10/2017] [Indexed: 12/19/2022]
Abstract
PURPOSE Cross-education (CE) of strength is a well-known phenomenon whereby exercise of one limb can induce strength gains in the contralateral untrained limb. The only available meta-analyses on CE, which date back to a decade ago, estimated a modest 7.8% increase in contralateral strength following unilateral training. However, in recent years new evidences have outlined larger contralateral gains, which deserve to be systematically evaluated. Therefore, the aim of this meta-analysis was to appraise current data on CE and determine its overall magnitude of effect. METHODS Five databases were searched from inception to December 2016. All randomized controlled trials focusing on unilateral resistance training were carefully checked by two reviewers who also assessed the eligibility of the identified trials and extracted data independently. The risk of bias was assessed using the Cochrane Risk-of-Bias tool. RESULTS Thirty-one studies entered the meta-analysis. Data from 785 subjects were pooled and subgroup analyses by body region (upper/lower limb) and type of training (isometric/concentric/eccentric/isotonic-dynamic) were performed. The pooled estimate of CE was a significant 11.9% contralateral increase (95% CI 9.1-14.8; p < 0.00001; upper limb: + 9.4%, p < 0.00001; lower limb: + 16.4%, p < 0.00001). Significant CE effects were induced by isometric (8.2%; p = 0.0003), concentric (11.3%; p < 0.00001), eccentric (17.7%; p = 0.003) and isotonic-dynamic training (15.9%; p < 0.00001), although a high risk of bias was detected across the studies. CONCLUSIONS Unilateral resistance training induces significant contraction type-dependent gains in the contralateral untrained limb. Methodological issues in the included studies are outlined to provide guidance for a reliable quantification of CE in future studies.
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Affiliation(s)
- A Manca
- Department of Biomedical Sciences, University of Sassari, Viale S. Pietro 43/b, 07100, Sassari, Italy
| | - D Dragone
- Department of Biomedical Sciences, University of Sassari, Viale S. Pietro 43/b, 07100, Sassari, Italy
| | - Z Dvir
- Department of Physical Therapy, Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel
| | - Franca Deriu
- Department of Biomedical Sciences, University of Sassari, Viale S. Pietro 43/b, 07100, Sassari, Italy.
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26
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Reid LB, Sale MV, Cunnington R, Mattingley JB, Rose SE. Brain changes following four weeks of unimanual motor training: Evidence from fMRI-guided diffusion MRI tractography. Hum Brain Mapp 2017; 38:4302-4312. [PMID: 28677154 DOI: 10.1002/hbm.23514] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2016] [Revised: 12/21/2016] [Accepted: 01/02/2017] [Indexed: 11/06/2022] Open
Abstract
We have reported reliable changes in behavior, brain structure, and function in 24 healthy right-handed adults who practiced a finger-thumb opposition sequence task with their left hand for 10 min daily, over 4 weeks. Here, we extend these findings by using diffusion MRI to investigate white-matter changes in the corticospinal tract, basal-ganglia, and connections of the dorsolateral prefrontal cortex. Twenty-three participant datasets were available with pre-training and post-training scans. Task performance improved in all participants (mean: 52.8%, SD: 20.0%; group P < 0.01 FWE) and widespread microstructural changes were detected across the motor system of the "trained" hemisphere. Specifically, region-of-interest-based analyses of diffusion MRI (n = 22) revealed significantly increased fractional anisotropy (FA) in the right caudate nucleus (4.9%; P < 0.05 FWE), and decreased mean diffusivity in the left nucleus accumbens (-1.3%; P < 0.05 FWE). Diffusion MRI tractography (n = 22), seeded by sensorimotor cortex fMRI activation, also revealed increased FA in the right corticospinal tract (mean 3.28%; P < 0.05 FWE) predominantly reflecting decreased radial diffusivity. These changes were consistent throughout the entire length of the tract. The left corticospinal tract did not show any changes. FA also increased in white matter connections between the right middle frontal gyrus and both right caudate nucleus (17/22 participants; P < 0.05 FWE) and right supplementary motor area (18/22 participants; P < 0.05 FWE). Equivalent changes in FA were not seen in the left (non-trained) hemisphere. In combination with our functional and structural findings, this study provides detailed, multifocal evidence for widespread neuroplastic changes in the human brain resulting from motor training. Hum Brain Mapp 38:4302-4312, 2017. © 2017 Wiley Periodicals, Inc.
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Affiliation(s)
- Lee B Reid
- The Australian e-Health Research Centre, CSIRO, Brisbane, Queensland, Australia.,School of Medicine, The University of Queensland, St Lucia, Brisbane, Queensland, Australia
| | - Martin V Sale
- School of Health and Rehabilitation Sciences, The University of Queensland, St Lucia, Brisbane, Queensland, Australia.,The Queensland Brain Institute, The University of Queensland, St Lucia, Brisbane, Queensland, Australia
| | - Ross Cunnington
- The Queensland Brain Institute, The University of Queensland, St Lucia, Brisbane, Queensland, Australia.,School of Psychology, The University of Queensland, St Lucia, Brisbane, Queensland, Australia
| | - Jason B Mattingley
- The Queensland Brain Institute, The University of Queensland, St Lucia, Brisbane, Queensland, Australia.,School of Psychology, The University of Queensland, St Lucia, Brisbane, Queensland, Australia
| | - Stephen E Rose
- The Australian e-Health Research Centre, CSIRO, Brisbane, Queensland, Australia
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Souron R, Farabet A, Féasson L, Belli A, Millet GY, Lapole T. Eight weeks of local vibration training increases dorsiflexor muscle cortical voluntary activation. J Appl Physiol (1985) 2017; 122:1504-1515. [PMID: 28385918 DOI: 10.1152/japplphysiol.00793.2016] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2016] [Revised: 03/10/2017] [Accepted: 03/30/2017] [Indexed: 01/03/2023] Open
Abstract
The aim of this study was to evaluate the effects of an 8-wk local vibration training (LVT) program on functional and corticospinal properties of dorsiflexor muscles. Forty-four young subjects were allocated to a training (VIB, n = 22) or control (CON, n = 22) group. The VIB group performed twenty-four 1-h sessions (3 sessions/wk) of 100-Hz vibration applied to the right tibialis anterior. Both legs were tested in each group before training (PRE), after 4 (MID) and 8 (POST) wk of training, and 2 wk after training (POST2W). Maximal voluntary contraction (MVC) torque was assessed, and transcranial magnetic stimulation (TMS) was used to evaluate cortical voluntary activation (VATMS), motor evoked potential (MEP), cortical silent period (CSP), and input-output curve parameters. MVC was significantly increased for VIB at MID for right and left legs [+7.4% (P = 0.001) and +6.2% (P < 0.01), respectively] and remained significantly greater than PRE at POST [+12.0% (P < 0.001) and +10.1% (P < 0.001), respectively]. VATMS was significantly increased for right and left legs at MID [+4.4% (P < 0.01) and +4.7% (P < 0.01), respectively] and at POST [+4.9% (P = 0.001) and +6.2% (P = 0.001), respectively]. These parameters remained enhanced in both legs at POST2W MEP and CSP recorded during MVC and input-output curve parameters did not change at any time point for either leg. Despite no changes in excitability or inhibition being observed, LVT seems to be a promising method to improve strength through an increase of maximal voluntary activation, i.e., neural adaptations. Local vibration may thus be further considered for clinical or aging populations.NEW & NOTEWORTHY The effects of a local vibration training program on cortical voluntary activation measured with transcranial magnetic stimulation were assessed for the first time in dorsiflexors, a functionally important muscle group. We observed that training increased maximal voluntary strength likely because of the strong and repeated activation of Ia spindle afferents during vibration training that led to changes in the cortico-motoneuronal pathway, as demonstrated by the increase in cortical voluntary activation.
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Affiliation(s)
- Robin Souron
- Laboratoire Interuniversitaire de Biologie de la Motricité, Université de Lyon, Université Jean Monnet Saint-Etienne, Saint-Etienne, France
| | - Adrien Farabet
- Laboratoire Interuniversitaire de Biologie de la Motricité, Université de Lyon, Université Jean Monnet Saint-Etienne, Saint-Etienne, France
| | - Léonard Féasson
- Laboratoire Interuniversitaire de Biologie de la Motricité, Université de Lyon, Université Jean Monnet Saint-Etienne, Saint-Etienne, France.,Myology Unit, Referent Center of Rare Neuromuscular Diseases, Centre Hospitalier Universitaire Saint-Etienne, France; and
| | - Alain Belli
- Laboratoire Interuniversitaire de Biologie de la Motricité, Université de Lyon, Université Jean Monnet Saint-Etienne, Saint-Etienne, France
| | - Guillaume Y Millet
- Human Performance Laboratory, Faculty of Kinesiology, University of Calgary, Calgary, Alberta, Canada
| | - Thomas Lapole
- Laboratoire Interuniversitaire de Biologie de la Motricité, Université de Lyon, Université Jean Monnet Saint-Etienne, Saint-Etienne, France;
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Wang E, Nyberg SK, Hoff J, Zhao J, Leivseth G, Tørhaug T, Husby OS, Helgerud J, Richardson RS. Impact of maximal strength training on work efficiency and muscle fiber type in the elderly: Implications for physical function and fall prevention. Exp Gerontol 2017; 91:64-71. [PMID: 28232199 DOI: 10.1016/j.exger.2017.02.071] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2016] [Revised: 01/26/2017] [Accepted: 02/14/2017] [Indexed: 11/25/2022]
Abstract
Although aging is typically associated with a decreased efficiency of locomotion, somewhat surprisingly, there is also a reduction in the proportion of less efficient fast-twitch Type II skeletal muscle fibers and subsequently a greater propensity for falls. Maximal strength training (MST), with an emphasis on velocity in the concentric phase, improves maximal strength, the rate of force development (RFD), and work efficiency, but the impact on muscle morphology in the elderly is unknown. Therefore we evaluated force production, walking work efficiency, and muscle morphology in 11 old (72±3years) subjects before and after MST of the legs. Additionally, for reference, the MST-induced morphometric changes were compared with 7 old (74±6years) subjects who performed conventional strength training (CST), with focus on hypertrophy, as well as 13 young (24±2years) controls. As expected, MST in the old improved maximal strength (68%), RFD (48%), and work efficiency (12%), restoring each to a level similar to the young. However, of importance, these MST-induced functional changes were accompanied by a significant increase in the size (66%) and shift toward a larger percentage (56%) of Type II skeletal muscle fibers, mirroring the adaptations in the hypertrophy trained old subjects, with muscle composition now being similar to the young. In conclusion, MST can increase both work efficiency and Type II skeletal muscle fiber size and percentage in the elderly, supporting the potential role of MST as a countermeasure to maintain both physical function and fall prevention in this population.
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Affiliation(s)
- Eivind Wang
- Department of Circulation and Medical Imaging, Faculty of Medicine, The Norwegian University of Science and Technology, Trondheim, Norway; Department of Medicine, University of Utah, Salt Lake City, UT, USA; Department of Research and Development, St. Olav's University Hospital, Trondheim, Norway.
| | - Stian Kwak Nyberg
- Department of Circulation and Medical Imaging, Faculty of Medicine, The Norwegian University of Science and Technology, Trondheim, Norway
| | - Jan Hoff
- Department of Circulation and Medical Imaging, Faculty of Medicine, The Norwegian University of Science and Technology, Trondheim, Norway; Department of Physical Medicine and Rehabilitation, St.Olavs University Hospital, Trondheim, Norway
| | - Jia Zhao
- Department of Medicine, University of Utah, Salt Lake City, UT, USA
| | - Gunnar Leivseth
- Department of Physical Medicine and Rehabilitation, St.Olavs University Hospital, Trondheim, Norway; Department of Clinical Medicine, Faculty of Medicine, The Arctic University of Norway, Trondheim, Norway
| | - Tom Tørhaug
- Department of Physical Medicine and Rehabilitation, St.Olavs University Hospital, Trondheim, Norway; Department of Neuroscience, Faculty of Medicine, The Norwegian University of Science and Technology. Trondheim, Norway
| | - Otto Schnell Husby
- Department of Orthopedics, St.Olavs University Hospital, Trondheim, Norway
| | - Jan Helgerud
- Department of Circulation and Medical Imaging, Faculty of Medicine, The Norwegian University of Science and Technology, Trondheim, Norway
| | - Russell S Richardson
- Department of Medicine, University of Utah, Salt Lake City, UT, USA; Department of Nutrition and Integrative Physiology, University of Utah, Salt Lake City, UT, USA; Geriatric Research, Education, and Clinical Center, Salt Lake City VAMC, UT, USA
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Effects of Short-Term Dynamic Constant External Resistance Training and Subsequent Detraining on Strength of the Trained and Untrained Limbs: A Randomized Trial. Sports (Basel) 2016; 4:sports4010007. [PMID: 29910255 PMCID: PMC5968943 DOI: 10.3390/sports4010007] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2015] [Revised: 01/18/2016] [Accepted: 01/25/2016] [Indexed: 11/17/2022] Open
Abstract
Short-term resistance training has been shown to increase isokinetic muscle strength and performance after only two to nine days of training. The purpose of this study was to examine the effects of three days of unilateral dynamic constant external resistance (DCER) training and detraining on the strength of the trained and untrained legs. Nineteen men were randomly assigned to a DCER training group or a non-training control group. Subjects visited the laboratory eight times, the first visit was a familiarization session, the second visit was a pre-training assessment, the subsequent three visits were for training sessions (if assigned to the training group), and the last three visits were post-training assessments 1, 2, and 3 (i.e., 48 h, 1 week, and 2 weeks after the final training session). Strength increased in both trained and untrained limbs from pre- to post-training assessment 1 for the training group and remained elevated at post-training assessments 2 and 3 (p ≤ 0.05). No changes were observed in the control (p > 0.05). Possible strength gains from short-term resistance training have important implications in clinical rehabilitation settings, sports injury prevention, as well as other allied health fields such as physical therapy, occupational therapy, and athletic training.
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Interpreting Intervention Induced Neuroplasticity with fMRI: The Case for Multimodal Imaging Strategies. Neural Plast 2015; 2016:2643491. [PMID: 26839711 PMCID: PMC4709757 DOI: 10.1155/2016/2643491] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2015] [Accepted: 09/27/2015] [Indexed: 12/03/2022] Open
Abstract
Direct measurement of recovery from brain injury is an important goal in neurorehabilitation, and requires reliable, objective, and interpretable measures of changes in brain function, referred to generally as “neuroplasticity.” One popular imaging modality for measuring neuroplasticity is task-based functional magnetic resonance imaging (t-fMRI). In the field of neurorehabilitation, however, assessing neuroplasticity using t-fMRI presents a significant challenge. This commentary reviews t-fMRI changes commonly reported in patients with cerebral palsy or acquired brain injuries, with a focus on studies of motor rehabilitation, and discusses complexities surrounding their interpretations. Specifically, we discuss the difficulties in interpreting t-fMRI changes in terms of their underlying causes, that is, differentiating whether they reflect genuine reorganisation, neurological restoration, compensation, use of preexisting redundancies, changes in strategy, or maladaptive processes. Furthermore, we discuss the impact of heterogeneous disease states and essential t-fMRI processing steps on the interpretability of activation patterns. To better understand therapy-induced neuroplastic changes, we suggest that researchers utilising t-fMRI consider concurrently acquiring information from an additional modality, to quantify, for example, haemodynamic differences or microstructural changes. We outline a variety of such supplementary measures for investigating brain reorganisation and discuss situations in which they may prove beneficial to the interpretation of t-fMRI data.
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Can musical training influence brain connectivity? Evidence from diffusion tensor MRI. Brain Sci 2014; 4:405-27. [PMID: 24961769 PMCID: PMC4101485 DOI: 10.3390/brainsci4020405] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2014] [Revised: 03/19/2014] [Accepted: 05/20/2014] [Indexed: 11/28/2022] Open
Abstract
In recent years, musicians have been increasingly recruited to investigate grey and white matter neuroplasticity induced by skill acquisition. The development of Diffusion Tensor Magnetic Resonance Imaging (DT-MRI) has allowed more detailed investigation of white matter connections within the brain, addressing questions about the effect of musical training on connectivity between specific brain regions. Here, current DT-MRI analysis techniques are discussed and the available evidence from DT-MRI studies into differences in white matter architecture between musicians and non-musicians is reviewed. Collectively, the existing literature tends to support the hypothesis that musical training can induce changes in cross-hemispheric connections, with significant differences frequently reported in various regions of the corpus callosum of musicians compared with non-musicians. However, differences found in intra-hemispheric fibres have not always been replicated, while findings regarding the internal capsule and corticospinal tracts appear to be contradictory. There is also recent evidence to suggest that variances in white matter structure in non-musicians may correlate with their ability to learn musical skills, offering an alternative explanation for the structural differences observed between musicians and non-musicians. Considering the inconsistencies in the current literature, possible reasons for conflicting results are offered, along with suggestions for future research in this area.
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Rae C, Henry RG, Gandevia SC. Training the brain and its connections to muscles. J Appl Physiol (1985) 2013; 115:155-6. [DOI: 10.1152/japplphysiol.00503.2013] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Affiliation(s)
- C. Rae
- Neuroscience Research Australia and University of New South Wales, Sydney, New South Wales, Australia; and
| | - R. G. Henry
- Department of Neurology, University of California, San Francisco, California
| | - S. C. Gandevia
- Neuroscience Research Australia and University of New South Wales, Sydney, New South Wales, Australia; and
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