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Cadwallader CJ, Curtin D, Taylor EM, de Moel T, Jarvis H, Hutchison C, Hendrikse J, Chong TTJ, Coxon JP. Exercise-induced cortical disinhibition mediates the relationship between fitness and memory in older adults. J Physiol 2024; 602:2945-2959. [PMID: 38747052 DOI: 10.1113/jp285537] [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: 08/22/2023] [Accepted: 04/19/2024] [Indexed: 06/15/2024] Open
Abstract
Regular exercise benefits learning and memory in older adults, but the neural mechanisms mediating these effects remain unclear. Evidence in young adults indicates that acute exercise creates a favourable environment for synaptic plasticity by enhancing cortical disinhibition. As such, we investigated whether plasticity-related disinhibition mediated the relationship between cardiorespiratory fitness and memory function in healthy older adults (n = 16, mean age = 66.06). Participants completed a graded maximal exercise test and assessments of visual and verbal memory, followed by two counterbalanced sessions involving 20 min of either high-intensity interval training exercise or rest. Disinhibition was measured following intermittent theta burst stimulation via paired-pulse transcranial magnetic stimulation. In line with our hypotheses, we observed a positive correlation between cardiorespiratory fitness and verbal memory, which was mediated by plasticity-related cortical disinhibition. Our novel finding implicates cortical disinhibition as a mechanism through which the effects of acute bouts of exercise may translate to improved memory in older adults. This finding extends current understanding of the physiological mechanisms underlying the positive influence of cardiorespiratory fitness for memory function in older adults, and further highlights the importance of promoting exercise engagement to maintain cognitive health in later life. KEY POINTS: There are well established benefits of regular exercise for memory function in older adults, but the mechanisms are unclear. Cortical disinhibition is important for laying down new memories, and is enhanced following acute exercise in young adults, suggesting it is a potential mechanism underlying these benefits in ageing. Older adults completed a fitness test and assessments of memory, followed by two sessions involving either 20 min of exercise or rest. Disinhibition was measured following intermittent theta burst stimulation via paired-pulse transcranial magnetic stimulation. Cardiorespiratory fitness was positively associated with memory performance. Higher fitness was associated with enhanced cortical disinhibition following acute exercise. Cortical disinhibition completely mediated the relationship between fitness and memory. This novel finding provides a mechanistic account for the positive influence of cardiorespiratory fitness on memory in later life, and emphasises the importance of regular exercise for cognitive health in older populations.
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Affiliation(s)
- Claire J Cadwallader
- School of Psychological Sciences, Turner Institute for Brain and Mental Health, Monash University, Victoria, Australia
| | - Dylan Curtin
- School of Psychological Sciences, Turner Institute for Brain and Mental Health, Monash University, Victoria, Australia
| | - Eleanor M Taylor
- School of Psychological Sciences, Turner Institute for Brain and Mental Health, Monash University, Victoria, Australia
| | - Tamar de Moel
- School of Psychological Sciences, Turner Institute for Brain and Mental Health, Monash University, Victoria, Australia
| | - Huw Jarvis
- School of Psychological Sciences, Turner Institute for Brain and Mental Health, Monash University, Victoria, Australia
| | - Christopher Hutchison
- School of Psychological Sciences, Turner Institute for Brain and Mental Health, Monash University, Victoria, Australia
- Cognitive, Dementia and Memory Service, Peninsula Health, Victoria, Australia
| | - Joshua Hendrikse
- School of Psychological Sciences, Turner Institute for Brain and Mental Health, Monash University, Victoria, Australia
| | - Trevor T-J Chong
- School of Psychological Sciences, Turner Institute for Brain and Mental Health, Monash University, Victoria, Australia
- Department of Neurology, Alfred Health, Victoria, Australia
- Department of Clinical Neurosciences, St Vincent's Hospital, Victoria, Australia
| | - James P Coxon
- School of Psychological Sciences, Turner Institute for Brain and Mental Health, Monash University, Victoria, Australia
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Hehl M, Swinnen SP, Cuypers K. Alterations of hand sensorimotor function and cortical motor representations over the adult lifespan. Aging (Albany NY) 2020; 12:4617-4640. [PMID: 32160591 PMCID: PMC7093194 DOI: 10.18632/aging.102925] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2019] [Accepted: 03/02/2020] [Indexed: 12/14/2022]
Abstract
Using a cross sectional design, we aimed to identify the effect of aging on sensorimotor function and cortical motor representations of two intrinsic hand muscles, as well as the course and timing of those changes. Furthermore, the link between cortical motor representations, sensorimotor function, and intracortical inhibition and facilitation was investigated. Seventy-seven participants over the full adult lifespan were enrolled. For the first dorsal interosseus (FDI) and abductor digiti minimi (ADM) muscle, cortical motor representations, GABAA-mediated short-interval intracortical inhibition (SICI), and glutamate-mediated intracortical facilitation (ICF) were assessed using transcranial magnetic stimulation over the dominant primary motor cortex. Additionally, participants' dexterity and force were measured. Linear, polynomial, and piecewise linear regression analyses were conducted to identify the course and timing of age-related differences. Our results demonstrated variation in sensorimotor function over the lifespan, with a marked decline starting around the mid-thirties. Furthermore, an age-related reduction in cortical motor representation volume and maximal MEP of the FDI, but not for ADM, was observed, occurring mainly until the mid-forties. Area of the cortical motor representation did not change with advancing age. Furthermore, cortical motor representations, sensorimotor function, and measures of intracortical inhibition and facilitation were not interrelated.
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Affiliation(s)
- Melina Hehl
- Movement Control and Neuroplasticity Research Group, Department of Movement Sciences, Group Biomedical Sciences, KU Leuven, Heverlee, Leuven, Belgium
| | - Stephan P. Swinnen
- Movement Control and Neuroplasticity Research Group, Department of Movement Sciences, Group Biomedical Sciences, KU Leuven, Heverlee, Leuven, Belgium
- KU Leuven, Leuven Brain Institute (LBI), Leuven, Belgium
| | - Koen Cuypers
- Movement Control and Neuroplasticity Research Group, Department of Movement Sciences, Group Biomedical Sciences, KU Leuven, Heverlee, Leuven, Belgium
- REVAL Research Institute, Hasselt University, Agoralaan, Diepenbeek, Belgium
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Borzuola R, Giombini A, Torre G, Campi S, Albo E, Bravi M, Borrione P, Fossati C, Macaluso A. Central and Peripheral Neuromuscular Adaptations to Ageing. J Clin Med 2020; 9:jcm9030741. [PMID: 32182904 PMCID: PMC7141192 DOI: 10.3390/jcm9030741] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2020] [Revised: 02/27/2020] [Accepted: 03/04/2020] [Indexed: 12/31/2022] Open
Abstract
Ageing is accompanied by a severe muscle function decline presumably caused by structural and functional adaptations at the central and peripheral level. Although researchers have reported an extensive analysis of the alterations involving muscle intrinsic properties, only a limited number of studies have recognised the importance of the central nervous system, and its reorganisation, on neuromuscular decline. Neural changes, such as degeneration of the human cortex and function of spinal circuitry, as well as the remodelling of the neuromuscular junction and motor units, appear to play a fundamental role in muscle quality decay and culminate with considerable impairments in voluntary activation and motor performance. Modern diagnostic techniques have provided indisputable evidence of a structural and morphological rearrangement of the central nervous system during ageing. Nevertheless, there is no clear insight on how such structural reorganisation contributes to the age-related functional decline and whether it is a result of a neural malfunction or serves as a compensatory mechanism to preserve motor control and performance in the elderly population. Combining leading-edge techniques such as high-density surface electromyography (EMG) and improved diagnostic procedures such as functional magnetic resonance imaging (fMRI) or high-resolution electroencephalography (EEG) could be essential to address the unresolved controversies and achieve an extensive understanding of the relationship between neural adaptations and muscle decline.
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Affiliation(s)
- Riccardo Borzuola
- Department of Movement, Human and Health Sciences, University of Rome “Foro Italico”, 00135 Rome, Italy; (R.B.); (A.G.); (P.B.); (C.F.); (A.M.)
| | - Arrigo Giombini
- Department of Movement, Human and Health Sciences, University of Rome “Foro Italico”, 00135 Rome, Italy; (R.B.); (A.G.); (P.B.); (C.F.); (A.M.)
| | - Guglielmo Torre
- Department of Orthopaedic And Trauma Surgery, Campus Bio-Medico University of Rome, 00128 Rome, Italy; (S.C.); (E.A.)
- Correspondence: ; Tel.: +6-225-418-825
| | - Stefano Campi
- Department of Orthopaedic And Trauma Surgery, Campus Bio-Medico University of Rome, 00128 Rome, Italy; (S.C.); (E.A.)
| | - Erika Albo
- Department of Orthopaedic And Trauma Surgery, Campus Bio-Medico University of Rome, 00128 Rome, Italy; (S.C.); (E.A.)
| | - Marco Bravi
- Department of Physical Medicine and Rehabilitation, Campus Bio-Medico University of Rome, 00128 Rome, Italy;
| | - Paolo Borrione
- Department of Movement, Human and Health Sciences, University of Rome “Foro Italico”, 00135 Rome, Italy; (R.B.); (A.G.); (P.B.); (C.F.); (A.M.)
| | - Chiara Fossati
- Department of Movement, Human and Health Sciences, University of Rome “Foro Italico”, 00135 Rome, Italy; (R.B.); (A.G.); (P.B.); (C.F.); (A.M.)
| | - Andrea Macaluso
- Department of Movement, Human and Health Sciences, University of Rome “Foro Italico”, 00135 Rome, Italy; (R.B.); (A.G.); (P.B.); (C.F.); (A.M.)
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Swanson CW, Fling BW. Associations between Turning Characteristics and Corticospinal Inhibition in Young and Older Adults. Neuroscience 2019; 425:59-67. [PMID: 31765624 DOI: 10.1016/j.neuroscience.2019.10.051] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2019] [Revised: 10/23/2019] [Accepted: 10/30/2019] [Indexed: 01/12/2023]
Abstract
The effects of aging are multifaceted including deleterious changes to the structure and function of the nervous system which often results in reduced mobility and quality of life. Turning while walking (dynamic) and in-place (stable) are ubiquitous aspects of mobility and have substantial consequences if performed poorly. Further, turning is thought to require higher cortical control compared to bouts of straight-ahead walking. This study sought to understand how relative amounts of corticospinal inhibition as measured by transcranial magnetic stimulation and the cortical silent period within the primary motor cortices are associated with various turning characteristics in neurotypical young (YA) and older adults (OA). In the current study, OA had reduced peak turn velocity and increased turn duration for both dynamic and stable turns. Further, OA demonstrated significantly reduced corticospinal inhibition within the right motor cortex. Finally, all associations between corticospinal inhibition and turning performance were specific to the right hemisphere, reflecting that those OA who maintained high levels of inhibition performed turning similar to their younger counterparts. These results compliment the right hemisphere model of aging and lateralization specification of cortically regulated temporal measures of dynamic movement. While additional investigations are required, these pilot findings provide an additional understanding as to the neural control of dynamic movements.
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Affiliation(s)
- Clayton W Swanson
- Department of Health & Exercise Science, Colorado State University, Fort Collins, CO, USA
| | - Brett W Fling
- Department of Health & Exercise Science, Colorado State University, Fort Collins, CO, USA; Molecular, Cellular, and Integrative Neuroscience Program, Colorado State University, Fort Collins, CO, USA.
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Škarabot J, Ansdell P, Temesi J, Howatson G, Goodall S, Durbaba R. Neurophysiological responses and adaptation following repeated bouts of maximal lengthening contractions in young and older adults. J Appl Physiol (1985) 2019; 127:1224-1237. [DOI: 10.1152/japplphysiol.00494.2019] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
A bout of maximal lengthening contractions is known to produce muscle damage, but confers protection against subsequent damaging bouts, with both tending to be lower in older adults. Neural factors contribute to this adaptation, but the role of the corticospinal pathway remains unclear. Twelve young (27 ± 5 yr) and 11 older adults (66 ± 4 yr) performed two bouts of 60 maximal lengthening dorsiflexions 2 weeks apart. Neuromuscular responses were measured preexercise, immediately postexercise, and at 24 and 72 h following both bouts. The initial bout resulted in prolonged reductions in maximal voluntary torque (MVC; immediately postexercise onward, P < 0.001) and increased creatine kinase (from 24 h onward, P = 0.001), with both responses being attenuated following the second bout ( P < 0.015), demonstrating adaptation. Smaller reductions in MVC following both bouts occurred in older adults ( P = 0.005). Intracortical facilitation showed no changes ( P ≥ 0.245). Motor-evoked potentials increased 24 and 72 h postexercise in young ( P ≤ 0.038). Torque variability ( P ≤ 0.041) and H-reflex size ( P = 0.024) increased, while short-interval intracortical inhibition (SICI; P = 0.019) and the silent period duration (SP) decreased ( P = 0.001) in both groups immediately postexercise. The SP decrease was smaller following the second bout ( P = 0.021), and there was an association between the change in SICI and reduction in MVC 24 h postexercise in young adults ( R = −0.47, P = 0.036). Changes in neurophysiological responses were mostly limited to immediately postexercise, suggesting a modest role in adaptation. In young adults, neural inhibitory changes are linked to the extent of MVC reduction, possibly mediated by the muscle damage–related afferent feedback. Older adults incurred less muscle damage, which has implications for exercise prescription. NEW & NOTEWORTHY This is the first study to have collectively assessed the role of corticospinal, spinal, and intracortical activity in muscle damage attenuation following repeated bouts of exercise in young and older adults. Lower levels of muscle damage in older adults are not related to their neurophysiological responses. Neural inhibition transiently changed, which might be related to the extent of muscle damage; however, the role of processes along the corticospinal pathway in the adaptive response is limited.
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Affiliation(s)
- Jakob Škarabot
- Faculty of Health and Life Sciences, Northumbria University, Newcastle Upon Tyne, England, United Kingdom
| | - Paul Ansdell
- Faculty of Health and Life Sciences, Northumbria University, Newcastle Upon Tyne, England, United Kingdom
| | - John Temesi
- Faculty of Health and Life Sciences, Northumbria University, Newcastle Upon Tyne, England, United Kingdom
| | - Glyn Howatson
- Faculty of Health and Life Sciences, Northumbria University, Newcastle Upon Tyne, England, United Kingdom
- Water Research Group, School of Environmental Sciences and Development, Northwest University, Potchefstroom, South Africa
| | - Stuart Goodall
- Faculty of Health and Life Sciences, Northumbria University, Newcastle Upon Tyne, England, United Kingdom
| | - Rade Durbaba
- Faculty of Health and Life Sciences, Northumbria University, Newcastle Upon Tyne, England, United Kingdom
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Tang X, Huang P, Li Y, Lan J, Yang Z, Xu M, Yi W, Lu L, Wang L, Xu N. Age-Related Changes in the Plasticity of Neural Networks Assessed by Transcranial Magnetic Stimulation With Electromyography: A Systematic Review and Meta-Analysis. Front Cell Neurosci 2019; 13:469. [PMID: 31708744 PMCID: PMC6822534 DOI: 10.3389/fncel.2019.00469] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2019] [Accepted: 10/01/2019] [Indexed: 01/03/2023] Open
Abstract
Objective: The excitability of cerebral cortical cells, neural pathway, and neural networks, as well as their plasticity, are key to our exploration of age-related changes in brain structure and function. The combination of transcranial magnetic stimulation (TMS) with electromyography (EMG) can be applied to the primary motor cortex; it activates the underlying neural group and passes through the corticospinal pathway, which can be quantified using EMG. This meta-analysis aimed to analyze changes in cortical excitability and plasticity in healthy elderly individuals vs. young individuals through TMS-EMG. Methods: The Cochrane Library, Medline, and EMBASE databases were searched to identify eligible trials published from database inception to June 3, 2019. The Cochrane Risk of Bias Tool and improved Jadad scale were used to assess the methodological quality. A meta-analysis of the comparative effects was conducted using the Review Manager 5.3 software and Stata 14.0 software. Results: The pooled results revealed that the resting motor threshold values in the elderly group were markedly higher than those reported in the young group (mean difference [MD]: −2.35; 95% confidence interval [CI]: −3.69 to −1.02]; p < (0.00001). The motor evoked potential amplitude significantly reduced in the elderly group vs. the young group (MD: 0.18; 95% CI: 0.09–0.27; p < 0.0001). Moreover, there was significantly longer motor evoked potential latency in the elderly group (MD: −1.07; 95% CI: −1.77 to −0.37]; p =(0.003). There was no significant difference observed in the active motor threshold between the elderly and young groups (MD: −1.52; 95% CI: −3.47 to −0.42]; p =(0.13). Meanwhile, only two studies reported the absence of adverse events. Conclusion: We found that the excitability of the cerebral cortex declined in elderly individuals vs. young individuals. The findings of the present analysis should be considered with caution owing to the methodological limitations in the included trials. Additional high-quality studies are warranted to validate our findings.
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Affiliation(s)
- Xiaorong Tang
- Medical College of Acu-Moxi and Rehabilitation, Guangzhou University of Chinese Medicine, Guangzhou, China
| | - Peidong Huang
- Acupuncture and Massage Rehabilitation Institute, Yunnan University of Chinese Medicine, Kunming, China
| | - Yitong Li
- Medical College of Acu-Moxi and Rehabilitation, Guangzhou University of Chinese Medicine, Guangzhou, China
| | - Juanchao Lan
- Medical College of Acu-Moxi and Rehabilitation, Guangzhou University of Chinese Medicine, Guangzhou, China
| | - Zhonghua Yang
- Medical College of Acu-Moxi and Rehabilitation, Guangzhou University of Chinese Medicine, Guangzhou, China
| | - Mindong Xu
- Medical College of Acu-Moxi and Rehabilitation, Guangzhou University of Chinese Medicine, Guangzhou, China
| | - Wei Yi
- Medical College of Acu-Moxi and Rehabilitation, Guangzhou University of Chinese Medicine, Guangzhou, China
| | - Liming Lu
- Clinical Research Center, South China Research Center for Acupuncture and Moxibustion, Medical College of Acu-Moxi and Rehabilitation, Guangzhou University of Chinese Medicine, Guangzhou, China
| | - Lin Wang
- Clinical Research Center, South China Research Center for Acupuncture and Moxibustion, Medical College of Acu-Moxi and Rehabilitation, Guangzhou University of Chinese Medicine, Guangzhou, China
| | - Nenggui Xu
- Medical College of Acu-Moxi and Rehabilitation, Guangzhou University of Chinese Medicine, Guangzhou, China
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7
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Associations between gait coordination, variability and motor cortex inhibition in young and older adults. Exp Gerontol 2018; 113:163-172. [DOI: 10.1016/j.exger.2018.10.002] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2018] [Revised: 08/23/2018] [Accepted: 10/03/2018] [Indexed: 11/30/2022]
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Bhandari A, Radhu N, Farzan F, Mulsant BH, Rajji TK, Daskalakis ZJ, Blumberger DM. A meta-analysis of the effects of aging on motor cortex neurophysiology assessed by transcranial magnetic stimulation. Clin Neurophysiol 2016; 127:2834-2845. [PMID: 27417060 DOI: 10.1016/j.clinph.2016.05.363] [Citation(s) in RCA: 93] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2016] [Revised: 05/13/2016] [Accepted: 05/31/2016] [Indexed: 12/17/2022]
Abstract
OBJECTIVE Transcranial magnetic stimulation (TMS) is a non-invasive tool used for studying cortical excitability and plasticity in the human brain. This review aims to quantitatively synthesize the literature on age-related differences in cortical excitability and plasticity, examined by TMS. METHODS A literature search was conducted using MEDLINE, Embase, and PsycINFO from 1980 to December 2015. We extracted studies with healthy old (50-89years) versus young (16-49years) individuals that utilized the following TMS measures: resting motor threshold (RMT), short-interval cortical inhibition (SICI), short-latency afferent inhibition (SAI), cortical silent period (CSP), intracortical facilitation (ICF), and paired associative stimulation (PAS). RESULTS We found a significant increase in RMT (g=0.414, 95% confidence interval (CI) [0.284, 0.544], p<0.001), a significant decrease in SAI (g=0.778, 95% CI [0.478, 1.078], p<0.001), and a trending decrease in LTP-like plasticity (g=-0.528, 95% CI [-1.157, 0.100] p<0.1) with age. CONCLUSIONS Our findings suggest an age-dependent reduction in cortical excitability and sensorimotor integration within the human motor cortex. SIGNIFICANCE Alterations in the ability to regulate cortical excitability, sensorimotor integration and plasticity may underlie several age-related motor deficits.
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Affiliation(s)
- Apoorva Bhandari
- Temerty Centre for Therapeutic Brain Intervention, Centre for Addiction and Mental Health, Toronto, Ontario M6J 1H4, Canada
| | - Natasha Radhu
- Temerty Centre for Therapeutic Brain Intervention, Centre for Addiction and Mental Health, Toronto, Ontario M6J 1H4, Canada
| | - Faranak Farzan
- Temerty Centre for Therapeutic Brain Intervention, Centre for Addiction and Mental Health, Toronto, Ontario M6J 1H4, Canada; Department of Psychiatry, University of Toronto, Toronto, Ontario M5T 1R8, Canada; Campbell Family Mental Health Research Institute, Centre for Addiction and Mental Health, Toronto, Ontario M5T 1R8, Canada
| | - Benoit H Mulsant
- Temerty Centre for Therapeutic Brain Intervention, Centre for Addiction and Mental Health, Toronto, Ontario M6J 1H4, Canada; Department of Psychiatry, University of Toronto, Toronto, Ontario M5T 1R8, Canada; Campbell Family Mental Health Research Institute, Centre for Addiction and Mental Health, Toronto, Ontario M5T 1R8, Canada
| | - Tarek K Rajji
- Temerty Centre for Therapeutic Brain Intervention, Centre for Addiction and Mental Health, Toronto, Ontario M6J 1H4, Canada; Department of Psychiatry, University of Toronto, Toronto, Ontario M5T 1R8, Canada; Campbell Family Mental Health Research Institute, Centre for Addiction and Mental Health, Toronto, Ontario M5T 1R8, Canada
| | - Zafiris J Daskalakis
- Temerty Centre for Therapeutic Brain Intervention, Centre for Addiction and Mental Health, Toronto, Ontario M6J 1H4, Canada; Department of Psychiatry, University of Toronto, Toronto, Ontario M5T 1R8, Canada; Campbell Family Mental Health Research Institute, Centre for Addiction and Mental Health, Toronto, Ontario M5T 1R8, Canada
| | - Daniel M Blumberger
- Temerty Centre for Therapeutic Brain Intervention, Centre for Addiction and Mental Health, Toronto, Ontario M6J 1H4, Canada; Department of Psychiatry, University of Toronto, Toronto, Ontario M5T 1R8, Canada; Campbell Family Mental Health Research Institute, Centre for Addiction and Mental Health, Toronto, Ontario M5T 1R8, Canada.
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9
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Papegaaij S, Baudry S, Négyesi J, Taube W, Hortobágyi T. Intracortical inhibition in the soleus muscle is reduced during the control of upright standing in both young and old adults. Eur J Appl Physiol 2016; 116:959-67. [PMID: 27002819 PMCID: PMC4834104 DOI: 10.1007/s00421-016-3354-6] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2015] [Accepted: 03/09/2016] [Indexed: 11/27/2022]
Abstract
Purpose In a previous study, we reported that a short-interval intracortical inhibition (SICI) decreases in old but not in young adults when standing on foam vs. a rigid surface. Here, we examined if such an age by task difficulty interaction in motor cortical excitability also occurs in easier standing tasks. Methods Fourteen young (23 ± 2.7 years) and fourteen old (65 ± 4.1 years) adults received transcranial magnetic brain stimulation and peripheral nerve stimulation, while they stood with or without support on a force platform. Results In the soleus, we found that SICI was lower in unsupported (35 % inhibition) vs. supported (50 %) standing (p = 0.007) but similar in young vs. old adults (p = 0.591). In the tibialis anterior, SICI was similar between conditions (p = 0.597) but lower in old (52 %) vs. young (72 %) adults (p = 0.030). Age and standing with or without support did not affect the Hoffmann reflex in the soleus. Conclusions The current data suggest that the motor cortex is involved in standing control, and that its role becomes more prominent with an increase in task difficulty.
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Affiliation(s)
- Selma Papegaaij
- Center for Human Movement Sciences, University of Groningen, University Medical Center Groningen, Antonius Deusinglaan 1, 9713 AV, Groningen, The Netherlands.
| | - Stéphane Baudry
- Laboratory of Applied Biology, Faculty for Motor Sciences, Université Libre de Bruxelles, CP 640, route de Lennik 808, 1070, Brussels, Belgium
| | - János Négyesi
- Center for Human Movement Sciences, University of Groningen, University Medical Center Groningen, Antonius Deusinglaan 1, 9713 AV, Groningen, The Netherlands
- Department of Biomechanics, Faculty of Physical Education and Sport Sciences, Semmelweis University, Alkotás utca 44, Budapest, 1123, Hungary
| | - Wolfgang Taube
- Department of Medicine, University of Fribourg, Ch. du Musée 8, 1700, Fribourg, Switzerland
| | - Tibor Hortobágyi
- Center for Human Movement Sciences, University of Groningen, University Medical Center Groningen, Antonius Deusinglaan 1, 9713 AV, Groningen, The Netherlands
- Department of Sport, Exercise and Rehabilitation, Northumbria University, Newcastle-upon-Tyne, NE1 8ST, UK
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Intracortical Inhibition Assessed with Paired-Pulse Transcranial Magnetic Stimulation is Modulated during Shortening and Lengthening Contractions in Young and Old Adults. Brain Stimul 2016; 9:258-67. [DOI: 10.1016/j.brs.2015.12.005] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2015] [Revised: 11/23/2015] [Accepted: 12/15/2015] [Indexed: 11/20/2022] Open
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11
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Aging reduces experience-induced sensorimotor plasticity. A magnetoencephalographic study. Neuroimage 2014; 104:59-68. [PMID: 25315784 DOI: 10.1016/j.neuroimage.2014.10.010] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2014] [Revised: 09/26/2014] [Accepted: 10/05/2014] [Indexed: 11/20/2022] Open
Abstract
Modulation of the mu-alpha and mu-beta spontaneous rhythms reflects plastic neural changes within the primary sensorimotor cortex (SM1). Using magnetoencephalography (MEG), we investigated how aging modifies experience-induced plasticity after learning a motor sequence, looking at post- vs. pre-learning changes in the modulation of mu rhythms during the execution of simple hand movements. Fifteen young (18-30 years) and fourteen older (65-75 years) right-handed healthy participants performed auditory-cued key presses using all four left fingers simultaneously (Simple Movement task - SMT) during two separate sessions. Following both SMT sessions, they repeatedly practiced a 5-elements sequential finger-tapping task (FTT). Mu power calculated during SMT was averaged across 18 gradiometers covering the right sensorimotor region and compared before vs. after sequence learning in the alpha (9/10/11Hz) and the beta (18/20/22Hz) bands separately. Source power maps in the mu-alpha and mu-beta bands were localized using Dynamic Statistical Parametric Mapping (dSPM). The FTT sequence was performed faster at retest than at the end of the learning session, indicating an offline boost in performance. Analyses conducted on SMT sessions revealed enhanced rebound after learning in the right SM1, 3000-3500ms after the initiation of movement, in young as compared to older participants. Source reconstruction indicated that mu-beta is located in the precentral gyrus (motor processes) and mu-alpha is located in the postcentral gyrus (somatosensory processes) in both groups. The enhanced post-movement rebound in young subjects potentially reflects post-training plastic changes in SM1. Age-related decreases in post-training modulatory effects suggest reduced experience-dependent plasticity in the aging brain.
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Age-related Differences in Short- and Long-interval Intracortical Inhibition in a Human Hand Muscle. Brain Stimul 2014; 7:665-72. [DOI: 10.1016/j.brs.2014.06.014] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2014] [Revised: 06/19/2014] [Accepted: 06/29/2014] [Indexed: 11/22/2022] Open
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Papegaaij S, Taube W, Hogenhout M, Baudry S, Hortobágyi T. Age-related decrease in motor cortical inhibition during standing under different sensory conditions. Front Aging Neurosci 2014; 6:126. [PMID: 24971063 PMCID: PMC4054792 DOI: 10.3389/fnagi.2014.00126] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2014] [Accepted: 05/28/2014] [Indexed: 11/13/2022] Open
Abstract
BACKGROUND Although recent studies point to the involvement of the primary motor cortex in postural control, it is unknown if age-related deterioration of postural control is associated with changes in motor cortical circuits. We examined the interaction between age and sensory condition in the excitability of intracortical motor pathways as indexed by short-interval intracortical inhibition (SICI) and intracortical facilitation (ICF) during standing. METHODS We used magnetic brain stimulation to evoke SICI and ICF in 11 young (range 21-25 years) and 12 healthy old adults (range 60-74 years) while they stood on a rigid platform or foam, with the eyes open or closed. RESULTS There was an overall age-related 43% reduction in SICI (p = 0.001). SICI lessened when standing on foam in old (31%) but not in young (1%) adults (condition × group interaction, p = 0.049). This reduction was associated with increases in center of pressure velocity (r = -0.648, p = 0.043). Age (p = 0.527) and sensory conditions (p = 0.325) did not affect ICF. CONCLUSION Motor cortical circuits controlling leg muscles are modulated differently in healthy old vs. young adults during upright posture. Future experiments will clarify whether this difference mediates impaired postural control or serves as a compensatory mechanism to counteract postural instability.
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Affiliation(s)
- Selma Papegaaij
- Center for Human Movement Sciences, University of Groningen, University Medical Center Groningen Groningen, Netherlands
| | - Wolfgang Taube
- Movement and Sports Science, Department of Medicine, University of Fribourg Fribourg, Switzerland
| | - Margot Hogenhout
- Center for Human Movement Sciences, University of Groningen, University Medical Center Groningen Groningen, Netherlands
| | - Stéphane Baudry
- Laboratory of Applied Biology, Faculty for Motor Sciences, Université Libre de Bruxelles Brussels, Belgium
| | - Tibor Hortobágyi
- Center for Human Movement Sciences, University of Groningen, University Medical Center Groningen Groningen, Netherlands ; Faculty of Health and Life Sciences, Northumbria University Newcastle Upon Tyne, UK
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Papegaaij S, Taube W, Baudry S, Otten E, Hortobágyi T. Aging causes a reorganization of cortical and spinal control of posture. Front Aging Neurosci 2014; 6:28. [PMID: 24624082 PMCID: PMC3939445 DOI: 10.3389/fnagi.2014.00028] [Citation(s) in RCA: 114] [Impact Index Per Article: 11.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2013] [Accepted: 02/13/2014] [Indexed: 11/13/2022] Open
Abstract
Classical studies in animal preparations suggest a strong role for spinal control of posture. In humans it is now established that the cerebral cortex contributes to postural control of unperturbed and perturbed standing. The age-related degeneration and accompanying functional changes in the brain, reported so far mainly in conjunction with simple manual motor tasks, may also affect the mechanisms that control complex motor tasks involving posture. This review outlines the age-related structural and functional changes at spinal and cortical levels and provides a mechanistic analysis of how such changes may be linked to the behaviorally manifest postural deficits in old adults. The emerging picture is that the age-related reorganization in motor control during voluntary tasks, characterized by differential modulation of spinal reflexes, greater cortical activation and cortical disinhibition, is also present during postural tasks. We discuss the possibility that this reorganization underlies the increased coactivation and dual task interference reported in elderly. Finally, we propose a model for future studies to unravel the structure-function-behavior relations in postural control and aging.
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Affiliation(s)
- Selma Papegaaij
- Center for Human Movement Sciences, University of Groningen, University Medical Center Groningen Groningen, Netherlands
| | - Wolfgang Taube
- Movement and Sports Science, Department of Medicine, University of Fribourg Fribourg, Switzerland
| | - Stéphane Baudry
- Laboratory of Applied Biology, Faculty for Motor Sciences, Université Libre de Bruxelles Brussels, Belgium
| | - Egbert Otten
- Center for Human Movement Sciences, University of Groningen, University Medical Center Groningen Groningen, Netherlands
| | - Tibor Hortobágyi
- Center for Human Movement Sciences, University of Groningen, University Medical Center Groningen Groningen, Netherlands ; Faculty of Health and Life Sciences, Northumbria University Newcastle Upon Tyne, UK
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Abstract
PURPOSE OF REVIEW Age-related muscle weakness causes a staggering economic, public, and personal burden. Most research has focused on internal muscular mechanisms as the root cause to strength loss. Here, we briefly discuss age-related impairments in the brain and peripheral nerve structures that may theoretically lead to muscle weakness in old age. RECENT FINDINGS Neuronal atrophy in the brain is accompanied by electrical noise tied to declines in dopaminergic neurotransmission that degrades communication between neurons. Additionally, sensorimotor feedback loops that help regulate corticospinal excitability are impaired. In the periphery, there is evidence for motor unit loss, axonal atrophy, demyelination caused by oxidative damage to proteins and lipids, and modified transmission of the electrical signal through the neuromuscular junction. SUMMARY Recent evidence clearly indicates that muscle weakness associated with aging is not entirely explained by classically postulated atrophy of muscle. In this issue, which focuses on 'Ageing: Biology and Nutrition' we will highlight new findings on how nervous system changes contribute to the aging muscle phenotype. These findings indicate that the ability to communicate neural activity to skeletal muscle is impaired with advancing age, which raises the question of whether many of these age-related neurological changes are mechanistically linked to impaired performance of human skeletal muscle. Collectively, this work suggests that future research should explore the direct link of these 'upstream' neurological adaptions and onset of muscle weakness in elders. In the long term, this new focus might lead to novel strategies to attenuate the age-related loss of muscle strength.
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Affiliation(s)
- Todd M Manini
- Institute of Aging and the Department of Aging and Geriatric Research, University of Florida, Gainesville, Florida 32611, USA.
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