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The Effects of Acute Aerobic Exercise on the Primary Motor Cortex

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Abstract

The effect of aerobic exercise on primary motor cortical excitability is a relevant area of interest for both motor learning and motor rehabilitation. Transient excitability changes that may follow an exercise session are a necessary precursor to more lasting neuroplastic changes. While the number of studies is limited, research suggests that a session of aerobic exercise can create an ideal environment for the early induction of plasticity. Potential mechanisms include the upregulation of neurotransmitter activity, altered cerebral metabolism and cortisol levels, and increases in brain-derived neurotrophic factor. While there is considerable evidence that chronic physical activity positively impacts brain health and function, studies examining cortical excitability changes and motor performance after a single session of exercise are lacking. Further research is required to determine the clinical utility and feasibility of aerobic exercise.

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... More specifically, this meta-analysis was conducted to evaluate the directional changes in inhibitory networks caused by AE exposure as accessed by TMS. Existing reviews were consulted and used to construct a basic understanding of recent knowledge (Singh & Staines, 2015;Taylor et al., 2016;. Experimental and clinical research published before and after these reviews were then systematically reviewed and used to expand on the findings presented in existing literature. ...
... Plasticity will be used to refer to these acute changes when they are associated with persistent changes to the structure and/or function of the nervous system, based on pervious use in review literature on the topic (Singh & Staines, 2015;Taylor et al., 2016;. These acute changes can be directional; meaning they could contribute positively, negatively, or not at all to the changes in fatigue or plasticity caused by exercise exposure. ...
... Little emphasis has been given to long-interval cortical inhibition (LICI) in recent reviews (Singh & Staines, 2015;Taylor et al., 2016;. This is likely due to a lack of literature providing evidence to suggest that LICI may possess measurable and insightful changes in neurophysiology post-exercise. ...
Thesis
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Introduction: The neurophysiological effects after acute endurance or aerobic exercise (AE) has emerging evidence that has shown some trends but it is somewhat conflicting. The combined directional findings of post-AE changes in measurements using transcranial magnetic stimulation (TMS) can provide insight into exercise fatigue and neuroplasticity modeling as it relates to the fields of motor learning, motor control, psychological disorders, and neurological disorders. This meta-analysis was written with a focus on TMS measurements of inhibitory cortical neural networks: long-interval cortical inhibition (LICI), short-interval cortical inhibition (SICI), cortical silent period (CSP), long-latency afferent inhibition (LAI), short-latency afferent inhibition (SAI), interhemispheric inhibition (IHI), cerebellar brain inhibition (CBI). Changes in these measures are associated with GABA-mediated inhibition, neurodegenerative disorders, motor learning, and many other physiological and behavioral outcomes. Purpose: This study was conducted with the goal of evaluating the changes in neuro- inhibitory measurements resulting from AE exposure in humans. Additionally, exercise intensity and post-exercise test timing were evaluated as covariates influencing neuro- inhibitory changes post-AE. Methods: The PRISMA guidelines were followed for this thesis. Subgroup divisions for the meta-analysis was carefully considered based on previous findings reported in the literature and preliminary correlation analysis. Mean difference (MD) was used to estimate effect size for each study, and Chi2, Z, I2 values were evaluated to determine between group difference, within group difference, and heterogeneity, respectively. Results: The studies found to meet inclusion criteria included: six studies evaluating LICI, 10 studies evaluating SICI, 11 studies evaluating CSP. LAI, SAI, IHI, and CBI did not have sufficient evidence to conduct a meta-analysis. All analyses were performed with small number of available studies and small total sample sizes. However, there was significant evidence supporting an overall disinhibition after AE exposure when measured using LICI (MD = 8.5%, 95% confidence interval [CI] = 0.5, 16.5; Z = 2.08, p = .04) and SICI (MD = 8.0%, 95% CI = 3.2, 12.8; Z = 3.27, p = .001). CSP was observed to have similar post-AE trends as LICI and SICI, but did not reach significance (MD = 7.3 ms, 95% CI = -0.2, 14.8; Z = 1.90, p = .06). These findings were largely driven by studies evaluating vigorous and moderate intensity exercise, not those evaluating light intensity exercise. Conclusions: GABAA- and GABAB-mediated inhibitory neural networks are altered (disinhibited) as a result of AE exercise. Although inconclusive at this time, it is possible that differences in exercise intensity prescription may result in differential changes in neuro-inhibitory measurements. Although differences in TMS methods, post-exercise test timing, and other variables were not the primary focus of the presented analysis, they may also be important in understanding the post-AE variance in TMS measurements. Future research should focus on performing randomized control trials (RCTs), establishing valid and consistent TMS methods, and evaluating the interaction between exercise intensity and post-AE test timing.
... 83,84 After stroke, motor recovery is hampered by a substantial degree of intracortical inhibition in the lesioned brain hemisphere; 85 and thus, by releasing inhibition aerobic exercise has the capacity to create a fertile brain environment in which learning can occur. 22,85,84,86 Motor learning involves the acquisition and refinement of movement sequences in a novel order. 14 Learning is temporally biphasic, characterized by distinguishable early and late phases: early learning involves rapid improvements in skill, 87 where brain activity is altered as a pattern necessary for optimal performance is selected 87 and changes begin to occur at a synaptic level; 88 late learning is more prolonged, 87 consisting of larger structural changes and neuronal reorganization. ...
... Despite improvements in standard neurorehabilitation techniques, in part due to the influx of motor learning research to inform practice, 12 existing methods do not consistently lead to positive motor outcomes. 12,19 Aerobic exercise has recently been promoted as a possible adjunct therapy to existing neurorehabilitation practice, 22,86 given its positive effects on motor learning, 23,24 neuroplasticity, 23,109,110 and brain health. [27][28][29][30] Yet the clinical application of exercise to enhance neurorehabilitation is undermined by a misalignment between present research findings in healthy young adults and exercise capacity in persons with stroke. ...
... 23 In this work we employed PAS, a TMS protocol that can modulate corticomotoneuronal excitability via spike timing-dependent plasticity (STDP) principles 83 (Figure 1-1). 78 Evidence that aerobic exercise can enhance motor learning in healthy young adults suggests that this intervention could be used to foster improvements in motor behavior after neurological insult 22,39,86 and during healthy aging. 40 However, much of the existing data demonstrating aerobic exercise effects on motor learning have, to date, focused on acute bouts of high-intensity exercise. ...
Thesis
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Aerobic exercise has been promoted as a possible adjunct therapy to neurorehabilitation practice, given its positive effects on brain health. In healthy young adults, acute high-intensity cycling can enhance motor performance and learning of a complex motor task, and promote neuroplasticity in the motor system. However, clinical populations may not be able to participate in high-intensity exercise. To date there is inconsistent evidence for the efficacy of moderate-intensity aerobic exercise to alter motor learning and neuroplasticity in healthy young adults. Using two experiments, we aimed to determine how acute moderate-intensity cycling affects motor behavior and neuroplasticity in healthy young individuals. First, 16 participants practiced a complex motor skill after 30 minutes of moderate-intensity cycling or seated rest, on separate occasions. Motor performance was assessed at baseline, immediately after, and 5 minutes after exercise or rest. Twenty-four hours later, we assessed motor learning at a no-exercise retention test. Under the exercise condition, participants maintained performance over time, whereas, performance diminished over time under the rest condition, and became worse than post-exercise performance. Conditions did not differ at retention. Second, another group of 16 participants underwent paired associative stimulation (PAS) a transcranial magnetic stimulation (TMS) protocol known to induce neuroplasticity in the motor system. Effects of PAS were separately compared after a 30-minute bout of moderate-intensity cycling versus seated rest. At baseline, immediately after PAS, and 30 minutes post-PAS, we measured corticomotoneuronal excitability and excitability of intracortical neural circuits using TMS. We found that PAS increased corticomotoneuronal excitability when performed after exercise, but not rest. Exercise and PAS modulated activity in specific neural circuits post-intervention, without similar results under the rest condition. Moderate-intensity aerobic exercise can promote neuroplasticity in the motor system, but in this study similar effects did not transfer to behavioral measures of motor learning. In order to evaluate the clinical feasibility of this pairing moderate intensity exercise with skilled motor practice, we must first elucidate the dose-response effects of exercise on motor behavior, explore timing effects of exercise on motor learning, and examine how long-term pairing of exercise with practice impacts motor learning.
... 6 In healthy people and people with stroke, a single bout of aerobic exercise (AE) is known to enhance cerebral blood flow, elevate serum levels of neurotrophic factors such as brain-derived neurotrophic factor, 7,8 and upregulate neuroprotective hormones and neurotransmitters, processes that promote neuroplasticity. [9][10][11][12][13] For this reason, there is an emerging field of research examining whether acute AE can "prime" the brain to synergistically enhance the benefits of other rehabilitation therapies among clinical populations, such as people with stroke. 7,14-17 Using transcranial magnetic stimulation (TMS), a noninvasive tool that assesses mechanisms of corticospinal excitability (CSE), 18 several studies in healthy individuals have proposed that the main factors responsible for enhancing neuroplasticity associated with improved brain function post-AE are the transient increases in glutamatergic-mediated intracortical excitation and decreases in γ -aminobutyric acid (GABA)-mediated intracortical inhibition. ...
... limb among people with progressive MS. Previous research has proposed that CSE changes following a bout of AE when measured in the nonexercised upper limb are likely mediated by neuroplasticity-related mechanisms 10,12,15,20,64 rather than peripheral exercise-induced fatigue. 65 In this preliminary pilot study, we showed that capacity for AE-induced improvements in brain excitability still exists in this group of people with progressive MS, who, because of significant central nervous system damage, require bilateral ambulatory assistive devices (eg, canes, walker) in order to walk. ...
... 18,51 Our results showing AE-induced shortening of CSP only when tested at lower TMS intensities suggest the predominant involvement of GABA A receptors. This finding aligns with those previously described in healthy populations exposed to acute AE, 10,12,64,71 supporting that the benefit of AE on reducing GABA A -mediated brain inhibition is preserved in people with progressive MS. It is important to note that this benefit was detected only in the hemisphere corresponding to the stronger hand. ...
Article
Background and purpose: Even a single bout of aerobic exercise (AE) enhances corticospinal excitability (CSE), a biomarker of neuroplasticity. Because neurodegeneration limits capacity for neuroplasticity, it is not clear whether AE would induce CSE changes in people with progressive multiple sclerosis (MS). Methods: People with progressive MS (n = 10) requiring ambulatory assistive devices completed a graded maximal exercise test. Dual-energy x-ray absorptiometry was used to quantify body fat and lean mass. Before and following one 40-minute AE session using body weight-supported (<10% support) treadmill at moderate intensity, CSE was measured using transcranial magnetic stimulation. Variables included resting and active motor thresholds, motor evoked potential (MEP) amplitudes, recruitment curves, and length of the cortical silent period (CSP). Results: Aerobic exercise reduced inhibition (shorter CSP) and increased excitation (increased MEP amplitude) only in the hemisphere corresponding to the stronger hand. Controlling for age, higher fitness and lower body fat significantly predicted exercise-induced reduction in resting motor threshold (ΔR = +0.458, P = 0.046) and CSP (ΔR = +0.568, P = 0.030), respectively. Discussion and conclusions: Despite high levels of disability, capacity for exercise-induced neuroplasticity was retained among people with progressive MS. The hemisphere contralateral to the weaker hand was resistant to exercise-induced CSE changes, suggesting less neuroplastic potential. Lower fitness and higher body fat were associated with diminished exercise-induced CSE benefits, suggesting that therapists should consider interventions aimed at improving fitness and combating sedentarism to ultimately enhance the benefits of exercise on the brain.Video Abstract available for more insights from the authors (see the Video, Supplemental Digital Content 1, available at: http://links.lww.com/JNPT/A302).
... Recent evidence shows that exercise influences the excitability of neurons in the primary motor cortex [30]. Transcranial magnetic stimulation (TMS) studies suggest that exercise suppresses inhibitory and promotes excitatory intracortical networks that impact corticospinal tract output [31]. ...
... Acute, moderate intensity aerobic exercise such as that used in this study appears to have a positive effect on the speed of performance of a variety of cognitive tasks [35]. A single session of exercise has been shown to increase cortical excitability and improve performance on tasks of executive function [30]. Neurologically, the positive impact of acute exercise on the prefrontal and primary motor cortices [30] may explain the results obtained in this study. ...
... A single session of exercise has been shown to increase cortical excitability and improve performance on tasks of executive function [30]. Neurologically, the positive impact of acute exercise on the prefrontal and primary motor cortices [30] may explain the results obtained in this study. Previous neuroimaging evidence has shown that the regulation of speed-accuracy responses is associated with functioning of prefrontal regions [36] including association areas as well as the presupplementary motor area [37]. ...
Article
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Movement time (MT) is one of the most important variables influencing the way we control our movements. A few previous studies have generally found that MT reduces with reaction time testing during exercise. However, limited evidence exists concerning change in MT following an acute bout of exercise. Our purpose was to investigate the effect of an acute bout of aerobic exercise on movement time as assessed by a Fitts' Law task. We also sought to determine if exercise would further lower MT during the more difficult task conditions compared with rest. Nineteen (12 male, 7 female) volunteers (19-28 yrs) completed a computerized paired serial pointing task to measure movement time before and after rest (R) and an acute bout of moderate aerobic exercise (E) using a within subjects crossover design. Comparisons between exercise and rest conditions were made to determine if there were differences in movement time. Exercise significantly reduced MT compared with rest. Movement time was reduced by an average of 208 ms following exercise compared with 108 ms following rest. Exercise did not further lower MT during the more difficult task conditions. These results suggest that an acute bout of aerobic exercise reduces movement time which is an important component of motor control. Further studies are needed to determine the duration of the effect as well as the optimum duration and intensity of exercise.
... Bien que nos connaissances sur les mécanismes comportementaux et neurophysiologiques sous-jacents à cet effet de l'exercice soient incomplètes, un faisceau d'études permet de suggérer que l'effet favorable de l'exercice sur la pratique physique est due à une potentialisation des phénomènes de neuroplasticité induits pendant et suite à cette pratique. Par exemple, l'exercice aérobie induirait une diminution transitoire de la SICI au niveau de M1 (Singh et al., 2014(Singh et al., , 2015, ce qui aurait pour effet de faciliter l'induction de tPLT au sein de ce dernier lors de l'acquisition motrice (El-Sayes et al., 2018). De même, l'exercice physique participerait à une augmentation de l'activité du système noradrénergique (Segal et al., 2012) ainsi que de la circulation du facteur neurotrophique dérivé du cerveau (ou BDNF pour « brain-derived neurotrophic factor », Clos et al., 2021), tous deux impliqués dans la consolidation des apprentissages (Bekinschtein et al., 2014 ;Kuo et al., 2021). ...
... Exercise also modulates the circulation of various neuroendocrine substances, as dopamine, that are implied in motor acquisition (Foley and Fleshner, 2008;de Sousa Fernandes et al., 2020). Importantly, exercise facilitates the induction of LTP-like plasticity by transiently reducing short-interval intracortical inhibition (SICI) at the level of the primary motor cortex (Devanne and Allart, 2019;Singh et al., 2014Singh et al., , 2015. Considering the latter mechanism, we suggest that the difference between MP and PP with regards to motor acquisition may rely in part to the effects of motor imagery on SICI. ...
... This is the case with M1, as the causal link between changes in M1 neurons' activity and improvement of PD symptoms has not yet been made. However, it could be possible that exercising increases M1 DA levels in PD patients, leading to improved motor and cognitive symptoms, since DA levels are increased during exercise in healthy people (Singh and Staines, 2015). Also, as serotonin, norepinephrine and brain derived neurotrophic factor levels are also increased in healthy people during physical activity (Singh and Staines, 2015) the levels of these compounds could be increased in PD patients during exercise and compensate for the DAergic depletion in M1 as well as in sub-cortical systems. ...
... However, it could be possible that exercising increases M1 DA levels in PD patients, leading to improved motor and cognitive symptoms, since DA levels are increased during exercise in healthy people (Singh and Staines, 2015). Also, as serotonin, norepinephrine and brain derived neurotrophic factor levels are also increased in healthy people during physical activity (Singh and Staines, 2015) the levels of these compounds could be increased in PD patients during exercise and compensate for the DAergic depletion in M1 as well as in sub-cortical systems. ...
Article
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The primary motor cortex (M1) is crucial for movement execution, especially dexterous ones, but also for cognitive functions like motor learning. The acquisition of motor skills to execute dexterous movements requires dopamine-dependent and -independent plasticity mechanisms within M1. In addition to the basal ganglia, M1 is disturbed in Parkinson’s disease (PD). However, little is known about how the lack of dopamine (DA), characteristic of PD, directly or indirectly impacts M1 circuitry. Here we review data from studies of PD patients and the substantial research in non-human primate and rodent models of DA depletion. These models enable us to understand the importance of DA in M1 physiology at the behavioral, network, cellular, and synaptic levels. We first summarize M1 functions and neuronal populations in mammals. We then look at the origin of M1 DA and the cellular location of its receptors and explore the impact of DA loss on M1 physiology, motor, and executive functions. Finally, we discuss how PD treatments impact M1 functions.
... The positive effects of aCE on neuroplasticity are thought to be related to several neurophysiological mechanisms. In this way, it is thought that exercise might act as a kind of primer to create a favorable environment for neuroplastic processes of motor learning [8,11,12] (see [13,14] for reviews); however, such exercise-induced neuromodulations on several neurophysiological system levels are yet not fully understood. Further insights into the neuroplastic mechanisms associated with the effects of aCE might be gained by investigating electrocortical signatures of motor performance and learning, as assessed via electroencephalography (EEG), which can be performed concurrently with the practiced motor task. ...
... However, although the alpha frequency band is involved in motor processing, they found no effect of high-intensity aCE on alpha power (8)(9)(10)(11)(12). ...
Article
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Acute cardiovascular exercise (aCE) seems to be a promising strategy to improve motor performance and learning. However, results are heterogeneous, and the related neurophysiological mechanisms are not well understood. Oscillatory brain activitiy, such as task-related power (TRPow) in the alpha and beta frequencies, are known neural signatures of motor activity. Here, we tested the effects of aCE on motor performance and learning, along with corresponding modulations in EEG TRPow over the sensorimotor cortex. Forty-five right-handed participants (aged 18-34 years) practiced a visuomotor force-matching (FM) task after either high-intensity (HEG), low-intensity (LEG), or no exercise (control group, CG). Motor performance was assessed immediately, 15 min, 30 min, and 24 h after aCE/control. EEG was measured during the FM task. Results of frequentist and Bayesian statistics revealed that high-and low-intensity aCE had no effect at the behavioral level, adding to the previous mixed results. Interestingly, EEG analyses showed an effect of aCE on the ipsilateral sensorimotor cortex, with a stronger decrease in β-TRPow 15 min after exercise in both groups compared to the CG. Overall, aCE applied before motor practice increased ipsilateral sensorimotor activity, while motor learning was not affected; it remains to be seen whether aCE might affect motor learning in the long run.
... dopamine) as well as neurotrophic factors (e.g. BDNF) (Dinoff, Herrmann, Swardfager, & Lanctôt, 2017;McMorris, Collard, Corbett, Dicks, & Swain, 2008), positive effects on the primary motor cortex, as well as synaptic plasticity (Mellow, Goldsworthy, Coussens, & Smith, 2020;Singh & Staines, 2015), and an increased cerebral metabolism (Ogoh & Ainslie, 2009). ...
... However, the exact role of exercise-induced BDNF in enhanced memory formation needs further investigation (Baird et al., 2018;Charalambous et al., 2018;Helm et al., 2017;Mang, Snow, Campbell, Ross, & Boyd, 2014). Furthermore, dopamine and BDNF might indirectly mediate changes on the corticospinal level and thereby facilitate motor memory consolidation (El-Sayes et al., 2019;Mellow et al., 2020;Singh & Staines, 2015). Findings from healthy adults showed that enhanced offline learning was directly linked to an exercise-induced increase in corticospinal excitability , reduction in short-interval intracortical inhibition (SICI; i.e. synaptic GABA A inhibition) (Stavrinos & Coxon, 2017), and improvement of neural activation in sensorimotor areas (Dal Maso et al., 2018). ...
Article
Acute cardiovascular exercise has shown to promote neuroplastic processes supporting the consolidation of newly acquired motor skills in healthy adults. First results suggest that this concept may be transferred to populations with motor and cognitive dysfunctions. In this context, Parkinson’s disease (PD) is highly relevant since patients demonstrate deficits in motor learning. Hence, in the present study we sought to explore the effect of a single post-practice exercise bout on motor memory consolidation in PD. For this purpose, 17 patients with PD (Hoehn and Yahr: 1 – 2.5, age: 60.1 ± 7.9 y) practiced a whole-body task followed by either (i) a moderate-intense bout of cycling, or (ii) seated rest for a total of 30 minutes. The motor task required the participants to balance on a tiltable platform (stabilometer) for 30 seconds. During skill practice, participants performed 15 trials followed by a retention test 1 day and 7 days later. We calculated time in balance (platform within ± 5° from horizontal) for each trial and within- and between-group differences in memory consolidation (i.e. offline learning = skill change from last acquisition block to retention tests) were analyzed. Groups revealed similar improvements during skill practice (F4,60 = .316, p = .866), but showed differences in offline learning, which were only evident after 7 days (F1,14 = 5.602, p = .033). Our results suggest that a single post-practice exercise bout is effective in enhancing long-term motor memory consolidation in a population with motor learning impairments. This may point at unique promoting effects of exercise on dopamine neurotransmission involved in memory formation. Future studies should investigate the potential role of exercise-induced effects on the dopaminergic system.
... BDNF, IGF-1, VEGF) (Dinoff et al., 2017;Huang et al., 2014;Knaepen et al., 2010;Szuhany et al., 2015). In addition, increased corticospinal excitability (CSE), reduced intracortical inhibition, and beneficial effects on synaptic efficacy, particularly indicated by an increase in longterm potentiation (LTP)-like plasticity, have been demonstrated (Mellow et al., 2020;Singh and Staines, 2015). This has lead researchers to suggest that exercise might create an optimized environment for neuroplasticity. ...
... BDNF) and their causal relationship with improved offline gains would contribute to our understanding (Loprinzi and Frith, 2019;McMorris, 2016). Moreover, while first studies examined effects of acute exercise on surrogates of brain plasticity, most studies did not directly link their findings to behavioral data (Mellow et al., 2020;Singh and Staines, 2015). Furthermore, emerging neuroimaging techniques should be used to gain a better understanding of the effects on brain networks and central processes (Ghosh et al., 2019;Herold et al., 2020). ...
Article
Emerging evidence indicates that acute bouts of cardiovascular exercise promote motor memory formation. In this preregistered meta-analysis (CRD42018106288) we synthesize data from 22 studies published until February 2020, including a total of 854 participants. We calculated standardized mean differences (SMDs) with 95% confidence intervals (CIs) to assess exercise effects on motor memory encoding and consolidation, respectively. The pooled data indicate that exercise mainly benefits the consolidation of memories, with exercise prior to motor practice improving early non-sleep consolidation (SMD, 0.58; 95% CI; 0.30-0.86; p < 0.001), and post-practice exercise facilitating sleep-dependent consolidation (SMD, 0.62; 95% CI, 0.34-0.90; p < 0.001). Strongest effects exist for high exercise intensities, and motor task nature appears to be another relevant modulator. We demonstrate that acute cardiovascular exercise particularly promotes the consolidation of acquired motor memories, and exercise timing, and intensity as well as motor task nature seem to critically modulate this relationship. These findings are discussed within currently proposed models of motor memory formation and considering molecular and systemic mechanisms of neural plasticity.
... Although the cortical and spinal contribution to the CSP length is still unclear (24,79), it is generally accepted that the cortex is the main modulator of CSP change (32). Because excessive GABAergicmediated intracortical inhibition is considered pathological (80,81), detrimental to neuroplasticity (39,40,81,82), and is associated with disease progression in MS (36) and stroke (83), decreasing its activity is an attractive treatment strategy to boost neuroplasticity (40,81). ...
... In healthy people and people with stroke, studies have confirmed that even a single bout of aerobic exercise is able to acutely reduce short intracortical inhibition (59,(83)(84)(85)(86) assessed with TMS paired pulse, a TMS biomarker of AMT, active motor threshold; CSP, cortical silent period; eREC, excitatory recruitment curve; iREC, inhibitory recruitment curve; MEP, motor evoked potential; MSO%, maximal stimulator output percentage; RMT, resting motor threshold; eREC Slope = MEP Amplitude (µV) by TMS intensity 105−155%AMT ; iREC Slope = CSP time (ms) by TMS intensity 105−155%AMT ; Area under the curve (AUC) was calculated for both excitatory and inhibitory RECs using the trapezoid rule ∆X x (Y1+Y2)/2, whereby X were the MSO% used (i.e., X axis values, 105-155% of AMT) and Y are the recorded CSP lengths (ms) or the MEP amplitudes (µV). *Difference between stronger and weaker hand is statistically significant at α < 0.05. ...
Article
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Background: Inflammatory lesions and neurodegeneration lead to motor, cognitive, and sensory impairments in people with multiple sclerosis (MS). Accumulation of disability is at least partially due to diminished capacity for neuroplasticity within the central nervous system. Aerobic exercise is a potentially important intervention to enhance neuroplasticity since it causes upregulation of neurotrophins and enhances corticospinal excitability, which can be probed using single-pulse transcranial magnetic stimulation (TMS). Whether people with progressive MS who have accumulated substantial disability could benefit from walking rehabilitative training to enhance neuroplasticity is not known. Objective: We aimed to determine whether 10 weeks of task-specific walking training would affect corticospinal excitability over time (pre, post, and 3-month follow-up) among people with progressive MS who required walking aids. Results: Eight people with progressive MS (seven female; 29–74 years old) with an Expanded Disability Status Scale of 6–6.5 underwent harness-supported treadmill walking training in a temperature controlled room at 16°C (10 weeks; three times/week; 40 min at 40–65% heart rate reserve). After training, there was significantly higher corticospinal excitability in both brain hemispheres, reductions in TMS active motor thresholds, and increases in motor-evoked potential amplitudes and slope of the recruitment curve (REC). Decreased intracortical inhibition (shorter cortical silent period) after training was noted in the hemisphere corresponding to the stronger hand only. These effects were not sustained at follow-up. There was a significant relationship between increases in corticospinal excitability (REC, area under the curve) in the hemisphere corresponding to the stronger hand and lessening of both intensity and impact of fatigue on activities of daily living (Fatigue Severity Scale and Modified Fatigue Impact Scale, respectively). Conclusion: Our pilot results support that vigorous treadmill training can potentially improve neuroplastic potential and mitigate symptoms of the disease even among people who have accumulated substantial disability due to MS.
... Briefly, this comprises the upregulation of catecholamines (e.g., dopamine) as well as neurotrophic factors (e.g. BDNF) (Dinoff, Herrmann, Swardfager, & Lanctôt, 2017;McMorris, Collard, Corbett, Dicks, & Swain, 2008), positive effects on the primary motor cortex as well as synaptic plasticity (Mellow, Goldsworthy, Coussens, & Smith, 2019;Singh & Staines, 2015), and an increased cerebral metabolism (Ogoh & Ainslie, 2009). ...
... Furthermore, dopamine and BDNF might indirectly mediate changes on the corticospinal level (i.e. system level of brain organization) and thereby facilitating motor memory consolidation (El-Sayes et al., 2018;Mellow et al., 2019;Singh & Staines, 2015). Findings from healthy adults showed that improved offline learning was directly linked to an exerciseinduced increase in corticospinal excitability , reduction in short-interval intracortical inhibition (SICI; i.e. synaptic GABAA inhibition) (Stavrinos & Coxon, 2017), and improvement of functional networks in sensorimotor areas (Dal Maso et al., 2018). ...
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Acute cardiovascular exercise has shown to promote neuroplastic processes, and thus to improve the consolidation of newly acquired motor skills in healthy adults. First results suggest that this concept may be transferred to populations with motor and cognitive dysfunctions. In this context, Parkinson’s disease (PD) is highly relevant since patients demonstrate deficits in motor learning. Hence, in the present study we sought to explore the effect of a single post-practice exercise bout on motor memory consolidation in PD patients. For this purpose, 17 PD patients (Hoehn and Yahr: 1 – 2.5, age: 60.1 ± 7.9 y) practiced a whole-body task followed by either (i) a moderate-intense bout of cycling, or (ii) seated rest for a total of 30 minutes. The motor task required the participants to balance on a tiltable platform (stabilometer) for 30 seconds. During skill practice, patients performed 15 trials followed by a retention test 1 day and 7 days later. We calculated time in balance (platform within ± 5° from horizontal) for each trial and within- and between-group differences in memory consolidation (i.e. offline learning = skill change from last acquisition block to retention tests) were analyzed. Groups revealed similar improvements during skill practice (F 4,60 = .316, p = .866), but showed differences in offline learning, which was only evident after 7 days (F 1,14 = 5.602, p = .033). Our results suggest that a single post-practice exercise bout is effective in enhancing long-term motor memory consolidation in a population with motor learning impairments. This may point at unique promoting effects of exercise on dopamine neurotransmission involved in memory formation. Future studies should investigate the potential role of exercise-induced effects on the dopaminergic system. Highlights Acute exercise enhanced motor memory consolidation in PD Effects were evident only at 7-day retention Results may indicate unique exercise-effects on the dopaminergic system Findings show promising potential of exercise for motor rehabilitation
... In addition, acute exercise may impact neuroplasticity in cortico-spinal pathways [9] as well as increase the excitability of central brain areas involved in motor learning, such as the primary motor cortex and supplemental motor area [10]. These latter mechanisms might positively affect motor memory and thus improve motor retention [11]. ...
... It has been suggested that exercise interacts more with mechanisms underlying the consolidation of motor skills compared to the processes associated with the motor skill acquisition phase. In neuroendocrinological theory, this effect emerges through acute cardiovascular exercise triggering neuroplasticity in cortico-spinal pathways [9] and increased excitability of central brain areas for motor learning [10]. This, in turn, is related to moderate increases in the magnitude of brain neurochemicals, which might originate from the lactate released from skeletal muscles during exercise [7,8]. ...
Article
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Acute exercise influences human cognition, and evidence suggests that learning can be improved. According to the cognitive–energetic approach towards exercise cognition, exercise represents a stressor that elevates physiological arousal, which, in turn, increases the availability of mental resources. However, the degree of arousal is hypothesized to have optimal and suboptimal states, and moderate intensity exercise is thus considered to be favorable compared to low intensity and vigorous exercise. The current evidence for such a moderating effect of exercise intensity on motor learning, however, appears somewhat mixed. Therefore, the purpose of this study was to explore the effect of aerobic exercise conducted with different exercise intensities on immediate practice, transfer, and 24-hour retention of a motor skill. To this end, young adults (n = 40, mean (SD) age: 23.80 (1.98) years) were randomized to exercise at either 50% or 75% of age-predicted maximal heart rate according to the Karvonen formulae. Immediately after exercising, participants practiced a high-precision golf putting task in a blocked design. Retention and transfer of skill were assessed after 24 h. Results indicated that both groups demonstrated motor learning, retention, and transfer at a similar level. Further works are thus needed to establish the specific relationship between exercise and learning and establish the factors that have an influence.
... The mechanism by which a single-session of aerobic exercise modifies response time remains unclear [8]. There are several potentials mechanisms that may contribute to the reduction of MT during aerobic exercise [15,17,45,47,55,56,58]. For example, peripheral physiological changes such as increase in temperature or altered muscle membrane properties could influence the propagation of action potential across the sarcolemma [58]. ...
... In this regard, studies have used transcranial magnetic stimulation to examine the corticospinal responses following aerobic exercise. The general findings suggest that a single-session of aerobic exercise reduces intracortical inhibition and increases intracortical facilitation [45,55,56]. It is possible that reduced inhibition in the descending motor pathways coupled with increased facilitation may contribute to the reduced MT reported in the current meta-analysis [17]. ...
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Recently, there have been several studies that have examined the acute effects of aerobic exercise on cognitive function. Importantly, one precise indicator of cognitive function is response time (RT), which has two main components; premotor time (PMT) and motor time (MT). PMT is the time for perception, decision making and response preparation, while MT is executing the response. Using fractionated response time (FRT) instead of RT provides a more precise estimate of the location of the effect of aerobic exercise on cognitive or motor components of the response. There is emerging evidence that shows an acute bout of exercise may improve FRT. Therefore, the purpose of this systematic review and meta-analysis was to explore the acute effect of aerobic exercise on FRT by considering the effects of various cognitive function tests. Fourteen studies were included investigating FRT during and/or after aerobic exercise. The results indicated that during exercise, PMT increased in simple reaction time and decreased in flanker task; MT decreased in choice reaction time; interestingly, RT decreased when it was assessed by choice reaction time and flanker task, almost similar to PMT and MT. After exercise, PMT decreased specifically in flanker and go/no-go tasks. However, MT and RT did not change significantly. In conclusion, as changes in RT are affected by both PMT and MT, FRT provides a more precise estimate of the locus of the effects of aerobic exercise on response time.
... Cortical neurons also express several serotonin (5-HT) receptor subtypes (5-HT 1A/B,2A/C,3,4,6,7 ; Celada et al., 2013), for example, cortical 5-HT 1A Rs have high mRNA expression in cortical layers V and VI (Pompeiano et al., 1992;Puig et al., 2005;Singh and Staines, 2015) (Figure 2B). It is suggested that 5-HT modulation of motor cortex excitability leans toward facilitation (Singh and Staines, 2015). ...
... Cortical neurons also express several serotonin (5-HT) receptor subtypes (5-HT 1A/B,2A/C,3,4,6,7 ; Celada et al., 2013), for example, cortical 5-HT 1A Rs have high mRNA expression in cortical layers V and VI (Pompeiano et al., 1992;Puig et al., 2005;Singh and Staines, 2015) (Figure 2B). It is suggested that 5-HT modulation of motor cortex excitability leans toward facilitation (Singh and Staines, 2015). Interestingly, cortical 5-HT 1A Rs activation has an overall excitatory effect on the neural networks that give rise to movement representations (Scullion et al., 2013). ...
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von Monakow's theory of diaschisis states the functional 'standstill' of intact brain regions that are remote from a damaged area, often implied in recovery of function. Accordingly, neural plasticity and activity patterns related to recovery are also occurring at the same regions. Recovery relies on plasticity in the periinfarct and homotopic contralesional regions and involves relearning to perform movements. Seeking evidence for a relearning mechanism following stroke, we found that rodents display many features that resemble classical learning and memory mechanisms. Compensatory relearning is likely to be accompanied by gradual shaping of these regions and pathways, with participating neurons progressively adapting cortico-striato-thalamic activity and synaptic strengths at different cortico-thalamic loops-adapting function relayed by the striatum. Motor cortex functional maps are progressively reinforced and shaped by these loops as the striatum searches for different functional actions. Several cortical and striatal cellular mechanisms that influence motor learning may also influence post-stroke compensatory relearning. Future research should focus on how different neuromodulatory systems could act before, during or after rehabilitation to improve stroke recovery.
... Although older adults are able to learn new and relearn motor skills [3], the consolidation of motor memory is diminished in older adulthood [4][5][6][7]. Acute bouts of cardiovascular exercise facilitate neuroplasticity in the primary motor cortex (M1) and enhance corticospinal excitability [8]. These effects are not specific to lower extremity motor areas and muscles engaged during exercise but also apparent in motor areas responsible for upper limbs, indicating that exercise has a generalized effect on M1 [9,10]. ...
... These heterogeneous results might have been influenced by the method of defining exercise intensity (% of VO 2 -peak vs. % of estimated agerelated maximum heart rate vs. % of maximum Watt) or by the exercise type (cycling vs. running). In the current study, a moderate intensity exercise session was used, as this load could be transferred from laboratory-based acute exercise studies to the setting of rehabilitation, i.e., patients or persons not experienced with exercise [8]. High-intensity exercise did not seem appropriate, as it is performed by or recommended only for older persons with exercise experience [85,86]. ...
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Acute bouts of exercise have been shown to improve fine motor control performance and to facilitate motor memory consolidation processes in young adults. Exercise effects might be reflected in EEG task-related power (TRPow) decreases in the beta band (13–30 Hz) as an indicator of active motor processing. This study aimed to investigate those effects in healthy older adults. Thirty-eight participants (65–74 years of age) were assigned to an experimental (EG, acute exercise) or a control group (CG, rest). Fine motor control was assessed using a precision grip force modulation (FM) task. FM performance and EEG were measured at (1) baseline (immediately before acute exercise/rest), (2) during practice sessions immediately after, (3) 30 minutes, and (4) 24 hours (FM only) after exercise/rest. A marginal significant effect indicated that EG revealed more improvement in fine motor performance immediately after exercise than CG after resting. EG showed enhanced consolidation of short-term and long-term motor memory, whereas CG revealed only a tendency for short-term motor memory consolidation. Stronger TRPow decreases were revealed immediately after exercise in the contralateral frontal brain area as compared to the control condition. This finding indicates that acute exercise might enhance cortical activation and thus, improves fine motor control by enabling healthy older adults to better utilize existing frontal brain capacities during fine motor control tasks after exercise. Furthermore, acute exercise can act as a possible intervention to enhance motor memory consolidation in older adults.
... In stroke, the fine-tuning of GABA mediated inhibitory networks may play a role in the induction of neuroplasticity (Taubert et al., 2015) and functional reorganization of both hemispheres (Manganotti et al., 2008;Takechi et al., 2014). TMS studies in healthy participants have shown that acute aerobic exercise can downregulate brain inhibition (Molteni et al., 2002;Singh and Staines, 2015) and upregulate brain facilitation (Singh and Staines, 2015). ...
... In stroke, the fine-tuning of GABA mediated inhibitory networks may play a role in the induction of neuroplasticity (Taubert et al., 2015) and functional reorganization of both hemispheres (Manganotti et al., 2008;Takechi et al., 2014). TMS studies in healthy participants have shown that acute aerobic exercise can downregulate brain inhibition (Molteni et al., 2002;Singh and Staines, 2015) and upregulate brain facilitation (Singh and Staines, 2015). ...
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Objective: Evaluate intensity-dependent effects of a single bout of high intensity interval training (HIIT) compared to moderate intensity constant-load exercise (MICE) on corticospinal excitability (CSE) and effects on upper limb performance in chronic stroke. Design: Randomized cross-over trial. Setting: Research laboratory in a tertiary rehabilitation hospital. Participants: Convenience sample of 12 chronic stroke survivors. Outcome measures: Bilateral CSE measures of intracortical inhibition and facilitation, motor thresholds, and motor evoked potential (MEP) latency using transcranial magnetic stimulation. Upper limb functional measures of dexterity (Box and Blocks Test) and strength (pinch and grip strength). Results: Twelve (10 males; 62.50 ± 9.0 years old) chronic stroke (26.70 ± 23.0 months) survivors with moderate level of residual impairment participated. MEP latency from the ipsilesional hemisphere was lengthened after HIIT (pre: 24.27 ± 1.8 ms, and post: 25.04 ± 1.8 ms, p = 0.01) but not MICE (pre: 25.49 ± 1.10 ms, and post: 25.28 ± 1.0 ms, p = 0.44). There were no significant changes in motor thresholds, intracortical inhibition or facilitation. Pinch strength of the affected hand decreased after MICE (pre: 8.96 ± 1.9 kg vs. post: 8.40 ± 2.0 kg, p = 0.02) but not after HIIT (pre: 8.83 ± 2.0 kg vs. post: 8.65 ± 2.2 kg, p = 0.29). Regardless of type of aerobic exercise, higher total energy expenditure was associated with greater increases in pinch strength in the affected hand after exercise (R2 = 0.31, p = 0.04) and decreases in pinch strength of the less affected hand (R2 = 0.26 p = 0.02). Conclusion: A single bout of HIIT resulted in lengthened nerve conduction latency in the affected hand that was not engaged in the exercise. Longer latency could be related to the cross-over effects of fatiguing exercise or to reduced hand spasticity. Somewhat counterintuitively, pinch strength of the affected hand decreased after MICE but not HIIT. Regardless of the structure of exercise, higher energy expended was associated with pinch strength gains in the affected hand and strength losses in the less affected hand. Since aerobic exercise has acute effects on MEP latency and hand strength, it could be paired with upper limb training to potentiate beneficial effects.
... In stroke, the fine-tuning of GABA mediated inhibitory networks may play a role in the induction of neuroplasticity (Taubert et al., 2015) and functional reorganization of both hemispheres (Manganotti et al., 2008;Takechi et al., 2014). TMS studies in healthy participants have shown that acute aerobic exercise can downregulate brain inhibition (Molteni et al., 2002;Singh and Staines, 2015) and upregulate brain facilitation (Singh and Staines, 2015). ...
... In stroke, the fine-tuning of GABA mediated inhibitory networks may play a role in the induction of neuroplasticity (Taubert et al., 2015) and functional reorganization of both hemispheres (Manganotti et al., 2008;Takechi et al., 2014). TMS studies in healthy participants have shown that acute aerobic exercise can downregulate brain inhibition (Molteni et al., 2002;Singh and Staines, 2015) and upregulate brain facilitation (Singh and Staines, 2015). ...
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Objective: Evaluate intensity-dependent effects of a single bout of high intensity interval training (HIIT) compared to moderate intensity constant-load exercise (MICE) on corticospinal excitability (CSE) and effects on upper limb performance in chronic stroke. Design: Randomized cross-over trial. Setting: Research laboratory in a tertiary rehabilitation hospital. Participants: Convenience sample of 12 chronic stroke survivors. Outcome measures: Bilateral CSE measures of intracortical inhibition and facilitation, motor thresholds, and motor evoked potential (MEP) latency using transcranial magnetic stimulation. Upper limb functional measures of dexterity (Box and Blocks Test) and strength (pinch and grip strength). Results: Twelve (10 males; 62.50 ± 9.0 years old) chronic stroke (26.70 ± 23.0 months) survivors with moderate level of residual impairment participated. MEP latency from the ipsilesional hemisphere was lengthened after HIIT (pre: 24.27 ± 1.8 ms, and post: 25.04 ± 1.8 ms, p = 0.01) but not MICE (pre: 25.49 ± 1.10 ms, and post: 25.28 ± 1.0 ms, p = 0.44). There were no significant changes in motor thresholds, intracortical inhibition or facilitation. Pinch strength of the affected hand decreased after MICE (pre: 8.96 ± 1.9 kg vs. post: 8.40 ± 2.0 kg, p = 0.02) but not after HIIT (pre: 8.83 ± 2.0 kg vs. post: 8.65 ± 2.2 kg, p = 0.29). Regardless of type of aerobic exercise, higher total energy expenditure was associated with greater increases in pinch strength in the affected hand after exercise (R2 = 0.31, p = 0.04) and decreases in pinch strength of the less affected hand (R2 = 0.26 p = 0.02). Conclusion: A single bout of HIIT resulted in lengthened nerve conduction latency in the affected hand that was not engaged in the exercise. Longer latency could be related to the cross-over effects of fatiguing exercise or to reduced hand spasticity. Somewhat counterintuitively, pinch strength of the affected hand decreased after MICE but not HIIT. Regardless of the structure of exercise, higher energy expended was associated with pinch strength gains in the affected hand and strength losses in the less affected hand. Since aerobic exercise has acute effects on MEP latency and hand strength, it could be paired with upper limb training to potentiate beneficial effects.
... For instance, acute exercise increases the availability of neurochemicals (Skriver et al., 2014), which may strengthen memory traces during consolidation . In addition, cardiovascular exercise may trigger transient neuroplasticity changes in cortico-spinal pathways (Singh and Staines, 2015) that could facilitate motor memory consolidation and thus improve skill retention (Singh et al., 2016). For example, our group has recently shown that a single bout of cardiovascular exercise, performed immediately after practicing a sequential motor task, increased cortico-spinal excitability when assessed by transcranial magnetic stimulation (TMS) applied over the primary motor cortex (M1) . ...
... Accordingly, increases in M1 ERD have been observed after the administration of benzodiazepines with a GABAa agonist effect (Hall et al., 2010;Jensen et al., 2005). The smaller beta-band ERD exhibited by the EXE group is consistent with the suppressing effect that acute cardiovascular exercise might have on post-GABAa receptor inhibitory activity (Singh and Staines, 2015). In addition, several TMS studies have shown that a single bout of cardiovascular exercise reduces M1 short-intracortical inhibition (Singh et al., 2014;Smith et al., 2014), which is also thought to reflect GABAa inhibitory activity in motor networks (Ziemann et al., 1996). ...
Article
A single bout of cardiovascular exercise performed immediately after practicing a visuo-motor tracking task has been shown to improve the long-term retention of this motor skill through an optimization of the memory consolidation process. The mechanisms underlying the time- dependent effects of acute cardiovascular exercise on motor memory consolidation, however, remain poorly understood. In this study, we sought to determine the impact of a single bout of cardiovascular exercise performed immediately after motor skill practice on those mechanisms using electroencephalography (EEG) and electromyography (EMG). Specifically, we assessed exercise-induced changes in the activity and connectivity of cortico-motor networks during early consolidation and the impact of these changes on skill retention. Participants practiced a visuo-motor tracking task followed by either a short bout of intense exercise or a rest period. EEG along with EMG data of hand muscles were collected during the production of low-force isometric contractions. Event-related desynchronization, functional connectivity and corticomuscular coherence were measured at baseline, 30, 60 and 90 minutes after the bout of exercise or the rest period. Improvements in motor memory were inferred via retention tests of the motor skill performed 8 and 24 hours after motor practice. We found that participants who performed the single bout of exercise showed better motor skill retention 24 hours after motor practice. This improvement in skill retention in the exercise group was associated with significant decreases in beta-band event-related desynchronization in EEG electrodes located over the left sensorimotor areas. We also found that after exercise, alpha-, and even more significantly, beta-band functional connectivity, increased between EEG electrodes located over left and right sensorimotor areas. The exercise group also showed greater beta-band corticomuscular coherence but only in a small number of electrodes. Neither functional connectivity nor corticomuscular coherence measures correlated with skill retention scores. This is the first study exploring brain mechanisms underlying the summative effects of motor learning and cardiovascular exercise on motor memory consolidation. We have identified potential neural substrates through which a single bout of acute exercise, when performed in close temporal proximity to motor practice, strengthens motor memories. Our findings provide new mechanistic insights into a better understanding of the complex temporal relationship existing between cardiovascular exercise and motor memory consolidation.
... It is believed that exercise stimulates neuron growth, which could prevent students' cognitive loss (Lundgren et al., 2016). According to Singh & Staines (2015), when engaging in physical exercise, the brain is engaged, which causes it to produce more Brain-Derived Neurotrophic Factor (BDNF). This BDNF protein is crucial for maintaining the health and fitness of nerve cells (Ploughman, 2008). ...
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Physical activity positively impacts cognitive function and can help avoid cognitive impairment. The study aimed to investigate the association between cognitive function and physical activity in junior high school students in Bandung. This research is quantitative research with a correlation analytic design. The instrument used in this study is a questionnaire. The sampling technique used is a random sample, the sample is 1870 respondents. The questionnaire used in this study is a closed questionnaire, which is a questionnaire whose answers have been provided so that respondents only need to choose. The study found that half of the respondents with less activity experienced less cognitive function (71,8%). Almost half of the respondents had a physical activity with good cognitive function (21.6%), and a small proportion of physical activity experienced quite a number of cognitive functions (8.6%). There is a relationship between physical activity and function cognitive in students. The results of this study are expected to be taken into consideration for further research by examining other factors related to cognitive function and other factors related to physical activity, such as gender, socioeconomic, and family factors.
... Another possible explanation for this finding is related to an increase in catecholamine (adrenaline, noradrenaline and dopamine) release, and ensuing changes in their concentration in the regions of the anterior cingulate and prefrontal cortexes, following physical effort (McMorris et al., 1999;Singh & Staines, 2015). The prefrontal cortex is involved in several complex cognitive processes, such as reasoning, action planning and learning (Miller & Cohen, 2001), whereas the anterior cingulate cortex is responsible for cognitive processing, and is characterised by its contributions to motor control (Devinsky et al., 1995). ...
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This study aimed to verify whether the peripheral perception and decision making of young soccer players are influenced by physical fatigue. The sample was composed of 48 soccer players from two youth academies of Brazilian clubs (17.03 ± 2.33 years old). In laboratory conditions, the Vienna Test System and the TacticUP® video test was used to assess peripheral perception and decision making (response time and decision-making quality), respectively. Physical fatigue was induced through T-SAFT 90 that simulated the metabolic and physical demands of a soccer game (e.g., acceleration, deacceleration, change direction, jump, and technical action). Peripheral perception and decision-making abilities were compared between the control and physical fatigue "conditions". Results displayed that physical fatigue did not influence peripheral perception and decision-making quality, although it improved decision-making response time for the tactical principles of penetration, width and length with the ball, delay, defensive coverage, and recovery balance. In summary, physical fatigue did not affect players' ability to detect information from the peripheral visual field and did not influence the quality of decision-making of soccer players. In addition, physical fatigue induced players to make quicker decisions regarding tactical actions near the ball and inside the centre of play. Thus, we conclude that only the response time of decision-making of youth soccer players is influenced by physical fatigue. ARTICLE HISTORY
... It is thought that these networks can control the induction of plasticity. Their sensitivity to exerciseinduced manipulation is of special interest (Singh & Staines, 2015). Various connections of the M1 that react and adapt to external stimuli appear to be highly plastic (Moscatelli et al., 2021). ...
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The purpose of this study was to investigate effects of brain excitability by transcranial direct current stimulation (tDCS) on spike performances of professional female volleyball players. Thirteen professional female volleyball players were recruited for participation. We performed a randomized single-blind, SHAM-stimulus controlled, and counter-balanced crossover design with two interventions in this study. An anodal tDCS current was applied over the primary motor cortex (M1) for 20 min at 2 mA. In the SHAM intervention, the current was first applied for 30 s, after which it was terminated. Exercise performance assessment which comprised spike performance (spike ball speed, spiking consistency), two vertical jumps (jump and reach: JaR, countermovement jump: CMJ), bench-press and back-squat one-repetition maximum (1RM) were tested pre- and post-intervention. Results indicated that spike ball speed and spiking consistency following tDCS were significantly higher than those after SHAM intervention (both p < 0.05). However, JaR and CMJ did not show any significant differences between tDCS and SHAM intervention groups (both p > 0.05). There was no significant difference in bench-press and back-squat 1RM between two groups either (both p > 0.05). These findings suggest that tDCS could be effective in enhancing motor coordination performances of professional female volleyball athletes.
... Aerobic exercise and non-invasive brain stimulation have each been explored as potential neuromodulation approaches that have the capacity to reinforce mechanisms that subserve neuroplasticity and promote motor learning (Nitsche et al., 2003;Singh et al., 2014b;Skriver et al., 2014;Holman and Staines, 2021;Kim et al., 2021a). Intensive aerobic exercise facilitates neuroplasticity through various mechanisms, including enhanced blood flow to the motor cortex (Singh and Staines, 2015), upregulation of glucocorticoids (Milani et al., 2010) and neurotrophic factors (He et al., 2013), and increased states of arousal (McMorris et al., 2015). A singlesession of moderate-to high-intensity aerobic exercise is associated with an increase in brain-derived neurotrophic factor (Mang et al., 2014), enhanced long-term potentiationlike plasticity (Singh et al., 2014b), and greater retention of skilled motor tasks (Holman and Staines, 2021). ...
Article
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Motor training to improve walking and balance function is a common aspect of rehabilitation following motor-incomplete spinal cord injury (MISCI). Evidence suggests that moderate- to high-intensity exercise facilitates neuroplastic mechanisms that support motor skill acquisition and learning. Furthermore, enhancing corticospinal drive via transcranial direct current stimulation (tDCS) may augment the effects of motor training. In this pilot study, we investigated whether a brief moderate-intensity locomotor-related motor skill training (MST) circuit, with and without tDCS, improved walking and balance outcomes in persons with MISCI. In addition, we examined potential differences between within-day (online) and between-day (offline) effects of MST. Twenty-six adults with chronic MISCI, who had some walking ability, were enrolled in a 5-day double-blind, randomized study with a 3-day intervention period. Participants were assigned to an intensive locomotor MST circuit and concurrent application of either sham tDCS (MST+tDCS sham ) or active tDCS (MST+tDCS). The primary outcome was overground walking speed measured during the 10-meter walk test. Secondary outcomes included spatiotemporal gait characteristics (cadence and stride length), peak trailing limb angle (TLA), intralimb coordination (ACC), the Berg Balance Scale (BBS), and the Falls Efficacy Scale-International (FES-I) questionnaire. Analyses revealed a significant effect of the MST circuit, with improvements in walking speed, cadence, bilateral stride length, stronger limb TLA, weaker limb ACC, BBS, and FES-I observed in both the MST+tDCS sham and MST+tDCS groups. No differences in outcomes were observed between groups. Between-day change accounted for a greater percentage of the overall change in walking outcomes. In persons with MISCI, brief intensive MST involving a circuit of ballistic, cyclic locomotor-related skill activities improved walking outcomes, and selected strength and balance outcomes; however, concurrent application of tDCS did not further enhance the effects of MST. Clinical Trial Registration [ ClinicalTrials.gov ], identifier [NCT03237234].
... 29 However, no effect of training was found in the activation of CREB in peripheral blood mononuclear cells (PBMCs). 29 PA increased neuroadaptation, neuroprotection and neurogenesis, through neurotrophic factor actions. 30 It restored hippocampal function by increasing expressions of neurotrophic factors for encouraging synaptic plasticity, angiogenesis and neurogenesis. 29 BDNF levels for example, increased with PA and regular exercise. ...
... Basierend auf diesen Ergebnissen nahmen die Untersuchungen zu den Wirkungen auf die motorische Gedächtnisbildung innerhalb der letzten Jahre zu. Ein Großteil der Arbeiten versuchte dabei die zugrundeliegenden Mechanismen zu erforschen(Mellow, Goldsworthy, Coussens & Smith, 2020;Singh & Staines, 2015).Taubert und Kollegen (2015, S. 1) propagieren beispielsweise, dass eine akute Herz-Kreislauf-Beanspruchung als "endogene Neuro-Enhancement-Strategie" zur Verbesserung motorischer Lernprozesse verstanden werden kann. ...
Thesis
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Die vorliegende kumulative Dissertation untersucht in vier Publikationen die Effekte einer akuten Herz-Kreislauf-Beanspruchung auf die motorische Gedächtnisbildung. Zudem sollen potentielle Moderatoren dieser Wechselbeziehung identifiziert und der Nutzen für die Bewegungstherapie am Beispiel der neurodegenerativen Erkrankung Morbus Parkinson geprüft werden. Die Ergebnisse der Arbeit unterstützen die positiven Effekte eines einmaligen Herz-Kreislauf-Trainings auf motorische Lernprozesse, insbesondere auf die motorische Konsolidierung (Forschungsziel I). Die Intensität und zeitliche Platzierung der kardiovaskulären Beanspruchung sowie die Eigenschaften der zu erlernenden motorischen Fertigkeit scheinen jedoch die Wirkung zu beeinflussen (Forschungsziel II). Darüber hinaus lassen die Untersuchungen der Dissertation darauf schließen, dass die positiven Effekte auf Personen mit motorischen Lerndefiziten übertragen werden und die Ergebnisse daher vielversprechende Implikationen für die motorische Rehabilitation haben können (Forschungsziel III).
... Animal models have demonstrated that exercise can enhance LTP [11,12]. Relatedly, particularly in the motor cortex, there is also accumulating research in human samples showing that exercise can augment the response to experimentally-induced neuroplasticity paradigms [13,14]. ...
Article
Exercise has been shown to enhance synaptic plasticity, therefore, potentially affecting memory. While the mechanism(s) responsible for this relationship have been explored in animal models, current research suggests that exercise may possess the ability to induce synaptic long-term potentiation (LTP). Most of the LTP mechanistic work has been conducted in animal models using invasive procedures. For that reason, the purpose of the present experiment was to investigate whether self-reported exercise is related to human sensory LTP-like responses. Nineteen participants (MAGE = 24 years; 52.6% male) completed the study. Long-term potentiation-like responses were measured by incorporating a non-invasive method that assess the change in potentiation of the N1b component produced from the visual stimulus paradigm presented bilaterally in the visual field. Results demonstrated that those with higher levels of moderate-to-vigorous physical activity (MVPA) had a greater N1b change from baseline to the early time period assessment, r = -0.43, p = 0.06. Our findings provide some suggestive evidence of an association between self-reported MVPA and LTP-like responses. Additional work is needed to support that the potentiation of the human sensory N1b component in the observed study is due to the exercise-induced synaptic changes similar to that detailed in prior animal research.
... Nevertheless, meta-analyses generally support the premise that resistance training alters excitability of the intracortical inhibitory interneurons, particularly when these are assessed during a voluntary contraction Siddique et al. 2020). Similar reductions in intracortical inhibition have been demonstrated following acute aerobic exercise (Singh and Staines 2015;El-Sayes et al. 2019), perhaps suggestive of a mechanism linked to exercise in general, rather than specific to resistance training. ...
Article
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The initial increases in force production with resistance training are thought to be primarily underpinned by neural adaptations. This notion is firmly supported by evidence displaying motor unit adaptations following resistance training; however, the precise locus of neural adaptation remains elusive. The purpose of this review is to clarify and critically discuss the literature concerning the site(s) of putative neural adaptations to short-term resistance training. The proliferation of studies employing non-invasive stimulation techniques to investigate evoked responses have yielded variable results, but generally support the notion that resistance training alters intracortical inhibition. Nevertheless, methodological inconsistencies and the limitations of techniques, e.g. limited relation to behavioural outcomes and the inability to measure volitional muscle activity, preclude firm conclusions. Much of the literature has focused on the corticospinal tract; however, preliminary research in non-human primates suggests reticulospinal tract is a potential substrate for neural adaptations to resistance training, though human data is lacking due to methodological constraints. Recent advances in technology have provided substantial evidence of adaptations within a large motor unit population following resistance training. However, their activity represents the transformation of afferent and efferent inputs, making it challenging to establish the source of adaptation. Whilst much has been learned about the nature of neural adaptations to resistance training, the puzzle remains to be solved. Additional analyses of motoneuron firing during different training regimes or coupling with other methodologies (e.g., electroencephalography) may facilitate the estimation of the site(s) of neural adaptations to resistance training in the future.
... Aerobic exercise (AE) is one example of movement-based priming that can promote generalized excitability of the primary motor cortex (M1) (Singh and Staines 2015). Recent studies using transcranial magnetic stimulation (TMS) in healthy individuals demonstrate that a single bout of AE facilitates neuroplasticity of the upper extremity M1 via an increase in CME (Opie and Semmler 2019) and intracortical facilitation (ICF) (Singh et al. 2014), and/or by a decrease in short interval intracortical inhibition (SICI) (Singh et al. 2014;Smith et al. 2014) and long interval intracortical inhibition (LICI) (Mooney et al. 2016), or an increase in transcallosal inhibition (TCI) (Neva et al. 2017). ...
Article
Aerobic exercise (AE) and transcranial direct current stimulation (tDCS) are priming techniques that have been studied for their potential neuromodulatory effects on corticomotor excitability (CME); however, the synergistic effects of AE and tDCS are not explored in stroke. Here we investigated the synergistic effects of AE and tDCS on CME, intracortical and transcallosal inhibition, and motor control for the lower limb in stroke. Twenty-six stroke survivors participated in 3 sessions: tDCS, AE, and AE+tDCS. AE included moderate-intensity exercise and tDCS included 1 mA of anodal tDCS to the lower limb motor cortex with or without AE. Outcomes included measures of CME, short-interval intracortical inhibition (SICI), ipsilateral silent period (iSP) (an index of transcallosal inhibition) for the tibialis anterior, and ankle reaction time. Ipsilesional CME significantly decreased for AE compared with AE+tDCS and tDCS. No differences were noted in SICI, iSP measures, or reaction time between all 3 sessions. Our findings suggest that a combination of exercise and tDCS, and tDCS demonstrate greater excitability of the ipsilesional hemisphere compared with exercise only; however, these effects were specific to the descending corticomotor pathways. No additive priming effects of exercise and tDCS over tDCS was observed. Novelty: An exercise and tDCS paradigm upregulated the descending motor pathways from the ipsilesional lower limb primary motor cortex compared with exercise. Exercise or tDCS administered alone or in combination did not affect intracortical or transcallosal inhibition or reaction time.
... The possible mechanism includes an increase in neurotransmitter activity, increased metabolism and increases in brain-derived neurotrophic factor Brain Sci. 2020, 10, 663 7 of 11 in the cerebral cortex [71]. It is possible, therefore, that the decrease in the N30 SEP peak amplitude found in the current study reflects changes in the primary motor area, premotor area, prefrontal cortex, primary sensory cortex, basal ganglia and/or thalamus associated with these neurotransmitter systems [20,26,27,[29][30][31]. ...
Article
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Mild cognitive impairment (MCI) is becoming a serious problem for developing countries as the lifespan of populations increases. Exercise is known to be clinically beneficial for MCI patients. Somatosensory-evoked potentials (SEPs) may be a potential diagnostic and prognostic marker for this population. The objective of this study was to determine the acute effects of aerobic exercise on SEPs in patients with MCI, to test whether SEPs are sensitive enough to detect improvements in early somatosensory processing. The study had a randomized parallel-group design and included 28 MCI subjects (14 in the experimental group and 14 in the control group). The experimental intervention was 20 min of aerobic exercise using a stationary bicycle. The control intervention involved 20 min of movements and stretches. Subjects were assessed before and after a single intervention session. SEPs were recorded by stimulating the median nerve of the dominant hand. Analysis of normalized SEP peak amplitudes showed that a single session of aerobic activity significantly reduced the N30 peak at the F3 channel (p = 0.03). There were no significant effects of aerobic exercise on SEP peak latencies. The results indicate that 20 min of aerobic exercise has a significant effect on the N30 SEP peak amplitude in MCI patients. The results suggest that aerobic exercise is likely to provide sensory-enriching inputs that enhance sensorimotor integration. Future studies should assess the effects of aerobic exercise on somatosensory processing in progressive stages of Alzheimer's disease, longer exercise durations, and multiple exercise sessions.
... This condition induces a more significant challenge in the creation of synergies for interlimb coordination 35 . We suppose that aerobic exercise can facilitate this mechanism by providing excitability in the motor cortex 36 . This condition probably may impact the movement pattern positively during the motor learning processes. ...
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Aims: This study aimed to investigate the effects of aerobic exercise on the learning of a sports motor skill. Methods: Forty individuals were allocated to the Practice + Exercise Group (PEG) and for the Practice Group (PG). All participants practiced the underhand serve of the Volleyball; all of them were naïve regarding the motor task. The participants (age/ years: PEG: 21.7 ± 3.06, PG: 20.25 ± 1.95) performed a pre-test with five trials, an acquisition phase with fifteen blocks/ 5 trials each, a post-test with five trials, and a twenty-four hours retention test composted by five trials. The PEG was submitted to an aerobic exercise session immediately after the acquisition phase. It was provided by running around the sports court, for 20 minutes, with an intensity of 85% of the máx heart rate. The PG rest after the acquisition phase. The score and variable errors were the dependent variables. For the motor improvement during the practice, the Anova two way followed by Tukey posthoc test was run, for the retention test was used a T-test, an alpha of 5% was adopted. Results: All groups increased their score through the practice, with no significant difference between them. In the retention test, the PEG demonstrated better motor performance than PG; it may be related to improvements in the consolidation mechanisms induced by aerobic exercise. Conclusion: The aerobic exercise may be a neuromodulatory strategy to enhance the learning of complex motor skills.
... • There is accumulating evidence that exercise can improve many physiological processes in the body, including neurophysiology, suggesting it as a potential alternative form of medical treatment for over 26 chronic diseases [1]. • There is evidence that exercise can cause beneficial plasticity changes in the sensorimotor systems of the brain [2][3][4]. • Plasticity changes in sensorimotor neurophysiology could explain the beneficial effects of exercise on movement in people with neurological disorders such as Stroke [5] and Parkinson's disease (PD) [6,7] and even aging [8] that have considerable motor impairments related to their disease process. • Recently, research has found evidence that exercising at higher intensities or forced exercise may be more beneficial than traditional moderate forms of exercise for PD symptoms [9,10]. ...
Poster
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Graded exercise testing (GXT) may cause neurophysiological changes in the primary motor cortex (M1) related to fatigue and/or plasticity. Investigating M1 inhibitory circuit changes over time in exercising and non-exercising muscles after GXT of the upper limbs (UL) and lower limbs (LL) may distinguish between different post-exercise mechanisms. PURPOSE: To evaluate M1 inhibitory circuit changes resulting from UL and LL GXT and determine their associations with fitness. METHODS: Six healthy subjects (30 ± 6 yrs) participated. Transcranial Magnetic Stimulation (TMS), Peripheral Nerve Stimulation (PNS), Electromyography (EMG) were used for neurophysiological testing. Gas analysis was performed to evaluate VO2max (UL: 24.2 ± 4.8, LL: 35.1 ± 5.9 mL/kg/min) during GXT. Surface electrodes were placed over the first dorsal interosseous (FDI) and tibialis anterior (TA) muscles. Measures of M1-related afferent inhibition included cortical silent period (CSP) and short-latency afferent inhibition (SAI). SAI inter-stimulus intervals (ISI) stimulations were 21-23ms (UL), and 32-35ms (LL). TMS coil orientation (CO) was altered between posterior-anterior (PA) and anterior-posterior (AP) for both measures. CSP and SAI were taken 0-45 min (POST1) and 45-90 min (POST2) post-exercise and compared to pre-exercise. Repeated measures ANOVAs were performed to evaluate effects of exercise type, CO, time, and ISI. RESULTS: CSP decreased at POST1 and increased at POST2 in FDI (97.9 ± 1.2% vs. 104.5 ± 2.5%, p < 0.05) with a trend toward significance in TA (99.3 ± 2.5% vs. 103.5 ± 4.9%, p = 0.19). Although SAI was found for the TA at 32ms (p<0.05) and FDI at 21-23ms (p < 0.05), exercise type, CO, and ISI interactions did not reach significance (FDI: p = 0.10, TA: p = 0.10). Univariate linear regression of VO2max and SAI revealed a potential relationship reliant on exercise type and CO (UL: R2 = 0.91, LL: R2 = 0.68). CONCLUSIONS: Changes in CSP suggest that exercise may cause early disinhibition followed by greater inhibition in M1 while changes in SAI may be influenced by fitness levels.
... corticospinal excitability) level of brain organization has been proposed to be highly intensity-dependent (e.g. Dinoff et al., 2017;McMorris et al., 2008;Singh and Staines, 2015). ...
Article
High-intensity cardiovascular exercise prior to motor skill practice is postulated to enhance motor memory consolidation (offline learning), whereas moderate-intensity bouts may benefit skill acquisition (online learning). This study aimed at investigating this suggested intensity-dependent effect of exercise in a complex whole-body task. 50 healthy young adults were randomized into one of three groups performing a bout of either 1) high-intense, 2) moderate-intense, or 3) minimal-intense cycling for a total of 17 minutes immediately prior to skill practice. The motor task required participants to balance on a tiltable platform (stabilometer) for 30 seconds. During acquisition 15 practice trials were carried out, followed by a retention test 24 hours later. Time in balance was calculated for each trial and within- and between-group differences in online (skill improvement during skill acquisition) and offline learning (skill change from last acquisition block to retention) were analyzed. All participants significantly improved balance time during acquisition, with no differences observed between experimental conditions. Similarly, there were no differences in offline learning between groups. Contrary to previous reports, the present data do not support an intensity-dependent effect on motor learning, when exercise is performed prior to task practice. One reason for this might be that similar muscle groups were involved in exercise and the motor task, potentially causing fatigue or interference effects. Further, the results indicate that the memory-promoting effects of acute exercise are task-dependent and may not apply equally for motor skills of different levels of complexity.
... Consequently, these results indicated that after exercise, reduced neural excitability in these areas was required to perform the fixed force handgrip task. As discussed in Dal Maso et al., the observed decrease in ERD could also be indicative of a reduction in gamma-aminobutyric acid (GABA) inhibitory activity due to exercise (Singh and Staines, 2015). Given that the task was a visuomotor one, we also expected changes in the visual areas. ...
Article
Full-text available
Cardiovascular exercise is known to promote the consolidation of newly acquired motor skills. Previous studies seeking to understand the neural correlates underlying motor memory consolidation that is modulated by exercise, have relied so far on using traditional statistical approaches for a priori selected features from neuroimaging data, including EEG. With recent advances in machine learning, data-driven techniques such as deep learning have shown great potential for EEG data decoding for brain-computer interfaces, but have not been explored in the context of exercise. Here, we present a novel Convolutional Neural Network (CNN)-based pipeline for analysis of EEG data to study the brain areas and spectral EEG measures modulated by exercise. To the best of our knowledge, this work is the first one to demonstrate the ability of CNNs to be trained in a limited sample size setting. Our approach revealed discriminative spectral features within a refined frequency band (27–29 Hz) as compared to the wider beta bandwidth (15–30 Hz), which is commonly used in data analyses, as well as corresponding brain regions that were modulated by exercise. These results indicate the presence of finer EEG spectral features that could have been overlooked using conventional hypothesis-driven statistical approaches. Our study thus demonstrates the feasibility of using deep network architectures for neuroimaging analysis, even in small-scale studies, to identify robust brain biomarkers and investigate neuroscience-based questions.
... 7,8 There is evidence in the animal and human literature to suggest that aerobic exercise (AE) training may have a role in facilitating neuroplasticity. [9][10][11][12][13] Animal models of stroke indicate that moderate-to high-intensity AE training primes the central nervous system (CNS) by creating a neural response that facilitates plasticity, thereby optimizing motor recovery. 7,[13][14][15][16] Accumulating data suggest AE leads to an upregulation of brain-derived neurotrophic factor (BDNF), a neurotrophin that has been implicated as a mediator of motor recovery after stroke. ...
Article
Full-text available
Background. The recovery of motor function following stroke is largely dependent on motor learning–related neuroplasticity. It has been hypothesized that intensive aerobic exercise (AE) training as an antecedent to motor task practice may prime the central nervous system to optimize motor recovery poststroke. Objective. The objective of this study was to determine the differential effects of forced or voluntary AE combined with upper-extremity repetitive task practice (RTP) on the recovery of motor function in adults with stroke. Methods. A combined analysis of 2 preliminary randomized clinical trials was conducted in which participants (n = 40) were randomized into 1 of 3 groups: (1) forced exercise and RTP (FE+RTP), (2) voluntary exercise and RTP (VE+RTP), or (3) time-matched stroke-related education and RTP (Edu+RTP). Participants completed 24 training sessions over 8 weeks. Results. A significant interaction effect was found indicating that improvements in the Fugl-Meyer Assessment (FMA) were greatest for the FE+RTP group ( P = .001). All 3 groups improved significantly on the FMA by a mean of 11, 6, and 9 points for the FE+RTP, VE+RTP, and Edu+RTP groups, respectively. No evidence of a treatment-by-time interaction was observed for Wolf Motor Function Test outcomes; however, those in the FE+RTP group did exhibit significant improvement on the total, gross motor, and fine-motor performance times ( P ≤ .01 for all observations). Conclusions. Results indicate that FE administered prior to RTP enhanced motor skill acquisition greater than VE or stroke-related education. AE, FE in particular, should be considered as an effective antecedent to enhance motor recovery poststroke.
... Studies with various species have revealed clear adaptations in brain regions such as the hippocampus (HP) following long term exercise interventions. Furthermore, even acute (≈ 20 min) bouts of moderately intense exercise can have a transient modulatory influence on excitability in the human motor cortex (Thacker et al., 2014;Singh and Staines, 2015;Neva et al., 2017). Exercise dependent changes in excitability may be indicative of a "primed" state allowing motor regions to more readily facilitate the acquisition of a novel skill (Roig et al., 2012;McDonnell et al., 2013;Stavrinos and Coxon, 2014;Statton et al., 2015); however, the biochemical changes caused by a single session of exercise remain relatively unexplored. ...
Article
A single session of aerobic exercisemay offer one means to “prime” motor regions to bemore receptive to the acquisition of a motor skill; however, the mechanisms whereby this priming may occur are not clear. One possible expla- nation may be related to the post-translational modification of plasticity-related receptors and their associated intracellu- lar signaling molecules, given that these proteins are integral to the development of synaptic plasticity. In particular, phosphorylation governs the biophysical properties (e.g., Ca2+ conductance) and the migratory patterns (i.e., trafficking) of plasticity-related receptors by altering the relative density of specific receptor subunits at synapses. We hypothesized that a single session of exercise would alter the subunit phosphorylation of plasticity-related receptors (AMPA receptors, NMDA receptors) and signalingmolecules (PKA, CaMKII) in amanner that would serve to primemotor cortex. Young, male Sprague–Dawley rats (n = 24) were assigned to either exercise (Moderate, Exhaustion), or non-exercising (Sedentary) groups. Immediately following a single session of treadmill exercise, whole tissue homogenates were prepared fromboth the motor cortex and hippocampus. We observed a robust (1.2–2.0× greater than sedentary) increase in tyrosine phos- phorylation ofAMPA (GluA1,2) and NMDA (GluN2A,B) receptor subunits, and a clear indication that exercise preferentially affects pPKA over pCaMKII. The changes were found, specifically, following moderate, but not maximal, acute aerobic exercise in bothmotor cortex and hippocampus. Given the requirement for these proteins during the early phases of plas- ticity induction, the possibility exists that exercise-induced priming may occur by altering the phosphorylation of plasticity-related proteins.
... L'analyse de la littérature ayant investigué l'effet de l'exercice sur l'excitabilité du cortex moteur par utilisation de la technique de Stimulation Magnétique Transcrânienne (« Transcranial Magnetic Stimulation », TMS), indique que cette augmentation de l'excitabilité corticale serait potentiellement liée par une diminution de l'inhibition intracorticale, indiquée sur l'électromyogramme par une réduction de la période de silence corticale . Les modifications neurochimiques induites par l'exercice notamment l'augmentation de la libération de DA et NA fourniraient une explication potentielle à cette augmentation de l'excitabilité du cortex moteur (Singh et Staines 2015). ...
Thesis
Dans de nombreuses activités physiques et sportives, la performance dépend de l’efficacité des processus physiologiques et cognitifs sollicités dans l’action. Plus précisément, il semblerait que celle-ci soit fréquemment influencée par l’efficacité des processus décisionnels qui s’effectuent sous pression temporelle. A ce titre, ce travail de thèse s’intéresse à l’effet de l’administration de trois supplémentations nutritionnelles classiquement consommées par les athlètes (hydrates de carbone, caféine et guarana) sur le fonctionnement cognitif au cours d’un exercice. Nos résultats indiquent que l’ingestion isolée de ces trois composés améliore la vitesse du traitement de l’information lors d'une tâche décisionnelle dès la fin d’un exercice. Par ailleurs, l’utilisation de la caféine en rinçage de bouche semble aussi pertinente, puisque nos résultats suggèrent une amélioration probable de l’efficacité des processus relatifs à la gestion d’un conflit au cours de l’exercice. Enfin, une diminution de la perception de l’effort est aussi rapportée lors de l’ingestion de caféine et de guarana, ou de l’utilisation d’hydrates de carbone en rinçage de bouche. L’ensemble de ces résultats indique une potentialisation de l’effet de l’exercice sur la performance cognitive. Il suggère aussi que la mise en place de supplémentations nutritionnelles lors d’un exercice améliore l’efficacité de processus cognitifs qui s’avèrent être essentiels à la performance sportive.
... Most studies have incorporated resistance training and/or range of motion and stretching exercises primarily in home-based programs. More recently, aerobic exercise training (AET) is being explored as a therapeutic intervention for improving cognitive function and relearning of complex motor skills, due to its ability to facilitate neuronal excitability and neuroplasticity in healthy individuals and those with neurological disorders [21][22][23][24][25][26]. AET has also been explored by few studies in ALS [16,19,20,27]. ...
Article
Objectives Aerobic exercise can promote neuroplastic responses in the healthy and injured brain. Although the role of exercise in amyotrophic lateral sclerosis (ALS) is debated, new evidence suggests that exercise may reduce disease progression. While common exercise modalities such as the treadmill and cycle ergometer have been explored in ALS, the safety and feasibility of a total body recumbent stepper have not been investigated. Additionally, the functional and neurophysiological effects of recumbent stepping in ALS are still unknown. Here, we investigated the safety and feasibility of a 4-week recumbent stepping program to slow disease progression in ALS and possibly facilitate neuroplasticity. Method Nine individuals with ALS performed moderate intensity recumbent stepping for four weeks. Outcomes included participation satisfaction questionnaire, ALS Functional Rating Scale Revised (ALSFRS-R), clinical tests of walking and endurance, fatigue severity scale, Beck depression inventory, SF-12, and transcranial magnetic stimulation-induced motor evoked potentials (MEPs). All measurements were collected at baseline, post-intervention, and at the 1-month follow-up. Results Eight participants completed the study without any adverse events. The ALSFRS-R scores were similar at the end of the study and at follow-up. No significant differences were noted for any of the clinical outcomes. MEPs were present only in two participants and changes in corticomotor excitability after exercise were minimal. Conclusions Results from this preliminary study support the safety and feasibility of 12 sessions of total body recumbent stepping in individuals with ALS.
... Induction of LTP in the motor cortex is strongly dependent on the reduction of GABAergic transmissions, as evidenced by Hess and Donoghue [7] who showed in rats that LTP occurred following TBS when bicuculline, an antagonist of GABA-A receptors, was applied prior to stimulation. In humans, physical exercise is also accompanied by the reduction of short latency intracortical inhibition (SICI) [14][19], a mechanism which depends on GABA-A receptors [5] and this lowering of GABA inhibition has been suggested to participate, at least in part, in the increase of NIBS-induced plasticity following exercise (for a review see [16]). ...
... Mental engagement is purported to be greatest when individuals attempt to learn new skills or perform novel tasks (Thayer, Hansen, Saus-Rose, & Johnsen, 2009). As suggested by Singh and Staines (2015) and Thacker, Middleton, Mcllroy, and Staines (2014), there may be a balance between physiological arousal and task complexity during bouts of acute exercise that is sufficient to promote neurological adaptations that underlie mental engagement and learning. The lack of agreement with previous studies that have examined the roles of arousal and task complexity may be due to the type of exercise task employed. ...
Article
Full-text available
The role of acute bouts of exercise on young adults' psychomotor learning was assessed in two experiments. In Experiment 1, 10 min of exercise performed immediately following pursuit-rotor training improved retention of tracking movements, but only when measured 7 days following encoding and only under exercise conditions that required complex decisions. In Experiment 2, 10 min of exercise performed immediately prior to encoding resulted in a retention pattern similar to that seen in Experiment 1; however, performance did not differ significantly between exercise and control groups. In both experiments, retention of motor movement was greater when measured 24 hr and 7 days after training, as opposed to immediately following encoding. The mnemonic benefits of moderately vigorous complex physical activity appear to assist a motor memory trace to transform from a fragile to a more persistent state.
... corticospinal excitability) level of brain organization has been proposed to be highly intensity-dependent (e.g. Dinoff et al., 2017;McMorris et al., 2008;Singh and Staines, 2015). ...
Conference Paper
INTRODUCTION: Recent evidence suggests that single bouts of aerobic exercise performed in close proximity to motor practice can enhance skill acquisition and consolidation (Roig et al., 2016). High-intensity bouts have been suggested to be particularly effective in improving consolidation (Roig et al., 2012). However, to date this has only been demonstrated for fine motor skills. Further, high-intensity exercise may interfere with skill acquisition, and is not practicable in all settings. Thus, the aim of this study was to investigate the effects of aerobic exercise i) carried out immediately prior to motor practice, and ii) performed at different exercise intensities on learning a novel balancing task. METHODS: 35 healthy young adults (age: 25.57 ± 2.66; BMI: 22.99 ± 2.15) were allocated after stratified block randomization to one of three groups performing either 1) high intensity interval exercise at 90%/60% Wmax (EX-H; n = 10), 2) moderate-intensity interval exercise at 45%/25% Wmax (EX-M; n = 12), or 3) continuous minimal-intense exercise at 25 W (CON; n = 13). All groups exercised on a cycle ergometer for a total of 17 min immediately prior to practicing a novel motor skill. The task required participants to stand on a tiltable (20°) wooden platform (stabilometer), and to stabilize it in a horizontal position for 30 seconds. For each experimental condition, subjects performed 15 trials (3 blocks of 5 trials), followed by a retention test (2 trials) 24 hours later. Time in balance (platform within ±5° from horizontal) and average angular deviation from horizontal (RMSE) were calculated for each trial. Within- and between-group changes over time were tested using repeated measures ANOVA. RESULTS: On acquisition day, all participants significantly improved balance time (+34.7%; TIME main effect: F14,270 = 17.8; p < .001) and RMSE (-56.2%; TIME main effect: F14,277 = 28.2; p < .001), with no differences observed between experimental conditions. At retention, all groups demonstrated sustained performance (change from last two acquisition trials to retention) in balance time (F1,32 = 0.86; p = 0.360), with no significant group differences (F2,32 = 0.87; p = 0.434). For RMSE, performance significantly worsened only in the EX-H group (+13.6%; p = 0.008), and a similar tendency existed in the CON group (+9.16%; p = 0.067). CONCLUSION: Motor skill acquisition was not improved by aerobic exercise, irrespective of exercise intensity. Interestingly, a trend existed for improved consolidation by moderate-intense cycling. The present findings do not confirm the positive effects of high intensity aerobic exercise on motor learning, when exercise is performed immediately prior to motor learning. REFERENCES: Roig, M., Skriver, K., et al. (2012). PloS one, 7(9), e44594. Roig, M., Thomas, R., et al. (2016). Exercise and sport sciences reviews, 44(2), 81–88.
... 31,32 Moreover, previous studies performed in human and animal models have demonstrated the role of physical exercises as a stimulating factor of neural plasticity by the increase of brain-derived neurotrophic factor (BDNF) levels, axonal regeneration, and the promotion of long-term potentiation (LTP)-like plasticity in the motor cortex. [33][34][35][36] Also, physical exercise has been proven to provide beneficial effects in the cerebellar mitochondrial bioenergetics systems of rats, 37 and this could be used as a model for a therapeutic approach for SCA2 patients in which the bioenergetic deficits caused by the ataxin-2 mutation 38-40 could be alleviated. ...
Article
Background: Neurorehabilitation has become in a widely used approach in spinocerebellar ataxias, but there are scarce powerful clinical studies supporting this notion. Objective: The objective of this study was to assess the efficacy of a 24‐week neurorehabilitative treatment in spinocerebellar ataxia type 2 patients. Methods: A total of 38 spinocerebellar ataxia type 2 patients were enrolled in a rater‐blinded, 1:1 randomized, controlled trial using neurorehabilitation for 24 weeks. The treated group received 6 hours of neurorehabilitation therapy, emphasizing on balance, coordination, and muscle strengthening on weekdays, whereas the control group did not receive this intervention. Primary outcome measure was the Scale for the Assessment and Rating of Ataxia score, whereas secondary outcome measures included the count of Inventory of Non‐Ataxia Symptoms and saccadic eye movement variables. Results: The rehabilitated group had high levels of adherence and retention to the therapy and showed a significant decrease of Scale for the Assessment and Rating of Ataxia score at 24 weeks when compared with the controls, mainly for the gait, stance, sitting, finger chase, and heel‐shin test items. Changes in Scale for the Assessment and Rating of Ataxia scores were inversely correlated with the mutation size in the rehabilitated group. The nonataxia symptom count and saccadic measures were unchanged during the study. Conclusions: A comprehensive 24‐week rehabilitation program significantly improves the motor cerebellar symptoms of spinocerebellar ataxia type 2 patients as assessed by the ataxia rating score likely as result of the partial preservation of motor learning and neural plasticity mechanisms. These findings provide evidence in support of this therapeutic approach as palliative treatment in spinocerebellar ataxia type 2 suggesting its use in combination with other symptomatic or neuroprotective drugs and in prodromal stages. © 2018 International Parkinson and Movement Disorder Society
... To date, metabolic explanations have constituted the most accomplished rationale for this inhibitory process (Piepmeier & Etnier, 2015;Singh & Staines, 2015; see also McMorris & Hale, 2012;McMorris et al., 2016 for mechanistic reviews). Apart from these propositions, however, recent research provides neurofunctional insights into the possible role of efferent and/or afferent mechanisms in executive functioning decline during exercise. ...
Article
Full-text available
Despite emotional, technical and endurance implications for athletes’ performance, a consensus has yet to be reached to explain the impairment of executive functioning during exercise. In particular, recent research challenges the original assumption of a linear dose–response effect of exercise intensity on cerebral physiology and executive functioning. We propose a fatigue-based neurocognitive perspective of executive functioning during prolonged exercise, suggesting that top-down (cognitive and physical efforts) and bottom-up processes (body sensations) act in parallel of arousing mechanisms to determine cognitive outcomes. In this perspective, executive functioning during prolonged exercise would be dynamical rather than steady (i.e. positively then negatively impacted by exercise) and would be to analyse in regards of exercise termination rather than of exercise intensity.
... 67 Cardiovascular exercise also promotes changes within the primary motor cortex (M1), a key target area to improve motor recovery following a stroke. 68 Even a single bout of cardiovascular exercise activates neuroplastic mechanisms responsible for motor learning. 69 Intensity has been shown to be critical in modulating the neuroplastic and motor learning effects of cardiovascular training in healthy individuals. ...
Article
Introduction: Stroke is the leading cause of adult disability. Individuals poststroke possess less than half of the cardiorespiratory fitness (CRF) as their nonstroke counterparts, leading to inactivity, deconditioning, and an increased risk of cardiovascular events. Preserving cardiovascular health is critical to lower stroke risk; however, stroke rehabilitation typically provides limited opportunity for cardiovascular exercise. Optimal cardiovascular training parameters to maximize recovery in stroke survivors also remains unknown. While stroke rehabilitation recommendations suggest the use of moderate-intensity continuous exercise (MICE) to improve CRF, neither is it routinely implemented in clinical practice, nor is the intensity always sufficient to elicit a training effect. High-intensity interval training (HIIT) has emerged as a potentially effective alternative that encompasses brief high-intensity bursts of exercise interspersed with bouts of recovery, aiming to maximize cardiovascular exercise intensity in a time-efficient manner. HIIT may provide an alternative exercise intervention and invoke more pronounced benefits poststroke. Objectives: To provide an updated review of HIIT poststroke through ( a) synthesizing current evidence; ( b) proposing preliminary considerations of HIIT parameters to optimize benefit; ( c) discussing potential mechanisms underlying changes in function, cardiovascular health, and neuroplasticity following HIIT; and ( d) discussing clinical implications and directions for future research. Results: Preliminary evidence from 10 studies report HIIT-associated improvements in functional, cardiovascular, and neuroplastic outcomes poststroke; however, optimal HIIT parameters remain unknown. Conclusion: Larger randomized controlled trials are necessary to establish ( a) effectiveness, safety, and optimal training parameters within more heterogeneous poststroke populations; (b) potential mechanisms of HIIT-associated improvements; and ( c) adherence and psychosocial outcomes.
... Second, these findings provide support for the claim of independence of the concatenation and execution processes central to Abrahamse et al.'s (2013) model thus lending further credence to the viability of this account for the production of sequential behaviors (De Kleine & Verwey, 2009a, b;Verwey, Abrahamse, & Jimenez, 2009). Finally, some discussion has occurred regarding a role for exercise on M1 plasticity or at least circuits involving this neural region in terms of supporting offline gain (Breton & Robertson, 2014;Singh & Staines, 2015;Stavrinos & Coxon, 2017). The finding that exercise exerts its influence on execution time, the component process most intimately linked to the motor rather than the cognitive processor in Abrahamse et al.'s model, seems congruent with the notion that the motor processor is most likely instantiated in motor areas, especially M1, within the neural architecture. ...
Article
Full-text available
Numerous studies have reported a positive impact of acute exercise for procedural skill memory. Previous work has revealed this effect, but these findings are confounded by a potential contribution of a night of sleep to the reported exercise-mediated reduction in interference. Thus, it remains unclear if exposure to a brief bout of exercise can provide protection to a newly acquired motor memory. The primary objective of the present study was to examine if a single bout of moderate intensity cardiovascular exercise after practice of a novel motor sequence reduces the susceptibility to retroactive interference. To address this shortcoming, seventeen individuals in a control condition practiced a novel motor sequence that was followed by test after a 6-hr wake-filled interval. A separate group of seventeen individuals experienced practice with an interfering motor sequence 45-min after practice with the original sequence and were then administered test trials 6-hr later. One additional group of twelve participants was exposed to an acute bout of exercise immediately after practice with the original motor sequence but prior to practice with the interfering motor sequence and the subsequent test. In comparison to the control condition, increased response times were revealed during the 6-hr test for the individuals that were exposed to interference. The introduction of an acute bout of exercise between the practice of the two motor sequences produced a reduction in interference from practice with the second task at the time of test, however, this effect was not statistically significant. These data reinforce the hypothesis that while there may be a contribution from exercise to post-practice consolidation of procedural skills which is independent of sleep, sleep may interact with exercise to strengthen the effects of the latter on procedural memory.
... 67 Cardiovascular exercise also promotes changes within the primary motor cortex (M1), a key target area to improve motor recovery following a stroke. 68 Even a single bout of cardiovascular exercise activates neuroplastic mechanisms responsible for motor learning. 69 Intensity has been shown to be critical in modulating the neuroplastic and motor learning effects of cardiovascular training in healthy individuals. ...
Conference Paper
Introduction: Stroke is the leading cause of adult disability. Individuals post-stroke possess less than half of the cardiorespiratory fitness (CRF) as their non-stroke counterparts, leading to inactivity, deconditioning and an increased risk of future cardiovascular events. Preserving cardiovascular health is critical to lower recurrent stroke risk, however, stroke rehabilitation typically provides limited opportunity for cardiovascular exercise. Optimal cardiovascular training parameters to maximize recovery in stroke survivors also remains unknown. While stroke rehabilitation guidelines suggest the use of moderate-intensity continuous exercise (MICE) to improve CRF, it is not always routinely implemented in clinical practice, nor is the intensity always sufficient to elicit a significant training effect. High-intensity interval training (HIIT) has emerged as a potentially effective alternative which encompasses brief high-intensity bursts of exercise interspersed with bouts of recovery, aiming to maximize cardiovascular exercise intensity in a time efficient manner. HIIT may provide an alternative exercise intervention and invoke more pronounced benefits. Objectives: To provide a clinical perspective of HIIT post-stroke through 1) synthesizing current evidence, 2) proposing preliminary considerations of HIIT parameters to optimize benefit, 3) discussing potential mechanisms underlying improvements in outcomes following HIIT, and 4) discussing clinical implications and directions for future research. Results: Preliminary evidence from 10 studies report HIIT-associated improvements in functional, cardiovascular and neuroplastic outcomes post-stroke; however, optimal HIIT parameters remain largely unknown. Conclusion: Larger randomized controlled trials are necessary to establish 1) the effectiveness, safety and optimal training parameters within more heterogeneous post-stroke populations, 2) potential mechanisms and 3) adherence and psychosocial outcomes. Key Words: High-Intensity Interval Training, Stroke, Cardiovascular Health, Neuroplasticity, Stroke Recovery.
Preprint
Full-text available
The optimization of mental practice (MP) protocols matters for sport and motor rehabilitation. In this study, we were interested in the benefits of aerobic exercise in MP, given its positive effects on the acquisition and consolidation of motor skills induced by physical practice (PP). Four experimental groups were tested: i) physical practice without exercise (PP-Rest), ii) mental practice without exercise (MP-Rest), iii) mental practice preceded by Exercise (Exe- MP), and iv) mental practice followed by Exercise (MP-Exe). We hypothesized that exercise before MP would potentiate motor acquisition, whereas exercise after MP would further promote motor consolidation. Motor performance (movement speed and accuracy) was measured during a sequential finger tapping task before (Pre-Test), immediately after (Post- Test 0h, acquisition), and one day after practice (Post-Test 24h, consolidation). Results suggest that exercise before MP did not additionally improve motor acquisition in comparison to the MP-Rest group. Interestingly, aerobic exercise after MP further increased performance during motor consolidation, at the level of the PP-Rest group. This novel finding represents a promising advance in the optimization of mental practice protocols in sport-related and rehabilitation settings.
Article
Background and purpose: Improved walking function is a priority among persons with motor-incomplete spinal cord injury (PwMISCI). Accessibility and cost limit long-term participation in locomotor training offered in specialized centers. Intensive motor training that facilitates neuroplastic mechanisms that support skill learning and can be implemented in the home/community may be advantageous for promoting long-term restoration of walking function. Additionally, increasing corticospinal drive via transcranial direct current stimulation (tDCS) may enhance training effects. In this pilot study, we investigated whether a moderate-intensity motor skill training (MST) circuit improved walking function in PwMISCI and whether augmenting training with tDCS influenced outcomes. Methods: Twenty-five adults (chronic, motor-incomplete spinal cord injury) were randomized to a 3-day intervention of a locomotor-related MST circuit and concurrent application of sham tDCS (MST+tDCSsham) or active tDCS (MST+tDCS). The primary outcome was overground walking speed. Secondary outcomes included walking distance, cadence, stride length, and step symmetry index (SI). Results: Analyses revealed significant effects of the MST circuit on walking speed, walking distance, cadence, and bilateral stride length but no effect on interlimb SI. No significant between-groups differences were observed. Post hoc analyses revealed within-groups change in walking speed (ΔM = 0.13 m/s, SD = 0.13) that app-roached the minimally clinically important difference of 0.15 m/s. Discussion and conclusions: Brief, intensive MST involving locomotor-related activities significantly increased walking speed, walking distance, and spatiotemporal measures in PwMISCI. Significant additive effects of tDCS were not observed; however, participation in only 3 days of MST was associated with changes in walking speed that were comparable to longer locomotor training studies.Video Abstract available for more insights from the authors (see the Video, Supplemental Digital Content 1, available at: http://links.lww.com/JNPT/A386).
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Regular physical activity is associated with enhanced plasticity in the motor cortex but the effect of a single session of aerobic exercise on neuroplasticity is unknown. The aim of this study was to compare corticospinal excitability and plasticity in the upper limb cortical representation following a single session of lower limb cycling at either low or moderate intensity, or a control condition. We recruited 25 healthy adults to take part in three experimental sessions. Cortical excitability was examined using transcranial magnetic stimulation to elicit motor evoked potentials (MEPs) in the right first dorsal interosseus (FDI) muscle. Levels of serum brain-derived neurotrophic factor (BDNF) and cortisol were also assessed. Following baseline testing, participants cycled on a stationary bike at a workload equivalent to 57% (low intensity, 30 mins) or 77% age-predicted maximal heart rate (moderate intensity, 15 minutes), or a seated control condition. Neuroplasticity within the primary motor cortex was examined using a continuous Theta Burst Stimulation (cTBS) paradigm. We found that exercise did not alter cortical excitability. Following cTBS, there was a transient inhibition of FDI MEPs during control and low intensity conditions but this was only significantly different following the low intensity state. Moderate intensity exercise alone increased serum cortisol levels, but BDNF levels did not increase across any condition. In summary, low intensity cycling promoted the neuroplastic response to cTBS within the motor cortex of healthy adults. These findings suggest that light exercise has the potential to enhance the effectiveness of motor learning or recovery following brain damage.
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Exercise represents a potent physiological stimulus upon the hypothalamo-pituitary-adrenal (HPA) axis. Two major factors modulate the HPA axis response to exercise: intensity and duration of exercise. Endurance training per se does not induce permanent hypercortisolism as endurance-trained subjects have similar biological markers of HPA axis activity in resting condition than healthy sedentary men. However, when the HPA axis is repeatedly challenged by exercise, humans demonstrate modifications in the activity of the HPA axis, suggesting an adaptive process to endurance-training. A great diversity of mechanisms is involved in this adaptation; these mechanisms act potentially at all levels in the cascade, leading to the biological effects of cortisol and decreased tissular sensitivity to glucocorticoids.
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An attempt to find pharmacological therapies to treat stroke patients and minimize the extent of cell death has seen the failure of dozens of clinical trials. As a result, stroke/cerebral ischemia is the leading cause of lasting adult disability. Stroke-induced cell death occurs due to an excess release of glutamate. As a consequence to this, a compensatory increased release of GABA occurs that results in the subsequent internalization of synaptic GABA(A) receptors and spillover onto perisynaptic GABA(A) receptors, resulting in increased tonic inhibition. Recent studies show that the brain can engage in a limited process of neural repair after stroke. Changes in cortical sensory and motor maps and alterations in axonal structure are dependent on patterned neuronal activity. It has been assumed that changes in neuronal excitability underlie processes of neural repair and remapping of cortical sensory and motor representations. Indeed, recent evidence suggests that local inhibitory and excitatory currents are altered after stroke and modulation of these networks to enhance excitability during the repair phase can facilitate functional recovery after stroke. More specifically, dampening tonic GABA inhibition can afford an early and robust improvement in functional recovery after stroke.
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The brain-derived neurotrophic factor (BDNF) Val66Met polymorphism is a common human single nucleotide polymorphism (SNP) that affects the regulated release of BDNF, and has been implicated in affective disorders and cognitive dysfunction. A decreased activation of the infralimbic medial prefrontal cortex (IL-mPFC), a brain region critical for the regulation of affective behaviors, has been described in BDNF(Met) carriers. However, it is unclear whether and how the Val66Met polymorphism affects the IL-mPFC synapses. Here, we report that spike timing-dependent plasticity (STDP) was absent in the IL-mPFC pyramidal neurons from BDNF(Met/Met) mice, a mouse that recapitulates the specific phenotypic properties of the human BDNF Val66Met polymorphism. Also, we observed a decrease in NMDA and GABA receptor-mediated synaptic transmission in the pyramidal neurons of BDNF(Met/Met) mice. While BDNF enhanced non-NMDA receptor transmission and depressed GABA receptor transmission in the wild-type mice, both effects were absent in BDNF(Met/Met) mice after BDNF treatment. Indeed, exogenous BDNF reversed the deficits in STDP and NMDA receptor transmission in BDNF(Met/Met) neurons. BDNF-mediated selective reversal of the deficit in plasticity and NMDA receptor transmission, but its lack of effect on GABA and non-NMDA receptor transmission in BDNF(Met/Met) mice, suggests separate mechanisms of Val66Met polymorphism upon synaptic transmission. The effect of the Val66Met polymorphism on synaptic transmission and plasticity in the IL-mPFC represents a mechanism to account for this impact of SNP on affective disorders and cognitive dysfunction.
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GABA modification plays an important role in motor cortical plasticity. We therefore hypothesized that interindividual variation in the responsiveness of the GABA system to modification influences learning capacity in healthy adults. We assessed GABA responsiveness by transcranial direct current stimulation (tDCS), an intervention known to decrease GABA. The magnitude of M1 GABA decrease induced by anodal tDCS correlated positively with both the degree of motor learning and the degree of fMRI signal change within the left M1 during learning. This study therefore suggests that the responsiveness of the GABAergic system to modification may be relevant to short-term motor learning behavior and learning-related brain activity.
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We present here a comprehensive, neurocognitive model to account for the psychological consequences of acute exercise. There is a substantial amount of disparate research and the proposed mechanistic explanation meaningfully integrates this body of brain and behavioral data into a single, unified model. The model's central feature is a cascading, two-step process. First, exercise engages arousal mechanisms in the reticular-activating system. This activation process, which involves a number of neurotransmitter systems, has several interrelated effects on cognition and emotion but, in general, has evolved to facilitate implicit information processing. Second, exercise disengages the higher-order functions of the prefrontal cortex. This deactivation process, which is caused in part by resource limitations, also has several interrelated effects but, in general, has evolved to keep the inefficient explicit system and unhelpful emotional processes from compromising the implicit system's functioning when optimal motor execution is needed most. In this article, we review evidence in support of this reticular-activating hypofrontality (RAH) model of acute exercise and place it into a larger evolutionary context.
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Transcranial Doppler ultrasound-determined middle (MCA) and anterior (ACA) cerebral artery mean flow velocities (Vmean) and pulsatility indexes (PI) were measured during “no-load” [21, 60, and 102 revolutions/min (rpm)] and loaded cycling (30, 60, and 149 W) at approximately 60 rpm. At rest Vmean MCA was 51 (36–55) cm/s (median and range; n = 10) and Vmean ACA was 41 (36–49) cm/s (n = 7; P < 0.05). With no load on the cycle Vmean MCA increased 4 (2–36), 10 (0–47), and 27% (4–58) (P < 0.05) at the three pedaling frequencies, respectively; arterial PCO2 (PaCO2) remained constant. During loaded cycling the increases were 19 (6–42), 25 (2–45), and 32% (12–67) (P < 0.01), respectively, with only a minimal change in PaCO2. No significant changes were observed in Vmean ACA. Changes in Vmean MCA were similar to those recorded by the initial slope index (ISI) of the 133Xe clearance method (n = 11), which in turn were smaller than increases recorded by the fast-compartment flow. PI ACA followed PI MCA during no-load as well as loaded exercise and increased with work rate, perhaps reflecting an increase in pulse pressure from 56 (48–63) mmHg at rest to 109 (88–123) mmHg at 149 W (P < 0.01). Data demonstrate a graded increase in regional cerebral perfusion during dynamic exercise corresponding to the MCA territory.
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In the present study, participants were randomly assigned to an exercise or a nonexercise group to measure brain activation (spontaneous EEG activity), affect, and cognitive functioning before and after a 15-min treatment period. Exercisers (a) sat quietly for 5 min, (b) exercised for 15 min, (c) recovered for 5 min, and (d) completed a 15-min vigilance task. Nonexercisers did not exercise. There was a significant (a) Condition × Band × Time interaction for EEG activity, (b) Condition × Time interaction for Activation-Deactivation Adjective Checklist (AD ACL) scores, and (c) Condition × Time interaction for reaction times (RTs). Post hoc tests showed (a) no significant group effects at the baseline and 15-min vigilance periods, and (b) significant group effects at the postexercise and 5-min vigilance periods. Exercisers had lower levels of brain activation (i.e., more theta and alpha activity and less beta activity), higher AD ACL scores, and slower RTs than nonexercisers during these periods.
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Following transcranial magnetic stimulation (TMS) at stimulation strength of 1.5 times the resting motor threshold, a silent period (SP) of approximately 180 ms duration can be observed in surface EMG-registrations of tonically activated small hand muscles. This SP is believed to be generated cortically and can be prolonged in stroke patients, but it is not known whether a prolongation of the SP has any functional significance. In order to answer the question of whether enhanced cortical inhibition can contribute to pathophysiology of motor dysfunction we studied stroke patients with clearly prolonged SP durations in the first dorsal interosseus muscle (> 2 times that of the intact side), but with normal magnetically evoked motor potentials. Sixteen patients out of a cohort of 174 consecutive patients presenting with acute hemiparetic stroke fulfilled the inclusion criteria. Serial TMS investigations were performed for up to 2 years post-stroke. In all patients, the SP duration decreased in parallel with clinical improvement. In two patients, intermittent clinical deterioration was accompanied by an increase in the SP duration. In four patients, in addition to a markedly prolonged SP duration, the phenomenon of a complete inability to initiate voluntary muscle activity for several seconds, following TMS, could be observed in a number of trials ('motor arrest'). Detailed clinical analysis revealed that, in addition to hemiparesis, distinct motor disturbances in patients with SP prolongation could be observed. These motor disturbances resembled those of motor neglect and were characterized by motivationally dependent under-utilization of the affected arm, impairment of movement initiation, inability to maintain a constant force level and to scale forces, and impairment of individual finger movements. In 12 of the 16 patients at least one additional behavioural manifestation of neglect was present. We suggest that in stroke patients severe motor dysfunction may be caused by hyperactivity of cortical inhibitory interneurons rather than by direct lesions of descending motor tracts. Cortical hyperinhibition may, in turn, result from damage to any of a number of afferent pathways to the motor cortex which modulate local interneuronal activity.
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The original central fatigue hypothesis suggested that an exercise-induced increase in extracellular serotonin concentrations in several brain regions contributed to the development of fatigue during prolonged exercise. Serotonin has been linked to fatigue because of its well known effects on sleep, lethargy and drowsiness and loss of motivation. Several nutritional and pharmacological studies have attempted to manipulate central serotonergic activity during exercise, but this work has yet to provide robust evidence for a significant role of serotonin in the fatigue process. However, it is important to note that brain function is not determined by a single neurotransmitter system and the interaction between brain serotonin and dopamine during prolonged exercise has also been explored as having a regulative role in the development of fatigue. This revised central fatigue hypothesis suggests that an increase in central ratio of serotonin to dopamine is associated with feelings of tiredness and lethargy, accelerating the onset of fatigue, whereas a low ratio favours improved performance through the maintenance of motivation and arousal. Convincing evidence for a role of dopamine in the development of fatigue comes from work investigating the physiological responses to amphetamine use, but other strategies to manipulate central catecholamines have yet to influence exercise capacity during exercise in temperate conditions. Recent findings have, however, provided support for a significant role of dopamine and noradrenaline (norepinephrine) in performance during exercise in the heat. As serotonergic and catecholaminergic projections innervate areas of the hypothalamus, the thermoregulatory centre, a change in the activity of these neurons may be expected to contribute to the control of body temperature whilst at rest and during exercise. Fatigue during prolonged exercise clearly is influenced by a complex interaction between peripheral and central factors.