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Effects of Motor Mental Imagery Training on Tennis Service Performance during the Ramadan Fasting: a Randomized, Controlled Trial.
Fekih, S, Zguira, MS, Koubaa, A, Masmoudi, L, Bragazzi, NL, Jarraya, M
Nutrients. 2020;(4)
Abstract
The objective of the present study is to analyze the effects of motor mental imagery training on tennis service performance among tennis athletes who fast during Ramadan. Participants were 38 young male tennis players, randomly divided into two groups: Imaging Training (IMG, n = 18) and control group (CG, n = 20). The CG has watched videos on the history of the Olympic Games, while IMG has followed a training program in motor imagery. The performance of the tennis service was obtained by the product between accuracy and speed of typing (accuracy x average speed of all shots (km/h)). The effect of group / time interaction (p < 0.01) was identified for all performance indicators (accuracy, running speed and performance (speed x precision)), with improvement only in IMG (p = 0.01). The results showed that motor imagery training could be an effective strategy for mitigating/counteracting the negative effects of Ramadan on the tennis service performance.
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Effects of daily L-dopa administration on learning and brain structure in older adults undergoing cognitive training: a randomised clinical trial.
Lebedev, AV, Nilsson, J, Lindström, J, Fredborg, W, Akenine, U, Hillilä, C, Andersen, P, Spulber, G, de Lange, ECM, van den Berg, DJ, et al
Scientific reports. 2020;(1):5227
Abstract
Cognitive aging creates major individual and societal burden, motivating search for treatment and preventive care strategies. Behavioural interventions can improve cognitive performance in older age, but effects are small. Basic research has implicated dopaminergic signalling in plasticity. We investigated whether supplementation with the dopamine-precursor L-dopa improves effects of cognitive training on performance. Sixty-three participants for this randomised, parallel-group, double-blind, placebo-controlled trial were recruited via newspaper advertisements. Inclusion criteria were: age of 65-75 years, Mini-Mental State Examination score >25, absence of serious medical conditions. Eligible subjects were randomly allocated to either receive 100/25 mg L-dopa/benserazide (n = 32) or placebo (n = 31) prior to each of twenty cognitive training sessions administered during a four-week period. Participants and staff were blinded to group assignment. Primary outcomes were latent variables of spatial and verbal fluid intelligence. Compared to the placebo group, subjects receiving L-dopa improved less in spatial intelligence (-0.267 SDs; 95%CI [-0.498, -0.036]; p = 0.024). Change in verbal intelligence did not significantly differ between the groups (-0.081 SDs, 95%CI [-0.242, 0.080]; p = 0.323). Subjects receiving L-dopa also progressed slower through the training and the groups displayed differential volumetric changes in the midbrain. No statistically significant differences were found for the secondary cognitive outcomes. Adverse events occurred for 10 (31%) and 7 (23%) participants in the active and control groups, correspondingly. The results speak against early pharmacological interventions in older healthy adults to improve broader cognitive functions by targeting the dopaminergic system and provide no support for learning-enhancing properties of L-dopa supplements in the healthy elderly. The findings warrant closer investigation about the cognitive effects of early dopamine-replacement therapy in neurological disorders. This trial was preregistered at the European Clinical Trial Registry, EudraCT#2016-000891-54 (2016-10-05).
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Motor Strategies Learned during Pain Are Sustained upon Pain-free Reexposure to Task.
Salomoni, SE, Marinovic, W, Carroll, TJ, Hodges, PW
Medicine and science in sports and exercise. 2019;(11):2334-2343
Abstract
INTRODUCTION Pain affects movement planning and execution, and may interfere with the ability to learn new motor skills. Variations among previous studies suggest task-specific effects of pain on the initial acquisition and subsequent retention of motor strategies. METHODS The present study assessed how acute pain in the anterior deltoid muscle affects movement accuracy of fast arm-reaching movements during force field perturbations and upon immediate pain-free repetition of the same task. RESULTS Despite having slower initial rate of improvement, individuals who experienced pain during training achieved the same final performance as pain-free controls. However, pain altered the strategy of muscle activation adopted to perform the task, which involved less activity of the shoulder and arm muscles. Strikingly, motor strategies developed during the first exposure to the force field were retained upon reexposure to the same perturbation after resolution of pain. CONCLUSIONS Although reduced muscle activation may be interpreted as metabolically efficient, it reduces joint stability and can have negative consequences for joint integrity. These results demonstrate that alternative motor strategies developed in the presence of pain can be maintained when training is resumed after resolution of pain. This effect could have deleterious consequences if it applies when learning motor skills in sports training and rehabilitation.
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Task errors contribute to implicit aftereffects in sensorimotor adaptation.
Leow, LA, Marinovic, W, de Rugy, A, Carroll, TJ
The European journal of neuroscience. 2018;(11):3397-3409
Abstract
Perturbations of sensory feedback evoke sensory prediction errors (discrepancies between predicted and actual sensory outcomes of movements), and reward prediction errors (discrepancies between predicted rewards and actual rewards). When our task is to hit a target, we expect to succeed in hitting the target, and so we experience a reward prediction error if the perturbation causes us to miss it. These discrepancies between intended task outcomes and actual task outcomes, termed "task errors," are thought to drive the use of strategic processes to restore success, although their role is incompletely understood. Here, as participants adapted to a 30° rotation of cursor feedback representing hand position, we investigated the role of task errors in sensorimotor adaptation: during target-reaching, we either removed task errors by moving the target mid-movement to align with cursor feedback of hand position, or enforced task error by moving the target away from the cursor feedback of hand position, by 20-30° randomly (clockwise in half the trials, counterclockwise in half the trials). Removing task errors not only reduced the extent of adaptation during exposure to the perturbation, but also reduced the amount of post-adaptation aftereffects that persisted despite explicit knowledge of the perturbation removal. Hence, task errors contribute to implicit adaptation resulting from sensory prediction errors. This suggests that the system which predicts the sensory consequences of actions via exposure to sensory prediction errors is also sensitive to reward prediction errors.
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Within-quadrant position and orientation specificity after extensive orientation discrimination learning is related to performance gains during late learning.
Lange, G, Lowet, E, Roberts, MJ, De Weerd, P
PloS one. 2018;(9):e0201520
Abstract
The last decade has seen the emergence of new views about the mechanisms underlying specificity (or, conversely, generalization) of visual skill learning. Here, we trained participants at orientation discrimination paradigm at a peripheral position to induce position and orientation specificity and to test its underlying mechanisms. Specifically, we aimed to test whether the within-quadrant spatial gradient of generalization is determined by cortical magnification, which would show that retinotopic plasticity contributes to learning and specificity. Additionally, we aimed to test whether late parts of the learning relate differently to specificity compared to early parts. This is relevant in the context of double training papers, which suggest that rule-based mechanisms of specificity in fast, early learning also would apply to late, slower learning. Our data showed partial but significant position and orientation specificity within quadrants. Interestingly, specificity was greatest for those participants who had continued to show threshold decreases during the last five sessions of training (late, asymptotic learning). Performance gains during early learning were less related to specificity. A trend for skill to spread over larger distances towards periphery than towards central vision suggested contributions to transfer of early visual areas showing cortical magnification of central vision. Control experiments however did not support this hypothesis. In summary, our study demonstrates significant specificity after extensive perceptual learning, and indicates that asymptotic learning recruits specific mechanisms that promote specificity, and that may not be recruited yet in early parts of the learning. The contributions of different mechanisms to early and late learning suggests that following these different learning periods, generalization relies on different principles and is subjected to different limits.
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Constraints representing a meta-stable régime facilitate exploration during practice and transfer of learning in a complex multi-articular task.
Orth, D, Davids, K, Seifert, L
Human movement science. 2018;:291-302
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Abstract
Previous investigations have shown that inducing meta-stability in behavior can be achieved by overlapping affordances through constraint manipulation, allowing cooperative and competitive tendencies to functionally coexist. The purpose of this paper was to test a number of conditions applying these design principles on performance during skills practice and transfer. Of additional interest, was whether the existing skill level interacted with the environmental properties of the experimental tasks (varying indoor climbing routes). Two skill groups practised on three routes per session over four separate sessions. At the end of the final session, climbers undertook a transfer test. Routes, matched for difficulty, were manipulated in terms of hand-hold design. Route-1 and Route-2 were designed with holds with a single graspable edge, aligned entirely parallel or perpendicular to the ground plane respectively. Route-3 had at each hold, two graspable edges (one parallel and one perpendicular to the ground plane). Behavioral exploration at the hip and hands were largest under the metastable condition (Route-3). Skill level also interacted with route properties during practice and influenced transfer. Data suggest meta-stability induces exploratory behaviors. Less skilled individuals explore both hand and hip levels, whereas, more experienced climbers explore at the hip level.
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Compromised tDCS-induced facilitation of motor consolidation in patients with multiple sclerosis.
Rumpf, JJ, Dietrich, S, Stoppe, M, Fricke, C, Weise, D, Then Bergh, F, Classen, J
Journal of neurology. 2018;(10):2302-2311
Abstract
OBJECTIVE To investigate whether consolidation after motor learning can be facilitated by offline (post-training) transcranial direct current stimulation (tDCS) in patients with multiple sclerosis (MS). METHODS In this cross-sectional double-blind interventional study, effects of tDCS on motor consolidation were examined in 14 patients with relapsing remitting MS [median Expanded Disability Status Scale score 2.0 (range 1-4)] and 14 age- and sex-matched healthy controls. tDCS with the anode placed over the left primary motor cortex and the cathode placed over the right supraorbital region was applied immediately after a training session of an explicit sequential finger-tapping task that was performed with the right (dominant) hand. Task performance was retested after an interval of 8 h to assess consolidation. Participants took part in two experimental sessions separated by at least 7 days which differed with respect to type of post-training tDCS, i.e., sham and verum stimulation. RESULTS Patients with MS performed worse than controls in functional motor tests and the motor sequence task. However, learning speed and magnitude of online performance increments during the training session were comparable to controls. While post-training tDCS facilitated motor consolidation in controls, patients with MS did not benefit from this type of intervention. CONCLUSION Absence of post-training tDCS-induced facilitation of consolidation in patients with MS suggests that the interaction of tDCS with the motor consolidation network is inefficient. Identification of the underlying disease-related mechanisms will have important implications for the design of studies aiming to promote motor recovery in MS by non-invasive brain stimulation.
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Associations between pro-inflammatory cytokines, learning, and memory in late-life depression and healthy aging.
Charlton, RA, Lamar, M, Zhang, A, Ren, X, Ajilore, O, Pandey, GN, Kumar, A
International journal of geriatric psychiatry. 2018;(1):104-112
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Abstract
OBJECTIVES Pro-inflammatory cytokines may play a role in learning and memory difficulties and may be exacerbated in late-life depression (LLD), where pro-inflammatory markers are already elevated because of aging and age-related vascular risk. METHODS Learning and memory, and pro-inflammatory cytokines-Interleukin-1β (IL-1β), tumor necrosis factor-α (TNF-α), and Interleukin-6 (IL-6) were measured in 24 individuals with LLD and 34 healthy older adults (HOA). Hippocampal volumes were segmented using Freesurfer software. RESULTS Pro-inflammatory cytokines were higher in LLD compared with HOA. Regression analyses demonstrated that educational level and right hippocampal volume significantly contributed to explaining the variance in learning. For memory performance, educational level, right hippocampal volume and a group-by-IL-6 interaction significantly contributed to the model. CONCLUSIONS High levels of IL-6 impact cognition in LLD but not HOA. Results suggest that high levels of inflammation alone are not sufficient to account for cognitive difficulties, but may interact with other factors in at-risk populations like LLD, to contribute to memory difficulties. Copyright © 2017 John Wiley & Sons, Ltd.
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BDNF Val66Met but not transcranial direct current stimulation affects motor learning after stroke.
van der Vliet, R, Ribbers, GM, Vandermeeren, Y, Frens, MA, Selles, RW
Brain stimulation. 2017;(5):882-892
Abstract
BACKGROUND tDCS is a non-invasive neuromodulation technique that has been reported to improve motor skill learning after stroke. However, the contribution of tDCS to motor skill learning has only been investigated in a small number of studies. In addition, it is unclear if tDCS effects are mediated by activity-dependent BDNF release and dependent on timing of tDCS relative to training. OBJECTIVE Investigate the role of activity-dependent BDNF release and timing of tDCS relative to training in motor skill learning. METHODS Double-blind, between-subjects randomized controlled trial of circuit tracing task improvement (ΔMotor skill) in 80 chronic stroke patients who underwent tDCS and were genotyped for BDNF Val66Met. Patients received either short-lasting tDCS (20 min) during training (short-lasting online group), long-lasting tDCS (10 min-25 min break - 10 min) one day before training (long-lasting offline group), short-lasting tDCS one day before training (short-lasting offline group), or sham tDCS. ΔMotor skill was defined as the skill difference on the circuit tracing task between day one and day nine of the study. RESULTS Having at least one BDNF Met allele was found to diminish ΔMotor skill (βBDNF,Met = -0.217 95%HDI = [-0.431 -0.0116]), indicating activity-dependent BDNF release is important for motor skill learning after stroke. However, none of the tDCS protocols affected ΔMotor skill (βShort-lasting,online = 0.0908 95%HDI = [-0.227 0.403]; βLong-lasting,offline = 0.0242 95%HDI = [-0.292 0.349]; βShort-lasting,offline = -0.108 95%HDI = [-0.433 0.210]). CONCLUSION BDNF Val66Met is a determinant of motor skill learning after stroke and could be important for prognostic models. tDCS does not modulate motor skill learning in our study and might be less effective than previously assumed.
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Influences of glutamine administration on response selection and sequence learning: a randomized-controlled trial.
Jongkees, BJ, Immink, MA, Colzato, LS
Scientific reports. 2017;(1):2693
Abstract
Precursors of neurotransmitters are increasingly often investigated as potential, easily-accessible methods of neuromodulation. However, the amino-acid glutamine, precursor to the brain's main excitatory and inhibitory neurotransmitters glutamate and GABA, remains notably little investigated. The current double-blind, randomized, placebo-controlled study provides first evidence 2.0 g glutamine administration in healthy adults affects response selection but not motor sequence learning in a serial reaction time task. Specifically, glutamine increased response selection errors when the current target response required a different hand than the directly preceding target response, which might indicate enhanced cortical excitability via a presumed increase in glutamate levels. These results suggest glutamine can alter cortical excitability but, despite the critical roles of glutamate and GABA in motor learning, at its current dose glutamine does not affect sequence learning.