Classic taxonomies of memory distinguish explicit and implicit memory systems, placing motor skills squarely in the latter branch. This assertion is in part a consequence of foundational discoveries ...showing significant motor learning in amnesics. Those findings suggest that declarative memory processes in the medial temporal lobe (MTL) do not contribute to motor learning. Here, we revisit this issue, testing an individual (L. S. J.) with severe MTL damage on four motor learning tasks and comparing her performance to age-matched controls. Consistent with previous findings in amnesics, we observed that L. S. J. could improve motor performance despite having significantly impaired declarative memory. However, she tended to perform poorly relative to age-matched controls, with deficits apparently related to flexible action selection. Further supporting an action selection deficit, L. S. J. fully failed to learn a task that required the acquisition of arbitrary action–outcome associations. We thus propose a modest revision to the classic taxonomic model: Although MTL-dependent memory processes are not necessary for some motor learning to occur, they play a significant role in the acquisition, implementation, and retrieval of action selection strategies. These findings have implications for our understanding of the neural correlates of motor learning, the psychological mechanisms of skill, and the theory of multiple memory systems.
People correct for movement errors when acquiring new motor skills (de novo learning) or adapting well-known movements (motor adaptation). While de novo learning establishes new control policies, ...adaptation modifies existing ones, and previous work have distinguished behavioral and underlying brain mechanisms for each motor learning type. However, it is still unclear whether learning in each type interferes with the other. In study 1, we use a within-subjects design where participants train with both 30° visuomotor rotation and mirror reversal perturbations, to compare adaptation and de novo learning respectively. We find no perturbation order effects, and find no evidence for differences in learning rates and asymptotes for both perturbations. Explicit instructions also provide an advantage during early learning in both perturbations. However, mirror reversal learning shows larger inter-participant variability and slower movement initiation. Furthermore, we only observe reach aftereffects following rotation training. In study 2, we incorporate the mirror reversal in a browser-based task, to investigate under-studied de novo learning mechanisms like retention and generalization. Learning persists across three or more days, substantially transfers to the untrained hand, and to targets on both sides of the mirror axis. Our results extend insights for distinguishing motor skill acquisition from adapting well-known movements.
Sequence learning and multitasking studies have largely focused on simple motor skills, which cannot be directly transferred to the plethora of complex skills found outside of laboratory conditions. ...Established theories e.g. for bimanual tasks and task integration thus have to be reassessed in the context of complex motor skills. We hypothesize that under more complex conditions, task integration facilitates motor learning, impedes or suppresses effector-specific learning and can still be observed despite partial secondary task interference. We used the Ξ-apparatus to assess the learning success of six groups in a bimanual dual-task, in which we manipulated the degree of possible integration between the right-hand and the left-hand sequences. We could show that task integration positively influences the learning of these complex, bimanual skills. However, the integration impedes but not fully suppresses effector-specific learning, as we could measure reduced hand-specific learning. Task integration improves learning despite the disruptive effect of partial secondary task interference, but its mitigating effect is only effective to some extent. Overall, the results suggest that previous insights on sequential motor learning and task integration can largely also be applied to complex motor skills.
Nicotine is recognized as one of the most addictive drugs, which in part could be attributed to progressive neuroadaptations and rewiring of dorsal striatal circuits. Since motor‐skill learning ...produces neuroplasticity in the same circuits, we postulate that rotarod training could be sufficient to block nicotine‐induced rewiring and thereby prevent long‐lasting impairments of neuronal functioning. To test this hypothesis, Wistar rats were subjected to 15 days of treatment with either nicotine (0.36 mg/kg) or vehicle. After treatment, a subset of animals was trained on the rotarod. Ex vivo electrophysiology was performed 1 week after the nicotine treatment period and after up to 3 months of withdrawal to define neurophysiological transformations in circuits of the striatum and amygdala. Our data demonstrate that nicotine alters striatal neurotransmission in a distinct temporal and spatial sequence, where acute transformations are initiated in dorsomedial striatum (DMS) and nucleus accumbens (nAc) core. Following 3 months of withdrawal, synaptic plasticity in the form of endocannabinoid‐mediated long‐term depression (eCB‐LTD) is impaired in the dorsolateral striatum (DLS), and neurotransmission is altered in DLS, nAc shell, and the central nucleus of the amygdala (CeA). Training on the rotarod, performed after nicotine treatment, blocks neurophysiological transformations in striatal subregions, and prevents nicotine‐induced impairment of eCB‐LTD. These datasets suggest that nicotine‐induced rewiring of striatal circuits can be extinguished by other behaviors that induce neuroplasticity. It remains to be determined if motor‐skill training could be used to prevent escalating patterns of drug use in experienced users or facilitate the recovery from addiction.
This preclinical study shows that nicotine alters amygdalo‐striatal circuits in a distinct temporal and spatial sequence and impairs endocannabinoid signaling in a long‐lasting manner. However, intense motor‐skill training during the initial week of withdrawal completely prevents both acute and progressive neuroadaptations in the striatum. If a functional shift in amygdalo‐striatal circuits is a neurobiological underpinning of substance abuse liability, restoring neuronal function by motor‐skill training might be sufficient to suppress escalated patters of substance use.
Stroke is one of the leading causes for disability worldwide. Motor function deficits due to stroke affect the patients' mobility, their limitation in daily life activities, their participation in ...society and their odds of returning to professional activities. All of these factors contribute to a low overall quality of life. Rehabilitation training is the most effective way to reduce motor impairments in stroke patients. This multiple systematic review focuses both on standard treatment methods and on innovating rehabilitation techniques used to promote upper extremity motor function in stroke patients. A total number of 5712 publications on stroke rehabilitation was systematically reviewed for relevance and quality with regards to upper extremity motor outcome. This procedure yielded 270 publications corresponding to the inclusion criteria of the systematic review. Recent technology-based interventions in stroke rehabilitation including non-invasive brain stimulation, robot-assisted training, and virtual reality immersion are addressed. Finally, a decisional tree based on evidence from the literature and characteristics of stroke patients is proposed. At present, the stroke rehabilitation field faces the challenge to tailor evidence-based treatment strategies to the needs of the individual stroke patient. Interventions can be combined in order to achieve the maximal motor function recovery for each patient. Though the efficacy of some interventions may be under debate, motor skill learning, and some new technological approaches give promising outcome prognosis in stroke motor rehabilitation.
Nusinersen is an antisense oligonucleotide drug that modulates pre-messenger RNA splicing of the survival motor neuron 2 ( SMN2) gene. It has been developed for the treatment of spinal muscular ...atrophy (SMA).
We conducted a multicenter, double-blind, sham-controlled, phase 3 trial of nusinersen in 126 children with SMA who had symptom onset after 6 months of age. The children were randomly assigned, in a 2:1 ratio, to undergo intrathecal administration of nusinersen at a dose of 12 mg (nusinersen group) or a sham procedure (control group) on days 1, 29, 85, and 274. The primary end point was the least-squares mean change from baseline in the Hammersmith Functional Motor Scale-Expanded (HFMSE) score at 15 months of treatment; HFMSE scores range from 0 to 66, with higher scores indicating better motor function. Secondary end points included the percentage of children with a clinically meaningful increase from baseline in the HFMSE score (≥3 points), an outcome that indicates improvement in at least two motor skills.
In the prespecified interim analysis, there was a least-squares mean increase from baseline to month 15 in the HFMSE score in the nusinersen group (by 4.0 points) and a least-squares mean decrease in the control group (by -1.9 points), with a significant between-group difference favoring nusinersen (least-squares mean difference in change, 5.9 points; 95% confidence interval, 3.7 to 8.1; P<0.001). This result prompted early termination of the trial. Results of the final analysis were consistent with results of the interim analysis. In the final analysis, 57% of the children in the nusinersen group as compared with 26% in the control group had an increase from baseline to month 15 in the HFMSE score of at least 3 points (P<0.001), and the overall incidence of adverse events was similar in the nusinersen group and the control group (93% and 100%, respectively).
Among children with later-onset SMA, those who received nusinersen had significant and clinically meaningful improvement in motor function as compared with those in the control group. (Funded by Biogen and Ionis Pharmaceuticals; CHERISH ClinicalTrials.gov number, NCT02292537 .).
There is a positive association between motor competence and physical activity in child populations. Little is known about the relative variance explained in physical activity when process- versus ...product-oriented approaches are used for evaluating motor competence. This study aimed to examine associations between product- and process-oriented motor competence assessments and their capability to explain variance in physical activity. Participants included 167 children between the ages of 6-9 years. The run, jump, throw and kick were assessed using process-oriented (Test of Gross Motor Development-2
nd
edition) and product-oriented (run time, jump distance, throw and kick speed) assessments. Physical activity was assessed via Yamax Digi-walker NL2000 pedometers. Weak to strong correlations between process and product assessments were found (range: r = ± 0.01 to ±0.81). Statistically significant correlations between process and product scores were more frequent for the kick and throw. Both product- and process-oriented assessments were poor at explaining variance in pedometer assessed physical activity. No more than 4% of variance in physical activity could be explained by a single skill, regardless of whether product or process scores were used. Continued examination of associations between process- and product-oriented assessments may provide a more holistic understanding of motor competence across developmental time.
Attentional focus research consistently demonstrates a benefit of an external focus relative to an internal focus. However, this dichotomous comparison may oversimplify the variety of attentional ...focus strategies a learner uses when acquiring a motor skill. Recent research suggests a holistic focus of attention provides a similar benefit over an internal focus in performing a standing long jump, but the generalizability of this effect is unknown. The purpose of this study was to determine how an internal (IF), external (EF), and holistic focus (HF) and control condition impact the learning of a badminton short serve. Novice participants (
N
= 60) were randomly assigned to IF, EF, HF, or control groups. They practiced the badminton short serve for 150 trials over 5 days and completed retention and transfer tests 48-h post-acquisition. Serve accuracy was analyzed in separate repeated-measures ANOVAs for acquisition and pretest/retention/transfer. All groups improved accuracy through acquisition with the HF group serving more accurately than the IF and control groups. In retention, the HF and EF group served more accurately than the control group, and in transfer, the HF group was more accurate than the IF and control groups. The present findings suggest a benefit of both a holistic and external focus in the learning of an accuracy-based task.
People show vast variability in skill performance and learning. What determines a person's individual performance and learning ability? In this study we explored the possibility to predict ...participants' future performance and learning, based on their behavior during initial skill acquisition. We recruited a large online multi-session sample of participants performing a sequential tapping skill learning task. We used machine learning to predict future performance and learning from raw data acquired during initial skill acquisition, and from engineered features calculated from the raw data. Strong correlations were observed between initial and final performance, and individual learning was not predicted. While canonical experimental tasks developed and selected to detect average effects may constrain insights regarding individual variability, development of novel tasks may shed light on the underlying mechanism of individual skill learning, relevant for real-life scenarios.
Background
There is evidence that physical fitness of children and adolescents (particularly cardiorespiratory endurance) has declined globally over the past decades. Ever since the first reports on ...negative trends in physical fitness, efforts have been undertaken by for instance the World Health Organization (WHO) to promote physical activity and fitness in children and adolescents. Therefore, it is timely to re-analyze the literature to examine whether previous reports on secular declines in physical fitness are still detectable or whether they need to be updated.
Objectives
The objective of this systematic review is to provide an ‘update’ on secular trends in selected components of physical fitness (i.e., cardiorespiratory endurance, relative muscle strength, proxies of muscle power, speed) in children and adolescents aged 6–18 years.
Data Sources
A systematic computerized literature search was conducted in the electronic databases PubMed and Web of Science to locate studies that explicitly reported secular trends in physical fitness of children and adolescents.
Study Eligibility Criteria
Studies were included in this systematic review if they examined secular trends between at least two time points across a minimum of 5 years. In addition, they had to document secular trends in any measure of cardiorespiratory endurance, relative muscle strength, proxies of muscle power or speed in apparently healthy children and adolescents aged 6–18 years.
Study Appraisal and Synthesis Methods
The included studies were coded for the following criteria: nation, physical fitness component (cardiorespiratory endurance, relative muscle strength, proxies of muscle power, speed), chronological age, sex (boys vs. girls), and year of assessment. Scores were standardized (i.e., converted to
z
scores) with sample-weighted means and standard deviations, pooled across sex and year of assessment within cells defined by study, test, and children’s age.
Results
The original search identified 524 hits. In the end, 22 studies met the inclusion criteria for review. The observation period was between 1972 and 2015. Fifteen of the 22 studies used tests for cardiorespiratory endurance, eight for relative muscle strength, eleven for proxies of muscle power, and eight for speed. Measures of cardiorespiratory endurance exhibited a large initial increase and an equally large subsequent decrease, but the decrease appears to have reached a floor for all children between 2010 and 2015. Measures of relative muscle strength showed a general trend towards a small increase. Measures of proxies of muscle power indicated an overall small negative quadratic trend. For measures of speed, a small-to-medium increase was observed in recent years.
Limitations
Biological maturity was not considered in the analysis because biological maturity was not reported in most included studies.
Conclusions
Negative secular trends were particularly found for cardiorespiratory endurance between 1986 and 2010–12, irrespective of sex. Relative muscle strength and speed showed small increases while proxies of muscle power declined. Although the negative trend in cardiorespiratory endurance appears to have reached a floor in recent years, because of its association with markers of health, we recommend further initiatives in PA and fitness promotion for children and adolescents. More specifically, public health efforts should focus on exercise that increases cardiorespiratory endurance to prevent adverse health effects (i.e., overweight and obesity) and muscle strength to lay a foundation for motor skill learning.
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