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Secrets of virtuoso: Neuromuscular attributes of motor virtuosity in expert musicians
Abstract and Figures
Musical performance requires extremely fast and dexterous limb movements. The underlying biological mechanisms have been an object of interest among scientists and non-scientists for centuries. Numerous studies of musicians and non-musicians have demonstrated that neuroplastic adaptations through early and deliberate musical training endowed superior motor skill. However, little has been unveiled about what makes inter-individual differences in motor skills among musicians. Here we determined the attributes of inter-individual differences in the maximum rate of repetitive piano keystrokes in twenty-four pianists. Among various representative factors of neuromuscular functions, anatomical characteristics, and training history, a stepwise multiple regression analysis and generalized linear model identified two predominant predictors of the maximum rate of repetitive piano keystrokes; finger tapping rate and muscular strength of the elbow extensor. These results suggest a non-uniform role of individual limb muscles in the production of extremely fast repetitive multi-joint movements. Neither age of musical training initiation nor the amount of extensive musical training before age twenty was a predictor. Power grip strength was negatively related to the maximum rate of piano keystrokes only during the smallest tone production. These findings highlight the importance of innate biological nature and explicit training for motor virtuosity.
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... For several decades, we have seen the publication of a number of works presenting methods for proper instrumental practice (e.g., Auer, 1960;Leimer and Gieseking, 1972), with an increasing number of studies investigating musicians' motor skill. The focus of these studies have primarily been on piano performance (e.g., Ortmann, 1962;Halsband et al., 1994;Engel et al., 1997;Jabusch et al., 2009;Furuya and Altenmüller, 2013;Goebl and Palmer, 2013;Metcalf et al., 2014;Furuya et al., 2015;Goebl, 2018), but a number of works also exist for bowed instruments such as violin, viola, cello, and double bass (e.g., Guettler, 1992;Winold and Thelen, 1994;Baader et al., 2005;Kazennikov and Wiesendanger, 2009;Schoonderwaldt and Demoucron, 2009;Kelleher et al., 2013;Verrel et al., 2013), wind instruments (e.g., Bejjani and Halpern, 1989;Cossette et al., 2008;Palmer et al., 2009;Albrecht et al., 2014), and percussion (e.g., Trappe et al., 1998;Dahl, 2004Dahl, , 2018Fujii et al., 2009a,b;Chen et al., 2016). ...
... Coordination related to movement optimization can contain several parts. As discussed above, the generation of highly skilled movements such as those in music performance, involves complex joint and muscle control by the central nervous system (Sosnik et al., 2004;Fujii et al., 2009b;Sakaguchi et al., 2014;Furuya et al., 2015;d'Avella, 2016). More specifically, these control challenges have been shown to depend on the ability to anticipate, segment, and coarticulate motor elements, all within the biomechanical constraints of the human body. ...
Virtuosity in music performance is often associated with fast, precise, and efficient sound-producing movements. The generation of such highly skilled movements involves complex joint and muscle control by the central nervous system, and depends on the ability to anticipate, segment, and coarticulate motor elements, all within the biomechanical constraints of the human body. When successful, such motor skill should lead to what we characterize as fluency in musical performance. Detecting typical features of fluency could be very useful for technology-enhanced learning systems, assisting and supporting students during their individual practice sessions by giving feedback and helping them to adopt sustainable movement patterns. In this study, we propose to assess fluency in musical performance as the ability to smoothly and efficiently coordinate while accurately performing slow, transitionary, and rapid movements. To this end, the movements of three cello players and three drummers at different levels of skill were recorded with an optical motion capture system, while a wireless electromyography (EMG) system recorded the corresponding muscle activity from relevant landmarks. We analyzed the kinematic and coarticulation characteristics of these recordings separately and then propose a combined model of fluency in musical performance predicting music sophistication. Results suggest that expert performers' movements are characterized by consistently smooth strokes and scaling of muscle phasic coactivation. The explored model of fluency as a function of movement smoothness and coarticulation patterns was shown to be limited by the sample size, but it serves as a proof of concept. Results from this study show the potential of a technology-enhanced objective measure of fluency in musical performance, which could lead to improved practices for aspiring musicians, instructors, and researchers.
... These faster patterns were also noted to contradict typical music teaching recommendations (Bella and Palmer 2011). Also in expert pianists, the maximum single finger (but not wrist and elbow) tapping voluntary movement rate (but not years of practice) was found to be a predictor of keystroke rate, which may constitute a performance advantage (Furuya et al. 2015). ...
The ability to produce high movement speeds is a crucial factor in human motor performance, from the skilled athlete to someone avoiding a fall. Despite this relevance, there remains a lack of both an integrative brain-to-behavior analysis of these movements and applied studies linking the known dependence on open-loop, central control mechanisms of these movements to their real-world implications, whether in the sports, performance arts, or occupational setting. In this review, we cover factors associated with the planning and performance of fast limb movements, from the generation of the motor command in the brain to the observed motor output. At each level (supraspinal, peripheral, and motor output), the influencing factors are presented and the changes brought by training and fatigue are discussed. The existing evidence of more applied studies relevant to practical aspects of human performance is also discussed. Inconsistencies in the existing literature both in the definitions and findings are highlighted, along with suggestions for further studies on the topic of fast limb movement control. The current heterogeneity in what is considered a fast movement and in experimental protocols makes it difficult to compare findings in the existing literature. We identified the role of the cerebellum in movement prediction and of surround inhibition in motor slowing, as well as the effects of fatigue and training on central motor control, as possible avenues for further research, especially in performance-driven populations.
... Moreover, regardless of the amount of musical instrumental practice our participants' results also correspond to the recently updated norms of finger tapping performance [34]. Similar results were reported in a study of adult professional piano players where neither the age of musical training initiation nor the amount of musical training before the age of twenty was a predictor of repetitive piano keystrokes [43]. The development of maximum motor speed as a function of repetitive finger tapping shows an inverted U-shaped curve peaking at 38 years and is related to the white matter myelination level in males [33]. ...
Background: Adolescence is a sensitive period in motor development but little is known about how long-term learning dependent processes shape hand function in tasks of different complexity.
Procedure: We mapped two fundamental aspects of hand function: simple repetitive and complex sequential finger movements, as a function of the length of musical instrumental training. We controlled maturational factors such as chronological and biological age of adolescent female participants (11 to 15 years of age, n=114).
Results: We demonstrated that experience improves performance as a function of task complexity, the more complex task being more susceptible for experience driven performance changes.
Conclusion: Overall, these results suggest that fine motor skills involving cognitive control and relying on long-range functional brain networks are substantially shaped by experience. On the other hand, performance in a simple repetitive task that explains fine motor speed is primarily determined by white matter development driven by maturational factors.
... Several recent studies reported the presence of genetic factors that determine musical expertise 24,25 . We also demonstrated that neither the age of starting musical training nor the amount of deliberate practice accounted for the inter-individual differences in the maximum speed of piano performance among skilled pianists 31 . Similarly, neither factors concerning the history of musical practice covaried with both the somatosensory and motor functions in the present pianists. ...
Skilled individuals are characterized by fine-tuned perceptual and motor functions. Here, we tested the idea that the sensory and motor functions of highly-trained individuals are coupled. We assessed the relationships among multifaceted somatosensory and motor functions of expert pianists. The results demonstrated a positive covariation between the acuity of weight discrimination and the precision of force control during piano keystrokes among the pianists but not among the non-musicians. However, neither the age of starting musical training nor the total amount of life-long piano practice was correlated with these sensory-motor functions in the pianists. Furthermore, a difference between the pianists and non-musicians was absent for the weight discrimination acuity but present for precise force control during keystrokes. The results suggest that individuals with innately superior sensory function had finer motor control only in a case of having undergone musical training. Intriguingly, the tactile spatial acuity of the fingertip was superior in the pianists compared with the non-musicians but was not correlated with any functions representing fine motor control among the pianists. The findings implicate the presence of two distinct mechanisms of sensorimotor learning elicited by musical training, which occur either independently in individual sensorimotor modalities or through interacting between modalities.
... A comprehensive introduction to this technique with parameterization is available 43,44 . The model was fitted using the R statistical package 45 . The Chla parameter was not shown in the list of independent covariates since the concentrations belonging to phytoplankton biomass were used to calculate E X_ECO and E X_SP indicators. ...
A lake ecosystem is continuously exposed to environmental stressors with non-linear interrelationships between abiotic factors and aquatic organisms. Ecosystem health depicts the capacity of system to respond to external perturbations and still maintain structure and function. In this study, we explored the effects of abiotic factors on ecosystem health of Taihu Lake in 2013, China from a system-level perspective. Spatiotemporal heterogeneities of eco-exergy and specific eco-exergy served as thermodynamic indicators to represent ecosystem health in the lake. The results showed the plankton community appeared more energetic in May, and relatively healthy in Gonghu Bay with both higher eco-exergy and specific eco-exergy; a eutrophic state was likely discovered in Zhushan Bay with higher eco-exergy but lower specific eco-exergy. Gradient Boosting Machine (GBM) approach was used to explain the non-linear relationships between two indicators and abiotic factors. This analysis revealed water temperature, inorganic nutrients, and total suspended solids greatly contributed to the two indicators that increased. However, pH rise driven by inorganic carbon played an important role in undermining ecosystem health, particularly when pH was higher than 8.2. This implies that climate change with rising CO2 concentrations has the potential to aggravate eutrophication in Taihu Lake where high nutrient loads are maintained.
... Das ist besonders wichtig, um präzise und geschmeidige Handbewegungen auszuführen. Für schnelle Fingerbewegungen einzelner Finger beim Klavierspielen wird die selektive und spezifische Aktivierung von Muskeln benötigt, um einzelne Finger in gewünschter Weise zu bewegen und Bewegungen der nicht beteiligten Finger zu hemmen (Furuya et al. 2015). Patienten, die an einer Dystonie der Hand leiden, zeigten in elektromyografischen Messungen eine abnormal verlängerte Aktivität von Muskelsignalen bei gleichzeitiger Kontraktion von antagonistischen Muskelgruppen und einer Überaktivierung von benachbarten Muskeln (Furuya und Altenmüller 2013b). ...
Zusammenfassung
Musiker sind ein hervorragendes Modell, um die Plastizität des menschlichen Gehirns zu ergründen. Die Anforderungen an das Nervensystem sind beim Musizieren außerordentlich hoch und bieten ein einzigartig reiches multisensorisches und motorisches Erlebnis. Dieser Artikel resümiert den aktuellen Forschungsstand zu den Auswirkungen musikalischer Ausbildung auf Hirnfunktionen, neuronale Konnektivität und Gehirnstruktur. Als Erstes wird diskutiert, welche Faktoren die Plastizität im Gehirn von Musikern auslösen und fortwährend anregen. Dabei stellen wir die Hypothese auf, dass kontinuierliches zielorientiertes Üben, multisensorische motorische Integration und emotionale und soziale Belohnungen an diesen plastizitätsinduzierten Veränderungen des Gehirns beteiligt sind. Im Anschluss daran fassen wir kurz die Neuroanatomie und Neurophysiologie des Musizierens zusammen. Der folgende Abschnitt beschäftigt sich mit dem Zusammenhang von musikalischer Ausbildung und strukturellen Anpassungen der grauen und weißen Substanz im Gehirn. Wir diskutieren kritisch den Befund, dass strukturelle Veränderungen am häufigsten beobachtet wurden, wenn die musikalische Ausbildung nach dem siebten Lebensjahr begonnen wurde, wohingegen die funktionelle Optimierung effektiver vor diesem Zeitraum stattfindet. Danach widmen wir uns dem Verlust der feinmotorischen Kontrolle, der „Musikerdystonie“. Dieser Zustand ist durch maladaptive Plastizität des Gehirns bedingt. Wir schließen mit einer kurzen Zusammenfassung über die Rolle von Hirnplastizität, Metaplastizität und maladaptiver Plastizität mit dem Erwerb und Verlust von musikalischer Expertise ab.
... This is particularly important in allowing precise and smooth hand movements. For example, rapid individuated finger movements in piano playing require selective and specific activation of muscles to move the intended finger in the desired manner, and to inhibit movements of uninvolved fingers ( Furuya et al., 2015). In patients suffering from hand dystonia, electromyographic recordings have revealed abnormally prolonged muscle firing with co-contraction of antagonistic muscles and overflow of activation to inappropriate muscles ( Furuya and Altenmüller, 2013b). ...
Musicians with extensive training and playing experience provide an excellent model for studying plasticity of the human brain. The demands placed on the nervous system by music performance are very high and provide a uniquely rich multisensory and motor experience to the player. As confirmed by neuroimaging studies, playing music depends on a strong coupling of perception and action mediated by sensory, motor, and multimodal integration regions distributed throughout the brain. A pianist, for example, must draw on a whole set of complex skills, including translating visual analysis of musical notation into motor movements, coordinating multisensory information with bimanual motor activity, developing fine motor skills in both hands coupled with metric precision, and monitoring auditory feedback to fine-tune a performance as it progresses. This article summarizes research on the effects of musical training on brain function, brain connectivity and brain structure. First we address factors inducing and continuously driving brain plasticity in dedicated musicians, arguing that prolonged goal-directed practice, multi-sensory-motor integration, high arousal, and emotional and social rewards contribute to these plasticity-induced brain adaptations. Subsequently, we briefly review the neuroanatomy and neurophysiology underpinning musical activities. Here we focus on the perception of sound, integration of sound and movement, and the physiology of motor planning and motor control. We then review the literature on functional changes in brain activation and brain connectivity along with the acquisition of musical skills, be they auditory or sensory-motor. In the following section we focus on structural adaptions in the gray matter of the brain and in fiber-tract density associated with music learning. Here we critically discuss the findings that structural changes are mostly seen when starting musical training after age seven, whereas functional optimization is more effective before this age. We then address the phenomenon of de-expertise, reviewing studies which provide evidence that intensive music-making can induce dysfunctional changes which are accompanied by a degradation of skilled motor behavior, also termed “musician’s dystonia”. This condition, which is frequently highly disabling, mainly affects male classical musicians with a history of compulsive working behavior, anxiety disorder or chronic pain. Functional and structural brain changes in these musicians are suggestive of deficient inhibition and excess excitation in the central nervous system, which leads to co-activation of antagonistic pairs of muscles during performance, reducing movement speed and quality. We conclude with a concise summary of the role of brain plasticity, metaplasticity and maladaptive plasticity in the acquisition and loss of musicians’ expertise.
... This is particularly important in allowing pre- cise and smooth hand movements. For example, rapid individuated finger movements in piano playing require selective and specific activation of muscles to move the intended finger in the desired manner, and to inhibit movements of uninvolved fingers ( Furuya et al., 2015). In patients suffering from hand dystonia, electromyographic recordings have revealed abnormally prolonged muscle firing with co-contraction of antagonistic muscles and overflow of activation to inappropriate muscles ( Furuya and Altenmüller, 2013b). ...
Making music is a powerful way of engaging multisensory and motor networks, inducing changes within these networks and linking together distant brain regions. These multimodal effects of music making together with music's ability to tap into the emotion and reward system in the brain can be used to facilitate therapy and rehabilitation of neurological disorders. In this article, we review short-and long-term effects of listening to music and making music on functional networks and structural components of the brain. The specific influence of music on the developing brain is emphasized and possible transfer effects on emotional and cognitive processes are discussed. Furthermore, we present data on the potential of music making to support and facilitate neurorehabilitation. We focus on interventions such as melodic intonation therapy and music-supported motor rehabilitation to showcase the effects of neurologic music therapies and discuss their underlying neural mechanisms.
... It is possible that stronger force production of a finger muscle results in faster unidirectional movements of the finger. We demonstrated that an individual difference in the maximum rate of repetitive flexion-extension motions of the upper-limb across expert pianists was associated positively with strength of the elbow extensor muscle 32 . The muscular strength can be also associated with independent motor control between the fingers, since the individuated finger movements can necessitate voluntary muscular force production for suppressing unwanted finger movements originating from the inter-digit connection. ...
Exceptional finger dexterity enables skillful motor actions such as those required for musical performance. However, it has been not known whether and in what manner neuromuscular or biomechanical features of the fingers subserve the dexterity. We aimed to identify the features firstly differentiating the finger dexterity between trained and untrained individuals and secondly accounting for the individual differences in the dexterity across trained individuals. To this aim, two studies were conducted. The first study compared the finger dexterity and several neuromuscular and biomechanical characteristics of the fingers between pianists and non-musicians. As a measure of the dexterity, we used the maximum rate of repetitive finger movements. The results showed no differences in any biomechanical constraints of the fingers between the two groups (i.e. anatomical connectivity between the fingers and range of motion). However, the pianists exhibited faster finger movements and more independent control of movements between the fingers. These observations indicate expertise-dependent enhancement of the finger dexterity and reduction of neuromuscular constraints on movement independence between the fingers. The second study assessed individual differences in the finger dexterity between trained pianists. A penalized regression determined an association of the maximum movement speed of the fingers with both muscular strength and biomechanical characteristics of the fingers, but not with neuromuscular constraints of the fingers. None of these features covaried with measures of early and deliberate piano practice. These findings indicate that distinct biological factors of finger motor dexterity differentiate between the effects of piano practicing and individual differences across skilled pianists.
... Pianists' long-term practice affects the motor tissue and muscle coordination in charge of volume control [43,81,94,95]. Moreover, the practice time (i.e., deliberate practice) accumulated before the age of twenty by professional pianists has been reported to be an indicator of the performance of highly skilled movements [98]. After years of extensive piano education and intensive practice, experienced pianists are able to independently control both hands and fingers [99], dexterously control the strength of the hands, and detect the reaction of the piano to elicit a range of volume. ...
Quantitative evaluation of piano performance is of interests in many fields, including music education and computational performance rendering. Previous studies utilized features extracted from audio or musical instrument digital interface (MIDI) files but did not address the difference between hands (DBH), which might be an important aspect of high-quality performance. Therefore, we investigated DBH as an important factor determining performance proficiency. To this end, 34 experts and 34 amateurs were recruited to play two excerpts on a Yamaha Disklavier. Each performance was recorded in MIDI, and handcrafted features were extracted separately for the right hand (RH) and left hand (LH). These were conventional MIDI features representing temporal and dynamic attributes of each note and computed as absolute values (e. g., MIDI velocity) or ratios between performance and corresponding scores (e. g., ratio of duration or inter-onset interval (IOI)). These note-based features were rearranged into additional features representing DBH by simple subtraction between features of both hands. Statistical analyses showed that DBH was more significant in experts than in amateurs across features. Regarding temporal features, experts pressed keys longer and faster with the RH than did amateurs. Regarding dynamic features, RH exhibited both greater values and a smoother change along melodic intonations in experts that in amateurs. Further experiments using principal component analysis (PCA) and support vector machine (SVM) verified that hand-difference features can successfully differentiate experts from amateurs according to performance proficiency. Moreover, existing note-based raw feature values (Basic features) and DBH features were tested repeatedly via 10-fold cross-validation, suggesting that adding DBH features to Basic features improved F1 scores to 93.6% (by 3.5%) over Basic features. Our results suggest that differently controlling both hands simultaneously is an important skill for pianists; therefore, DBH features should be considered in the quantitative evaluation of piano performance.
... Moreover, regardless of the amount of musical instrumental practice our participants' results also correspond to the recently updated norms of finger tapping performance (Skogan et al. 2018). Similar results were reported in a study of adult professional piano players where neither the age of musical training initiation nor the amount of musical training before the age of twenty was a predictor of repetitive piano keystrokes (Furuya et al. 2015). The development of maximum motor speed as a function of repetitive finger tapping shows an inverted Ushaped curve peaking at 38 years and is related to the white matter myelination level in males (Bartzokis et al. 2010). ...
Adolescence is a sensitive period in motor development but little is known about how long-term learning dependent processes shape hand function in tasks of different complexity. We mapped two fundamental aspects of hand function: simple repetitive and complex sequential finger movements, as a function of the length of musical instrumental training. We controlled maturational factors such as chronological and biological age of adolescent female participants (11 to 15 years of age, n=114). We demonstrated that experience improves performance as a function of task complexity, the more complex task being more susceptible for experience driven performance changes. Overall, these results suggest that fine motor skills involving cognitive control and relying on long-range functional brain networks are substantially shaped by experience. On the other hand, performance in a simple repetitive task that explains fine motor speed is primarily shaped by white matter development driven by maturational factors.
Musical virtuosity is often studied with an emphasis on the outstanding skills of the performer and their sensory and emotional effects on the listener. However, Franz Liszt, one of the main virtuosos in music history, was convinced that what matters in virtuosity is its specific function within the semantic and communicative processing of music. This article proposes a theoretical framework to further investigate Liszt’s intuitions in light of contemporary research on musical meaning and communication. First, we analyze philological data concerning Liszt’s creative process in the Mazeppa works, a set of works including both his virtuoso and program music. Second, we compare our results with recent research on music semantics based on inferential processes about the composer/performer’s intentions (Antović, Stamenković, & Figar, 2016; Schlenker, 2017). We criticize the associationist hypothesis (the idea that the composer’s intention is that the listener infers an association between the music and a real or fictional state of the world) and we defend a causalist hypothesis (the idea that the composer’s intention is that the listener recognizes the music as being an intentional “rewriting” of the states of the world, mental or physical, that are the causes of the music itself). Third, we suggest that what distinguishes Liszt’s virtuoso and program music rewritings are the visual and gestural components of two listening experiences: the virtuoso music “rewrites” its episodic causes (memories, personal experiences) whereas the program music “rewrites” its genetic causes (the work’s creative path and intertextual relations).
The grace of a musician has always fascinated people in the world. It has been widely accepted that quantity of musical practice is a prerequisite but not sufficient for acquisition of musical expertise. An increasing number of studies have recently proposed that an interaction between gene and environment underlies musical expertise, based on empirical evidences demonstrating roles of genetic predisposition. In contrast, it has not been elucidated how ways of musical practice play a role in the expertise, which limits optimizing musical training and education that realizes expressive and virtuosic performance. The present article proposes a theoretical framework for possible impacts of how to practice on acquisition of fast, accurate, and efficient musical performance, on the basis of principles and empirical evidences of motor learning.
Motor skills tend to deteriorate with age, due to muscular wasting, degradation of sensory organs, for example, vision impairment, and changes in the biomechanics of fibrous tissues, joints, and tendons with resulting stiffness. Physiological age-related apoptosis and neurodegeneration of sensory–motor systems induce numerous degradations of neurobiological processes at all levels of the central and peripheral nervous system. This also leads to cognitive decline, including reduced executive function and memory capacity, that additionally impacts motor behavior. However, activities supporting lifelong neuroplasticity, such as making music, may counteract these processes and allow for reacquisition of motor and cognitive skills in elderly following brain tissue damage after stroke. In this chapter, we first outline how musical activity promotes behavioral benefits based on central nervous adaptations related to brain plasticity. We then focus on supposed neurobiological mechanisms underlying these beneficial effects and review the potential of music-supported therapy in restoration of motor skills in seniors suffering from deterioration of motor function following stroke. Keyboard playing may improve fine motor functions along with neurophysiological changes in audiomotor networks. Rhythmic cueing has a positive effect in gait disorders, improving stride length, speed, and overall mobility. Melodic intonation therapy can improve recovery from nonfluent aphasia via activation of right hemispheric networks. Finally, the rewarding effects of music making and listening provoking neurochemical effects, in combination with music-induced brain plasticity, may strongly facilitate neurorehabilitation.
Dexterous object manipulation in skilful behaviours such as surgery, craft making, and musical performance involves fast, precise, and efficient control of force with the fingers. A challenge in playing musical instruments is the requirement of independent control of the magnitude and rate of force production, which typically vary in relation to loudness and tempo. However, it is unknown how expert musicians skilfully control finger force to elicit tones with a wide range of loudness and tempi. Here, we addressed this issue by comparing the variation of spatiotemporal characteristics of force during repetitive and simultaneous piano keystrokes in relation to the loudness and tempo between pianists and musically untrained individuals. While the peak key-descending velocity varied with loudness but not with tempo in both groups, the peak and impulse of the key-depressing force were smaller in pianists than in the non-musicians, specifically when eliciting loud tones, suggesting superior energetic efficiency in the trained individuals. The key-depressing force was more consistent across strikes in pianists than in the non-musicians at all loudness levels but only at slow tempi, confirming expertise-dependency of precise force control. A regression analysis demonstrated that individual differences in the keystroke rates when playing at the fastest tempo across the trained pianists were negatively associated with the force impulse during the key depression but not with the peak force only at the loudest tone. This suggests that rapid reductions of force following the key depression plays a role in considerably fast performance of repetitive piano keystrokes.
Early and extensive musical training provides plastic adaptations of the nervous system and enhanced sensory, motor, and cognitive functions. Over decades, neuronal mechanism underlying the plastic adaptation through musical training has been investigated using neuroimaging and transcranial stimulation techniques. Recently, plastic changes in neuroplastic functions through musical training have gradually gained some interest, so-called metaplasticity. Metaplasticity enables faster and more stable skill acquisition for individuals with a history of prior musical training. This mechanism may also serve for prevention of developing maladaptive changes in the nervous system, being pathophysiology of focal dystonia in musicians. The present chapter introduces neurophysiological mechanisms and functional significances of brain plasticity and metaplasticity of the sensory and motor systems of musicians.
Zusammenfassung
Musizieren auf professionellem Niveau ist eine der komplexesten menschlichen Leistungen. Extrem schnelle und komplexe, zeitlichräumlich präzis definierte Bewegungsmuster müssen mit hoher Zuverlässigkeit gelernt, gespeichert und abgerufen werden, um die Erwartungen der Zuhörer zu erfüllen. Um diese Fähigkeiten zu erwerben, müssen Musiker über viele Jahre hinweg intensiv üben. Steigende Arbeitsbelastung am Instrument kann zu maladaptiver Plastizität des Zentralnervensystems führen und motorische Störungen, wie z. B. die Musikerdystonie auslösen. Die Musikerdystonie ist durch den permanenten Verlust der Kontrolle hoch präziser Bewegungen beim Spielen eines Musikinstruments gekennzeichnet. Sie betrifft etwa 1–2% der Berufsmusiker. Pathophysiologisch liegen gestörte Inhibition und sensomotorische Integration, möglicherweise auf dem Boden einer genetischen Veranlagung vor. Als „dynamisches Stereotyp” wird eine zunächst vorübergehende Verschlechterung der Feinmotorik bezeichnet, die häufig durch psychologische Stressoren oder Müdigkeit ausgelöst wird und als Vorform der Dystonie betrachtet werden kann.
Die Behandlung der motorischen Störungen bei Musikern umfassen ergonomische Anpassungen, Anticholinergika, Retraining, und lokale Injektionen mit Botulinumtoxin. Präventionsstrategien in der Ausbildung junger Berufsmusiker sollten auf ein gesundes Arbeitsverhalten, Selbstmanagement, und psychologisch unterstützenden Unterricht ausgerichtet sein.
In this chapter, we explore what happens in the brain of an expert musician during performance. Understanding expert music performance is interesting to cognitive neuroscientists not only because it tests the limits of human memory and movement, but also because studying expert musicianship can help us understand skilled human behavior in general. In this chapter, we outline important facets of our current understanding of the cognitive and neural basis for music performance, and developmental factors that may underlie musical ability. We address three main questions. (1) What is expert performance? (2) How do musicians achieve expert-level performance? (3) How does expert performance come about? We address the first question by describing musicians' ability to remember, plan, execute, and monitor their performances in order to perform music accurately and expressively. We address the second question by reviewing evidence for possible cognitive and neural mechanisms that may underlie or contribute to expert music performance, including the integration of sound and movement, feedforward and feedback motor control processes, expectancy, and imagery. We further discuss how neural circuits in auditory, motor, parietal, subcortical, and frontal cortex all contribute to different facets of musical expertise. Finally, we address the third question by reviewing evidence for the heritability of musical expertise and for how expertise develops through training and practice. We end by discussing outlooks for future work.
© 2015 Elsevier B.V. All rights reserved.
The relative importance of nature and nurture for various forms of expertise has been intensely debated. Music proficiency is viewed as a general model for expertise, and associations between deliberate practice and music proficiency have been interpreted as supporting the prevailing idea that long-term deliberate practice inevitably results in increased music ability. Here, we examined the associations (rs = .18-.36) between music practice and music ability (rhythm, melody, and pitch discrimination) in 10,500 Swedish twins. We found that music practice was substantially heritable (40%-70%). Associations between music practice and music ability were predominantly genetic, and, contrary to the causal hypothesis, nonshared environmental influences did not contribute. There was no difference in ability within monozygotic twin pairs differing in their amount of practice, so that when genetic predisposition was controlled for, more practice was no longer associated with better music skills. These findings suggest that music practice may not causally influence music ability and that genetic variation among individuals affects both ability and inclination to practice.
Theories of skilled performance that emphasize training history, such as K. Anders Ericsson and colleagues' deliberate-practice theory, have received a great deal of recent attention in both the scientific literature and the popular press. Twin studies, however, have demonstrated evidence for moderate-to-strong genetic influences on skilled performance. Focusing on musical accomplishment in a sample of over 800 pairs of twins, we found evidence for gene-environment correlation, in the form of a genetic effect on music practice. However, only about one quarter of the genetic effect on music accomplishment was explained by this genetic effect on music practice, suggesting that genetically influenced factors other than practice contribute to individual differences in music accomplishment. We also found evidence for gene-environment interaction, such that genetic effects on music accomplishment were most pronounced among those engaging in music practice, suggesting that genetic potentials for skilled performance are most fully expressed and fostered by practice.
Musical performance requires motor skills to coordinate the movements of multiple joints in the hand and arm over a wide range of tempi. However, it is unclear whether the coordination of movement across joints would differ for musicians with different skill levels and how inter-joint coordination would vary in relation to music tempo. The present study addresses these issues by examining the kinematics and muscular activity of the hand and arm movements of professional and amateur pianists who strike two keys alternately with the thumb and little finger at various tempi. The professionals produced a smaller flexion velocity at the thumb and little finger and greater elbow pronation and supination velocity than did the amateurs. The experts also showed smaller extension angles at the metacarpo-phalangeal joint of the index and middle fingers, which were not being used to strike the keys. Furthermore, muscular activity in the extrinsic finger muscles was smaller for the experts than for the amateurs. These findings indicate that pianists with superior skill reduce the finger muscle load during keystrokes by taking advantage of differences in proximal joint motion and hand postural configuration. With an increase in tempo, the experts showed larger and smaller increases in elbow velocity and finger muscle co-activation, respectively, compared to the amateurs, highlighting skill level-dependent differences in movement strategies for tempo adjustment. Finally, when striking as fast as possible, individual differences in the striking tempo among players were explained by their elbow velocities but not by their digit velocities. These findings suggest that pianists who are capable of faster keystrokes benefit more from proximal joint motion than do pianists who are not capable of faster keystrokes. The distinct movement strategy for tempo adjustment in pianists with superior skill would therefore ensure a wider range of musical expression.
Production of a variety of finger-key touches in the piano is essential for expressive musical performance. However, it remains unknown how expert pianists control multi-joint finger and arm movements for manipulating the touch. The present study investigated differences in kinematics and kinetics of the upper-limb movements while expert pianists were depressing a key with two different touches: pressed and struck. The former starts key-depression with the finger-tip contacting the key, whereas the latter involves preparatory arm-lift before striking the key. To determine the effect of individual muscular torque (MUS) as well as non-muscular torques on joint acceleration, we performed a series of inverse and forward dynamics computations.
The pressed touch showed smaller elbow extension velocity, and larger shoulder and finger flexion velocities during key-depression compared with the struck touch. The former touch also showed smaller elbow extension acceleration directly attributed to the shoulder MUS. In contrast, the shoulder flexion acceleration induced by elbow and wrist MUS was greater for the pressed touch than the struck touch. Towards the goal of producing the target finger-key contact dynamics, the pressed and struck touches effectively took advantage of the distal-to-proximal and proximal-to-distal inter-segmental dynamics, respectively. Furthermore, a psychoacoustic experiment confirmed that a tone elicited by the pressed touch was perceived softer than that by the struck touch.
The present findings suggest that manipulation of tone timbre depends on control of inter-segmental dynamics in piano keystroke.
This study investigated performance and wrist muscle activity during rapid-repetitive unimanual tapping with a drumstick in right-handed drummers and nondrummers. Analyses of performances revealed no difference in tapping frequency and peak tap force between drummers and nondrummers, although the drummers showed less variability in intertap interval than the nondrummers. Analyses of the electromyographic (EMG) data obtained by recording the activity of the flexor carpi ulnalis and the extensor carpi radialis muscles of the right wrist revealed several distinct differences between the two groups: the drummers showed a lower level of muscle cocontraction together with an earlier decline of wrist flexor muscle activity and a smaller variability of muscle activation time in the wrist flexors compared with the nondrummers. We suggest that these characteristics in wrist muscle activity in the drummers have been acquired following extensive practice for the efficient use of wrist muscles and stable drumming performance.
This study investigates the influence of extensive bimanual training in professional musicians on the incidence of handedness in the most basic form of right-handedness (RH) and non-right-handedness (NRH), according to Annett's "right shift theory". The lateralisation coefficients (LCs) of a total sample of 128 bimanually performing music students were calculated for speed, regularity, and fatigue of tapping by using the speed tapping paradigm. Additionally, the accumulated amount of practice was recorded by means of retrospective interviews. The proportion of designated right-handers (dRH) and non-right-handers (dNRH) in hand performance was identified by binary logistic regression from LCs. A proportion of 30.8% designated NRH in the group of musicians was found, while in the control group of non-musicians (matched for age range) a proportion of 21.7% designated NRH was observed. Incidence of dNRH was higher in string players (35.6%) than in pianists (27.1%). As an effect of the extensive training of the left hand, tapping regularity increased and tapping fatigue decreased among those participants who evidenced an increased amount of accumulated practice time on the instrument. However, speed difference between hands (as indicated by LCs) remained uninfluenced by bimanual training. This finding is in contrast to those of Jancke, Schlaug, and Steinmetz (1997). Finally, our study provides a more reliable (statistical) classification as an external criterion for future genetic analyses of handedness.
The human brain has the remarkable capacity to alter in response to environmental demands. Training-induced structural brain changes have been demonstrated in the healthy adult human brain. However, no study has yet directly related structural brain changes to behavioral changes in the developing brain, addressing the question of whether structural brain differences seen in adults (comparing experts with matched controls) are a product of "nature" (via biological brain predispositions) or "nurture" (via early training). Long-term instrumental music training is an intense, multisensory, and motor experience and offers an ideal opportunity to study structural brain plasticity in the developing brain in correlation with behavioral changes induced by training. Here we demonstrate structural brain changes after only 15 months of musical training in early childhood, which were correlated with improvements in musically relevant motor and auditory skills. These findings shed light on brain plasticity and suggest that structural brain differences in adult experts (whether musicians or experts in other areas) are likely due to training-induced brain plasticity.
A longitudinal study was conducted to investigate the influence of practice on the long-term development of expert pianists' motor skills in a relevant musical context. Temporal evenness in standardized scale playing was assessed twice in 19 pianists within an average time interval of 27 months. Questionnaires were used for retrospective assessment of practice quantity and several qualitative parameters related to practicing of scales. The development of temporal evenness in scale playing over the follow-up period correlated with the practice time accumulated during that period and with the average daily practice time. Expert pianists with an average daily practice time of 3.75h or more showed an improvement of performance in this selected motor skill. No significant association was observed between motor skill development during the follow-up period and the content of practice. Stepwise linear regression revealed a model predicting 43% of the variance of motor skill development, with practice time accumulated during the follow-up period as the only predictor. It was concluded that, in expert pianists, maintenance of motor skills in the selected motor task was strongly influenced by practice quantity.
There is an infinity of impedance parameter values, and thus different co-contraction levels, that can produce similar movement kinematics from which the CNS must select one. Although signal-dependent noise (SDN) predicts larger motor-command variability during higher co-contraction, the relationship between impedance and task performance is not theoretically obvious and thus was examined here. Subjects made goal-directed, single-joint elbow movements to either move naturally to different target sizes or voluntarily co-contract at different levels. Stiffness was estimated as the weighted summation of rectified EMG signals through the index of muscle co-contraction around the joint (IMCJ) proposed previously. When subjects made movements to targets of different sizes, IMCJ increased with the accuracy requirements, leading to reduced endpoint deviations. Therefore without the need for great accuracy, subjects accepted worse performance with lower co-contraction. When subjects were asked to increase co-contraction, the variability of EMG and torque both increased, suggesting that noise in the neuromotor command increased with muscle activation. In contrast, the final positional error was smallest for the highest IMCJ level. Although co-contraction increases the motor-command noise, the effect of this noise on the task performance is reduced. Subjects were able to regulate their impedance and control endpoint variance as the task requirements changed, and they did not voluntarily select the high impedance that generated the minimum endpoint error. These data contradict predictions of the SDN-based theory, which postulates minimization of only endpoint variance and thus require its revision.
Using fast tapping tasks with each of the four fingers (single-finger tapping) and with two of the fingers used alternately (double-finger tapping), the ability to make rapid tapping movement by the individual fingers was compared between expert pianists and nonmusician controls in both genders. Maximal pinch and grasp forces were also measured to assess strength of individual fingers and whole hand, respectively. Movement of the ring and little fingers was slower than that of the index and middle fingers in both the pianists and controls. The slowness of the ring and little fingers was, however, much less evident in the pianists than the controls in both tapping tasks. The pianists also had smaller intertap interval variability for the index and middle fingers. No pianist-control difference was found for the pinch and grasp forces. Piano training, therefore, effectively changed the ability to move individual fingers rapidly, but not their flexor strength. No gender difference was found in any of the tapping tasks though males had greater strength. Gender thus does not appear to be a factor differentiating the ability to move individual fingers rapidly.
There is evidence of a strong capacity for functional and structural reorganization in the human motor system. However, past research has focused mainly on complex movement sequences over rather short training durations. In this study we investigated changes in corticospinal excitability associated with longer training of elementary, maximum-speed tapping movements. All participating subjects were consistent right-handers and were trained using either the right (experiment 1) or the left thumb (experiment 2). Transcranial magnetic stimulation was applied to obtain motor evoked potentials (MEPs) from the abductor pollicis brevis (APB) muscle of the right and the left hand before and after training. As a result of training, a significant increase was observed in tapping speed accompanied by increased MEPs, recorded from the trained APB muscle, following contralateral M1 stimulation. In the case of subdominant-hand training we additionally demonstrate increased MEP amplitudes evoked at the right APB (untrained hand) in the first training week. Enhanced corticospinal excitability associated with practice of elementary movements may constitute a necessary precursor for inducing plastic changes within the motor system. The involvement of the ipsilateral left M1 likely reflects the predominant role of the left M1 in the general control (modification) of simple motor parameters in right-handed subjects.
This study investigated how the human CNS organizes complex three-dimensional (3D) ball-throwing movements that require both speed and accuracy. Skilled baseball players threw a baseball to a target at three different speeds. Kinematic analysis revealed that the fingertip speed at ball release was mainly produced by trunk leftward rotation, shoulder internal rotation, elbow extension, and wrist flexion in all speed conditions. The study participants adjusted the angular velocities of these four motions to throw the balls at three different speeds. We also analyzed the dynamics of the 3D multijoint movements using a recently developed method called "nonorthogonal torque decomposition" that can clarify how angular acceleration about a joint coordinate axis (e.g., shoulder internal rotation) is generated by the muscle, gravity, and interaction torques. We found that the study participants utilized the interaction torque to generate larger angular velocities of the shoulder internal rotation, elbow extension, and wrist flexion. To increase the interaction torque acting at these joints, the ball throwers increased muscle torque at the shoulder and trunk but not at the elbow and wrist. These results indicates that skilled ball throwers adopted a hierarchical control in which the proximal muscle torques created a dynamic foundation for the entire limb motion and beneficial interaction torques for distal joint rotations.
The relationship between the key depression force on an upright piano and the level of loudness of a generated tone was examined when pianists hit a force-sensor built-in key with "struck" or "pressed" type of touch. The vertical displacement of the key, and the radiated piano sounds were also recorded. It was found that for both types of touch, simple exponential functions could adequately describe the relation of the force amplitude with the level of the piano tone as well as that of the impulse of the force with the piano tone. The impulse of the force generated before the maximum key depression moment commonly amounted to above 80% of the total impulse produced at the tone below mezzo-forte. It, however, decreased to around 60% at fortissimo, indicating a decrease in the efficiency of the force application for sound production. The two types of touch differed in their force profiles. The struck touch was characterized by a steeper initial force increase with greater fluctuations in the subsequent period than the pressed touch. The struck touch also demonstrated lower maximum force and less impulse at fortissimo. The inter-pianist variation in the force and impulse, and the "finger-noise" are also herein examined.
Precise control of movement timing plays a key role in musical performance. This motor skill requires coordination across multiple joints and muscles, which is acquired through extensive musical training from childhood. However, extensive training has a potential risk of causing neurological disorders that impair fine motor control, such as task-specific tremor and focal dystonia. Recent technological advances in measurement and analysis of biological data, as well as noninvasive manipulation of neuronal activities, have promoted the understanding of computational and neurophysiological mechanisms underlying acquisition, loss, and reacquisition of dexterous movements through musical practice and rehabilitation. This paper aims to provide an overview of the behavioral and neurophysiological basis of motor virtuosity and disorder in musicians, representative extremes of human motor skill. We also report novel evidence of effects of noninvasive neurorehabilitation that combined transcranial direct-current stimulation and motor rehabilitation over multiple days on musician's dystonia, which offers a promising therapeutic means.
© 2015 New York Academy of Sciences.
The two experiments of this study exploited individual variation in timing ability to ask whether the production of time intervals by different motor effectors and the judgement of perceptually based time intervals all share common timing mechanisms. In one task subjects produced a series of taps, attempting to maintain constant intervals between them. Individual differences in variability of the produced intervals correlated across the effectors of finger and foot. That is, people that were ‘good timers’ with one effector tended to be ‘good timers’ with another. Besides timing motor production, the subjects also judged durations of brief perceptual events. The acuity of perceptual judgements correlate substantially with regularity of motor production. Further results involving maximum speed of motor production suggested that variability of motor timing comes from two sources, one source in common with perception, and hence called clock variability, and the other source in common with motor speed, and hence called motor implementation variability. The second experiment showed that people high in skill on the piano were better at both types of timing on the average than control subjects with no expertise.
One of the primary goals of cognitive neuroscience is to understand the interaction between genes, development and specific experience. A particularly fascinating example of this interaction is a sensitive period - a time during development when experience has a differential effect on behavior and the brain. Behavioral and brain imaging studies in musicians have provided suggestive evidence for a possible sensitive period for musical training; showing that musicians who began training early show better task performance and greater changes in auditory and motor regions of the brain. However, these studies have not controlled for likely differences between early- (ET) and late-trained (LT) musicians in the number of years of musical experience. This review presents behavioral work from our laboratory comparing the performance of ET (before age seven) and LT musicians who were matched for years of experience on the ability to tap in synchrony with auditory and visual rhythms. The results demonstrate the existence of a possible sensitive period for musical training that has its greatest impact on measures of sensorimotor integration. Work on motor learning in children and how this might relate to the observed sensitive period effect is also reviewed. These studies are described in the context of what is currently known about sensitive periods in animals and humans; drawing on evidence from anatomy and physiology, studies of deafness, as well as structural and functional neuroimaging studies in trained musicians. The possible mechanisms underlying sensitive periods for musical training are discussed based on current theories describing the influence of both low-level features of sensory experience and higher-level cognitive processing.
Running speed is limited by a mechanical interaction between the stance and swing phases of the stride. Here, we tested whether stance phase limitations are imposed by ground force maximums or foot-ground contact time minimums. We selected one-legged hopping and backward running as experimental contrasts to forward running and had seven athletic subjects complete progressive discontinuous treadmill tests to failure to determine their top speeds in each of the three gaits. Vertical ground reaction forces [in body weights (W(b))] and periods of ground force application (T(c); s) were measured using a custom, high-speed force treadmill. At top speed, we found that both the stance-averaged (F(avg)) and peak (F(peak)) vertical forces applied to the treadmill surface during one-legged hopping exceeded those applied during forward running by more than one-half of the body's weight (F(avg) = 2.71 +/- 0.15 vs. 2.08 +/- 0.07 W(b); F(peak) = 4.20 +/- 0.24 vs. 3.62 +/- 0.24 W(b); means +/- SE) and that hopping periods of force application were significantly longer (T(c) = 0.160 +/- 0.006 vs. 0.108 +/- 0.004 s). Next, we found that the periods of ground force application at top backward and forward running speeds were nearly identical, agreeing to within an average of 0.006 s (T(c) = 0.116 +/- 0.004 vs. 0.110 +/- 0.005 s). We conclude that the stance phase limit to running speed is imposed not by the maximum forces that the limbs can apply to the ground but rather by the minimum time needed to apply the large, mass-specific forces necessary.
The present study investigated a skill-level-dependent interaction between gravity and muscular force when striking piano keys. Kinetic analysis of the arm during the downswing motion performed by expert and novice piano players was made using an inverse dynamic technique. The corresponding activities of the elbow agonist and antagonist muscles were simultaneously recorded using electromyography (EMG). Muscular torque at the elbow joint was computed while excluding the effects of gravitational and motion-dependent interaction torques. During descending the forearm to strike the keys, the experts kept the activation of the triceps (movement agonist) muscle close to the resting level, and decreased anti-gravity activity of the biceps muscle across all loudness levels. This suggested that elbow extension torque was produced by gravity without the contribution of agonist muscular work. For the novices, on the other hand, a distinct activity in the triceps muscle appeared during the middle of the downswing, and its amount and duration were increased with increasing loudness. Therefore, for the novices, agonist muscular force was the predominant contributor to the acceleration of elbow extension during the downswing. We concluded that a balance shift from muscular force dependency to gravity dependency for the generation of a target joint torque occurs with long-term piano training. This shift would support the notion of non-muscular force utilization for improving physiological efficiency of limb movement with respect to the effective use of gravity.
Studies of rapid unimanual tapping have assumed that the human rate limit for voluntary rhythmic movement is 5-7 Hz, which corresponds to an inter-tap interval (ITI) of 150-200ms. In fact, the winner of a recent contest to find the world's fastest drummer (WFD) can perform such movements using a handheld drumstick at 10 Hz, which corresponds to an ITI of 100 ms. Because the contest measured only the number of taps by the WFD, we examined the stability of the ITI and the underlying wrist muscle activity of the WFD. By comparing the performance and wrist muscle activity of the WFD with those of two control groups (non-drummers (NDs) and ordinary skilled drummers (ODs)), we found that the WFD had a relatively stable ITI and more pronounced reciprocal wrist muscle activity during the 10-Hz performance. Our result indicates that very fast, stable tapping performance can be achieved by keeping the wrist joint compliant rather than stiff.
The problem of skill-level-dependent modulation in the joint dynamics of multi-joint arm movements is addressed in this study using piano keystroke performed by expert and novice piano players. Using the measured kinematic and key-force data, the time varying net, gravitational, motion-dependent interaction (INT), key-reaction (REA), and muscular (MUS) torques at the shoulder, elbow, wrist, and metacarpophalangeal (MP) joints were computed using inverse dynamics techniques. INTs generated at the elbow and wrist joints, but not those at the MP joint, were greater for the experts as compared with the novices. REA at the MP joint, but not at the other joints, was less for the experts as compared with the novices. The MUSs at the MP, wrist, and elbow joints were smaller, and that at the shoulder joint was larger for the experts as compared with the novices. The experts also had a lesser inter-strike variability of key striking force and key descending velocity as compared with the novices. These findings indicated that the relationship among the INT, REA, and MUS occurring at the joints of the upper-extremity differed between the expert and novice piano players, suggesting that the organization of multi-joint arm movement is modulated by long-term motor training toward facilitating both physiological efficiency and movement accuracy.
This study investigated how baseball players generate large angular velocity at each joint by coordinating the joint torque and velocity-dependent torque during overarm throwing. Using a four-segment model (i.e., trunk, upper arm, forearm, and hand) that has 13 degrees of freedom, we conducted the induced acceleration analysis to determine the accelerations induced by these torques by multiplying the inverse of the system inertia matrix to the torque vectors. We found that the proximal joint motions (i.e., trunk forward motion, trunk leftward rotation, and shoulder internal rotation) were mainly accelerated by the joint torques at their own joints, whereas the distal joint motions (i.e., elbow extension and wrist flexion) were mainly accelerated by the velocity-dependent torques. We further examined which segment motion is the source of the velocity-dependent torque acting on the elbow and wrist accelerations. The results showed that the angular velocities of the trunk and upper arm produced the velocity-dependent torque for initial elbow extension acceleration. As a result, the elbow joint angular velocity increased, and concurrently, the forearm angular velocity relative to the ground also increased. The forearm angular velocity subsequently accelerated the elbow extension and wrist flexion. It also accelerated the shoulder internal rotation during the short period around the ball-release time. These results indicate that baseball players accelerate the distal elbow and wrist joint rotations by utilizing the velocity-dependent torque that is originally produced by the proximal trunk and shoulder joint torques in the early phase.
Reports of 3 experiments testing the hypothesis that the average duration of responses is directly proportional to the minimum average amount of information per response. The results show that the rate of performance is approximately constant over a wide range of movement amplitude and tolerance limits. This supports the thesis that "the performance capacity of the human motor system plus its associated visual and proprioceptive feedback mechanisms, when measured in information units, is relatively constant over a considerable range of task conditions." 25 references. (PsycINFO Database Record (c) 2006 APA, all rights reserved).
The purpose of this study was to investigate whether genetically determined properties of muscle metabolism contribute to the exceptional physical endurance of world-class distance runners. ATP, phosphocreatine, inorganic phosphate, and pH were quantitatively determined by 31P nuclear magnetic resonance spectroscopy in the wrist flexor muscles of elite long-distance runners and sedentary control subjects. These muscles had not been exposed to any specific program of exercise training in either group of subjects. The "untrained" muscles were examined at rest, during two cycles of three grades of exercise, and in recovery. The flexor muscles of the athletes had higher concentrations of phosphocreatine and ATP than did those of the control subjects at rest and during exercise. The athletes' muscles possessed a higher capacity for generation of ATP by oxidative metabolism than did control subjects' muscles according to the following criteria: (i) high force output, 60% of maximum voluntary contraction, was more easily reached and better maintained in both exercise cycles; (ii) the ratio of inorganic phosphate to phosphocreatine rose less during exercise and recovered faster in the postexercise period; (iii) there was no loss of adenine nucleotides or total phosphate from the athletes' muscles but significant losses from the control subjects' muscles; and (iv) the pH decreased no more than 0.1 unit in the athletes' muscles during exercise, attesting to a relatively slow glycolysis and/or a rapid oxidation of lactate. In the muscles of the control subjects, on the other hand, the pH decreased nearly 0.4 unit early in the first exercise cycle, indicating a relatively fast glycolysis and/or slower oxidation of lactate. In the second exercise cycle, the pH returned to near normal in the control subjects' muscles, reflecting diminished lactate formation because of glycogen depletion and lactate washout by the high blood flow induced by exercise. By the end of the exercise program, the maximum voluntary contractile force for the control subjects had declined to less than 60% of the initial value. This decline could be explained best by exhaustion of the glycolytic contribution to muscle contraction. Therefore, the residual maximum strength provided a measure of the oxidative capacity to support contraction, as is discussed. In conclusion, we suggest that a greater oxidative capacity relative to glycolytic capacity for support of contraction in untrained muscle of world-class runners reflects a genetic endowment for physical endurance. Additional systemic effects of training cannot be completely excluded. 31P magnetic resonance spectroscopy provides a noninvasive method for assessing this endowment.
Two studies investigated the role of deliberate practice in the maintenance of cognitive-motor skills in expert and accomplished amateur pianists. Older expert and amateur pianists showed the normal pattern of large age-related reductions in standard measures of general processing speed. Performance on music-related tasks showed similar age-graded decline for amateur pianists but not for expert pianists, whose average performance level was only slightly below that of young expert pianists. The degree of maintenance of relevant pianistic skills for older expert pianists was predicted by the amount of deliberate practice during later adulthood. The role of deliberate practice in the active maintenance of superior domain-specific performance in spite of general age-related decline is discussed.
The present paper focused on the role of mechanical factors arising from the multijoint structure of the musculoskeletal system and their use in the control of different patterns of cyclical elbow-wrist movements. Across five levels of cycling frequency (from 0.45 Hz up to 3.05 Hz), three movement patterns were analyzed: (1) unidirectional, including rotations at the elbow and wrist in the same direction; (2) bidirectional, with rotation at the joints in opposite directions, and (3) free-wrist pattern, which is characterized by alternating flexions and extensions at the elbow with the wrist relaxed. Angular position of both joints and electromyographic activity of biceps, triceps, the wrist flexor, and the wrist extensor were recorded. It was demonstrated that control at the elbow was principally different from control at the wrist. Elbow control in all three patterns was similar to that typically observed during single-joint movements: elbow accelerations-decelerations resulted from alternating activity of the elbow flexor and extensor and were largely independent of wrist motion at all frequency plateaus. The elbow muscles were responsible not only for the elbow movement, but also for the generation of interactive torques that played an important role in wrist control. There were two types of interactive torques exerted at the wrist: inertial torque arising from elbow motion and restraining torque arising from physical limits imposed on wrist rotation. These interactive torques were the primary source of wrist motion, whereas the main function of wrist-muscle activity was to intervene with the interactive effects and to adjust the wrist movement to comply with the required coordination pattern. The unidirectional pattern was more in agreement with interactive effects than the bidirectional pattern, thus causing their differential difficulty at moderate cycle frequencies. When cycling frequency was further increased, both the unidirectional and bidirectional movements lost their individual features and acquired features of the free-wrist pattern. The deterioration of the controlled patterns at high cycling frequencies suggests a crucial role for proprioceptive information in wrist control. These results are supportive of a hierarchical organization of control with respect to elbow-wrist coordination, during which the functions of control at the elbow and wrist are principally different: the elbow muscles generate movement of the whole linkage and the wrist muscles produce corrections of the movement necessary to fulfill the task.
Cocontraction (the simultaneous activation of antagonist muscles around a joint) provides the nervous system with a way to adapt the mechanical properties of the limb to changing task requirements-both in statics and during movement. However, relatively little is known about the conditions under which the motor system modulates limb impedance through cocontraction. The goal of this study was to test for a possible relationship between cocontraction and movement accuracy in multi-joint limb movements. The electromyographic activity of seven single- and double-joint shoulder and elbow muscles was recorded using surface electrodes while subjects performed a pointing task in a horizontal plane to targets that varied randomly in size. Movement speed was controlled by providing subjects with feedback on a trial-to-trial basis. Measures of cocontraction were estimated both during movement and during a 200-ms window immediately following movement end. We observed an inverse relationship between target size and cocontraction: as target size was reduced, cocontraction activity increased. In addition, trajectory variability decreased and endpoint accuracy improved. This suggests that, although energetically expensive, cocontraction may be a strategy used by the motor system to facilitate multi-joint arm movement accuracy. We also observed a general trend for cocontraction levels to decrease over time, supporting the idea that cocontraction and associated limb stiffness are reduced over the course of practice.
Maximum-speed movements have been suggested to put maximum neural control demands on the primary motor cortex; hence, we are asking how primary motor cortex function changes to enable enhanced maximum movement rates induced by long-lasting practice. Cortical function was assessed by recording task-related spectral electroencephalogram alpha-power. Low-resolution brain electromagnetic tomography was used to localize intracortical neuronal sources. The main result is a decrease in neural activity in the left hemisphere (ipsilateral to trained hand) from pretraining to posttraining, whereas right hemispheric activity remained constant across training. This likely reflects the initially limited capacity of the right hemisphere to control demanding left-hand movements, but also highlights its ability to become more efficient with training, indicated by reduced involvement of the left primary motor cortex after training.
The purpose of this study was to investigate tapping speed asymmetry in 13 right-handed drummers and 13 right-handed nondrummers. The participants executed single-hand tapping with a stick as fast as possible for 10 sec. with the left and right hand. There was no significant difference in the tapping speed of the right hand between the drummers and the nondrummers, whereas in the left hand, the drummers tapped significantly faster than the nondrummers. Drummers showed less tapping speed asymmetry than nondrummers. These results suggest that the tapping speed of the nonpreferred hand progressed nearly to the level of the preferred hand through daily drum training.
15750 | DOi: 10 Musical training shapes structural brain development
- K L Hyde
Scientific RepoRts | 5:15750 | DOi: 10.1038/srep15750
25. Hyde, K. L. et al. Musical training shapes structural brain development. J Neurosci 29, 3019–3025, doi: 10.1523/
JNEUROSCI.5118-08.2009 (2009).