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Shoja O, Towhidkhah F, Hassanlouei H, Levin MF, Bahramian A, Nadeau S, Zhang L, Feldman AG. Reaction of human walking to transient block of vision: analysis in the context of indirect, referent control of motor actions. Exp Brain Res 2023; 241:1353-1365. [PMID: 37010540 DOI: 10.1007/s00221-023-06593-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2022] [Accepted: 03/05/2023] [Indexed: 04/04/2023]
Abstract
Human locomotion may result from monotonic shifts in the referent position, R, of the body in the environment. R is also the spatial threshold at which muscles can be quiescent but are activated depending on the deflection of the current body configuration Q from R. Shifts in R are presumably accomplished with the participation of proprioceptive and visual feedback and responsible for transferring stable body balance (equilibrium) from one place in the environment to another, resulting in rhythmic activity of multiple muscles by a central pattern generator (CPG). We tested predictions of this two-level control scheme. In particular, in response to a transient block of vision during locomotion, the system can temporarily slow shifts in R. As a result, the phase of rhythmical movements of all four limbs will be changed for some time, even though the rhythm and other characteristics of locomotion will be fully restored after perturbation, a phenomenon called long-lasting phase resetting. Another prediction of the control scheme is that the activity of multiple muscles of each leg can be minimized reciprocally at specific phases of the gait cycle both in the presence and absence of vision. Speed of locomotion is related to the rate of shifts in the referent body position in the environment. Results confirmed that human locomotion is likely guided by feedforward shifts in the referent body location, with subsequent changes in the activity of multiple muscles by the CPG. Neural structures responsible for shifts in the referent body configuration causing locomotion are suggested.
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Affiliation(s)
- Otella Shoja
- Department of Neuroscience, University of Montreal, Montreal, QC, Canada
| | - Farzad Towhidkhah
- Department of Biomedical Engineering, Amirkabir University of Technology, Tehran, Iran
| | - Hamidollah Hassanlouei
- Department of Motor Behaviour, Faculty of Sport Science and Health, Shahid Beheshti University, Tehran, Iran
| | - Mindy F Levin
- School of Physical and Occupational Therapy, McGill University, Montreal, QC, Canada
- Center for Interdisciplinary Research in Rehabilitation of Greater Montreal (CRIR), Montreal, QC, Canada
| | - Alireza Bahramian
- Department of Neuroscience, University of Montreal, Montreal, QC, Canada
| | - Sylvie Nadeau
- Center for Interdisciplinary Research in Rehabilitation of Greater Montreal (CRIR), Montreal, QC, Canada
- Faculté de Médecine-École de Réadaptation, Montreal, QC, Canada
| | - Lei Zhang
- Institute for Neural Computation, Ruhr University Bochum, Bochum, Germany
| | - Anatol G Feldman
- Department of Neuroscience, University of Montreal, Montreal, QC, Canada.
- Center for Interdisciplinary Research in Rehabilitation of Greater Montreal (CRIR), Montreal, QC, Canada.
- Institut de réadaptation Gingras-Lindsay-de-Montréal (IRGLM), 6300 Darlington, Montreal, QC, H3S 2J4, Canada.
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Sensing Technology for Assessing Motor Behavior in Ballet: A Systematic Review. SPORTS MEDICINE - OPEN 2022; 8:39. [PMID: 35286494 PMCID: PMC8921372 DOI: 10.1186/s40798-022-00429-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/22/2021] [Accepted: 02/27/2022] [Indexed: 11/10/2022]
Abstract
Abstract
Background
Human performance in classical ballet is a research field of growing interest in the past decades. Technology used to acquire data in human movement sciences has evolved, and is specifically being applied to evaluate ballet movements to better understand dancers’ profiles. We aimed to systematically review sensing technologies that were used to extract data from dancers, in order to improve knowledge regarding the performance of ballet movements through quantification.
Methods
PubMed, MEDLINE, EMBASE, and Web of Science databases were accessed through 2020. All studies that used motor control tools to evaluate classical ballet movements, and possible comparisons to other types of dance and sports movements were selected. Pertinent data were filled into a customized table, and risk of bias was carefully analyzed.
Results
Eighty studies were included. The majority were regarding classical ballet and with pre-professional dancers. Forty-four studies (55%) used two or more types of technology to collect data, showing that motion capture technique, force plates, electromyography, and inertial sensors are the most frequent ways to evaluate ballet movements.
Discussion
Research to evaluate ballet movements varies greatly considering study design and specific intervention characteristics. Combining two or more types of technology may increase data reliability and optimize the characterization of ballet movements. A lack of studies addressing muscle–brain interaction in dancers were observed, and given the potential of novel insights, further studies in this field are warranted. Finally, using quantitative tools opens the perspective of defining what is considered an elite dancer.
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Motor Control: A Conceptual Framework for Rehabilitation. Motor Control 2022; 26:497-517. [PMID: 35894963 DOI: 10.1123/mc.2022-0026] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2022] [Revised: 04/09/2022] [Accepted: 05/02/2022] [Indexed: 11/18/2022]
Abstract
There is a lack of conceptual and theoretical clarity among clinicians and researchers regarding the control of motor actions based on the use of the term "motor control." It is important to differentiate control processes from observations of motor output to improve communication and to make progress in understanding motor disorders and their remediation. This article clarifies terminology related to theoretical concepts underlying the control of motor actions, emphasizing how the term "motor control" is applied in neurorehabilitation. Two major opposing theoretical frameworks are described (i.e., direct and indirect), and their strengths and pitfalls are discussed. Then, based on the proposition that sensorimotor rehabilitation should be predicated on one comprehensive theory instead of an eclectic mix of theories and models, several solutions are offered about how to address controversies in motor learning, optimality, and adaptability of movement.
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Feldman AG, Levin MF, Garofolini A, Piscitelli D, Zhang L. Central pattern generator and human locomotion in the context of referent control of motor actions. Clin Neurophysiol 2021; 132:2870-2889. [PMID: 34628342 DOI: 10.1016/j.clinph.2021.08.016] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2021] [Revised: 07/13/2021] [Accepted: 08/08/2021] [Indexed: 11/26/2022]
Abstract
Unperturbed human locomotion presumably results from feedforward shifts in stable body equilibrium in the environment, thus avoiding falling and subsequent catching considered in alternative theories of locomotion. Such shifts are achieved by relocation of the referent body configuration at which multiple muscle recruitment begins. Rather than being directly specified by a central pattern generator, multiple muscles are activated depending on the extent to which the body is deflected from the referent, threshold body configuration, as confirmed in previous studies. Based on the referent control theory of action and perception, solutions to classical problems in motor control are offered, including the previously unresolved problem of the integration of central and reflex influences on motoneurons and the problem of how posture and movement are related. The speed of locomotion depends on the rate of shifts in the referent body configuration. The transition from walking to running results from increasing the rate of referent shifts. It is emphasised that there is a certain hierarchy between reciprocal and co-activation of agonist and antagonist muscles during locomotion and other motor actions, which is also essential for the understanding of how locomotor speed is regulated. The analysis opens a new avenue in neurophysiological approaches to human locomotion with clinical implications.
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Affiliation(s)
- Anatol G Feldman
- Department of Neuroscience, University of Montreal, 2900 Edouard Montpetit Blvd, Montreal, Quebec H3T 1J4, Canada.
| | - Mindy F Levin
- School of Physical and Occupational Therapy, McGill University, 3654 Promenade Sir-William-Osler, Montreal, Quebec H3G 1Y5, Canada
| | - Alessandro Garofolini
- Institute for Health and Sport (IHES), Victoria University, PO Box 14428, Melbourne, VIC 8001, Australia
| | - Daniele Piscitelli
- School of Physical and Occupational Therapy, McGill University, 3654 Promenade Sir-William-Osler, Montreal, Quebec H3G 1Y5, Canada
| | - Lei Zhang
- Institut für Neuroinformatik, Ruhr-Universität Bochum, Universitätsstraße 150, 44801 Bochum, Germany
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Basso JC, Satyal MK, Rugh R. Dance on the Brain: Enhancing Intra- and Inter-Brain Synchrony. Front Hum Neurosci 2021; 14:584312. [PMID: 33505255 PMCID: PMC7832346 DOI: 10.3389/fnhum.2020.584312] [Citation(s) in RCA: 23] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2020] [Accepted: 12/03/2020] [Indexed: 12/11/2022] Open
Abstract
Dance has traditionally been viewed from a Eurocentric perspective as a mode of self-expression that involves the human body moving through space, performed for the purposes of art, and viewed by an audience. In this Hypothesis and Theory article, we synthesize findings from anthropology, sociology, psychology, dance pedagogy, and neuroscience to propose The Synchronicity Hypothesis of Dance, which states that humans dance to enhance both intra- and inter-brain synchrony. We outline a neurocentric definition of dance, which suggests that dance involves neurobehavioral processes in seven distinct areas including sensory, motor, cognitive, social, emotional, rhythmic, and creative. We explore The Synchronicity Hypothesis of Dance through several avenues. First, we examine evolutionary theories of dance, which suggest that dance drives interpersonal coordination. Second, we examine fundamental movement patterns, which emerge throughout development and are omnipresent across cultures of the world. Third, we examine how each of the seven neurobehaviors increases intra- and inter-brain synchrony. Fourth, we examine the neuroimaging literature on dance to identify the brain regions most involved in and affected by dance. The findings presented here support our hypothesis that we engage in dance for the purpose of intrinsic reward, which as a result of dance-induced increases in neural synchrony, leads to enhanced interpersonal coordination. This hypothesis suggests that dance may be helpful to repattern oscillatory activity, leading to clinical improvements in autism spectrum disorder and other disorders with oscillatory activity impairments. Finally, we offer suggestions for future directions and discuss the idea that our consciousness can be redefined not just as an individual process but as a shared experience that we can positively influence by dancing together.
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Affiliation(s)
- Julia C Basso
- Department of Human Nutrition, Foods, and Exercise, Virginia Tech, Blacksburg, VA, United States.,Center for Transformative Research on Health Behaviors, Fralin Biomedical Research Institute, Virginia Tech, Blacksburg, VA, United States.,School of Neuroscience, Virginia Tech, Blacksburg, VA, United States
| | - Medha K Satyal
- Graduate Program in Translational Biology, Medicine, and Health, Virginia Tech, Blacksburg, VA, United States
| | - Rachel Rugh
- Center for Communicating Science, Virginia Tech, Blacksburg, VA, United States.,School of Performing Arts, Virginia Tech, Blacksburg, VA, United States
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Feldman AG, Zhang L. Eye and head movements and vestibulo-ocular reflex in the context of indirect, referent control of motor actions. J Neurophysiol 2020; 124:115-133. [PMID: 32490708 PMCID: PMC7474454 DOI: 10.1152/jn.00076.2020] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2020] [Revised: 05/06/2020] [Accepted: 05/23/2020] [Indexed: 01/03/2023] Open
Abstract
Conventional explanations of the vestibulo-ocular reflex (VOR) and eye and head movements are revisited by considering two alternative frameworks addressing the question of how the brain controls motor actions. Traditionally, biomechanical and/or computational frameworks reflect the views of several prominent scholars of the past, including Helmholtz and von Holst, who assumed that the brain directly specifies the desired motor outcome and uses efference copy to influence perception. However, empirical studies resulting in the theory of referent control of action and perception (an extension of the equilibrium-point hypothesis) revealed that direct specification of motor outcome is inconsistent with nonlinear properties of motoneurons and with the physical principle that the brain can control motor actions only indirectly, by changing or maintaining the values of neurophysiological parameters that influence, but can remain independent of, biomechanical variables. Some parameters are used to shift the origin (referent) points of spatial frames of reference (FRs) or system of coordinates in which motor actions emerge without being predetermined. Parameters are adjusted until the emergent motor actions meet the task demands. Several physiological parameters and spatial FRs have been identified, supporting the notion of indirect, referent control of movements. Instead of integration of velocity-dependent signals, position-dimensional referent signals underlying head motion can likely be transmitted to motoneurons of extraocular muscles. This would produce compensatory eye movement preventing shifts in gaze during head rotation, even after bilateral destruction of the labyrinths. The referent control framework symbolizes a shift in the paradigm for the understanding of VOR and eye and head movement production.
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Affiliation(s)
- Anatol G Feldman
- Department of Neuroscience, University of Montreal, Montreal, Quebec, Canada
| | - Lei Zhang
- Institut für Neuroinformatik, Ruhr-Universität Bochum, Bochum, Germany
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Scheidler AM, Kinnett-Hopkins D, Learmonth YC, Motl R, López-Ortiz C. Targeted ballet program mitigates ataxia and improves balance in females with mild-to-moderate multiple sclerosis. PLoS One 2018; 13:e0205382. [PMID: 30335774 PMCID: PMC6193654 DOI: 10.1371/journal.pone.0205382] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2017] [Accepted: 09/25/2018] [Indexed: 11/30/2022] Open
Abstract
Background Multiple sclerosis (MS) is a disease of the central nervous system that causes ataxia and deficits in balance. Exercise-based therapies have been identified as integral to the recovery of motor function in MS, but few studies have investigated non-traditional movement interventions. We examined a targeted ballet program (TBP) designed to mitigate ataxia and improve balance in females with mild-to-moderate relapsing-remitting MS. Methods and findings Twelve females with mild-to-moderate disability due to MS were assessed for study eligibility for the study. Ten participants met the inclusion criteria. Two were lost to unrelated health complications. Eight participants completed the TBP. The TBP met twice a week for 60 minutes for 16 weeks. Assessments included (a) the International Cooperative Ataxia Rating Scale (ICARS), (b) the Mini-Balance Evaluations Systems Test (Mini-BESTest), (c) smoothness of movement during a five-meter walk, and (d) balance in a step to stand task before and after the TBP. There were no TBP-related adverse events. Single-tailed paired samples t-tests and Wilcoxon tests were conducted. Improvements were observed in ICARS (p = 7.11E-05), Mini-BESTest (p = 0.001), smoothness of movement in the left (p = 0.027) and right (p = 0.028) sides of the body, and balance in a step-to-stand task in the back (p = 0.025) direction. Results yielded 42% and 58% improvements in the mean Mini-BESTest and ICARS scores, respectively. Conclusions This study adds to current research by providing support for a TBP intervention targeting ataxia and balance in MS. The TBP was well tolerated, improved balance, and mitigated ataxia. Clinical improvements were larger than those of previous studies on physical rehabilitation in MS with similar outcome measures. Trial registration ISRCTN ISRCTN67916624.
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Affiliation(s)
- Andrew M. Scheidler
- Department of Kinesiology and Community Health, University of Illinois, Urbana-Champaign, Illinois, United States of America
| | - Dominique Kinnett-Hopkins
- Department of Kinesiology and Community Health, University of Illinois, Urbana-Champaign, Illinois, United States of America
| | - Yvonne C. Learmonth
- Department of Kinesiology and Community Health, University of Illinois, Urbana-Champaign, Illinois, United States of America
| | - Robert Motl
- Department of Kinesiology and Community Health, University of Illinois, Urbana-Champaign, Illinois, United States of America
| | - Citlali López-Ortiz
- Department of Kinesiology and Community Health, University of Illinois, Urbana-Champaign, Illinois, United States of America
- Joffrey Ballet Academy, The Official School of the Joffrey Ballet, Chicago, Illinois, United States of America
- * E-mail:
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8
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A Comparative Study of the Effects of Pilates and Latin Dance on Static and Dynamic Balance in Older Adults. J Aging Phys Act 2017; 25:412-419. [DOI: 10.1123/japa.2016-0164] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
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9
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Should Ballet Dancers Vary Postures and Underfoot Surfaces When Practicing Postural Balance? Motor Control 2017; 22:45-66. [PMID: 28338396 DOI: 10.1123/mc.2016-0076] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
BACKGROUND Postural balance (PB) is an important component skill for professional dancers. However, the effects of different types of postures and different underfoot surfaces on PB have not adequately been addressed. PURPOSE The main aim of this study was to investigate the effect of different conditions of footwear, surfaces, and standing positions on static and dynamic PB ability of young ballet dancers. METHODS A total of 36 male and female young professional ballet dancers (aged 14-19 years) completed static and dynamic balance testing, measured by head and lumbar accelerometers, while standing on one leg in the turnout position, under six different conditions: (1) "relaxed" posture; (2) "ballet" posture; (3) barefoot; (4) ballet shoes with textured insoles; (5) barefoot on a textured mat; and (6) barefoot on a spiky mat. RESULTS A condition effect was found for static and dynamic PB. Static PB was reduced when dancers stood in the ballet posture compared with standing in the relaxed posture and when standing on a textured mat and on a spiky mat (p < .05), and static PB in the relaxed posture was significantly better than PB in all the other five conditions tested. Dynamic PB was significantly better while standing in ballet shoes with textured insoles and when standing on a spiky mat compared with all other conditions (p < .05). CONCLUSIONS The practical implications derived from this study are that both male and female dancers should try to be relaxed in their postural muscles when practicing a ballet aligned position, including dance practice on different types of floors and on different types of textured/spiky materials may result in skill transfer to practice on normal floor surfaces, and both static and dynamic PB exercises should be assessed and generalized into practical dance routines.
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Sofianidis G, Elliott MT, Wing AM, Hatzitaki V. Can dancers suppress the haptically mediated interpersonal entrainment during rhythmic sway? Acta Psychol (Amst) 2014; 150:106-13. [PMID: 24866454 DOI: 10.1016/j.actpsy.2014.05.002] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2013] [Revised: 04/22/2014] [Accepted: 05/05/2014] [Indexed: 11/18/2022] Open
Abstract
Interpersonal entrainment emerges spontaneously when partners performing rhythmic movements together exchange sensory feedback about the other's movements. In this study, we asked whether couples of expert dancers, non-dancers and mixed couples can suppress the spontaneous haptically mediated inter-personal entrainment when their rhythmic sway is paced by differing metronome tempos. Fifty-four young participants formed three types of couples: nine dancer couples, consisting of individuals with at least eight years systematic practice in traditional Greek dance; nine non-dancer couples, consisting of individuals with no prior experience in dance and nine mixed couples, consisting of one dancer and one novice partner. Partners swayed rhythmically for 60 s, at different pacing frequencies (one at 0.25 Hz and the other at 0.35 Hz) under three haptic contact conditions: no contact between them; light fingertip touch established in the 2nd trial segment (30 s); and light fingertip touch released in the 2nd trial segment (30 s). Spectral analysis of the antero-posterior center of pressure displacement revealed that light touch increased the deviation of the dominant from the target (pacing) sway frequency, decreased the proportion of the signal's power at the target frequency and increased the coherence between the partners' sway signals (inter-personal coherence). These effects were specific to the mixed group whereas touch interference was weaker in non-dancers and absent in dancers. In addition, the coherence between the trial segments (intra-personal coherence) significantly decreased with touch only for the non-dancer while it remained unchanged for the dancer partner of the mixed group suggesting that the dancer was leading the non-dancer partner. It is concluded that systematic practice with traditional dance can modulate the spontaneous tendency towards haptically mediated interpersonal entrainment.
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Affiliation(s)
- George Sofianidis
- Laboratory of Motor Control and Learning, School of Physical Education and Sport Sciences, Aristotle University of Thessaloniki, Thessaloniki, Greece
| | - Mark T Elliott
- Behavioural Brain Sciences Centre, School of Psychology, University of Birmingham, Birmingham, United Kingdom
| | - Alan M Wing
- Behavioural Brain Sciences Centre, School of Psychology, University of Birmingham, Birmingham, United Kingdom
| | - Vassilia Hatzitaki
- Laboratory of Motor Control and Learning, School of Physical Education and Sport Sciences, Aristotle University of Thessaloniki, Thessaloniki, Greece.
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Teplá L, Procházková M, Svoboda Z, Janura M. Kinematic analysis of the gait in professional ballet dancers. ACTA GYMNICA 2014. [DOI: 10.5507/ag.2014.009] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
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12
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Bilateral coupling facilitates recovery of rhythmical movements from perturbation in healthy and post-stroke subjects. Exp Brain Res 2013; 227:263-74. [DOI: 10.1007/s00221-013-3509-1] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2012] [Accepted: 04/02/2013] [Indexed: 10/26/2022]
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Neurocognitive control in dance perception and performance. Acta Psychol (Amst) 2012; 139:300-8. [PMID: 22305351 DOI: 10.1016/j.actpsy.2011.12.005] [Citation(s) in RCA: 164] [Impact Index Per Article: 13.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2011] [Revised: 12/05/2011] [Accepted: 12/09/2011] [Indexed: 11/21/2022] Open
Abstract
Dance is a rich source of material for researchers interested in the integration of movement and cognition. The multiple aspects of embodied cognition involved in performing and perceiving dance have inspired scientists to use dance as a means for studying motor control, expertise, and action-perception links. The aim of this review is to present basic research on cognitive and neural processes implicated in the execution, expression, and observation of dance, and to bring into relief contemporary issues and open research questions. The review addresses six topics: 1) dancers' exemplary motor control, in terms of postural control, equilibrium maintenance, and stabilization; 2) how dancers' timing and on-line synchronization are influenced by attention demands and motor experience; 3) the critical roles played by sequence learning and memory; 4) how dancers make strategic use of visual and motor imagery; 5) the insights into the neural coupling between action and perception yielded through exploration of the brain architecture mediating dance observation; and 6) a neuroesthetics perspective that sheds new light on the way audiences perceive and evaluate dance expression. Current and emerging issues are presented regarding future directions that will facilitate the ongoing dialog between science and dance.
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Sangani SG, Raptis HA, Feldman AG. Subthreshold corticospinal control of anticipatory actions in humans. Behav Brain Res 2011; 224:145-54. [DOI: 10.1016/j.bbr.2011.05.041] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2011] [Revised: 05/28/2011] [Accepted: 05/31/2011] [Indexed: 11/26/2022]
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15
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Feldman AG, Krasovsky T, Baniña MC, Lamontagne A, Levin MF. Changes in the referent body location and configuration may underlie human gait, as confirmed by findings of multi-muscle activity minimizations and phase resetting. Exp Brain Res 2011; 210:91-115. [DOI: 10.1007/s00221-011-2608-0] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2010] [Accepted: 02/14/2011] [Indexed: 11/29/2022]
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16
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Feldman AG. Space and time in the context of equilibrium‐point theory. WILEY INTERDISCIPLINARY REVIEWS. COGNITIVE SCIENCE 2010; 2:287-304. [DOI: 10.1002/wcs.108] [Citation(s) in RCA: 53] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Anatol G. Feldman
- Department of Physiology, University of Montreal, Montreal, Quebec, H3C 3T4, Canada
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17
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New insights into action–perception coupling. Exp Brain Res 2008; 194:39-58. [PMID: 19082821 DOI: 10.1007/s00221-008-1667-3] [Citation(s) in RCA: 67] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2008] [Accepted: 11/18/2008] [Indexed: 10/21/2022]
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18
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Arshavsky YI. On mathematical modeling of neurophysiological functions. Neuroscience 2008; 155:565-6. [PMID: 18597945 DOI: 10.1016/j.neuroscience.2008.05.031] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2008] [Accepted: 05/22/2008] [Indexed: 11/28/2022]
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Postural preparation to making a step: is there a 'motor program' for postural preparation? J Appl Biomech 2008; 23:261-74. [PMID: 18089924 DOI: 10.1123/jab.23.4.261] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
We tested the hypothesis that a sequence of mechanical events occurs preceding a step that scales in time and magnitude as a whole in a task-specific manner, and is a reflection of a "motor program." Young subjects made a step under three speed instructions and four tasks: stepping straight ahead, down a stair, up a stair, and over an obstacle. Larger center-of-pressure (COP) and force adjustments in the anterior-posterior direction and smaller COP and force adjustments in the mediolateral direction were seen during stepping forward and down a stair, as compared with the tasks of stepping up a stair and over an obstacle. These differences were accentuated during stepping under the simple reaction time instruction. These results speak against the hypothesis of a single motor program that would underlie postural preparation to stepping. They are more compatible with the reference configuration hypothesis of whole-body actions.
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Pilon JF, De Serres SJ, Feldman AG. Threshold position control of arm movement with anticipatory increase in grip force. Exp Brain Res 2007; 181:49-67. [PMID: 17340124 DOI: 10.1007/s00221-007-0901-8] [Citation(s) in RCA: 59] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2006] [Accepted: 02/07/2007] [Indexed: 10/23/2022]
Abstract
The grip force holding an object between fingers usually increases before or simultaneously with arm movement thus preventing the object from sliding. We experimentally analyzed and simulated this anticipatory behavior based on the following notions. (1) To move the arm to a new position, the nervous system shifts the threshold position at which arm muscles begin to be recruited. Deviated from their activation thresholds, arm muscles generate activity and forces that tend to minimize this deviation by bringing the arm to a new position. (2) To produce a grip force, with or without arm motion, the nervous system changes the threshold configuration of the hand. This process defines a threshold (referent) aperture (R(a)) of appropriate fingers. The actual aperture (Q(a)) is constrained by the size of the object held between the fingers whereas, in referent position R(a), the fingers virtually penetrate the object. Deviated by the object from their thresholds of activation, hand muscles generate activity and grip forces in proportion to the gap between the Q(a) and R(a). Thus, grip force emerges since the object prevents the fingers from reaching the referent position. (3) From previous experiences, the system knows that objects tend to slide off the fingers when arm movements are made and, to prevent sliding, it starts narrowing the referent aperture simultaneously with or somewhat before the onset of changes in the referent arm position. (4) The interaction between the fingers and the object is accomplished via the elastic pads on the tips of fingers. The pads are compressed not only due to the grip force but also due to the tangential inertial force ("load") acting from the object on the pads along the arm trajectory. Compressed by the load force, the pads move back and forth in the gap between the finger bones and object, thus inevitably changing the normal component of the grip force, in synchrony with and in proportion to the load force. Based on these notions, we simulated experimental elbow movements and grip forces when subjects rapidly changed the elbow angle while holding an object between the index finger and the thumb. It is concluded that the anticipatory increase in the grip force with or without correlation with the tangential load during arm motion can be explained in neurophysiological and biomechanical terms without relying on programming of grip force based on an internal model.
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Affiliation(s)
- Jean-François Pilon
- Department of Physiology, Neurological Science Research Center, Institute of Biomedical Engineering, University of Montreal, Montreal, QC, Canada
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Feldman AG, Goussev V, Sangole A, Levin MF. Threshold position control and the principle of minimal interaction in motor actions. PROGRESS IN BRAIN RESEARCH 2007; 165:267-81. [PMID: 17925252 DOI: 10.1016/s0079-6123(06)65017-6] [Citation(s) in RCA: 54] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
The answer to the question of how the nervous system controls multiple muscles and body segments while solving the redundancy problem in choosing a unique action from the set of many possible actions is still a matter of controversy. In an attempt to clarify the answer, we review data showing that motor actions emerge from central resetting of the threshold position of appropriate body segments, i.e. the virtual position at which muscles are silent but deviations from it will elicit activity and resistive forces (threshold position control). The difference between the centrally-set threshold position and the sensory-signaled actual position is responsible for the activation of neuromuscular elements and interactions between them and the environment. These elements tend to diminish the evoked activity and interactions by minimizing the gap between the actual position and the threshold position (the principle of minimal interaction). Threshold control per se does not solve the redundancy problem: it only limits the set of possible actions. The principle of minimal interaction implies that the system relies on the natural capacity of neuromuscular elements to interact between themselves and with the environment to reduce this already restricted set to a unique action, thus solving the redundancy problem in motor control. This theoretical framework appears to be helpful in the explanation of the control and production of a variety of actions (reaching movements, specification of different hand configurations, grip force generation, and whole-body movements such as sit-to-stand or walking). Experimental tests of this theory are provided. The prediction that several types of neurons specify referent control variables for motor actions may be tested in future studies. The theory may also be advanced by applying the notion of threshold control to perception and cognition.
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Affiliation(s)
- Anatol G Feldman
- Department of Physiology, Neurological Science Research Center, Institute of Biomedical Engineering, University of Montreal, Montreal, QC, Canada.
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