Inter-Personal Motor Synergy: Co-working Strategy Depends on Task Constraints

2021 ◽  
Author(s):  
Sara Honarvar ◽  
Mia Caminita ◽  
Hossein Ehsani ◽  
Hyun Joon Kwon ◽  
Yancy Diaz-Mercado ◽  
...  
Keyword(s):  
Force Production ◽  
Matching Task ◽  
Task Constraint ◽  
Experimental Conditions ◽  
Task Constraints ◽  
Force Matching ◽  
Additional Task ◽  
Central Nervous Systems ◽  
Fixed Condition ◽  
Motor Synergy

We investigated the role of task constraints on inter-personal interactions. Twenty-one pairs of co-workers performed a finger force production task on force sensors placed at two ends of a seesaw-like apparatus and matched a combined target force of 20N for 23 seconds over ten trials. There were two experimental conditions: 1) FIXED: the seesaw apparatus was mechanically held in place so that the only task constraint was to match the 20N resultant force, and 2) MOVING: the lever in the apparatus was allowed to rotate freely around its fulcrum, acting like a seesaw, so an additional task constraint to (implicitly) balance the resultant moment was added. We hypothesized that the additional task constraint of moment stabilization imposed on the MOVING condition would deteriorate task performance compared to the FIXED condition; however, this was rejected as the performance of the force matching task was similar between two conditions. We also hypothesized that the central nervous systems (CNSs) would employ distinct co-working strategies or inter-personal motor synergy (IPMS) between conditions to satisfy different task constraints, which was supported by our results. Negative covariance between co-worker's forces in the FIXED condition suggested a force stabilization strategy, while positive covariance in the MOVING condition suggested a moment stabilization strategy, implying that independent CNSs adopt distinct IPMSs depending on task constraints. We speculate that, in the absence of a central neural controller, shared visual and mechanical connections between co-workers may suffice to trigger modulations in the cerebellum of each CNS to satisfy competing task constraints.

scholarly journals Neurophysiological changes in the visuomotor network after practicing a motor task

2018 ◽  
Vol 120 (1) ◽  
pp. 239-249 ◽  
Author(s):  
James E. Gehringer ◽  
David J. Arpin ◽  
Elizabeth Heinrichs-Graham ◽  
Tony W. Wilson ◽  
Max J. Kurz
Keyword(s):  
Motor Learning ◽  
Motor Planning ◽  
Motor Task ◽  
Force Production ◽  
Oscillatory Activity ◽  
Matching Task ◽  
Force Output ◽  
Motor Action ◽  
Visuomotor Transformations ◽  
Target Matching

Although it is well appreciated that practicing a motor task updates the associated internal model, it is still unknown how the cortical oscillations linked with the motor action change with practice. The present study investigates the short-term changes (e.g., fast motor learning) in the α- and β-event-related desynchronizations (ERD) associated with the production of a motor action. To this end, we used magnetoencephalography to identify changes in the α- and β-ERD in healthy adults after participants practiced a novel isometric ankle plantarflexion target-matching task. After practicing, the participants matched the targets faster and had improved accuracy, faster force production, and a reduced amount of variability in the force output when trying to match the target. Parallel with the behavioral results, the strength of the β-ERD across the motor-planning and execution stages was reduced after practice in the sensorimotor and occipital cortexes. No pre/postpractice changes were found in the α-ERD during motor planning or execution. Together, these outcomes suggest that fast motor learning is associated with a decrease in β-ERD power. The decreased strength likely reflects a more refined motor plan, a reduction in neural resources needed to perform the task, and/or an enhancement of the processes that are involved in the visuomotor transformations that occur before the onset of the motor action. These results may augment the development of neurologically based practice strategies and/or lead to new practice strategies that increase motor learning. NEW & NOTEWORTHY We aimed to determine the effects of practice on the movement-related cortical oscillatory activity. Following practice, we found that the performance of the ankle plantarflexion target-matching task improved and the power of the β-oscillations decreased in the sensorimotor and occipital cortexes. These novel findings capture the β-oscillatory activity changes in the sensorimotor and occipital cortexes that are coupled with behavioral changes to demonstrate the effects of motor learning.

A Grounded Theory of Expert Cognition in Orienteering

2002 ◽  
Vol 24 (1) ◽  
pp. 68-88 ◽  
Author(s):  
David W. Eccles ◽  
Susanne E. Walsh ◽  
David K. Ingledew
Keyword(s):  
Grounded Theory ◽  
Cognitive Skills ◽  
Research Literature ◽  
Optimal Management ◽  
Sources Of Information ◽  
Task Constraint ◽  
Task Constraints ◽  
Coaching Process ◽  
Processing Resources

The objective of this study was to gain an understanding of expert cognition in orienteering. The British orienteering squad was interviewed (N = 17) and grounded theory was used to develop a theory of expert cognition in orienteering. A task constraint identified as central to orienteering is the requirement to manage attention to three sources of information: the map, the environment, and travel. Optimal management is constrained by limited processing resources. However, consistent with the research literature, the results reveal considerable adaptations by experts to task constraints, characterized primarily by various cognitive skills including anticipation and simplification. By anticipating the environment from the map, and by simplifying the information required to navigate, expert orienteers can circumvent processing limitations. Implications of this theory for other domains involving navigation, and for the coaching process within the sport, are discussed.

Modeling constraints to redundancy in bimanual force coordination

2011 ◽  
Vol 105 (5) ◽  
pp. 2169-2180 ◽  
Author(s):  
Xiaogang Hu ◽  
Karl M. Newell
Keyword(s):  
Muscle Force ◽  
Coupling Effect ◽  
Isometric Force ◽  
Force Production ◽  
Force Output ◽  
Task Constraints ◽  
Task Goal ◽  
Force Coordination ◽  
Finger Forces ◽  
Coordination Patterns

This study investigated the interactive influence of organismic, environmental, and task constraints on the organization of redundant force coordination patterns and the hypothesis that each of the three categories of constraints is weighted based on their relative influence on coordination patterns and the realization of the task goal. In the bimanual isometric force experiment, the task constraint was manipulated via different coefficients imposed on the finger forces such that the weighted sum of the finger forces matched the target force. We examined three models of task constraints based on the criteria of task variance (minimum variance model) and efficiency of muscle force output (coefficient-independent and coefficient-dependent efficiency models). The environmental constraint was quantified by the perceived performance error, and the organismic constraint was quantified by the bilateral coupling effect (i.e., symmetric force production) between hands. The satisficing approach was used in the models to quantify the constraint weightings that reflect the interactive influence of different categories of constraints on force coordination. The findings showed that the coefficient-dependent efficiency model best predicted the redundant force coordination patterns across trials. However, the within-trial variability structure revealed that there was not a consistent coordination strategy in the online control of the individual trial. The experimental findings and model tests show that the force coordination patterns are adapted based on the principle of minimizing muscle force output that is coefficient dependent rather than on the principle of minimizing signal-dependent variance. Overall, the results support the proposition that redundant force coordination patterns are organized by the interactive influence of different categories of constraints.

scholarly journals Robotic Assessment of Wrist Proprioception During Kinaesthetic Perturbations: A Neuroergonomic Approach

2021 ◽  
Vol 15 ◽  
Author(s):  
Erika D'Antonio ◽  
Elisa Galofaro ◽  
Jacopo Zenzeri ◽  
Fabrizio Patané ◽  
Jürgen Konczak ◽  
...  
Keyword(s):  
Degrees Of Freedom ◽  
Neurological Diseases ◽  
External Perturbation ◽  
Recovery Process ◽  
Position Sense ◽  
Matching Task ◽  
Experimental Conditions ◽  
Clinical Scales ◽  
Flexion Extension ◽  
Presentation Sequence

Position sense refers to an aspect of proprioception crucial for motor control and learning. The onset of neurological diseases can damage such sensory afference, with consequent motor disorders dramatically reducing the associated recovery process. In regular clinical practice, assessment of proprioceptive deficits is run by means of clinical scales which do not provide quantitative measurements. However, existing robotic solutions usually do not involve multi-joint movements but are mostly applied to a single proximal or distal joint. The present work provides a testing paradigm for assessing proprioception during coordinated multi-joint distal movements and in presence of kinaesthetic perturbations: we evaluated healthy subjects' ability to match proprioceptive targets along two of the three wrist's degrees of freedom, flexion/extension and abduction/adduction. By introducing rotations along the pronation/supination axis not involved in the matching task, we tested two experimental conditions, which differed in terms of the temporal imposition of the external perturbation: in the first one, the disturbance was provided after the presentation of the proprioceptive target, while in the second one, the rotation of the pronation/ supination axis was imposed during the proprioceptive target presentation. We investigated if (i) the amplitude of the perturbation along the pronation/supination would lead to proprioceptive miscalibration; (ii) the encoding of proprioceptive target, would be influenced by the presentation sequence between the target itself and the rotational disturbance. Eighteen participants were tested by means of a haptic neuroergonomic wrist device: our findings provided evidence that the order of disturbance presentation does not alter proprioceptive acuity. Yet, a further effect has been noticed: proprioception is highly anisotropic and dependent on perturbation amplitude. Unexpectedly, the configuration of the forearm highly influences sensory feedbacks, and significantly alters subjects' performance in matching the proprioceptive targets, defining portions of the wrist workspace where kinaesthetic and proprioceptive acuity are more sensitive. This finding may suggest solutions and applications in multiple fields: from general haptics where, knowing how wrist configuration influences proprioception, might suggest new neuroergonomic solutions in device design, to clinical evaluation after neurological damage, where accurately assessing proprioceptive deficits can dramatically complement regular therapy for a better prediction of the recovery path.

scholarly journals Deficits in Quadriceps Force Control After Anterior Cruciate Ligament Injury: Potential Central Mechanisms

2019 ◽  
Vol 54 (5) ◽  
pp. 505-512 ◽  
Author(s):  
Sarah H. Ward ◽  
Luke Perraton ◽  
Kim Bennell ◽  
Brian Pietrosimone ◽  
Adam L. Bryant
Keyword(s):  
Anterior Cruciate Ligament ◽  
Force Control ◽  
Cortical Excitability ◽  
Cruciate Ligament ◽  
Acl Injury ◽  
Matching Task ◽  
Matching Error ◽  
Force Matching ◽  
Quadriceps Force ◽  
Anterior Cruciate

Context Poor quadriceps force control has been observed after anterior cruciate ligament (ACL) reconstruction but has not been examined after ACL injury. Whether adaptations within the central nervous system are contributing to these impairments is unknown. Objective To examine quadriceps force control in individuals who had sustained a recent ACL injury and determine the associations between cortical excitability and quadriceps force control in these individuals. Design Cross-sectional study. Setting Research laboratory. Patients or Other Participants Eighteen individuals with a recent unilateral ACL injury (6 women, 12 men; age = 29.6 ± 8.4 years, height = 1.74 ± 0.07 m, mass = 76.0 ± 10.4 kg, time postinjury = 69.5 ± 42.5 days) and 18 uninjured individuals (6 women, 12 men; age = 29.2 ± 6.8 years, height = 1.79 ± 0.07 m, mass = 79.0 ± 8.4 kg) serving as controls participated. Main Outcome Measure(s) Quadriceps force control was quantified as the root mean square error between the quadriceps force and target force during a cyclical force-matching task. Cortical excitability was measured as the active motor threshold and cortical silent period. Outcome measures were determined bilaterally in a single testing session. Group and limb differences in quadriceps force control were assessed using mixed analyses of variance (2 × 2). Pearson product moment correlations were performed between quadriceps force control and cortical excitability in individuals with an ACL injury. Results Individuals with an ACL injury exhibited greater total force-matching error with their involved (standardized mean difference [SMD] = 0.8) and uninvolved (SMD = 0.9) limbs than did controls (F1,27 = 11.347, P = .03). During the period of descending force, individuals with an ACL injury demonstrated greater error using their involved (SMD = 0.8) and uninvolved (SMD = 0.8) limbs than uninjured individuals (F1,27 = 4.941, P = .04). Greater force-matching error was not associated with any cortical excitability measures (P > .05). Conclusions Quadriceps force control was impaired bilaterally after recent ACL injury but was not associated with selected measures of cortical excitability. The findings highlight a need to incorporate submaximal-force control tasks into rehabilitation and “prehabilitation,” as the deficits were present before surgery.

scholarly journals THE DEPOSITION OF EXOGENOUS COPPER UNDER EXPERIMENTAL CONDITIONS WITH OBSERVATIONS ON ITS NEUROTOXIC AND NEPHROTOXIC PROPERTIES IN RELATION TO WILSON'S DISEASE

1959 ◽  
Vol 110 (5) ◽  
pp. 801-810 ◽  
Author(s):  
F. Stephen Vogel
Keyword(s):  
Epithelial Cells ◽  
Wilson’S Disease ◽  
Wilson's Disease ◽  
Renal Tubules ◽  
Human Beings ◽  
Experimental Conditions ◽  
Renal Epithelium ◽  
Central Nervous Systems ◽  
Parenchymal Cells ◽  
Large Neurons

Goldfish kept in water containing ionized copper and a detergent added with the aim of decreasing coagulation of the mucus on the gills, took in and retained this metal in their brains, livers, and kidneys, in concentrations comparable to those that occur naturally in Wilson's disease, as chemical assays disclosed. Histochemical studies made it clear that much copper had accumulated within the large neurons, principally in those of the telencephalon and anterior horn region of the spinal cord and in the tubular epithelial cells of the kidneys, the nuclei of the parenchymal cells of the liver, the sarcoplasm of the skeletal muscle, and in the epithelial covering of the gills. The intraneuronal deposition of copper was regularly associated after a time with conspicuous cytologic changes, notably contraction and hyperchromaticity of the nerve cells with tortuosity and fragmentation of the axis cylinders and lysis and loss of neurons. The accumulation of metal in the renal epithelium was frequently accompanied by necrosis and was regularly associated with hyperplasia and calcification of the epithelial cells of the larger renal tubules in all goldfish kept for prolonged periods in copper-rich water. The deposition of copper in the liver was not accompanied by consistent cytologic changes. The similarity of the cytologic alterations induced in the central nervous systems by copper and those that occur naturally in hepatolenticular degeneration in human beings provides evidence that copper itself plays an important role in the pathologic alterations of the brain in Wilson's disease.

Position Coding in Two-Digit Arabic Numbers

2011 ◽  
Vol 58 (2) ◽  
pp. 85-91 ◽  
Author(s):  
Javier García-Orza ◽  
Manuel Perea
Keyword(s):  
Visual Processing ◽  
Response Times ◽  
Letter Position ◽  
Masked Priming ◽  
Initial Position ◽  
Matching Task ◽  
Experimental Conditions ◽  
Unrelated Control ◽  
Arabic Number ◽  
Position Coding

Digit position coding in two-digit Arabic numbers was examined in two masked priming experiments. In Experiment 1, participants had to decide whether the presented stimulus was a two-digit Arabic number (e.g., 67) or not (e.g., G7). Target stimuli could be preceded by a prime which (i) shared one digit in the initial position (e.g., 13-18), (ii) shared one digit but in a different position (83-18), and (iii) was a transposed number (81-18). Two unrelated control conditions, equalized in terms of the distance between primes and targets with the experimental conditions, were also included (e.g., 79-18). Results showed a priming effect only when prime and target shared digits in the same position. Experiment 2 employed a masked priming same-different matching task – a task that has been successfully employed in the literature on letter position coding. Results showed faster response times when prime and target shared digits – including the transposed-digit condition – relative to the control conditions. Thus, the identity of each digit in the early stages of visual processing is not associated with a specific position in two-digit Arabic numbers. We examine the implication of these findings for models of Arabic number processing.

Myosin light chain phosphorylation and tension potentiation in mouse skeletal muscle

1989 ◽  
Vol 257 (5) ◽  
pp. C1012-C1019 ◽  
Author(s):  
B. M. Palmer ◽  
R. L. Moore
Keyword(s):  
Skeletal Muscle ◽  
Light Chain ◽  
Force Production ◽  
Quantitative Relationship ◽  
Isometric Tension ◽  
Contractile Element ◽  
Phosphate Content ◽  
Experimental Conditions ◽  
Intact Mouse ◽  
Isometric Twitch

In intact mammalian fast-twitch skeletal muscle, a quantitative relationship exists between the phosphate content of myosin P-light chain (PLC) and the extent of isometric twitch tension potentiation. It has been proposed that PLC phosphorylation causes twitch potentiation in intact muscle by rendering the contractile element more sensitive to activation by Ca2+. If this hypothesis is correct, then an obligatory experimental outcome is that the slope of the "PLC phosphate vs. isometric tension potentiation (ITP)" relationship should increase when the amount of Ca2+ available to activate the contractile element is decreased. Intact mouse extensor digitorum longus muscles were studied in the absence and presence of sodium dantrolene, an agent that partially inhibits Ca2+ release from the sarcoplasmic reticulum (SR). Treatment of muscles with dantrolene produced a 73% reduction in isometric twitch tension and an approximately threefold increase in the slope of the PLC phosphate vs. ITP relationship. Under experimental conditions that produced fused, tetanic contractions equal to 0.52, 0.72, 0.94, and 1.0 force production, contraction-induced changes in PLC phosphate content were directly proportional to the extent of contractile element activation, whereas the extent of ITP was inversely proportional to the extent of contractile element activation. These data indicate that the slope of the PLC phosphate vs. ITP relationship varies inversely as a function of the amount of Ca2+ that is released from the SR to activate the contractile element during both twitch and fused, submaximal tetanic contractions. Furthermore, these findings support the hypothesis that ITP in intact skeletal muscle is due to a PLC phosphorylation-induced sensitization of the contractile element to activation by Ca2+.

Effects of age and gender on finger coordination in MVC and submaximal force-matching tasks

2003 ◽  
Vol 94 (1) ◽  
pp. 259-270 ◽  
Author(s):  
Minoru Shinohara ◽  
Sheng Li ◽  
Ning Kang ◽  
Vladimir M. Zatsiorsky ◽  
Mark L. Latash
Keyword(s):  
Age Groups ◽  
Force Production ◽  
Voluntary Contraction ◽  
Total Force ◽  
Age And Gender ◽  
Force Matching ◽  
Single Finger ◽  
The Difference ◽  
Young Subjects ◽  
And Gender

The objective of the study is to examine the effects of age and gender on finger coordination. Twelve young (24 ± 8 yr; 6 men and 6 women) and 12 elderly (75 ± 5 yr; 6 men and 6 women) subjects performed single-finger maximal contraction [maximal voluntary contraction (MVC)], four-finger MVC, and four-finger ramp force production tasks by pressing on individual force transducers. A drop in the force of individual fingers during four-finger MVC tasks compared with single-finger MVC tasks (force deficit) was larger, whereas unintended force production by other fingers during single-finger MVC tasks (enslaving) was smaller, in elderly than in young subjects and in women than in men. Force deficit was smaller and enslaving was larger in subjects with higher peak force. During the ramp task, the difference between the variance of total force and the sum of variances of individual forces showed a logarithmic relation to the level of total force, across all subject groups. These findings suggest that indexes of finger coordination scale with force-generating capabilities across gender and age groups.

scholarly journals The Piano Keyboard as Task Constraint: Timing Patterns of Pianists’ Scales Persist Across Instruments

2019 ◽  
Vol 2 ◽  
pp. 205920431987073
Author(s):  
Tracy Lipke-Perry ◽  
Darren J. Dutto ◽  
Morris Levy
Keyword(s):  
Motor Performance ◽  
Degrees Of Freedom ◽  
Movement Control ◽  
The Body ◽  
Musical Structure ◽  
Piano Performance ◽  
Task Constraint ◽  
Task Constraints ◽  
Action Model ◽  
Human Motor

Variation in one form or another is an inevitable aspect of human motor performance as the body negotiates the degrees of freedom problem while also adapting to ever-changing task constraints. The constraints to action model suggests that movement patterns arise from within a framework of environmental, task, and personal constraints. Like athletes, musicians adapt to a wide variety of constraints such as the presence and effect of spectators; acoustics in different performing spaces; humidity affecting tuning; and interpersonal interactions characterizing chamber and ensemble music. A crucial constraint particular to piano performance is adapting to the unique attributes of a wide variety of keyboard instruments. Pianists often refer to the distinct “feel” of a particular instrument: its responsiveness and sensitivity; key resistance; and the evenness and predictability of the instrument. Movement control both within and across pianos is essential for optimal performance, and in that sense, each instrument presents a type of task constraint. In this study, seven pianists performed 10 bimanual, two-octave, C major scales on 3 different piano keyboards to facilitate comparison of performance characteristics across instruments. Pianists performed 4 keystrokes per second, paced by a metronome set at 60 BPM. No timing differences were observed among keyboards as consistent patterns emerged, specifically anticipatory adjustments prior to thumb strokes. These results suggest that pianists are able to produce performances of similar musical structure across different instruments.

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