Abundant Degrees of Freedom Are Not a Problem

2018 ◽  
Vol 7 (1) ◽  
pp. 64-72 ◽  
Author(s):  
Mark L. Latash
Keyword(s):  
Degrees Of Freedom ◽  
Optimization Methods ◽  
Uncontrolled Manifold ◽  
Motor Tasks ◽  
Uncontrolled Manifold Hypothesis ◽  
Motor Synergies ◽  
External Forces ◽  
Applied Fields ◽  
The Brain ◽  
Additional Constraints

The problem of motor redundancy has been one of the fundamental, albeit elusive, problems in motor control. Traditionally, it has been viewed as a computational problem for the brain, solved with either optimization methods or by introducing additional constraints to motor tasks. This review suggests that the problem was wrongly formulated, and that the abundant degrees of freedom are not to be eliminated but used to ensure dynamic stability of motor performance, which is vital given the unpredictable intrinsic states and external forces. The idea of synergies as mechanisms ensuring action stability is introduced based on the uncontrolled manifold hypothesis and the theory of control with spatial referent coordinates. The importance of controlled stability is illustrated with the phenomena of anticipatory synergy adjustments. This approach is productive for both basic and applied fields as illustrated, in particular, by changes in motor synergies with neurological disorder and exercise.

Motor Control: Creating a Natural Science of Biological Movement

2021 ◽  
pp. 1-7
Author(s):  
Mark L. Latash
Keyword(s):  
Motor Control ◽  
Natural Science ◽  
Uncontrolled Manifold ◽  
Uncontrolled Manifold Hypothesis ◽  
The Past ◽  
Spatial Coordinates ◽  
Applied Fields ◽  
The Brain ◽  
Recent Version ◽  
Theoretical Developments

Motor control is a young and aspiring field of natural science. Over the past 40 years, it has become an established field of study with several important theoretical developments, including the equilibrium-point hypothesis and its more recent version known as the control with referent spatial coordinates, the principle of abundance, the uncontrolled manifold hypothesis, and the concept of dynamic neural field as the means of task formulation. Important experimental advances have included the exploration of the notion of synergies, the links between descending signals from the brain and referent coordinates of the effectors, and applications of motor control principles to analysis of disordered movements. Further maturation of motor control requires focusing on theory-driven studies. It promises fruitful applications to applied fields such as movement disorders and rehabilitation.

scholarly journals Postural Synergies and Their Development

2005 ◽  
Vol 12 (2-3) ◽  
pp. 119-130 ◽  
Author(s):  
Mark L. Latash ◽  
Vijaya Krishnamoorthy ◽  
John P. Scholz ◽  
Vladimir M. Zatsiorsky
Keyword(s):  
Uncontrolled Manifold ◽  
Motor Tasks ◽  
Performance Variables ◽  
Motor Synergies ◽  
Motor Abundance ◽  
Motor Practice ◽  
Recent Developments ◽  
The Central Nervous System ◽  
Postural Perturbations ◽  
Postural Synergies

The recent developments of a particular approach to analyzing motor synergies based on the principle of motor abundance has allowed a quantitative assessment of multieffector coordination in motor tasks involving anticipatory adjustments to self-triggered postural perturbations and in voluntary posturalsway. This approach, the uncontrolled manifold (UCM) hypothesis, is based on an assumption that the central nervous system organizes covariation of elemental variables to stabilize important performance variables in a task-specific manner. In particular, this approach has been used to demonstrate and to assess the emergence of synergies and their modification with motor practice in typical persons and persons with Down syndrome. The framework of the UCM hypothesis allows the formulation of testable hypotheses with respect to developing postural synergies in typically and atypically developing persons.

scholarly journals Number of Trials Necessary to Apply Analysis within the Framework of the Uncontrolled Manifold Hypothesis at Different Levels of Hierarchical Synergy Control

2021 ◽  
Vol 76 (1) ◽  
pp. 131-143
Author(s):  
Michał Pawłowski ◽  
Mariusz P. Furmanek ◽  
Grzegorz Sobota ◽  
Wojciech Marszałek ◽  
Kajetan J. Słomka ◽  
...  
Keyword(s):  
Intraclass Correlation ◽  
Hierarchical Control ◽  
Large Body ◽  
Elbow Flexion ◽  
Uncontrolled Manifold ◽  
Uncontrolled Manifold Hypothesis ◽  
Motor Synergies ◽  
Minimum Number ◽  
Motor Actions ◽  
Different Levels

Abstract The uncontrolled manifold hypothesis is a method used to quantify motor synergies, defined as a specific central nervous system organization that maintains the task-specific stability of motor actions. The UCM allows for inter-trial variance analysis between consecutive trials. However, despite the large body of literature within this framework, there is no report on the number of movement repetitions required for reliable results. Based on the hypothetical hierarchical control of motor synergies, this study aims to determine the minimum number of trials necessary to achieve a good to excellent level of reliability. Thirteen young, healthy participants performed fifteen bilateral isometric contractions of elbow flexion when visual feedback was provided. The force and electromyography data were recorded to investigate synergies at different levels of hierarchical control. The intraclass correlation coefficient was used to determine the reliability of the variance indices. Based on the obtained results, at least twelve trials are required to analyze the inter-trial variance in both force and muscle synergies within the UCM framework.

scholarly journals Recent Design Optimization Methods for Energy-Efficient Electric Motors and Derived Requirements for a New Improved Method—Part 1

Proceedings ◽  
2018 ◽  
Vol 2 (22) ◽  
pp. 1400
Author(s):  
Johannes Schmelcher ◽  
Max Kleine Büning ◽  
Kai Kreisköther ◽  
Dieter Gerling ◽  
Achim Kampker
Keyword(s):  
Rare Earth ◽  
Design Optimization ◽  
Energy Efficient ◽  
Degrees Of Freedom ◽  
High Efficiency ◽  
Optimization Problems ◽  
Computing Time ◽  
Optimization Methods ◽  
Electric Motors ◽  
Electric Cars

Energy-efficient electric motors are gathering an increased attention since they are used in electric cars or to reduce operational costs, for instance. Due to their high efficiency, permanent-magnet synchronous motors are used progressively more. However, the need to use rare-earth magnets for such high-efficiency motors is problematic not only in regard to the cost but also in socio-political and environmental aspects. Therefore, an increasing effort has to be put in finding the best design possible. The goals to achieve are, among others, to reduce the amount of rare-earth magnet material but also to increase the efficiency. In the first part of this multipart paper, characteristics of optimization problems in engineering and general methods to solve them are presented. In part two, different approaches to the design optimization problem of electric motors are highlighted. The last part will evaluate the different categories of optimization methods with respect to the criteria: degrees of freedom, computing time and the required user experience. As will be seen, there is a conflict of objectives regarding the criteria mentioned above. Requirements, which a new optimization method has to fulfil in order to solve the conflict of objectives will be presented in this last paper.

scholarly journals Orexin receptor blockers: A tool for lowering alcohol intake and alcohol addictive behavior in the light of preclinical studies

2021 ◽  
Vol 75 (1) ◽  
pp. 959-969
Author(s):  
Kamila Czora-Poczwardowska ◽  
Radosław Kujawski ◽  
Julia Słyńko-Krzyżostaniak ◽  
Przemysław Ł. Mikołajczak ◽  
Michał Szulc
Keyword(s):  
Alcohol Intake ◽  
Selective Reduction ◽  
Optimization Methods ◽  
Sugar Solution ◽  
Behavioral Studies ◽  
Potential Efficacy ◽  
Bioactive Ligands ◽  
Receptor Blockers ◽  
Rats And Mice ◽  
The Brain

Abstract Alcohol use disorder (AUD) is a severe and globally widespread neurological and psychiatric problem. The treatment with currently used drugs often does not bring the expected effect. New optimization methods or directions in pharmacotherapy are still being sought. The group of bioactive ligands, targeted at neuropeptides called orexins (OXs) and their receptors (OXRs), affects a number of functions including ingestion, sleep-wake regulation, as well as the brain reward system which is the basis of addiction. The purpose of this paper is to systematize the knowledge in the field of preclinical behavioral studies on rodents (rats and mice) in several models of alcohol consumption using the OXRs antagonists. The results of the experiments indicated a potential efficacy of particular OXRs antagonists in the AUD treatment, especially those selectively blocking the OX1R. Among them, SB-334867 in the lowest effective dose of 3 mg/kg i.p. was most studied, as shown in the model of two-bottle choice using C57BL/6 mice. Moreover, this compound did not affect the reduction of cognitive functions. GSK1059865 was also involved in the selective reduction of ethanol intake, and simultaneously did not alter the consumption of sugar solution. The other group of selective OX2R antagonists, such as TCS-OX2-29 and LSN2424100, was less efficient. In summary, the OX1R antagonists proved to have the potential in AUD therapy, not only through the reduction of ethanol consumption but also in the treatment of coexisting behavioral and physiological disorders, such as insomnia and anxiety.

scholarly journals Computational Modeling: Human Dynamic Model

2021 ◽  
Vol 15 ◽  
Author(s):  
Lijia Liu ◽  
Joseph L. Cooper ◽  
Dana H. Ballard
Keyword(s):  
Dynamic Model ◽  
Degrees Of Freedom ◽  
Dynamic Models ◽  
Movement Analysis ◽  
Human Movement ◽  
Uncontrolled Manifold ◽  
Human In The Loop ◽  
Joint Forces ◽  
Internal Joint ◽  
Movement Function

Improvements in quantitative measurements of human physical activity are proving extraordinarily useful for studying the underlying musculoskeletal system. Dynamic models of human movement support clinical efforts to analyze, rehabilitate injuries. They are also used in biomechanics to understand and diagnose motor pathologies, find new motor strategies that decrease the risk of injury, and predict potential problems from a particular procedure. In addition, they provide valuable constraints for understanding neural circuits. This paper describes a physics-based movement analysis method for analyzing and simulating bipedal humanoid movements. The model includes the major body segments and joints to report human movements' energetic components. Its 48 degrees of freedom strike a balance between very detailed models that include muscle models and straightforward two-dimensional models. It has sufficient accuracy to analyze and synthesize movements captured in real-time interactive applications, such as psychophysics experiments using virtual reality or human-in-the-loop teleoperation of a simulated robotic system. The dynamic model is fast and robust while still providing results sufficiently accurate to be used to animate a humanoid character. It can also estimate internal joint forces used during a movement to create effort-contingent stimuli and support controlled experiments to measure the dynamics generating human behaviors systematically. The paper describes the innovative features that allow the model to integrate its dynamic equations accurately and illustrates its performance and accuracy with demonstrations. The model has a two-foot stance ability, capable of generating results comparable with an experiment done with subjects, and illustrates the uncontrolled manifold concept. Additionally, the model's facility to capture large energetic databases opens new possibilities for theorizing as to human movement function. The model is freely available.

scholarly journals Preface. Religion and education

2014 ◽  
pp. 5-7
Author(s):  
Liudmyla O. Fylypovych
Keyword(s):  
Human Existence ◽  
New Approaches ◽  
The World ◽  
Information Research ◽  
External Forces ◽  
The Relationship ◽  
The Brain ◽  
Negative Sense

Religion and education are a topic that has emerged relatively recently in the Ukrainian information, research, and educational space. The relationship between religion and education meditated before, but usually in a negative sense. New circumstances also dictate new approaches to the stated topic. Polyphony of thoughts holds in itself and explicit criticism of any possibility of coexistence of religion and education, vulgarly linking religion with obscurantism, which can not bear any enlightenment, blurring the brain of a person. Such pre-historic estimates of religion are less and less popular in society, which in those years has "opened" a religion (as opposed to the present and still existing perception of it as a fantastic reflection in the heads of people of those external forces that prevail over them) as a spiritually rich reality as something that fills the meaning of human existence, defines the vocation of the person asserting it in the world, in society, in their own lives.

The Stories Stones Tell of Language and Its Evolution

2019 ◽  
pp. 304-318
Author(s):  
Shelby S. Putt
Keyword(s):  
Language Evolution ◽  
Evolutionary Relationship ◽  
Stone Tools ◽  
Stone Tool ◽  
Motor Tasks ◽  
Activation Patterns ◽  
Cognitive Operations ◽  
Pars Opercularis ◽  
The Brain ◽  
Neuroimaging Techniques

Language origins remain shrouded in mystery. With little remaining from our earliest ancestors, language evolution researchers have turned to stone tools to learn about ancestral language capacities, as discussed in this chapter. Because inferior frontal areas of the brain, once thought specific to language, are now known to participate during manual motor tasks as well, technological-origin hypotheses propose that tool-making was a potential cause or contributor to the evolution of language. Cutting-edge neuroimaging techniques to monitor regional brain activation patterns associated with tool-making processes are helping to investigate the potential evolutionary relationship between language and tool-making. These experiments have identified one area in the left dorsal pars opercularis portion of Broca’s area where language and stone tool-making functions rely on similar cognitive operations. A more general motor origin for language seems likely in other inferior frontal areas of the brain. Clearly, stone tools have stories to tell if we know how to listen.

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