scholarly journals Limb Dominance Results from Asymmetries in Predictive and Impedance Control Mechanisms

PLoS ONE ◽  
2014 ◽  
Vol 9 (4) ◽  
pp. e93892 ◽  
Author(s):  
Vivek Yadav ◽  
Robert L. Sainburg
Keyword(s):  
Impedance Control ◽  
Control Mechanisms ◽  
Limb Dominance

Different Mechanisms Involved in Adaptation to Stable and Unstable Dynamics

2003 ◽  
Vol 90 (5) ◽  
pp. 3255-3269 ◽  
Author(s):  
Rieko Osu ◽  
Etienne Burdet ◽  
David W. Franklin ◽  
Theodore E. Milner ◽  
Mitsuo Kawato
Keyword(s):  
Force Field ◽  
Inverse Dynamics ◽  
Impedance Control ◽  
Early Stage ◽  
Control Mechanisms ◽  
Dynamics Model ◽  
Trajectory Error ◽  
Feedback Error Learning ◽  
Model Formation ◽  
Unstable Dynamics

Recently, we demonstrated that humans can learn to make accurate movements in an unstable environment by controlling magnitude, shape, and orientation of the endpoint impedance. Although previous studies of human motor learning suggest that the brain acquires an inverse dynamics model of the novel environment, it is not known whether this control mechanism is operative in unstable environments. We compared learning of multijoint arm movements in a “velocity-dependent force field” (VF), which interacted with the arm in a stable manner, and learning in a “divergent force field” (DF), where the interaction was unstable. The characteristics of error evolution were markedly different in the 2 fields. The direction of trajectory error in the DF alternated to the left and right during the early stage of learning; that is, signed error was inconsistent from movement to movement and could not have guided learning of an inverse dynamics model. This contrasted sharply with trajectory error in the VF, which was initially biased and decayed in a manner that was consistent with rapid feedback error learning. EMG recorded before and after learning in the DF and VF are also consistent with different learning and control mechanisms for adapting to stable and unstable dynamics, that is, inverse dynamics model formation and impedance control. We also investigated adaptation to a rotated DF to examine the interplay between inverse dynamics model formation and impedance control. Our results suggest that an inverse dynamics model can function in parallel with an impedance controller to compensate for consistent perturbing force in unstable environments.

scholarly journals Similar stretch reflexes and behavioral patterns are expressed by the dominant and non-dominant arms during postural control

2021 ◽  
Author(s):  
Philipp Maurus ◽  
Isaac L. Kurtzer ◽  
Ryan Antonawich ◽  
Tyler Cluff
Keyword(s):  
Impedance Control ◽  
Behavioral Responses ◽  
Posture Control ◽  
Strong Correlations ◽  
Directional Tuning ◽  
Stretch Reflexes ◽  
Return Times ◽  
Control Limb ◽  
Limb Posture ◽  
Limb Dominance

Limb dominance is evident in many daily activities leading to the prominent idea that each hemisphere of the brain specializes in controlling different aspects of movement. Past studies suggest the dominant arm is primarily controlled via an internal model of limb dynamics that enables the nervous system to produce efficient movements. In contrast, the non-dominant arm may be primarily controlled via impedance mechanisms that rely on the strong modulation of sensory feedback from individual joints to control limb posture. We tested whether such differences are evident in behavioral responses and stretch reflexes following sudden displacement of the arm during posture control. Experiment 1 applied specific combinations of elbow-shoulder torque perturbations (the same for all participants). Peak joint displacements, return times, endpoint accuracy, and the directional tuning and amplitude of stretch reflexes in nearly all muscles were not statistically different between the two arms. Experiment 2 induced specific combinations of joint motion (the same for all participants). Again, peak joint displacements, return times, endpoint accuracy, and the directional tuning and amplitude of stretch reflexes in nearly all muscles did not differ statistically when countering the imposed loads with each arm. Moderate to strong correlations were found between stretch reflexes and behavioral responses to the perturbations with the two arms across both experiments. Collectively, the results do not support the idea that the dominant arm specializes in exploiting internal models and the non-dominant arm in impedance control by increasing reflex gains to counter sudden loads imposed on the arms during posture control.

scholarly journals Feedforward compensation for novel dynamics depends on force field orientation but is similar for the left and right arms

2016 ◽  
Vol 116 (5) ◽  
pp. 2260-2271 ◽  
Author(s):  
Eva-Maria Reuter ◽  
Ross Cunnington ◽  
Jason B. Mattingley ◽  
Stephan Riek ◽  
Timothy J. Carroll
Keyword(s):  
Force Field ◽  
Hybrid Control ◽  
Impedance Control ◽  
Dynamic Environment ◽  
Field Trials ◽  
Control Mechanisms ◽  
Functional Requirements ◽  
Field Orientation ◽  
Opposite Limb ◽  
Kinematic Errors

There are well-documented differences in the way that people typically perform identical motor tasks with their dominant and the nondominant arms. According to Yadav and Sainburg's ( Neuroscience 196: 153–167, 2011) hybrid-control model, this is because the two arms rely to different degrees on impedance control versus predictive control processes. Here, we assessed whether differences in limb control mechanisms influence the rate of feedforward compensation to a novel dynamic environment. Seventy-five healthy, right-handed participants, divided into four subsamples depending on the arm (left, right) and direction of the force field (ipsilateral, contralateral), reached to central targets in velocity-dependent curl force fields. We assessed the rate at which participants developed predictive compensation for the force field using intermittent error-clamp trials and assessed both kinematic errors and initial aiming angles in the field trials. Participants who were exposed to fields that pushed the limb toward ipsilateral space reduced kinematic errors more slowly, built up less predictive field compensation, and relied more on strategic reaiming than those exposed to contralateral fields. However, there were no significant differences in predictive field compensation or kinematic errors between limbs, suggesting that participants using either the left or the right arm could adapt equally well to novel dynamics. It therefore appears that the distinct preferences in control mechanisms typically observed for the dominant and nondominant arms reflect a default mode that is based on habitual functional requirements rather than an absolute limit in capacity to access the controller specialized for the opposite limb.

scholarly journals A myoelectric prosthetic hand with muscle synergy–based motion determination and impedance model–based biomimetic control

2019 ◽  
Vol 4 (31) ◽  
pp. eaaw6339 ◽  
Author(s):  
Akira Furui ◽  
Shintaro Eto ◽  
Kosuke Nakagaki ◽  
Kyohei Shimada ◽  
Go Nakamura ◽  
...  
Keyword(s):  
Upper Limb ◽  
Impedance Control ◽  
Three Dimensional ◽  
Human Motion ◽  
Muscle Synergy ◽  
Prosthetic Hand ◽  
Control Mechanisms ◽  
Finger Movements ◽  
Prosthetic Hands

Prosthetic hands are prescribed to patients who have suffered an amputation of the upper limb due to an accident or a disease. This is done to allow patients to regain functionality of their lost hands. Myoelectric prosthetic hands were found to have the possibility of implementing intuitive controls based on operator’s electromyogram (EMG) signals. These controls have been extensively studied and developed. In recent years, development costs and maintainability of prosthetic hands have been improved through three-dimensional (3D) printing technology. However, no previous studies have realized the advantages of EMG-based classification of multiple finger movements in conjunction with the introduction of advanced control mechanisms based on human motion. This paper proposes a 3D-printed myoelectric prosthetic hand and an accompanying control system. The muscle synergy–based motion-determination method and biomimetic impedance control are introduced in the proposed system, enabling the classification of unlearned combined motions and smooth and intuitive finger movements of the prosthetic hand. We evaluate the proposed system through operational experiments performed on six healthy participants and an upper-limb amputee participant. The experimental results demonstrate that our prosthetic hand system can successfully classify both learned single motions and unlearned combined motions from EMG signals with a high degree of accuracy. Furthermore, applications to real-world uses of prosthetic hands are demonstrated through control tasks conducted by the amputee participant.

Human enterocytic apoptosis and survival: Differentiation state-specific control mechanisms

2001 ◽  
Vol 120 (5) ◽  
pp. A502-A502
Author(s):  
R GAUTHIER ◽  
J DROLET ◽  
J REED ◽  
A VEZINA ◽  
P VACHON
Keyword(s):  
Control Mechanisms ◽  
Specific Control

Do Executive Motor-Control Mechanisms Regulate Monetary Choice and Gambling?

2011 ◽  
Author(s):  
Frederick Verbruggen ◽  
Rachel Adams ◽  
Chris Chambers
Keyword(s):  
Motor Control ◽  
Control Mechanisms

The Center for International Biomedical Communications Research

1966 ◽  
Vol 05 (03) ◽  
pp. 142-146
Author(s):  
A. Kent ◽  
P. J. Vinken
Keyword(s):  
Information Needs ◽  
English Language ◽  
Medical Information ◽  
Biomedical Literature ◽  
Information Storage ◽  
Control Mechanisms ◽  
University Of Pittsburgh ◽  
The World ◽  
The University ◽  
Excerpta Medica Foundation

A joint center has been established by the University of Pittsburgh and the Excerpta Medica Foundation. The basic objective of the Center is to seek ways in which the health sciences community may achieve increasingly convenient and economical access to scientific findings. The research center will make use of facilities and resources of both participating institutions. Cooperating from the University of Pittsburgh will be the School of Medicine, the Computation and Data Processing Center, and the Knowledge Availability Systems (KAS) Center. The KAS Center is an interdisciplinary organization engaging in research, operations, and teaching in the information sciences.Excerpta Medica Foundation, which is the largest international medical abstracting service in the world, with offices in Amsterdam, New York, London, Milan, Tokyo and Buenos Aires, will draw on its permanent medical staff of 54 specialists in charge of the 35 abstracting journals and other reference works prepared and published by the Foundation, the 700 eminent clinicians and researchers represented on its International Editorial Boards, and the 6,000 physicians who participate in its abstracting programs throughout the world. Excerpta Medica will also make available to the Center its long experience in the field, as well as its extensive resources of medical information accumulated during the Foundation’s twenty years of existence. These consist of over 1,300,000 English-language _abstract of the world’s biomedical literature, indexes to its abstracting journals, and the microfilm library in which complete original texts of all the 3,000 primary biomedical journals, monitored by Excerpta Medica in Amsterdam are stored since 1960.The objectives of the program of the combined Center include: (1) establishing a firm base of user relevance data; (2) developing improved vocabulary control mechanisms; (3) developing means of determining confidence limits of vocabulary control mechanisms in terms of user relevance data; 4. developing and field testing of new or improved media for providing medical literature to users; 5. developing methods for determining the relationship between learning and relevance in medical information storage and retrieval systems’; and (6) exploring automatic methods for retrospective searching of the specialized indexes of Excerpta Medica.The priority projects to be undertaken by the Center are (1) the investigation of the information needs of medical scientists, and (2) the development of a highly detailed Master List of Biomedical Indexing Terms. Excerpta Medica has already been at work on the latter project for several years.

Control of Thrombin Mediated Cleavage of Protein S

1986 ◽  
Vol 56 (02) ◽  
pp. 151-154 ◽  
Author(s):  
Christina A Mitchell ◽  
Lena Hau ◽  
Hatem H Salem
Keyword(s):  
Anticoagulant Activity ◽  
Activated Protein C ◽  
Surface Protein ◽  
Protein S ◽  
Intact Protein ◽  
Control Mechanisms ◽  
Physiological Control ◽  
Endothelial Cell Surface ◽  
Thrombin Cleavage ◽  
Cofactor Activity

SummaryThrombin has been shown to cleave the vitamin K dependent cofactor protein S with subsequent loss of its cofactor activity. This study examines the control mechanisms for thrombin cleavage of protein S.The anticoagulant activity of activated protein C (APC) is enhanced fourteen fold by the addition of protein S. Thrombin cleaved protein S is seven fold less efficient than the native protein, and this loss of activity is due to reduced affinity of cleaved protein S for APC or the lipid surface compared to the intact protein.In the absence of Ca++, protein S is very sensitive to minimal concentrations of thrombin. As little as 1.5 nM thrombin results in complete cleavage of 20 nM protein S in 10 min and loss of cofactor activity. Ca++, in concentrations greater than 0.5 mM, will inhibit this cleavage and in the presence of physiological Ca++ concentrations, no cleavage of protein S could be demonstrated in spite of high concentrations of thrombin (up to 1 μM) and prolonged incubations (up to two hours). The endothelial surface protein thrombomodulin is very efficient in inhibiting the cleavage of protein S by thrombin suggesting that any thrombin formed on the endothelial cell surface is unlikely to cleave protein S, thus allowing the intact protein to act as a cofactor to APC.We conclude that the inhibitory effects of Ca++ and thrombomodulin on thrombin mediated cleavage of protein S imply that this event, by itself, is unlikely to represent a physiological control of the activity of protein S.

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