scholarly journals Feasibility of Muscle Synergy Outcomes in Clinics, Robotics, and Sports: A Systematic Review

2018 ◽  
Vol 2018 ◽  
pp. 1-19 ◽  
Author(s):  
Juri Taborri ◽  
Valentina Agostini ◽  
Panagiotis K. Artemiadis ◽  
Marco Ghislieri ◽  
Daniel A. Jacobs ◽  
...  
Keyword(s):  
Central Nervous System ◽  
Nervous System ◽  
Motor Task ◽  
Muscle Synergy ◽  
Modular Organization ◽  
Single Subject ◽  
Muscle Synergies ◽  
Neural Encoding ◽  
Research Fields ◽  
The Central Nervous System

In the last years, several studies have been focused on understanding how the central nervous system controls muscles to perform a specific motor task. Although it still remains an open question, muscle synergies have come to be an appealing theory to explain the modular organization of the central nervous system. Even though the neural encoding of muscle synergies remains controversial, a large number of papers demonstrated that muscle synergies are robust across different tested conditions, which are within a day, between days, within a single subject, and between subjects that have similar demographic characteristics. Thus, muscle synergy theory has been largely used in several research fields, such as clinics, robotics, and sports. The present systematical review aims at providing an overview on the applications of muscle synergy theory in clinics, robotics, and sports; in particular, the review is focused on the papers that provide tangible information for (i) diagnosis or pathology assessment in clinics, (ii) robot-control design in robotics, and (iii) athletes’ performance assessment or training guidelines in sports.

scholarly journals Modular organization of the murine locomotor pattern in presence and absence of sensory feedback from muscle spindles

2018 ◽  
Author(s):  
Alessandro Santuz ◽  
Turgay Akay ◽  
William P. Mayer ◽  
Tyler L. Wells ◽  
Arno Schroll ◽  
...  
Keyword(s):  
Central Nervous System ◽  
Nervous System ◽  
Sensory Feedback ◽  
Genetically Modified ◽  
Muscle Spindles ◽  
Modular Organization ◽  
Muscle Synergies ◽  
Activation Patterns ◽  
The Central Nervous System ◽  
Genetically Modified Mice

AbstractFor exploiting terrestrial and aquatic locomotion, vertebrates must build their locomotor patterns based on an enormous amount of variables. The great number of muscles and joints, together with the constant need for sensory feedback information (e.g. proprioception), make the task of creating and controlling movement a problem with overabundant degrees of freedom. It is widely accepted that the central nervous system might simplify the creation and control of movement. This could happen through the generation of activation patterns, which are common to many different muscles, rather than specific to individual muscles. These activation patterns, called muscle synergies, can be extracted from electromyographic data and describe the modular organization of movement. We extracted muscle synergies from the hindlimb muscle activities of wild type and genetically modified mice, in which sensory feedback from muscle spindles is eliminated. Muscle spindle-deficient mice underwent a modification of the temporal structure (motor primitives) of muscle synergies that resulted in diminished functionality during walking. In addition, both the temporal and spatial components (motor modules) of muscle synergies were severely affected when external perturbations were introduced of when animals were immersed in water. These findings show that group Ia/II sensory feedback from muscle spindles regulates motor function in normal and perturbed walking. Moreover, when group Ib Golgi tendon organ feedback is lacking due to the reduction of gravitational load in conditions of enhanced buoyancy, the modular organization of swimming is almost completely compromised.Significance statementLocomotion on land and in water requires the coordination of a great number of muscle activations and joint movements. Moreover, constant feedback about the position of own body parts in relation to the surrounding environment and the body itself (proprioception) is required to maintain stability and avoid failure. The theory of muscle synergies states that the central nervous system might control muscles in orchestrated groups (synergies) rather than individually. We used this concept on genetically modified mice, lacking one of the two classes of proprioceptors. Our results provide evidence that proprioceptive feedback is required by the central nervous system to accurately tune the modular organization of locomotion.

scholarly journals A Fair and EMG-validated Comparison of Recruitment Criteria, Musculotendon Models and Muscle Coordination Strategies, for the Inverse-dynamics Based Optimization of Muscle Forces During Gait

2020 ◽  
Author(s):  
Florian MICHAUD ◽  
Mario Lamas ◽  
Urbano Lugrís ◽  
Javier Cuadrado
Keyword(s):  
Central Nervous System ◽  
Nervous System ◽  
Cost Function ◽  
Inverse Dynamics ◽  
Experimental Studies ◽  
Motor Task ◽  
Muscle Coordination ◽  
Actuator Dynamics ◽  
Moment Arms ◽  
The Central Nervous System

Abstract Experimental studies and EMG collections suggest that a specific strategy of muscle coordination is chosen by the central nervous system to perform a given motor task. A popular mathematical approach for solving the muscle recruitment problem is optimization. Optimization-based methods minimize or maximize some criterion (objective function or cost function) which reflects the mechanism used by the central nervous system to recruit muscles for the movement considered. The proper cost function is not known a priori, so the adequacy of the chosen function must be validated according to the obtained results. In addition of the many criteria proposed, several physiological representations of the musculotendon actuator dynamics along with different musculoskeletal models can be found in the literature, which hinders the selection of the best neuromusculotendon model for each application. Seeking to provide a fair base for comparison, this study measures the efficiency and accuracy of: i) four different criteria; ii) one static and three physiological representations of the musculotendon actuator dynamics; iii) a synergy-based method; all of them within the framework of inverse-dynamics based optimization. Motion/force/EMG gait analyses were performed on ten healthy subjects. A musculoskeletal model of the right leg actuated by 43 Hill-type muscles was scaled to each subject and used to calculate joint moments, musculotendon kinematics and moment arms. Muscle activations were then estimated using the different approaches, and these estimates were compared with EMG measurements. Although similar results were obtained with all the methods, it must be pointed out that a higher complexity of the method does not guarantee better results, as the best correlations with experimental values were obtained with two simplified approaches.

scholarly journals Flexible recruitments of fundamental muscle synergies in the trunk and lower limbs for highly variable movements and postures

2021 ◽  
Author(s):  
Hiroki Saito ◽  
Hikaru Yokoyama ◽  
Atsushi Sasaki ◽  
Tatsuya Kato ◽  
Kimitaka Nakazawa
Keyword(s):  
Central Nervous System ◽  
Nervous System ◽  
Neural Control ◽  
Static Stability ◽  
Neural Representation ◽  
Lower Limbs ◽  
Muscle Synergies ◽  
Lower Limb Muscles ◽  
The Central Nervous System ◽  
Almost All

The extent to which muscle synergies represent the neural control of human behavior remains unknown. Here, we tested whether certain sets of muscle synergies that are fundamentally necessary across behaviors exist. We measured the electromyographic activities of 26 muscles including bilateral trunk and lower limb muscles during 24 locomotion, dynamic and static stability tasks, and extracted the muscle synergies using non-negative matrix factorization. Our results showed that 13 muscle synergies that may have unique functional roles accounted for almost all 24 tasks by combinations of single and/or merging of synergies. Therefore, our results may support the notion of the low dimensionality in motor outputs, in which the central nervous system flexibly recruits fundamental muscle synergies to execute diverse human behaviors. Further studies using manipulations of the central nervous system and/or neural recording are required the neural representation with such fundamental components of muscle synergies.

scholarly journals When 90% of the variance is not enough: residual EMG from muscle synergy extraction influences task performance

2020 ◽  
Vol 123 (6) ◽  
pp. 2180-2190 ◽  
Author(s):  
Victor R. Barradas ◽  
Jason J. Kutch ◽  
Toshihiro Kawase ◽  
Yasuharu Koike ◽  
Nicolas Schweighofer
Keyword(s):  
Central Nervous System ◽  
Nervous System ◽  
Motor Control ◽  
Dimensionality Reduction ◽  
Task Performance ◽  
Muscle Activity ◽  
Muscle Synergy ◽  
Systematic Effect ◽  
Extraction Techniques ◽  
The Central Nervous System

The muscle synergy hypothesis posits that the central nervous system simplifies motor control by grouping muscles into modules. Current techniques use dimensionality reduction, such that the identified synergies reconstruct 90% of the muscle activity. We show that residual muscle activity following such identification can have a large systematic effect on movements, even when the number of synergies approaches the number of muscles. Current synergy extraction techniques must therefore be updated to identify true physiological synergies.

scholarly journals Humans exploit robust locomotion by improving the stability of control signals

2019 ◽  
Author(s):  
Alessandro Santuz ◽  
Leon Brüll ◽  
Antonis Ekizos ◽  
Arno Schroll ◽  
Nils Eckardt ◽  
...  
Keyword(s):  
Central Nervous System ◽  
Nervous System ◽  
Older Age ◽  
Muscle Synergies ◽  
Rough Terrain ◽  
Control Signals ◽  
Age Related ◽  
The Central Nervous System ◽  
The Stability ◽  
Over Time

AbstractIs the control of movement less stable when we walk or run in challenging settings? One might intuitively answer affirmatively, given that adding constraints to locomotion (e.g. rough terrain, age-related impairments, etc.) imply less stable movements. We investigated how young and old humans synergistically activate muscles during locomotion, when different perturbation levels are introduced. Of these control signals, called muscle synergies, we then analyzed the stability over time. Surprisingly, we found that perturbations and older age force the central nervous system to produce more stable signals. These outcomes show that robust locomotion in challenging settings is achieved by increasing the stability of control signals, whereas easier tasks allow for more unstable control.

Effects of Hyperoxia on Lung Utrastructure

1970 ◽  
Vol 28 ◽  
pp. 26-27
Author(s):  
Gladys Harrison
Keyword(s):  
Central Nervous System ◽  
Nervous System ◽  
Light Microscopy ◽  
Oxygen Effects ◽  
Age Dependent ◽  
The Central Nervous System ◽  
The Subject ◽  
Space Age ◽  
Alveolar Septa ◽  
Extensive Damage

With the advent of the space age and the need to determine the requirements for a space cabin atmosphere, oxygen effects came into increased importance, even though these effects have been the subject of continuous research for many years. In fact, Priestly initiated oxygen research when in 1775 he published his results of isolating oxygen and described the effects of breathing it on himself and two mice, the only creatures to have had the “privilege” of breathing this “pure air”.Early studies had demonstrated the central nervous system effects at pressures above one atmosphere. Light microscopy revealed extensive damage to the lungs at one atmosphere. These changes which included perivascular and peribronchial edema, focal hemorrhage, rupture of the alveolar septa, and widespread edema, resulted in death of the animal in less than one week. The severity of the symptoms differed between species and was age dependent, with young animals being more resistant.

Emigration of neutrophils in the central nervous system

1983 ◽  
Vol 41 ◽  
pp. 788-789
Author(s):  
John L.Beggs ◽  
John D. Waggener ◽  
Wanda Miller ◽  
Jane Watkins
Keyword(s):  
Central Nervous System ◽  
Nervous System ◽  
Osmium Tetroxide ◽  
White Blood Cells ◽  
Arterial Perfusion ◽  
E Coli ◽  
Intracisternal Injection ◽  
The Central Nervous System ◽  
Brain And Spinal Cord ◽  
Interendothelial Junctions

Studies using mesenteric and ear chamber preparations have shown that interendothelial junctions provide the route for neutrophil emigration during inflammation. The term emigration refers to the passage of white blood cells across the endothelium from the vascular lumen. Although the precise pathway of transendo- thelial emigration in the central nervous system (CNS) has not been resolved, the presence of different physiological and morphological (tight junctions) properties of CNS endothelium may dictate alternate emigration pathways.To study neutrophil emigration in the CNS, we induced meningitis in guinea pigs by intracisternal injection of E. coli bacteria.In this model, leptomeningeal inflammation is well developed by 3 hr. After 3 1/2 hr, animals were sacrificed by arterial perfusion with 3% phosphate buffered glutaraldehyde. Tissues from brain and spinal cord were post-fixed in 1% osmium tetroxide, dehydrated in alcohols and propylene oxide, and embedded in Epon. Thin serial sections were cut with diamond knives and examined in a Philips 300 electron microscope.

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