Identifying representative synergy matrices for describing muscular activation patterns during multidirectional reaching in the horizontal plane.

  title={Identifying representative synergy matrices for describing muscular activation patterns during multidirectional reaching in the horizontal plane.},
  author={Silvia Muceli and Andreas Tr{\o}llund Boye and Andrea d’Avella and Dario Farina},
  journal={Journal of neurophysiology},
  volume={103 3},
Muscle synergies have been proposed as a simplifying principle of generation of movements based on a low-dimensional control by the CNS. This principle may be useful for movement restoration by, e.g., functional electrical stimulation (FES), if a limited set of synergies can describe several functional tasks. This study investigates the possibility of describing a multijoint reaching task of the upper limb by a linear combination of one set of muscle synergies common to multiple directions… 

Figures and Tables from this paper

Direction Modulation of Muscle Synergies in a Hand-Reaching Task

Muscle synergies that were extracted from movements to the center of the reaching space could be generalized to synergies for other movement directions, and might reinforce the notion that the CNS flexibly combines a single set of small number of synergies in different amplitudes to modulate movement for different directions.

Modulation of muscle synergies with direction and distance during reaching movements

The results demonstrate that the control of a repertoire of reaching movements can be achieved by flexibly modulating the activation of several muscle synergies.

Robustness of muscle synergies underlying three-dimensional force generation at the hand in healthy humans.

The findings of this study are consistent with the view that the nervous system can generate isometric forces by assembling a combination of a small number of muscle synergies, differentially weighted according to task constraints.

Muscle synergy extraction during arm reaching movements at different speeds.

The results indicated a lower reconstruction error using the center of the muscle synergy clusters in comparison with the average of the activation coefficients, which confirms the current research's hypothesis of human reaching movements at different speeds.

Biceps Brachii Muscle Synergy and Target Reaching in a Virtual Environment

This work investigates how a muscle synergy extracted from a single muscle can be at the origin of different signals which could facilitate the control of modern upper limb myoelectric prostheses with many degrees of freedom.

Muscle Synergies Control during Hand-Reaching Tasks in Multiple Directions Post-stroke

The study findings support the existence of a representative set of synergies, which are modulated to execute movements in different directions, which were suggested to represent a simplifying motor control mechanism by the brainstem and spinal cord.

Are muscle synergies useful for neural control?

It is shown that the number of synergies required to approximate the optimal muscle pattern for an arbitrary biomechanical system increases with task-space dimensionality, which indicates that the capacity of synergy decomposition to explain behavior depends critically on the scope of the original database.

Applying muscle synergy analysis to forearm high-density electromyography of healthy people

The findings suggest that applying muscle synergy analysis to HDEMG is feasible, and that the traditional muscle synergies defined by whole-muscle components may be broadened to include sub-Muscle components represented by the HDEMGs channels.

The flexible recruitment of muscle synergies depends on the required force-generating capability.

It is suggested that the CNS selects appropriate muscle synergies and controls their activation patterns based on the force-generating capability of muscles with merging or decomposing descending neural inputs.

Reorganization of muscle synergies during multidirectional reaching in the horizontal plane with experimental muscle pain.

Results indicate that nociceptive stimulation may induce a reorganization of modular control in reaching, and speculate that such reorganization may be due to the recruitment of synergies specific to the painful condition.



A limited set of muscle synergies for force control during a postural task.

It is suggested that, within the context of active balance control, postural synergies reflect a neural command signal that specifies endpoint force of a limb.

Muscular and postural synergies of the human hand.

It appears that the organization of the global pattern of hand muscle activation is highly distributed, which mirrors the highly fractured somatotopy of cortical hand representations and may provide an ideal substrate for motor learning and recovery from injury.

Modulation of phasic and tonic muscle synergies with reaching direction and speed.

It is found that the amplitude modulation of three time-invariant synergies captured the variations in the postural muscle patterns at the end of the movement, suggesting that muscle synergies are basic control modules that allow generating the appropriate muscle patterns through simple modulation and combination rules.

Combinations of muscle synergies in the construction of a natural motor behavior

It is shown that combinations of three time-varying muscle synergies underlie the variety of muscle patterns required to kick in different directions, that the recruitment of these synergies is related to movement kinematics, and that there are similarities among the synergies extracted from different behaviors.

Muscle synergies characterizing human postural responses.

The results suggest that muscle synergies represent a general neural strategy underlying muscle coordination in postural tasks that represents variations in the amplitude of descending neural commands that activate individual Muscle synergies.

Five basic muscle activation patterns account for muscle activity during human locomotion

A systematic phase shift of all five factors with speed in the same direction as the shift in the onset of the swing phase supports the idea that the origin of the gait cycle generation is the propulsion rather than heel strike event.

General coordination of shoulder, elbow and wrist dynamics during multijoint arm movements

A difference in dynamics between joints is a general feature of horizontal plane arm movements, and this difference is most commonly reflected in a shoulder-centered pattern, which fits well with other general shoulder-elbow differences suggested in the literature on arm movements.

Simplified and effective motor control based on muscle synergies to exploit musculoskeletal dynamics

This study proposes a principle for the design of a low-dimensional controller, that it endeavors to control the natural dynamics of the limb, taking into account the nature of the task being performed.

Feasibility of EMG-Based Neural Network Controller for an Upper Extremity Neuroprosthesis

A neural network controller based on an artificial neural network that extracts information from the activity of muscles that remain under voluntary control sufficient to predict appropriate stimulation levels for several paralyzed muscles in the upper extremity was designed.

Muscle synergies as a predictive framework for the EMG patterns of new hand postures.

It is suggested that global muscle coordination may be a combination of higher order control of robust subject-specific muscle synergies and lower order controlof individuated muscles, and that this control paradigm may be useful in the control of EMG-based technologies, such as artificial limbs and functional electrical stimulation systems.