Fusimotor control of spindle sensitivity regulates central and peripheral coding of joint angles

Lan, Ning; He, Xin

doi:10.3389/fncom.2012.00066

Cited by 24 publications

(24 citation statements)

References 44 publications

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“…The centrally encoded joint angle information is conveyed to the periphery by a plausible function of γ fusimotor control through regulating spindle sensitivity, so that the Ia signaling from spindle afferents is kept faithfully proportional to the joint angle during the movement and muscle contraction [54]. In our study, significant difference on the mean WP-LPSE values in each time interval exists among different angles of elbow flexion (Figures 3 and 4).…”

Section: Discussionmentioning

confidence: 71%

Local Band Spectral Entropy Based on Wavelet Packet Applied to Surface EMG Signals Analysis

Chen

Xie

Liu

et al. 2016

Entropy

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An efficient analytical method for electromyogram (EMG) signals is of great significance to research the inherent mechanism of a motor-control system. In this paper, we proposed an improved approach named wavelet-packet-based local band spectral entropy (WP-LBSE) by introducing the concept of frequency band local-energy (ELF) into the wavelet packet entropy, in order to characterize the time-varying complexity of the EMG signals in the local frequency band. The EMG data were recorded from the biceps brachii (BB) muscle and triceps brachii (TB) muscle at 40˝, 100˝and 180ő f elbow flexion by 10 healthy participants. Significant differences existed among any pair of the three patterns (p < 0.05). The WP-LBSE values of the EMG signals in BB muscle and TB muscle demonstrated a decreased tendency from 40˝to 180˝of elbow flexion, while the distributions of spectral energy were decreased to a stable state as time periods progressed under the same pattern. The result of this present work is helpful to describe the time-varying complexity characteristics of the EMG signals under different joint angles, and is meaningful to research the dynamic variation of the activated motor units and muscle fibers in the motor-control system.

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Section: Discussionmentioning

confidence: 71%

Local Band Spectral Entropy Based on Wavelet Packet Applied to Surface EMG Signals Analysis

Chen

Xie

Liu

et al. 2016

Entropy

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“…We neglect other types of proprioceptive feedback, for example from Golgi tendon organs, which may provide a link to joint-based control (Kistemaker et al, 2013). Furthermore, more detailed representations of the proprioceptors (Loeb and Mileusnic, 2015) allow for a detailed analysis of, e.g., the role of alpha-gamma co-activation (Lan and Zhu, 2007;Lan and He, 2012).…”

Section: Model Assumptions and Limitationsmentioning

confidence: 99%

Predicting Perturbed Human Arm Movements in a Neuro-Musculoskeletal Model to Investigate the Muscular Force Response

Stollenmaier

Ilg

Haeufle

2020

Front. Bioeng. Biotechnol.

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Human movement is generated by a dynamic interplay between the nervous system, the biomechanical structures, and the environment. To investigate this interaction, we propose a neuro-musculoskeletal model of human goal-directed arm movements. Using this model, we simulated static perturbations of the inertia and damping properties of the arm, as well as dynamic torque perturbations for one-degree-of freedom movements around the elbow joint. The controller consists of a feed-forward motor command and feedback based on muscle fiber length and contraction velocity representing short-latency (25 ms) or long-latency (50 ms) stretch reflexes as the first neuronal responses elicited by an external perturbation. To determine the open-loop control signal, we parameterized the control signal resulting in a piecewise constant stimulation over time for each muscle. Interestingly, such an intermittent open-loop signal results in a smooth movement that is close to experimental observations. So, our model can generate the unperturbed point-to-point movement solely by the feed-forward command. The feedback only contributed to the stimulation in perturbed movements. We found that the relative contribution of this feedback is small compared to the feed-forward control and that the characteristics of the musculoskeletal system create an immediate and beneficial reaction to the investigated perturbations. The novelty of these findings is (1) the reproduction of static as well as dynamic perturbation experiments in one neuro-musculoskeletal model with only one set of basic parameters. This allows to investigate the model's neuro-muscular response to the perturbations that-at least to some degree-represent stereotypical interactions with the environment; (2) the demonstration that in feed-forward driven movements the muscle characteristics generate a mechanical response with zero-time delay which helps to compensate for the perturbations; (3) that this model provides enough biomechanical detail to allow for the prediction of internal forces, including joint loads and muscle-bone contact forces which are relevant in ergonomics and for the development of assistive devices but cannot be observed in experiments.

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“…The physiological system of human motor control is not only highly redundant (Bernstein, 1967 ; Martin et al, 2009 ), but also endowed with intricate dual α and γ sensorimotor control (Granit, 1975 ; Pierrot-Deseilligny and Burke, 2005 ; Lan and He, 2012 ; Prochazka and Ellaway, 2012 ). Our understanding about how movements are organized and how muscles are coordinated in performing different tasks remains incomplete due to lack of in vivo data during behaviors.…”

Section: Introductionmentioning

confidence: 99%

“…The co-activation of γ motoneurons with α motor activity was generally viewed to compensate for the unloading effects of muscle contraction to spindle sensitivity. Using a realistic virtual arm (VA) model (He et al, 2013 ), Lan and He ( 2012 ) suggested a plausible function of γ s fusimotor control to convey centrally encoded joint angle information to the periphery through regulating spindle sensitivity, so that the Ia signaling from spindle afferents is kept faithfully proportional to the joint angle during movement and muscle contraction. This not only explains γ co-activation with α activity, but also supports the hypothesis that the γ s command reinforces the centrally planned kinematics of movement and posture by way of spinal circuits.…”

Section: Introductionmentioning

confidence: 99%

Coordinated alpha and gamma control of muscles and spindles in movement and posture

Cheng

Hao

et al. 2015

Front. Comput. Neurosci.

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Mounting evidence suggests that both α and γ motoneurons are active during movement and posture, but how does the central motor system coordinate the α-γ controls in these tasks remains sketchy due to lack of in vivo data. Here a computational model of α-γ control of muscles and spindles was used to investigate α-γ integration and coordination for movement and posture. The model comprised physiologically realistic spinal circuitry, muscles, proprioceptors, and skeletal biomechanics. In the model, we divided the cortical descending commands into static and dynamic sets, where static commands (αs and γs) were for posture maintenance and dynamic commands (αd and γd) were responsible for movement. We matched our model to human reaching movement data by straightforward adjustments of descending commands derived from either minimal-jerk trajectories or human EMGs. The matched movement showed smooth reach-to-hold trajectories qualitatively close to human behaviors, and the reproduced EMGs showed the classic tri-phasic patterns. In particular, the function of γd was to gate the αd command at the propriospinal neurons (PN) such that antagonistic muscles can accelerate or decelerate the limb with proper timing. Independent control of joint position and stiffness could be achieved by adjusting static commands. Deefferentation in the model indicated that accurate static commands of αs and γs are essential to achieve stable terminal posture precisely, and that the γd command is as important as the αd command in controlling antagonistic muscles for desired movements. Deafferentation in the model showed that losing proprioceptive afferents mainly affected the terminal position of movement, similar to the abnormal behaviors observed in human and animals. Our results illustrated that tuning the simple forms of α-γ commands can reproduce a range of human reach-to-hold movements, and it is necessary to coordinate the set of α-γ descending commands for accurate and stable control of movement and posture.

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Fusimotor control of spindle sensitivity regulates central and peripheral coding of joint angles

Cited by 24 publications

References 44 publications

Local Band Spectral Entropy Based on Wavelet Packet Applied to Surface EMG Signals Analysis

Local Band Spectral Entropy Based on Wavelet Packet Applied to Surface EMG Signals Analysis

Predicting Perturbed Human Arm Movements in a Neuro-Musculoskeletal Model to Investigate the Muscular Force Response

Coordinated alpha and gamma control of muscles and spindles in movement and posture

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