Rebalancing the Spastic Wrist by Transposition of Antagonistic Muscle-Tendon Complex

2021 ◽  
Vol Publish Ahead of Print ◽  
Author(s):  
Silvia Schibli ◽  
Jan Fridén
Keyword(s):  
Antagonistic Muscle

Excitability of primary afferents in feline spinal cord: taurine, homotaurine, and γ-aminobutyric acid compared

1982 ◽  
Vol 60 (6) ◽  
pp. 850-855 ◽  
Author(s):  
Radan Čapek ◽  
Barbara Esplin
Keyword(s):  
Primary Afferents ◽  
Aminobutyric Acid ◽  
Primary Afferent Depolarization ◽  
Conditioning Stimulation ◽  
Primary Afferent ◽  
Antagonistic Muscle ◽  
Consistent Change ◽  
Muscle Nerve ◽  
Gaba Synthesis ◽  
Stimulation Of

Effects of taurine and homotaurine (3-aminopropancsuIfonic acid), on excitability of primary afferents were compared with effects of γ-aminobutyric acid (GABA) in spinal unanaesthesized cats. Homotaurine and GABA, administered intravenously or topically, produced a marked increase in afferent excitability. Homotaurine was about 10 times more potent than GABA. Taurine (up to 2 mmol/kg i.v., or 10 mM topically) did not produce a consistent change in afferent excitability. The effect of homotaurine was antagonized by bicuculline or picrotoxin in doses which suppressed the primary afferent depolarization, as indicated by an increase of afferent excitability, evoked by conditioning stimulation of an antagonistic muscle nerve. Semicarbazidc, an inhibitor of GABA synthesis, did not attenuate the homotaurine-induced excitability changes of afferents while suppressing entirely the primary afferent depolarization. These findings suggest that homotaurine exerts a direct GABA-like action on feline primary afferents.

scholarly journals Enhancing the smoothness of joint motion induced by functional electrical stimulation using co-activation strategies

2017 ◽  
Vol 3 (2) ◽  
pp. 155-159
Author(s):  
Mirjana Ruppel ◽  
Christian Klauer ◽  
Thomas Schauer
Keyword(s):  
Electrical Stimulation ◽  
Functional Electrical Stimulation ◽  
Joint Stiffness ◽  
Joint Motion ◽  
Activation Level ◽  
Pendulum Test ◽  
Co Activation ◽  
Antagonistic Muscle ◽  
Induced Motion ◽  
Neuroprosthetic Devices

AbstractThe motor precision of today’s neuroprosthetic devices that use artificial generation of limb motion using Functional Electrical Stimulation (FES) is generally low. We investigate the adoption of natural co-activation strategies as present in antagonistic muscle pairs aiming to improve motor precision produced by FES. In a test in which artificial knee-joint movements were generated, we could improve the smoothness of FES-induced motion by 513% when applying co-activation during the phases in which torque production is switched between muscles – compared to no co-activation. We further demonstrated how the co-activation level influences the joint stiffness in a pendulum test.

scholarly journals Human motor fatigability as evoked by repetitive movements results from a gradual breakdown of surround inhibition

2019 ◽  
Author(s):  
Marc Bächinger ◽  
Rea Lehner ◽  
Felix Thomas ◽  
Samira Hanimann ◽  
Joshua Henk Balsters ◽  
...  
Keyword(s):  
Primary Motor Cortex ◽  
Extended Period ◽  
Movement Speed ◽  
Central Component ◽  
Surround Inhibition ◽  
Link Performance ◽  
Motor Network ◽  
Antagonistic Muscle ◽  
Human Motor ◽  
Muscle Groups

SummaryMotor fatigability emerges when demanding tasks are executed over an extended period of time. Here, we used repetitive low-force movements that cause a gradual reduction in movement speed (or “motor slowing”) to study the central component of fatigability in healthy adults. We show that motor slowing is associated with a gradual increase of net excitability in the motor network and, specifically, in primary motor cortex (M1), which results from overall disinhibition. Importantly, we link performance decrements to a breakdown of surround inhibition in M1, which is associated with high coactivation of antagonistic muscle groups. This is consistent with the model that a loss of inhibitory control might broaden the tuning of population vectors such that movement patterns become more variable, ill-timed and effortful. We propose that the release of inhibition in M1 is an important mechanism underpinning motor fatigability and, potentially, also pathological fatigue as frequently observed in patients with brain disorders.

Re-description of Azygokeras columbiae Koeller & Littlepage, 1976 (Calanoida: Aetideidae) and musculature of the male grasping antennule

Zootaxa ◽  
2019 ◽  
Vol 4565 (3) ◽  
pp. 361
Author(s):  
JANET M. BRADFORD-GRIEVE ◽  
GEOFFREY A. BOXSHALL
Keyword(s):  
British Columbia ◽  
Knee Joint ◽  
Original Description ◽  
Antagonistic Muscle ◽  
The Right

Azygokeras columbiae from Bute Inlet, British Columbia, Canada, is re-described, correcting some details and adding information not available in the original description. Azygokeras columbiae is unique amongst male Aetideidae in having the right antennule modified for grasping but without a true knee joint (geniculation) between segments XX and XXI nor a hiatus in the musculature at this joint, typical of taxa with a geniculate male antennule. Male Azygokeras have wide pivot points and arthrodial membranes between segments XXI and XXII, XXIII and XXIV and XXV and XXVI that allow greater movement in several planes than in homologous segments of Euaugaptilus and Heterorhabdus. Modifications of the terminal antennular joints allow for extensive movement in several planes associated with a series of short muscles in segments XIX to XXVI. These muscles become progressively more massive from proximal to distal on the antennule and are paired with an antagonistic muscle also increasing in mass distally. 

Prediction of Antagonistic Muscle Forces Using Inverse Dynamic Optimization During Flexion/Extension of the Knee

1999 ◽  
Vol 121 (3) ◽  
pp. 316-322 ◽  
Author(s):  
G. Li ◽  
K. R. Kaufman ◽  
E. Y. S. Chao ◽  
H. E. Rubash
Keyword(s):  
Dynamic Optimization ◽  
Optimization Procedure ◽  
Muscle Forces ◽  
Inverse Dynamic ◽  
Optimization Criteria ◽  
Flexion Extension ◽  
Antagonistic Muscle ◽  
Joint Reaction Forces ◽  
Reaction Forces ◽  
Joint Reaction

This paper examined the feasibility of using different optimization criteria in inverse dynamic optimization to predict antagonistic muscle forces and joint reaction forces during isokinetic flexion/extension and isometric extension exercises of the knee. Both quadriceps and hamstrings muscle groups were included in this study. The knee joint motion included flexion/extension, varus/valgus, and internal/external rotations. Four linear, nonlinear, and physiological optimization criteria were utilized in the optimization procedure. All optimization criteria adopted in this paper were shown to be able to predict antagonistic muscle contraction during flexion and extension of the knee. The predicted muscle forces were compared in temporal patterns with EMG activities (averaged data measured from five subjects). Joint reaction forces were predicted to be similar using all optimization criteria. In comparison with previous studies, these results suggested that the kinematic information involved in the inverse dynamic optimization plays an important role in prediction of the recruitment of antagonistic muscles rather than the selection of a particular optimization criterion. Therefore, it might be concluded that a properly formulated inverse dynamic optimization procedure should describe the knee joint rotation in three orthogonal planes.

scholarly journals THE ANALYSIS OF NEUROMUSCULAR MECHANISMS IN CHITON

1920 ◽  
Vol 2 (6) ◽  
pp. 627-634 ◽  
Author(s):  
W. J. Crozier
Keyword(s):  
Early Stage ◽  
Ventral Surface ◽  
Reciprocal Inhibition ◽  
Relative Strength ◽  
The Body ◽  
Antagonistic Muscle ◽  
Flexor Muscles ◽  
Neuromuscular Apparatus ◽  
Neuromuscular Responses ◽  
Muscle Groups

1. The degree of curvature of the body and of the girdle of a Chiton is determined by the activity of antagonistic muscle groups. At a certain, early stage in the strychninization of a Chiton the reciprocal inhibition involved in the natural use of these muscle groups is reversed, such that extensor muscles, rather than, as normally, flexor muscles, contract as the result of stimulation. This condition involves a reversal, under strychnine, of the normally positive stereotropism of the foot, and of the usual response of the mollusk to an increased illumination of its ventral surface. Strychnine reversal of this character is not a matter of the relative strength of the opposed muscle groups, for the flexor muscles are the more powerful and are the ones always shortened in tetanic contraction. 2. Nicotine, in contrast to strychnine, primarily induces contraction of flexor muscles. Its effects, moreover, are in a degree selective, being notably exerted on "cerebral" nervous structures. Curare is devoid of characteristic action on the neuromuscular responses of Chiton. 3. The chemical organization of the neuromuscular organs of Chiton, as far as revealed by these tests, corresponds to a more simple condition than is inferred for gastropods. In particular, the behavior with respect to curare resembles more that of the neuromuscular apparatus of flatworms.

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