scholarly journals Egr3-Dependent Muscle Spindle Stretch Receptor Intrafusal Muscle Fiber Differentiation and Fusimotor Innervation Homeostasis

2015 ◽  
Vol 35 (14) ◽  
pp. 5566-5578 ◽  
Author(s):  
M. Oliveira Fernandes ◽  
W. G. Tourtellotte
Keyword(s):  
Muscle Fiber ◽  
Muscle Spindle ◽  
Stretch Receptor ◽  
Intrafusal Muscle ◽  
Fusimotor Innervation ◽  
Intrafusal Muscle Fiber

ESTIMATION OF ANKLE JOINT ANGLE FROM PERONEAL AND TIBIAL ELECTRONEUROGRAMS — A MUSCLE SPINDLE MODEL APPROACH

2012 ◽  
Vol 12 (04) ◽  
pp. 1250080 ◽  
Author(s):  
CHING-CHAO CHAN ◽  
CHOU-CHING K. LIN ◽  
MING-SHAUNG JU
Keyword(s):  
Ankle Joint ◽  
Muscle Fiber ◽  
Muscle Spindle ◽  
Joint Angle ◽  
Fuzzy Inference ◽  
Optimization Method ◽  
Model Parameters ◽  
Inference System ◽  
Intrafusal Muscle ◽  
Intrafusal Muscle Fiber

This study develops a method for estimating the angle of a passively stretched ankle joint from electroneurograms (ENGs) based on structural muscle spindle models of the tibial and peroneal nerves. Passive ramp-and-hold and alternating stretches of the ankle joint are performed on an anesthetized rabbit. Two cuff electrodes are employed to measure the ENGs of peroneal and tibial nerves simultaneously. From the two ENG signals and the joint angle trajectory, two intrafusal muscle fiber models are constructed and their inverse models are derived. The results of the two models are combined to generate the final angle estimate. An optimization method, called sequential quadratic programming, is employed to find the model parameters that minimize the squared errors between the ankle angles predicted by the model and the measured ankle angles. The performance of the proposed approach is compared with those of an adaptive neuro-fuzzy inference system and an artificial neural network model. The results reveal that the proposed model has the best performance in estimating the ankle joint angle in large-range movements and the smallest tracing error. The proposed method effectively estimates the passive ankle joint angle using the inverse physiological model of an intrafusal muscle fiber.

scholarly journals Transcriptional regulation of myotube fate specification and intrafusal muscle fiber morphogenesis

2005 ◽  
Vol 169 (2) ◽  
pp. 257-268 ◽  
Author(s):  
Y'vonne Albert ◽  
Jennifer Whitehead ◽  
Laurie Eldredge ◽  
John Carter ◽  
Xiaoguang Gao ◽  
...  
Keyword(s):  
Gene Expression ◽  
Signal Transduction ◽  
Muscle Fiber ◽  
Muscle Fibers ◽  
Sensory Innervation ◽  
Sensory Axon ◽  
Fate Specification ◽  
Intrafusal Muscle ◽  
Intrafusal Muscle Fibers ◽  
Intrafusal Muscle Fiber

Vertebrate muscle spindle stretch receptors are important for limb position sensation (proprioception) and stretch reflexes. The structurally complex stretch receptor arises from a single myotube, which is transformed into multiple intrafusal muscle fibers by sensory axon–dependent signal transduction that alters gene expression in the contacted myotubes. The sensory-derived signal transduction pathways that specify the fate of myotubes are very poorly understood. The zinc finger transcription factor, early growth response gene 3 (Egr3), is selectively expressed in sensory axon–contacted myotubes, and it is required for normal intrafusal muscle fiber differentiation and spindle development. Here, we show that overexpression of Egr3 in primary myotubes in vitro leads to the expression of a particular repertoire of genes, some of which we demonstrate are also regulated by Egr3 in developing intrafusal muscle fibers within spindles. Thus, our results identify a network of genes that are regulated by Egr3 and are involved in intrafusal muscle fiber differentiation. Moreover, we show that Egr3 mediates myotube fate specification that is induced by sensory innervation because skeletal myotubes that express Egr3 independent of other sensory axon regulation are transformed into muscle fibers with structural and molecular similarities to intrafusal muscle fibers. Hence, Egr3 is a target gene that is regulated by sensory innervation and that mediates gene expression involved in myotube fate specification and intrafusal muscle fiber morphogenesis.

Two unusual satellite cell-intrafusal muscle fiber relationships

1973 ◽  
Vol 140 (1) ◽  
pp. 1-9 ◽  
Author(s):  
Jerry A. Maynard ◽  
Reginald R. Cooper
Keyword(s):  
Satellite Cell ◽  
Muscle Fiber ◽  
Intrafusal Muscle ◽  
Intrafusal Muscle Fiber

scholarly journals A HISTOCHEMICAL INVESTIGATION OF INTRAFUSAL FIBERS IN TORTOISE MUSCLE SPINDLES

1972 ◽  
Vol 20 (3) ◽  
pp. 200-204 ◽  
Author(s):  
ALAN CROWE ◽  
ABDUL H.M.F. RAGAB
Keyword(s):  
Propylene Glycol ◽  
Muscle Spindle ◽  
Succinic Dehydrogenase ◽  
Muscle Spindles ◽  
Histochemical Investigation ◽  
Intrafusal Muscle ◽  
Intrafusal Fibers ◽  
Intrafusal Muscle Fibers ◽  
Extensor Digitorum Brevis ◽  
Intrafusal Muscle Fiber

Histochemical investigations upon intrafusal muscle fibers of spindles in the extensor digitorum brevis 1 muscle of the tortoise have been carried out. The localization of phosphorylase, succinic dehydrogenase and adenosine activities together with the demonstration of lipids by the propylene glycol-Sudan method all failed to produce results which could be used to categorize the intrafusal fibers into more than one type. From these results and from previous histologic investigations it is suggested that the tortoise muscle spindle contains just one kind of intrafusal muscle fiber.

scholarly journals Testing the Classification of Static γ Axons Using Different Patterns of Random Stimulation

1999 ◽  
Vol 81 (6) ◽  
pp. 2823-2832 ◽  
Author(s):  
Julien Petit ◽  
Robert W. Banks ◽  
Yves Laporte
Keyword(s):  
Muscle Fiber ◽  
Muscle Fibers ◽  
Muscle Spindles ◽  
Intrafusal Fiber ◽  
Intrafusal Muscle ◽  
Intrafusal Muscle Fibers ◽  
Initial Peak ◽  
Stimulation Of ◽  
Intrafusal Muscle Fiber

Testing the classification of static γ axons using different patterns of random stimulation. The possibility of using randomly generated stimulus intervals (with a Poisson distribution) to identify the type(s) of intrafusal fiber activated by the stimulation of single static γ axons was tested in Peroneus tertius muscle spindles of anesthetized cats. Three patterns of random stimulation with different values of mean intervals [20 ± 4.47, 30 ± 8.94, and 40 ± 8.94 (SD) ms] were used. Single static γ axons activating, in single spindles, either the bag2 fiber alone or the chain fibers alone or both types of intrafusal fiber were prepared. Responses of spindle primary endings elicited by the stimulation of γ axons were recorded from Ia fibers in cut dorsal root filaments. Cross-correlograms between stimuli and spikes of the primary ending responses, autocorrelograms, interval histograms of responses, and stimulations were built. The characteristics of cross-correlograms were found to be related not only to the type of intrafusal muscle fibers activated but also to the parameters of the stimulation. Moreover some cross-correlograms with similar characteristics were produced by the activation of different intrafusal muscle fibers. It also was observed that, whatever the type of intrafusal muscle fiber activated, cross-correlograms could exhibit oscillations after an initial peak, provided the extent in frequency of the primary ending response was small; these oscillations arise in part from the autocorrelation of the primary ending responses. Therefore, cross-correlograms obtained during random stimulation of static γ axons cannot be used for unequivocally identifying the type(s) of intrafusal muscle fiber these axons supply.

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