A muscle architecture model offering control over motor unit fiber density distributions

The aim of this study was to develop a muscle architecture model able to account for the observed distributions of innervation ratios and fiber densities of different types of motor units in a muscle. A model algorithm is proposed and mathematically analyzed in order to obtain an inverse procedure that allows, by modification of input parameters, control over the output distributions of motor unit fiber densities. The model’s performance was tested with independent data from a glycogen depletion study of the medial gastrocnemius of the rat. Results show that the model accurately reproduces the observed physiological distributions of innervation ratios and fiber densities and their relationships. The reliability and accuracy of the new muscle architecture model developed here can provide more accurate models for the simulation of different electromyographic signals.

[1]  Sanjeev D Nandedkar,et al.  Models and simulations in electromyography , 2002, Muscle & nerve. Supplement.

[2]  Hermanus J. Hermens,et al.  EMG Modeling and Simulation , 2004 .

[3]  Javier Navallas,et al.  Mathematical analysis of a muscle architecture model. , 2009, Mathematical biosciences.

[4]  R. Merletti,et al.  Modeling of surface myoelectric signals--Part II: Model-based signal interpretation. , 1999, IEEE transactions on bio-medical engineering.

[5]  D W Stashuk,et al.  Simulation of electromyographic signals. , 1993, Journal of electromyography and kinesiology : official journal of the International Society of Electrophysiological Kinesiology.

[6]  R. Burke,et al.  Anatomy and innervation ratios in motor units of cat gastrocnemius , 1973, The Journal of physiology.

[7]  A Garfinkel,et al.  Spatial distribution of motor unit fibers in the cat soleus and tibialis anterior muscles: local interactions , 1988, The Journal of neuroscience : the official journal of the Society for Neuroscience.

[8]  R. Merletti,et al.  Modeling of surface myoelectric signals--Part I: Model implementation. , 1999, IEEE transactions on bio-medical engineering.

[9]  G Rau,et al.  The presence of unknown layer of skin and fat is an obstacle to a correct estimation of the motor unit size from surface detected potentials. , 2002, Electromyography and clinical neurophysiology.

[10]  E Stålberg,et al.  Macro EMG, a new recording technique. , 1980, Journal of neurology, neurosurgery, and psychiatry.

[11]  Dario Farina,et al.  Influence of motor unit properties on the size of the simulated evoked surface EMG potential , 2006, Experimental Brain Research.

[12]  E. Henneman,et al.  RELATIONS BETWEEN STRUCTURE AND FUNCTION IN THE DESIGN OF SKELETAL MUSCLES. , 1965, Journal of neurophysiology.

[13]  Ralph M. Jell.  Eight channel scanning and timing controller for physiological data aquisition , 2006, Medical and biological engineering.

[14]  F. Richmond,et al.  Compartmentalization of motor units in the cat neck muscle, biventer cervicis. , 1988, Journal of neurophysiology.

[15]  S D Nandedkar,et al.  EMG of reinnervated motor units: a simulation study. , 1988, Electroencephalography and clinical neurophysiology.

[16]  F BUCHTHAL,et al.  Volume conduction of the spike of the motor unit potential investigated with a new type of multielectrode. , 1957, Acta physiologica Scandinavica.

[17]  N. Dimitrova,et al.  Simulation analysis of interference EMG during fatiguing voluntary contractions. Part I: What do the intramuscular spike amplitude-frequency histograms reflect? , 2008, Journal of electromyography and kinesiology : official journal of the International Society of Electrophysiological Kinesiology.

[18]  K. Kanda,et al.  Factors causing difference in force output among motor units in the rat medial gastrocnemius muscle. , 1992, The Journal of physiology.

[19]  Roberto Merletti,et al.  The extraction of neural strategies from the surface EMG. , 2004, Journal of applied physiology.

[20]  Javier Rodríguez,et al.  Comparative evaluation of motor unit architecture models , 2009, Medical & Biological Engineering & Computing.

[21]  E. Stålberg,et al.  Causes of the increased fiber density in muscular dystrophies studied with single fiber EMG during electrical stimulation , 1985, Muscle & nerve.

[22]  G V Dimitrov,et al.  Simulation analysis of interference EMG during fatiguing voluntary contractions. Part II--changes in amplitude and spectral characteristics. , 2008, Journal of electromyography and kinesiology : official journal of the International Society of Electrophysiological Kinesiology.

[23]  Lars Karlsson,et al.  An application of a muscle model to study electromyographic signals , 2003, Comput. Methods Programs Biomed..

[24]  A Garfinkel,et al.  Three‐dimensional structure of cat tibialis anterior motor units , 1995, Muscle & nerve.

[25]  R. Merletti,et al.  Modeling of surface myoelectric signals. I. Model implementation , 1999, IEEE Transactions on Biomedical Engineering.

[26]  Daniel W. Stashuk,et al.  Physiologically based simulation of clinical EMG signals , 2005, IEEE Transactions on Biomedical Engineering.

[27]  D. Farina,et al.  The linear electrode array: a useful tool with many applications. , 2003, Journal of electromyography and kinesiology : official journal of the International Society of Electrophysiological Kinesiology.

[28]  P. Griffin,et al.  Physical processes associated with the deactivation of dopants in laser annealed silicon , 2002 .

[29]  E Stålberg,et al.  Simulation of macro EMG motor unit potentials. , 1983, Electroencephalography and clinical neurophysiology.

[30]  E Stålberg,et al.  Modeling studies on irregular motor unit potentials , 2004, Clinical Neurophysiology.

[31]  D. Stegeman,et al.  Motor unit size estimation: confrontation of surface EMG with macro EMG. , 1997, Electroencephalography and clinical neurophysiology.

[32]  Roberto Merletti,et al.  Needle and Wire Detection Techniques , 2004 .

[33]  E. Zalewska.  Insight into the motor unit activation and structure properties gained from EMG signal analysis , 2009, Clinical Neurophysiology.

[34]  L. Edström,et al.  Histochemical composition, distribution of fibres and fatiguability of single motor units. Anterior tibial muscle of the rat. , 1968, Journal of neurology, neurosurgery, and psychiatry.

[35]  G. Somjen,et al.  FUNCTIONAL SIGNIFICANCE OF CELL SIZE IN SPINAL MOTONEURONS. , 1965, Journal of neurophysiology.

[36]  Mark B. Bromberg,et al.  Updating motor unit number estimation (MUNE) , 2007, Clinical Neurophysiology.

[37]  M J Campbell,et al.  Electrophysiological estimation of the number of motor units within a human muscle , 1971, Journal of neurology, neurosurgery, and psychiatry.

[38]  Roberto Merletti,et al.  Motor unit recruitment strategies investigated by surface EMG variables. , 2002, Journal of applied physiology.

[39]  E Stålberg,et al.  Simulation of the normal concentric needle electromyogram by using a muscle model , 2001, Clinical Neurophysiology.

[40]  E Stålberg,et al.  Macro EMG in healthy subjects of different ages. , 1982, Journal of neurology, neurosurgery, and psychiatry.

[41]  Javier Navallas,et al.  Studying motor end-plate topography by means of scanning-electromyography , 2009, Clinical Neurophysiology.

[42]  E Stålberg,et al.  Scanning EMG in normal muscle and in neuromuscular disorders. , 1991, Electroencephalography and clinical neurophysiology.

[43]  M.-A. Schnetzer,et al.  Three-dimensional model of a muscle and simulation of its surface EMG , 2001, 2001 Conference Proceedings of the 23rd Annual International Conference of the IEEE Engineering in Medicine and Biology Society.

[44]  D. M. Lewis,et al.  Contractile characteristics and innervation ratio of rat soleus motor units. , 1989, The Journal of physiology.

[45]  V. Edgerton,et al.  An analysis of the spatial distribution of muscle fibers within the territory of a motor unit , 1989 .

[46]  E. Stålberg,et al.  Simulation of fibre density in single-fibre electromyography and its relationship to macro-EMG , 1985, Medical and Biological Engineering and Computing.

[47]  E Stålberg,et al.  On the measurement of fibre density in human muscles. , 1982, Electroencephalography and clinical neurophysiology.

[48]  Erik Stålberg,et al.  Simulation of EMG in pathological situations , 2001, Clinical Neurophysiology.

[49]  Karin Roeleveld,et al.  Motor unit size estimation of enlarged motor units with surface electromyography , 1998, Muscle & nerve.

[50]  Jacques Duchêne,et al.  A model of EMG generation , 2000, IEEE Transactions on Biomedical Engineering.

[51]  D. Farina,et al.  Estimating motor unit discharge patterns from high-density surface electromyogram , 2009, Clinical Neurophysiology.

[52]  F. Buchthal,et al.  Multielectrode study of the territory of a motor unit. , 1957, Acta physiologica Scandinavica.

[53]  A J Fuglevand,et al.  Simulation of motor unit recruitment and microvascular unit perfusion: spatial considerations. , 1997, Journal of applied physiology.

[54]  A. Miller-Larsson,et al.  Motor unit action potential field — Modelling results , 1986, Biological Cybernetics.

[55]  R B Stein,et al.  The orderly recruitment of human motor units during voluntary isometric contractions , 1973, The Journal of physiology.

[56]  D. Winter,et al.  Models of recruitment and rate coding organization in motor-unit pools. , 1993, Journal of neurophysiology.

[57]  E Eldred,et al.  Maximal force as a function of anatomical features of motor units in the cat tibialis anterior. , 1987, Journal of neurophysiology.

[58]  R. Enoka,et al.  Motor unit physiology: Some unresolved issues , 2001, Muscle & nerve.

[59]  Serge H. Roy,et al.  Modeling of surface myoelectric signals. II. Model-based signal interpretation , 1999, IEEE Transactions on Biomedical Engineering.

[60]  Francisco J Valero-Cuevas,et al.  Experimentally valid predictions of muscle force and EMG in models of motor-unit function are most sensitive to neural properties. , 2007, Journal of neurophysiology.

[61]  Todd A. Kuiken,et al.  Simulation of Intramuscular EMG Signals Detected Using Implantable Myoelectric Sensors (IMES) , 2006, IEEE Transactions on Biomedical Engineering.

[62]  C. Coërs,et al.  Terminal Innervation Ratio in Neuromuscular Disease: I. Methods and Controls , 1973 .

[63]  T Gordon,et al.  Self-reinnervated cat medial gastrocnemius muscles. I. comparisons of the capacity for regenerating nerves to form enlarged motor units after extensive peripheral nerve injuries. , 1996, Journal of neurophysiology.

[64]  L Antoni,et al.  Electrophysiological cross section of the motor unit. , 1980, Journal of neurology, neurosurgery, and psychiatry.

[65]  J. Roche,et al.  Hypercalcaemia associated with cerebral vasospasm causing infarction. , 1980, Journal of neurology, neurosurgery, and psychiatry.

[66]  N. Chino,et al.  Quantitative EMG and motor unit recruitment threshold using a concentric needle with quadrifilar electrode , 2000, Muscle & nerve.

[67]  E Stålberg,et al.  Motor unit fibre density in the extensor digitorum communis muscle. Single fibre electromyographic study in normal subjects at different ages. , 1975, Journal of neurology, neurosurgery, and psychiatry.

[68]  L. Edström,et al.  Mapping of motor units in experimentally reinnervated rat muscle , 1970, Journal of neurology, neurosurgery, and psychiatry.

[69]  V. Edgerton,et al.  Role of motor unit structure in defining function , 2001, Muscle & nerve.