Modeling motoneuron firing properties: dependency on size and calcium dynamics

The origin of functional differences between motoneurons of varying size was investigated by employing a one-compartmental motoneuron model containing a slow K+ conductance dependent on the intracellular calcium concentration. The size of the cell was included as an explicit parameter. Simulations show that motoneurons of varying size cannot be regarded as simple ‘scaled’ versions of each other. Rather, they are expected to have intrinsic properties that vary with cell size. These intrinsic properties refer to the membrane conductances per unit area and the dynamics of the intracellular calcium concentration.

[1]  R. Llinás,et al.  Compartmentalization of the submembrane calcium activity during calcium influx and its significance in transmitter release. , 1985, Biophysical journal.

[2]  D. Kernell,et al.  Motoneurone models based on 'voltage clamp equations' for peripheral nerve. , 1972, Acta physiologica Scandinavica.

[3]  R. Llinás,et al.  The spatial distribution of ionic conductances in normal and axotomized motorneurons , 1977, Neuroscience.

[4]  D. Kernell,et al.  Dendrites of cat's spinal motoneurones: relationship between stem diameter and predicted input conductance. , 1989, The Journal of physiology.

[5]  原田 嘉夫.  The Calcium component of the action potential in spinal motoneurones of the rat , 1984 .

[6]  D. Kernell,et al.  Input conductance, axonal conduction velocity and cell size among hindlimb motoneurones of the cat , 1981, Brain Research.

[7]  R. Traub.  Motorneurons of different geometry and the size principle , 1977, Biological Cybernetics.

[8]  Örjan Ekeberg,et al.  A computer based model for realistic simulations of neural networks , 1991, Biological Cybernetics.

[9]  J. R. Clay,et al.  Relationship between membrane excitability and single channel open-close kinetics. , 1983, Biophysical journal.

[10]  K. Krnjević,et al.  Evidence for Ca2+-activated K+ conductance in cat spinal motoneurons from intracellular EGTA injections. , 1975, Canadian journal of physiology and pharmacology.

[11]  D. Kernell,et al.  Repetitive impulse firing: comparisons between neurone models based on 'voltage clamp equations' and spinal motoneurones. , 1973, Acta physiologica Scandinavica.

[12]  Thomas Sinkjær,et al.  Simulations of the alpha motoneuron pool electromyogram reflex at different preactivation levels in man , 1994, Biological Cybernetics.

[13]  I Segev,et al.  Electrotonic architecture of type-identified alpha-motoneurons in the cat spinal cord. , 1988, Journal of neurophysiology.

[14]  D. Kernell,et al.  Input Resistance, Electrical Excitability, and Size of Ventral Horn Cells in Cat Spinal Cord , 1966, Science.

[15]  R. McBurney,et al.  Neuronal calcium homeostasis , 1987, Trends in Neurosciences.

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

[17]  D. Kernell,et al.  Matching between motoneurone and muscle unit properties in rat medial gastrocnemius. , 1993, The Journal of physiology.

[18]  D. Kernell,et al.  The duration of after-hyperpolarization in hindlimb alpha motoneurones of different sizes in the cat , 1980, Neuroscience Letters.

[19]  M D Binder,et al.  Computer simulation of the steady-state input-output function of the cat medial gastrocnemius motoneuron pool. , 1991, Journal of neurophysiology.

[20]  D. Kernell.  The Limits of Firing Frequency in Cat Lumbosacral Motoneurones Possessing Different Time Course of Afterhyperpolarization , 1965 .

[21]  D. Kernell,et al.  Threshold current for repetitive impulse firing in motoneurones innervating muscle fibres of different fatigue sensitivity in the cat , 1981, Brain Research.

[22]  G. Somjen,et al.  Excitability and inhibitability of motoneurons of different sizes. , 1965, Journal of neurophysiology.

[23]  D. Kernell.  The Adaptation and the Relation between Discharge Frequency and Current Strength of Cat Lumbosacral Motoneurones Stimulated by Long‐Lasting Injected Currents , 1965 .

[24]  F. Parmiggiani,et al.  A model for refractoriness accumulation and secondary range firing in spinal motoneurones , 1976, Biological Cybernetics.

[25]  S. Grillner,et al.  Computer simulations of N-methyl-D-aspartate receptor-induced membrane properties in a neuron model. , 1991, Journal of neurophysiology.

[26]  K. Krnjević,et al.  Motoneuronal after-potentials and extracellular divalent cations. , 1978, Canadian journal of physiology and pharmacology.