Conduction in uniform myelinated axons (Moore et al 1978)

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Accession:9851
Examines the relative sensitivity of the velocity of impulse propagation to changes in nodal and internodal parameters.
Reference:
1 . Moore JW, Joyner RW, Brill MH, Waxman SD, Najar-Joa M (1978) Simulations of conduction in uniform myelinated fibers. Relative sensitivity to changes in nodal and internodal parameters. Biophys J 21:147-60 [PubMed]
Model Information (Click on a link to find other models with that property)
Model Type: Axon;
Brain Region(s)/Organism:
Cell Type(s): Myelinated neuron;
Channel(s): I Na,t; I K;
Gap Junctions:
Receptor(s):
Gene(s):
Transmitter(s):
Simulation Environment: NEURON;
Model Concept(s): Axonal Action Potentials; Multiple sclerosis;
Implementer(s): Hines, Michael [Michael.Hines at Yale.edu];
Search NeuronDB for information about:  I Na,t; I K;
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moore78
README
cable.hoc
fig2.hoc
fig2.ses
fig3.hoc
fig3.ses
init.hoc
init.ses
mosinit.hoc
                            
load_file("nrngui.hoc")
load_file("cable.hoc")
load_file("init.ses")

secondorder = 2

len = 0

objref v1, v2, tvec

v1 = new Vector(2000)
v2 = new Vector(2000)
tvec = new Vector(2000)
tvec.record(&t)

// iterpolated time at which voltage = threshold
func where() {local i, v1, v2, t1, t2, x
	i = $o1.indwhere(">=", $2)
	v1 = $o1.x[i-1]
	v2 = $o1.x[i]
	t1 = tvec.x[i-1]
	t2 = tvec.x[i]
	x = ($2 - v1)/(v2 - v1)
	return t1 + x*(t2 - t1)
}

func velocity() {local i, thresh // m/s
	v1.record(&node[10].v(.5))
	v2.record(&node[11].v(.5))
	thresh = 50 - 65
	run()
	t1 = where(v1, thresh)
	t2 = where(v2, thresh)
	return (myelin[10].L + node[10].L)/(t2 - t1) * (1e-3)
}

normal_vel = velocity()
print "velocity of standard model = ", normal_vel, " (m/s)"

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