Dorsal root ganglion (DRG) neuronal model (Amir, Devor 2003)

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Accession:51022
The model shows that an electrically excitable soma is not necessary for spike through-conduction in the t-shaped geometry of a dorsal root ganglion neuron axon. Electrical excitability of the soma is required, however, for soma spike invasion. See papers for details and more.
References:
1 . Amir R, Devor M (2003) Electrical excitability of the soma of sensory neurons is required for spike invasion of the soma, but not for through-conduction. Biophys J 84:2181-91 [PubMed]
2 . Amir R, Devor M (2003) Extra spike formation in sensory neurons and the disruption of afferent spike patterning. Biophys J 84:2700-8 [PubMed]
Model Information (Click on a link to find other models with that property)
Model Type: Neuron or other electrically excitable cell;
Brain Region(s)/Organism:
Cell Type(s): Myelinated neuron; Dorsal Root Ganglion (DRG) cell;
Channel(s): I Na,t; I K;
Gap Junctions:
Receptor(s):
Gene(s):
Transmitter(s):
Simulation Environment: NEURON;
Model Concept(s): Activity Patterns; Detailed Neuronal Models; Axonal Action Potentials; Action Potentials;
Implementer(s): Amir, Ron [ronamir at pob.huji.ac.il];
Search NeuronDB for information about:  I Na,t; I K;
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amirdevor03
readme.txt
fh.mod
CellNOhill.hoc
figs2_3.ses
mosinit.hoc
standard.inc
                            
objectvar save_window_, rvp_
objectvar scene_vector_[5]
objectvar ocbox_, ocbox_list_, scene_, scene_list_
{ocbox_list_ = new List()  scene_list_ = new List()}

//Begin PointProcessGroupManager
{
load_file("pointgrp.hoc")
}
{
ocbox_ = new PointProcessGroupManager(0)
}
{object_push(ocbox_)}
{
ms = new MechanismStandard("IClamp")
ms.set("del", 1, 0)
ms.set("dur", 0.2, 0)
ms.set("amp", 5, 0)
mnews("IClamp", ms)
select(0)
execute("nodepn[20] ocbox_.move(1)")
}
{object_pop() doNotify()}
{
ocbox_ = ocbox_.v1
ocbox_.map("PointProcessGroupManager", 400, 163, 556.8, 295.68)
}
objref ocbox_
//End PointProcessGroupManager
{
xpanel("soma(0 - 1) (Parameters)", 0)
xlabel("soma(0 - 1) (Parameters)")
xlabel("nseg = 1")
soma.L = 80
xvalue("L","soma.L", 1,"define_shape()", 0, 0 )
soma.diam = 80
xvalue("diam","soma.diam", 1,"", 0, 0 )
soma.cm = 1
xvalue("cm","soma.cm", 1,"", 0, 0 )
soma.pnabar_fh = 8e-5
xvalue("pnabar_fh","soma.pnabar_fh", 1,"", 0, 0 )
soma.ppbar_fh = 0
xvalue("ppbar_fh","soma.ppbar_fh", 1,"", 0, 0 )
soma.pkbar_fh = 3.5e-05
xvalue("pkbar_fh","soma.pkbar_fh", 1,"", 0, 0 )
soma.gl_fh = 0.0002
xvalue("gl_fh","soma.gl_fh", 1,"", 0, 0 )
soma.el_fh = -69.74
xvalue("el_fh","soma.el_fh", 1,"", 0, 0 )
soma.nai = 13.74
xvalue("nai","soma.nai", 1,"", 0, 0 )
soma.nao = 114.5
xvalue("nao","soma.nao", 1,"", 0, 0 )
soma.ki = 120
xvalue("ki","soma.ki", 1,"", 0, 0 )
soma.ko = 2.5
xvalue("ko","soma.ko", 1,"", 0, 0 )
xpanel(731,462)
}
objectvar scene_vector_[2]
{doNotify()}
v_init=-70
tstop=10

objref vgraphbox, g[3]

vgraphbox = new VBox()
vgraphbox.intercept(1)

for i=0,2 {
	g[i] = new Graph()
	g[i].exec_menu("Keep Lines")
}

objref Vsoma, VR1, VR2, VR5
vec_sizes = tstop/dt+1
Vsoma = new Vector(vec_sizes)
Vsoma.record(&soma.v(.5))

init()
run()

Vsoma.line(g[0],dt)

soma.pnabar_fh = 0 // turns off transient Na channel in soma
v_init=-70

init()
run()

Vsoma.line(g[0],dt)

g[0].label(.1,.9,"Figure 2.  Soma spike invasion.")
g[0].label("Simulations with and without")
g[0].label("transient Na channels in soma.")

VR1 = new Vector(vec_sizes)
VR1.record(&nodepn[12].v(.5)) // 12th index is 13th node
VR2 = new Vector(vec_sizes)
VR2.record(&nodedr[1].v(.5)) // 1st index is 2nd node
VR5 = new Vector(vec_sizes)
VR5.record(&nodedr[29].v(.5)) // 30th node closets to 34th node reported in paper
soma.pnabar_fh=40e-5	// high Na chan state

objref anotheric	// another IClamp
tstop=15
nodepn[20] anotheric = new IClamp(1)

anotheric.del=1+2.26
anotheric.dur=.2
anotheric.amp=6.25  // 2.5xThresh

v_init=-70
init()
run()

VR1.add(200)
VR2.add(100)

VR1.line(g[1],dt)
VR2.line(g[1],dt)
VR5.line(g[1],dt)

g[1].label(.1,.9,"Figure 3A.  Pulse pair tranmission")
g[1].label("with high soma-initial segment pNA_max")

soma.pnabar_fh=0	// 0 Na chan state
iseg.pnabar_fh=0	// 0 Na chan state

v_init=-70
init()
run()

VR1.add(200)
VR2.add(100)

VR1.line(g[2],dt)
VR2.line(g[2],dt)
VR5.line(g[2],dt)

g[2].label(.1,.9,"Figure 3B.  Pulse pair transmission")
g[2].label("with 0 soma-initial segment pNA_max")

for i=0,2 {
	g[i].exec_menu("View = plot")
}

vgraphbox.intercept(0)
vgraphbox.map()

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