//MYELINATED SENSORY NEURON (different diam for DR and peripheral axon)
//SOMA & INITIAL SEG have REDUCED Frankenhaueser-Huxley 64 conductance
//node has Frankenhaueser-Huxley 64 conductance
//MORPHOLOGICALLY BASED ON ITO & TAKAHASHI 60 (TOAD DRG)
pwman_place(0,0)
objref tempobj
{
// the following are now obsolete:
// load_file("stdgui.hoc")
// load_file("electrod.hoc")
// load_file("pointman.hoc")
// load_file("showmech.hoc")
}
//CONSTRACTING CELL SOMA
create soma //Soma for myelinated axons
soma { diam=80 //Ito & Takahashi 60 (60-100micron)
L=80 //<0.1Lambda
nseg=1 //Lambda~3015micron. nseg=L/0.05Lambda
cm=1
insert fh
nai=13.74 //the fh.mod file does not REALY install this param
nao=114.5 //the fh.mod file does not REALY install this param
ki=120 //the fh.mod file does not REALY install this param
ko=2.5 //the fh.mod file does not REALY install this param
pnabar_fh=0.08e-3 //pNabar_fh/100 (Carbone & Lux 86; Campbell 92)
ppbar_fh=0
pkbar_fh=0.035e-3 //to match Ito 57 spike AHP amplitude
gl_fh=0.0002 // Ito 1957 (Table 2 - Rin by hyperpol. pulses)
}
//CONSTRACTING T-STEM AXON
create iseg //unmyelinated
iseg { diam=5 //See below (node1m). Lenhossek 1886 (cited in Ito 1959).
//Also Fits Shinder & Devor 94 (Figs 6,7)
L=200 //to block M-NM spike by hyper. from soma (Ito & Saiga 59)
//can reach x5.5(Spencer 73) up to x10(Cajal 09) soma diam
nseg=6 //Lambda~754micron
cm=1
// insert pas
// g_pas=0.0002
insert fh
nai=13.74 //the fh.mod file does not REALY install this param
nao=114.5 //the fh.mod file does not REALY install this param
ki=120 //the fh.mod file does not REALY install this param
ko=2.5 //the fh.mod file does not REALY install this param
pnabar_fh=0.08e-3 //like soma
ppbar_fh=0 //like soma
pkbar_fh=0.035e-3 //like soma
gl_fh=0.0002 //like soma
}
create node1m[1] //"m" after "node" for Monopolar axon (Ito & Takahasi 60)
node1m { diam=5 //Diam=~0.6 of 1st internode (Spencer et al 73 Fig 7, Ha 70)
} //Lambda=61micron
create myelin1m //11 myelin wraps. see below
myelin1m {diam=8 //0.95 (Spencer et al 73) of ex. diam (8.4, Ito & Takahashi 60)
L=85 //Lambda=1318micron
nseg=2
cm=0.08 //Cm=1micro/N wraps+1 - Moore e-mail
//N wraps = ex diam-int diam/2/wrap thick (18nM, THE AXON)
insert pas
g_pas=0.0001046 //Assuming g_pas=0.0000085 (MYELIN p.123) for 147 myelin wraps
//in the normal peripheral internode (see below).
//Hence for 11 wraps g_pas increase by factor of 147+1/11+1=12.3
}
create node2m[1]
node2m { diam=8 //No constriction of node in area of abnormal myelin (Spencer 73)
} //Lambda=77micron
create myelin2m //69 myelin wraps
myelin2m {diam=8
L=130
nseg=1 //Lambda=3187micron
cm=0.014 //see above for way of calculation
insert pas
g_pas=0.0000179 //see above for way of calculation
}
create node3m[1]
node3m { diam=8
} //Lambda=77micron
create myelin3m //94 myelin wraps
myelin3m {diam=8
L=168
nseg=1 //Lambda=3697micron
cm=0.011
insert pas
g_pas=0.0000133
}
create node4m[1]
node4m { diam=8
} //Lambda=77micron
create myelin4m //142 myelin wraps
myelin4m {diam=8 //Although 7.8micron reported by Ito & Takahashi 60
L=201
nseg=1 //Lambda=4545micron
cm=0.007
insert pas
g_pas=0.0000088
}
create node5m[1]
node5m { diam=8
} //Lambda=77micron
soma connect iseg(0),1
iseg connect node1m(0),1
node1m connect myelin1m(0),1
myelin1m connect node2m(0),1
node2m connect myelin2m(0),1
myelin2m connect node3m(0),1
node3m connect myelin3m(0),1
myelin3m connect node4m(0),1
node4m connect myelin4m(0),1
myelin4m connect node5m(0),1
//CONSTRACT MYELINATED AXONS
//ABNORMAL SEGMENTS (NODE+MYELIN) OF DORSAL ROOT
create node1d[1] //"d"- Dorsal (Ito & Takahashi 60)
node1d { diam=1.6 //Ha 1970 Fig.7 - ~0.25 of abmyelin1d diam
} //Lambda=35micron
create abmyelin1d //100 myelin wraps
abmyelin1d {diam=6.5
L=358
nseg=3 //Lambda=3438micron
cm=0.01
insert pas
g_pas=0.0000125
}
create node2d[1]
node2d { diam=6.5 //No node constrict. in area of abnormal myelin (Spencer 73)
}
create abmyelin2d //95 myelin wraps
abmyelin2d {diam=6.7
L=780
nseg=5 //Lambda=3409micron
cm=0.01
insert pas
g_pas=0.0000131
}
create node3d[1]
node3d { diam=6.7
} //Lambda=71micron
create abmyelin3d //100 myelin wraps
abmyelin3d {diam=7.6
L=1170
nseg=7 //Lambda=3717micron
cm=0.01
insert pas
g_pas=0.0000125
}
create node4d[1]
node4d { diam=7.6 //Lambda=75micron
}
//ABNORMAL SEGMENTS (NODE+MYELIN) OF PERIPHERAL NERVE
create node1p[1] //"p"- Peripheral (Ito & Takahashi 60)
node1p { diam=2.6 //Ha 1970 Fig.7 - X1.6 of node1d
} //Lambda=44micron
create abmyelin1p //136 myelin wraps
abmyelin1p {diam=8
L=461
nseg=3 //Lambda=4446micron
cm=0.007
insert pas
g_pas=0.0000092
}
create node2p[1]
node2p { diam=8 //No node constrict. in area of abnormal myelin (Spencer 73)
} //Lambda=77micron
create abmyelin2p //133 myelin wraps
abmyelin2p {diam=8.7
L=670
nseg=3 //Lambda=4586micron
cm=0.007
insert pas
g_pas=0.0000094
}
create node3p[1]
node3p { diam=8.7
} //Lambda=81micron
create abmyelin3p //136 myelin wraps
abmyelin3p {diam=10.1
L=1119
nseg=5 //Lambda=4995micron
cm=0.007
insert pas
g_pas=0.0000092
}
create node4p[1]
node4p { diam=10.1
}
//CONNECT DORSAL ROOT ABNORMAL SEGMENTS
node1d connect abmyelin1d(0),1
abmyelin1d connect node2d(0),1
node2d connect abmyelin2d(0),1
abmyelin2d connect node3d(0),1
node3d connect abmyelin3d(0),1
abmyelin3d connect node4d(0),1
//CONNECT PERIPHERAL NERVE ABNORMAL SEGMENTS
node1p connect abmyelin1p(0),1
abmyelin1p connect node2p(0),1
node2p connect abmyelin2p(0),1
abmyelin2p connect node3p(0),1
node3p connect abmyelin3p(0),1
abmyelin3p connect node4p(0),1
//CONNECT ABNORMAL SEGMENTS TO T-STEM AXON
node5m connect node1d(0),1
node1d connect node1p(0),0
node5m connect node1p(0),1
//NORMAL SEGMENTS (NODE+MYELIN) OF DORSAL ROOT
create myelindr[30], nodedr[30]
proc create_DR(){
for i=$1,$2 {
myelindr[i]{diam=9.3 //0.7 (Spencer et al 73) of ex diam (Ito & Takahashi 60)
L=1450 //Ito & Takahashi 60.
nseg=7 //Lambda=sqrt[(d/4)*(Rm/Ri)]~4344micron. Rm~89,000 Ri=110
cm=0.009 //111 myelin wraps
insert pas
g_pas=0.0000112
}
nodedr[i]{ diam=9.3 //IGNORE node diam/internode diam=0.4 (THE AXON Fig 2-12, Table 2-3)
} //Lambda=84micron
myelindr[i] connect nodedr[i](0),1
if (i != $2) {
nodedr[i] connect myelindr[i+1](0),1
}
}
}
create_DR(0, 29)
//NORMAL SEGMENTS (NODE+MYELIN) OF PERIPHERAL NERVE
create myelinpn[30], nodepn[30]
proc create_PN(){
for i=$1,$2 {
myelinpn[i]{diam=12.5 //0.7 (Spencer et al 73) of ex diam (based on Ito & Takahashi 60)
L=1567 //Ito & Takahashi 60.
nseg=6 //Lambda=sqrt[(d/4)*(Rm/Ri)]~5781micron. Rm~118,000 Ri=110
cm=0.007 //147 myelin wraps
insert pas
g_pas=0.0000085
}
nodepn[i]{ diam=12.5 //IGNORE node diam/internode diam=0.4 (THE AXON Fig 2-12, Table 2-3)
} //Lambda=97micron
myelinpn[i] connect nodepn[i](0),1
if (i != $2) {
nodepn[i] connect myelinpn[i+1](0),1
}
}
}
create_PN(0, 29)
//CONNECT NORMAL TO ABNORMAL DORSAL ROOT
node4d connect myelindr[0](0),1
//CONNECT NORMAL TO ABNORMAL PERIPHERAL NERVE
node4p connect myelinpn[0](0),1
forsec "node" { L=1.5 //1-1.5micron (THE AXON p. 34). independent of axon diam
nseg=1
cm=1
insert fh
nai=13.74 //the fh.mod file does not REALY install this param
nao=114.5 //the fh.mod file does not REALY install this param
ki=120 //the fh.mod file does not REALY install this param
ko=2.5 //the fh.mod file does not REALY install this param
}
forall {Ra=110} //FROG NEUROBIOLOGY p.13 Table 1. Lenhossek (1886, cited in Ito 59)
celsius=20 //moore et al. 78
//objectvar stim[2]
//node[30] stim[0]=new IClamp(0.5)
//stim[0].del=1
//stim[0].dur=1
//stim[0].amp=0
//node1p[0] stim[1]=new IClamp(0.5)
//stim[1].del=1
//stim[1].dur=1
//stim[1].amp=0
access nodepn[15]
//access node1p[0]
load_proc("nrnmainmenu")
nrnmainmenu()
steps_per_ms=100
dt=1/steps_per_ms
tstop=5
nrncontrolmenu()
secondorder=1
// define vectro to record the voltage
//objref el1
//el1 = new Vector(tstop/dt+2)
//el1.record(&soma.v(0.5))
//objref out
//proc savedat(){
// out = new File()
// out.wopen($s1)
// out.printf("vsoma = [ ")
// el1.printf(out,"%g\n")
// out.printf("]; \n")
// out.close()
//}