Locational influence of dendritic PIC on input-output properties of spinal motoneurons (Kim 2017)

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Accession:239039
How does the dendritic location of calcium persistent inward current (Ca-PIC) influence dendritic excitability and firing behavior across the spinal motoneuron pool? This issue was investigated developing a model motoneuron pool where model parameters were analytically determined to reflect key motoneuron type-specific properties experimentally identified. The simulation results point out the negative relationship between the distance of Ca-PIC source from the soma and cell recruitment threshold as a basis underlying the systematic variation in input-output properties of motoneurons over the motoneuron pool.
References:
1 . Kim H (2017) Impact of the localization of dendritic calcium persistent inward current on the input-output properties of spinal motoneuron pool: a computational study. J Appl Physiol (1985) 123:1166-1187 [PubMed]
2 . Kim H, Jones KE, Heckman CJ (2014) Asymmetry in signal propagation between the soma and dendrites plays a key role in determining dendritic excitability in motoneurons. PLoS One 9:e95454 [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): Spinal cord lumbar motor neuron alpha ACh cell;
Channel(s): I Calcium; I Potassium; I Sodium; I_AHP;
Gap Junctions:
Receptor(s):
Gene(s):
Transmitter(s):
Simulation Environment: XPP;
Model Concept(s): Active Dendrites;
Implementer(s): Kim, Hojeong [hojeong.kim03 at gmail.com];
Search NeuronDB for information about:  Spinal cord lumbar motor neuron alpha ACh cell; I Sodium; I Calcium; I Potassium; I_AHP;
# FIG 3C: V-Is properties
# Written by Hojeong Kim

## [soma equations]
dvs/dt=(I_s+ins(vs,snam,snah,scam,scah,snapm,vca)+outs(vs,skdr)-gms*(vs-(vl+vrest))+gc*(vd-vs)/parea)/cms
# inward voltage-gated current
ins(vs,snam,snah,scam,scah,snapm,vca)=-sina(vs,snam,snah)-sica(vs,scam,scah,vca)-sinap(vs,snapm)
sina(vs,snam,snah)=sgna*snam**3*snah*(vs-(vna+vrest))
dsnam/dt=alpha_m(vs)*(1-snam)-beta_m(vs)*snam
alpha_m(vs)=anamc*(vs-anamv)/(exp(-(vs-anamv)/anama)+anamb)
beta_m(vs)=bnamc*(vs-bnamv)/(exp((vs-bnamv)/bnama)+bnamb)
dsnah/dt=(snahinf(vs)-snah)/snahtau(vs)
snahinf(vs)=1.0/(1.0+exp((vs-snahth)/snahslp))
snahtau(vs)=snahc/(exp((vs-snahv)/snaha)+exp(-(vs-snahv)/snahb))
sica(vs,scam,scah,vca)=sgca*scam**2*scah*(vs-(vca+vrest))
dscam/dt=(scaminf(vs)-scam)/camtau
dscah/dt=(scahinf(vs)-scah)/cahtau
scaminf(vs)=1.0/(1.0+exp(-(vs-camth)/camslp))
scahinf(vs)=1.0/(1.0+exp((vs-cahth)/cahslp))
vca=(1000*R*Temp/Zca/Fe)*log(CAo/sca)
dsca/dt=-f*alpha*sica(vs,scam,scah,vca)-f*kca*sca
sinap(vs,snapm)=sgnap*snapm**3*(vs-(vna+vrest))
dsnapm/dt=alphasnapm(vs)*(1-snapm)-betasnapm(vs)*snapm
alphasnapm(vs)=anapmc*(vs-anapmv)/(exp(-(vs-anapmv)/anapma)+anapmb)
betasnapm(vs)=bnapmc*(vs-bnapmv)/(exp((vs-bnapmv)/bnapma)+bnapmb)
# outward voltage-gated currents
outs(vs,skdr)=-sikdr(vs,skdr)-sikca(vs)
sikdr(vs,skdr)=sgkdr*skdr**4*(vs-(vk+vrest))
dskdr/dt=(skdrinf(vs)-skdr)/skdrtau(vs)
skdrinf(vs)=1.0/(1.0+exp(-(vs-skdrth)/skdrslp))
skdrtau(vs)=skdrc/(exp((vs-skdrv)/skdra)+exp(-(vs-skdrv)/skdrb))
sikca(vs)=sgkca*(sca/(sca+kd))*(vs-(vk+vrest))

## [dendrite equations]
dvd/dt=(ind(vd,dcal)-gmd*(vd-(vl+vrest))+gc*(vs-vd)/(1.0-parea))/cmd
# inward voltage-gated current
ind(vd,dcal)=-dgcal*dcal*(vd-(vdcal+vrest))
ddcal/dt=(dcalinf(vd)-dcal)/dcaltau
dcalinf(vd)=1.0/(1.0+exp(-(vd-dcalth)/dcalslp))

## [cable parameters] gms(mS/cm^2),gmd(mS/cm^2),gc(mS/cm^2),cms(uF/cm^2),cmd(uF/cm^2)
p gms=0.143, gmd=0.131, gc=0.211, cms=1.058, cmd=0.915, parea=0.492

## [active parameters]
# reversal and resting potentials
p vna=120.0,vk=-10.0,vl=0.0,vdcal=130.0,vrest=-70
# constants
p kd=0.0005,f=0.01,kca=8.0,alpha=1
p R=8.31441,Temp=309.15,Zca=2,Fe=96485.309,CAo=2
# [soma]: v(mV),t(ms),g(mS/cm^2)
p sgna=26.75,anamc=-0.4,anamv=-49,anama=5,anamb=-1.0
p bnamc=0.4,bnamv=-25,bnama=5,bnamb=-1.0
p snahth=-58.0,snahslp=7.0,snahv=-60.0,snaha=15.0,snahb=16.0,snahc=30.0
p sgkdr=6.2,skdrth=-31.0,skdrslp=15.0,skdrv=-50.0,skdra=40.0,skdrb=50.0,skdrc=5.0
p sgca=0.008,camth=-25.0,camslp=5.0,camtau=15.0
p cahth=-43.0,cahslp=5.0,cahtau=50.0
p sgkca=0.54
p sgnap=0.00086,anapmc=-0.0353,anapmv=-21.4,anapma=5,anapmb=-1.0
p bnapmc=0.000883,bnapmv=-25.7,bnapma=5,bnapmb=-1.0
# [dendrite]: v(mV),t(ms),g(mS/cm^2)
p dgcal=0.124,dcalth=-43.0,dcalslp=6.0,dcaltau=60.0

## [initial conditions]
# soma
vs(0)=-70.0
snam(0)=0.001
snah(0)=0.5829
scam(0)=0.004199
scah(0)=0.9219
sca(0)=0.0001
skdr(0)=0.1239
snapm(0)=0.001
# dendrites
vd(0)=-70.0
dcal(0)=0.001

## [current stimulation at soma]: mA/cm^2
p i0=0,m=6.33,t_m=5000
I_s=i0+m-(m/t_m)*abs(t-t_m)

## [simulation outputs]: V(mV), I(nA)
aux Vsoma=vs
aux Iapp=I_s*3.16

## [simulation environment]
@ maxstor=2000000
@ total=10000
@ method=gear, toler=0.009, dtmax=0.5
@ NPLOT=2, XP=t, YP=Vsoma, XP2=t, YP2=Iapp
@ xlo=0, xhi=10000, ylo=-80, yhi=40
@ bound=10000
@ create=1

done

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