Distinct current modules shape cellular dynamics in model neurons (Alturki et al 2016)

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Accession:223649
" ... We hypothesized that currents are grouped into distinct modules that shape specific neuronal characteristics or signatures, such as resting potential, sub-threshold oscillations, and spiking waveforms, for several classes of neurons. For such a grouping to occur, the currents within one module should have minimal functional interference with currents belonging to other modules. This condition is satisfied if the gating functions of currents in the same module are grouped together on the voltage axis; in contrast, such functions are segregated along the voltage axis for currents belonging to different modules. We tested this hypothesis using four published example case models and found it to be valid for these classes of neurons. ..."
Reference:
1 . Alturki A, Feng F, Nair A, Guntu V, Nair SS (2016) Distinct current modules shape cellular dynamics in model neurons. Neuroscience 334:309-331 [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: Hippocampus; Amygdala;
Cell Type(s): Abstract single compartment conductance based cell;
Channel(s):
Gap Junctions:
Receptor(s):
Gene(s):
Transmitter(s):
Simulation Environment: NEURON;
Model Concept(s): Simplified Models; Activity Patterns; Oscillations; Methods; Olfaction;
Implementer(s):
/
AlturkiEtAl2016
1_Hemond
Segregated
cacumm.mod
cagk.mod
cal2.mod
can2.mod *
cat.mod *
distr.mod *
h.mod
KahpM95.mod
kaprox.mod
kd.mod
kdrca1.mod
km.mod
na3n.mod
naxn.mod *
ca3b-cell1zr.hoc
ca3b-cell1zr.ses
fixnseg.hoc *
geo-cell1zr.hoc *
mosinit.hoc
                            
TITLE l-calcium channel
: l-type calcium channel


UNITS {
	(mA) = (milliamp)
	(mV) = (millivolt)

	FARADAY = 96520 (coul)
	R = 8.3134 (joule/degC)
	KTOMV = .0853 (mV/degC)
}

PARAMETER {
	v (mV)
	celsius 	(degC)
	gcalbar=.003 (mho/cm2)
	ki=.001 (mM)
	cai = 50.e-6 (mM)
	cao = 2 (mM)
	q10 = 5
	mmin=0.2
	tfa = 1
	a0m =0.1
	zetam = 2
	vhalfm = 4
	gmm=0.1	
	ggk
}


NEURON {
	SUFFIX cal
	USEION ca READ cai,cao WRITE ica
        RANGE gcalbar,cai, ica, gcal, i, ggk
        GLOBAL minf,tau
}

STATE {
	m
}

ASSIGNED {
	ica (mA/cm2)
	i		(mA/cm2)
        gcal (mho/cm2)
        minf
        tau   (ms)
}

INITIAL {
	rate(v)
	m = minf
}

BREAKPOINT {
	SOLVE state METHOD cnexp
	gcal = gcalbar*m*m*h2(cai)
	ggk=ghk(v,cai,cao)
	ica = gcal*ggk
	i = ica

}

FUNCTION h2(cai(mM)) {
	h2 = ki/(ki+cai)
}


FUNCTION ghk(v(mV), ci(mM), co(mM)) (mV) {
        LOCAL nu,f

        f = KTF(celsius)/2
        nu = v/f
        ghk=-f*(1. - (ci/co)*exp(nu))*efun(nu)
}

FUNCTION KTF(celsius (DegC)) (mV) {
        KTF = ((25./293.15)*(celsius + 273.15))
}


FUNCTION efun(z) {
	if (fabs(z) < 1e-4) {
		efun = 1 - z/2
	}else{
		efun = z/(exp(z) - 1)
	}
}

FUNCTION alp(v(mV)) (1/ms) {
	alp = 15.69*(-1.0*v+81.5)/(exp((-1.0*v+81.5)/10.0)-1.0)
}

FUNCTION bet(v(mV)) (1/ms) {
	bet = 0.29*exp(-v/10.86)
}

FUNCTION alpmt(v(mV)) {
  alpmt = exp(0.0378*zetam*(v-vhalfm)) 
}

FUNCTION betmt(v(mV)) {
  betmt = exp(0.0378*zetam*gmm*(v-vhalfm)) 
}

DERIVATIVE state {  
        rate(v)
        m' = (minf - m)/tau
}

PROCEDURE rate(v (mV)) { :callable from hoc
        LOCAL a, b, qt
        qt=q10^((celsius-25)/10)
        a = alp(v)
        b = 1/((a + bet(v)))
		if (v < -52.5 ) {    : -57.5
		minf = 0
		} else {
        minf = a*b
		}
	tau = betmt(v)/(qt*a0m*(1+alpmt(v)))
	if (tau<mmin/qt) {tau=mmin/qt}
}

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