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 CaGk
: Calcium activated K channel.
: Modified from Moczydlowski and Latorre (1983) J. Gen. Physiol. 82

UNITS {
	(molar) = (1/liter)
}

UNITS {
	(mV) =	(millivolt)
	(mA) =	(milliamp)
	(mM) =	(millimolar)
}


NEURON {
	SUFFIX cagk
	USEION ca READ cai
	USEION k READ ek WRITE ik
	RANGE gbar,gkca,ik, i
	GLOBAL oinf, tau
}

UNITS {
	FARADAY = (faraday)  (kilocoulombs)
	R = 8.313424 (joule/degC)
}

PARAMETER {
	celsius		(degC)
	v		(mV)
	gbar=.01	(mho/cm2)	: Maximum Permeability
	cai 		(mM)
	ek		(mV)

	d1 = .84
	d2 = 1.
	k1 = .48e-3	(mM)
	k2 = .13e-6	(mM)
	abar = .28	(/ms)
	bbar = .48	(/ms)
        st=1            (1)
}

ASSIGNED {
	ik		(mA/cm2)
	i		(mA/cm2)
	oinf
	tau		(ms)
        gkca          (mho/cm2)
}

INITIAL {
        rate(v,cai)
        o=oinf
}

STATE {	o }		: fraction of open channels

BREAKPOINT {
	SOLVE state METHOD cnexp
	gkca = gbar*o^st
	ik = gkca*(v - ek)
	i = ik
}

DERIVATIVE state {	: exact when v held constant; integrates over dt step
	rate(v, cai)
	o' = (oinf - o)/tau
}

FUNCTION alp(v (mV), c (mM)) (1/ms) { :callable from hoc
	alp = c*abar/(c + exp1(k1,d1,v))
}

FUNCTION bet(v (mV), c (mM)) (1/ms) { :callable from hoc
	bet = bbar/(1 + c/exp1(k2,d2,v))
}

FUNCTION exp1(k (mM), d, v (mV)) (mM) { :callable from hoc
	exp1 = k*exp(-2*d*FARADAY*v/R/(273.15 + celsius))
}

PROCEDURE rate(v (mV), c (mM)) { :callable from hoc
	LOCAL a
	a = alp(v,c)
	tau = 1/(a + bet(v, c))
	if (v < -52.5 ) {     : -57.5
	oinf = 0
	} else {
	oinf = a*tau
	}
}


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