AP shape and parameter constraints in optimization of compartment models (Weaver and Wearne 2006)

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Accession:87473
"... We construct an objective function that includes both time-aligned action potential shape error and errors in firing rate and firing regularity. We then implement a variant of simulated annealing that introduces a recentering algorithm to handle infeasible points outside the boundary constraints. We show how our objective function captures essential features of neuronal firing patterns, and why our boundary management technique is superior to previous approaches."
Reference:
1 . Weaver CM, Wearne SL (2006) The role of action potential shape and parameter constraints in optimization of compartment models Neurocomputing 69:1053-1057
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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): Vestibular neuron;
Channel(s): I Na,p; I Na,t; I A; I K,Ca;
Gap Junctions:
Receptor(s):
Gene(s):
Transmitter(s):
Simulation Environment: NEURON;
Model Concept(s): Parameter Fitting; Methods;
Implementer(s): Weaver, Christina [christina.weaver at fandm.edu];
Search NeuronDB for information about:  I Na,p; I Na,t; I A; I K,Ca;
COMMENT
	high-threshold calcium channel from Av-Ron and Vidal, 1999
	Implemented by C. Weaver, 2003
ENDCOMMENT

UNITS {
	(molar) =	(1/liter)
	(mM) =	(millimolar)
	(mA) = (milliamp)
	(mV) = (millivolt)

}

NEURON {
	SUFFIX cahi
	USEION ca READ eca WRITE ica
        RANGE gbar
        GLOBAL xinf
	RANGE tot
}

PARAMETER {
	v (mV)
	celsius 	(degC)
	: gbar=.001 (mho/cm2)
	gbar = 0.0002 (mho/cm2)
	: cai (mM)
	: cao (mM)
	xtau=5 (ms)
	Kc=1   (mM)
	ax=0.08 (/mV)
	vhx=-30 (mV)
	vrest = 124	(mV)
	simp = 0
}


STATE {
	x
}

ASSIGNED {
	ica (mA/cm2)
	tot (mA/cm2)
	cai (mM)
        gca (mho/cm2)
        xinf
	eca (mV)
}

INITIAL {
	rate(v)
	x = xinf
: printf("cahi ica=%g\n",ica)
}

BREAKPOINT {
	SOLVE state METHOD cnexp
	gca = gbar*x*x*Kc/(Kc+cai)
	tot = gca*(v-eca)
	if( simp > 0 ) {
		: Av-Ron 1991, simpler
		gca = gbar*x
		: gca = gbar*x*x
	}
	: ica = gca*(v-vrest)
	ica = gca*(v-eca)
}

FUNCTION expn(v (mV),a(/mV), vhalf(mV)) {
  	expn = exp(-2*a*(v-vhalf))
}

DERIVATIVE state {  
        rate(v)
        x' = (xinf - x)/xtau
}

PROCEDURE rate(v (mV)) { :callable from hoc
	xinf = 1/(1 + expn(v,ax,vhx))
}