Selective control of cortical axonal spikes by a slowly inactivating K+ current (Shu et al. 2007)

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Accession:135898
We discovered a low-threshold, slowly inactivating K+ current, containing Kv1.2 alpha subunits, in axon initial segment, playing a key role in the modulation of spike threshold and spike duration as well as the spike timing in prefrontal cortex layer V pyramidal cell of ferrets and rats. A kd.mod file implements this D current and put it in the axonal model: Neuron_Dcurrent.hoc. Run the model to see the gradual modulation effect over seconds on spike shape.
Reference:
1 . Shu Y, Yu Y, Yang J, McCormick DA (2007) Selective control of cortical axonal spikes by a slowly inactivating K+ current. Proc Natl Acad Sci U S A 104:11453-8 [PubMed]
Model Information (Click on a link to find other models with that property)
Model Type: Neuron or other electrically excitable cell; Axon;
Brain Region(s)/Organism: Neocortex;
Cell Type(s): Neocortex L5/6 pyramidal GLU cell; Neocortex L2/3 pyramidal GLU cell;
Channel(s): I Na,t; I K; I h; I Potassium;
Gap Junctions:
Receptor(s):
Gene(s): Kv1.2 KCNA2;
Transmitter(s):
Simulation Environment: NEURON;
Model Concept(s): Action Potential Initiation; Action Potentials;
Implementer(s):
Search NeuronDB for information about:  Neocortex L5/6 pyramidal GLU cell; Neocortex L2/3 pyramidal GLU cell; I Na,t; I K; I h; I Potassium;
TITLE I-h channel from Magee 1998

NEURON {
	SUFFIX hd
	NONSPECIFIC_CURRENT i
    RANGE ghdbar, vhalfl, ghd, i, kl
    GLOBAL qtl
}
UNITS {
	(mA) = (milliamp)
	(mV) = (millivolt)

}

PARAMETER {
	v 				(mV)
    ehd  			(mV)
	celsius 		(degC)
	ghdbar=.0001 	(mho/cm2)
    vhalfl=-81   	(mV)
	kl=-8
	vhalft=-75   	(mV)
	a0t=0.011      	(/ms)
	zetat=2.2    	(1)
	gmt=.4   		(1)
	q10=4.5
	qtl=1
}

STATE {
        l
}

ASSIGNED {
	i (mA/cm2)
	linf
	taul
	ghd
}

INITIAL {
	rate(v)
	l=linf
}


BREAKPOINT {
	SOLVE states METHOD cnexp
	ghd = ghdbar*l
	i = ghd*(v-ehd)
}

DERIVATIVE states {
        rate(v)
        l' =  (linf - l)/taul
}

FUNCTION alpt(v(mV)) {
  		alpt = exp(0.0378*zetat*(v-vhalft))
}

FUNCTION bett(v(mV)) {
  		bett = exp(0.0378*zetat*gmt*(v-vhalft))
}


PROCEDURE rate(v (mV)) {
        LOCAL a,qt
        qt=q10^((celsius-33)/10)
        a = alpt(v)
        linf = 1/(1 + exp(-(v-vhalfl)/kl))
        taul = bett(v)/(qtl*qt*a0t*(1+a))
}















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