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 V1 L6 pyramidal corticothalamic GLU cell; Neocortex V1 L2/6 pyramidal intratelencephalic 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 V1 L6 pyramidal corticothalamic GLU cell; Neocortex V1 L2/6 pyramidal intratelencephalic GLU cell; I Na,t; I K; I h; I Potassium;
TITLE K-D
: K-D current for prefrontal cortical neuron ------Yuguo Yu  2007

NEURON {
	SUFFIX kd
	USEION k WRITE ik
	RANGE  gkbar, ik, ek
	GLOBAL minf, mtau, hinf, htau
}

PARAMETER {
	gkbar = 0.1   	(mho/cm2)	
								
	celsius
	ek = -100	(mV)            : must be explicitly def. in hoc
	v 		(mV)
	vhalfm=-43  (mV)
	km=8
	vhalfh=-67  (mV) 
      kh=7.3
	q10=2.3
}


UNITS {
	(mA) = (milliamp)
	(mV) = (millivolt)
	(pS) = (picosiemens)
	(um) = (micron)
} 

ASSIGNED {
	ik 		(mA/cm2)
	minf 		mtau (ms)	 	
	hinf 		htau (ms)	 	
}
 

STATE { m h}

BREAKPOINT {
        SOLVE states METHOD cnexp
       ik = gkbar * m*h*(v-ek)
} 

INITIAL {
	trates(v)
	m=minf  
	h=hinf  
}

DERIVATIVE states {   
        trates(v)      
        m' = (minf-m)/mtau
        h' = (hinf-h)/htau
}

PROCEDURE trates(v) {  
	LOCAL qt
        qt=q10^((celsius-22)/10)
        minf=1-1/(1+exp((v-vhalfm)/km))
        hinf=1/(1+exp((v-vhalfh)/kh))

  	 mtau = 0.6
	 htau = 1500
}


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