AP back-prop. explains threshold variability and rapid rise (McCormick et al. 2007, Yu et al. 2008)

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Accession:135839
This simple axon-soma model explained how the rapid rising phase in the somatic spike is derived from the propagated axon initiated spike, and how the somatic spike threshold variance is affected by spike propagation.
References:
1 . McCormick DA, Shu Y, Yu Y (2007) Hodgkin and Huxley model still standing? Nature 445:E1-E2 [PubMed]
2 . Yu Y, Shu Y, McCormick DA (2008) Cortical action potential backpropagation explains spike threshold variability and rapid-onset kinetics. J Neurosci 28:7260-72 [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 pyramidal corticothalamic L6 cell; Neocortex V1 pyramidal intratelencephalic L2-6 cell;
Channel(s): I Na,t; I L high threshold; I T low threshold; I A; I K; I M; I h; I K,Ca; I_AHP;
Gap Junctions:
Receptor(s): GabaA; NMDA;
Gene(s):
Transmitter(s):
Simulation Environment: NEURON;
Model Concept(s): Action Potential Initiation; Detailed Neuronal Models;
Implementer(s):
Search NeuronDB for information about:  Neocortex V1 pyramidal corticothalamic L6 cell; Neocortex V1 pyramidal intratelencephalic L2-6 cell; GabaA; NMDA; I Na,t; I L high threshold; I T low threshold; I A; I K; I M; I h; I K,Ca; I_AHP;
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McCormickEtAl2007YuEtAl2008
readme.txt
ca.mod *
cad.mod *
caL3d.mod *
capump.mod
gabaa5.mod *
Gfluct.mod *
ia.mod *
iahp.mod *
iahp2.mod *
ih.mod
im.mod *
kca.mod *
km.mod *
kv.mod *
na.mod *
NMDA_Mg.mod *
nmda5.mod *
release.mod *
for_plot_spike.m
mosinit.hoc
neuron_soma.dat
Rapid_rising_somatic_spike_soma_axon.hoc
                            
TITLE slowly activating potassium current (M-current)

COMMENT
        *********************************************
        reference:   	Yamada, Koch & Adams (1989) 
			Methods in Neuronal Modeling, MIT press
        found in:       bullfrog sympathetic ganglion cells
        *********************************************
	Assembled for MyFirstNEURON by Arthur Houweling
ENDCOMMENT

INDEPENDENT {t FROM 0 TO 1 WITH 1 (ms)}

NEURON {
	SUFFIX iM
	USEION k READ ek WRITE ik 
        RANGE gkbar, m_inf, tau_m, ik
}

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

PARAMETER {
	v		(mV)
	celsius		(degC)
        dt              (ms)
	ek		(mV)
	gkbar= 0.00031	(mho/cm2)
:	gkbar= 0.0006	(mho/cm2)
}

STATE {
	m
}

ASSIGNED {
	ik		(mA/cm2)
	m_inf
	tau_m		(ms)
	tau_h		(ms)
	tadj
}

BREAKPOINT { 
	SOLVE states :METHOD euler
:	ik = gkbar * m * (v-ek)
	ik = gkbar * m * (v+105)
}

:DERIVATIVE states {
:       evaluate_fct(v)
:
:       m'= (m_inf-m) / tau_m 
:}
  
PROCEDURE states() {
        evaluate_fct(v)

        m= m + (1-exp(-dt/tau_m))*(m_inf-m)
}

UNITSOFF
INITIAL {
:	tadj = 2.3^((celsius-23)/10)
	tadj = 3^((celsius-23.5)/10)
	evaluate_fct(v)
	m = m_inf
}

PROCEDURE evaluate_fct(v(mV)) {  LOCAL a,b
	tau_m = 1000.0/(3.3*(exp((v+35)/20)+exp(-(v+35)/20))) / tadj
	m_inf = 1.0 / (1+exp(-(v+35)/10))
}
UNITSON

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