Intracortical synaptic potential modulation by presynaptic somatic potential (Shu et al. 2006, 2007)

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Accession:135787
" ... Here we show that the voltage fluctuations associated with dendrosomatic synaptic activity propagate significant distances along the axon, and that modest changes in the somatic membrane potential of the presynaptic neuron modulate the amplitude and duration of axonal action potentials and, through a Ca21- dependent mechanism, the average amplitude of the postsynaptic potential evoked by these spikes. These results indicate that synaptic activity in the dendrite and soma controls not only the pattern of action potentials generated, but also the amplitude of the synaptic potentials that these action potentials initiate in local cortical circuits, resulting in synaptic transmission that is a mixture of triggered and graded (analogue) signals."
References:
1 . Shu Y, Duque A, Yu Y, Haider B, McCormick DA (2007) Properties of action-potential initiation in neocortical pyramidal cells: evidence from whole cell axon recordings. J Neurophysiol 97:746-60 [PubMed]
2 . Shu Y, Hasenstaub A, Duque A, Yu Y, McCormick DA (2006) Modulation of intracortical synaptic potentials by presynaptic somatic membrane potential. Nature 441:761-5 [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:
Cell Type(s): Neocortex V1 L6 pyramidal corticothalamic cell;
Channel(s): I Na,t; I L high threshold; I A; I K; I M; I h; I K,Ca; I_AHP; I_KD;
Gap Junctions:
Receptor(s): GabaA; AMPA; NMDA;
Gene(s):
Transmitter(s):
Simulation Environment: NEURON;
Model Concept(s): Action Potential Initiation; Detailed Neuronal Models; Action Potentials; Synaptic Integration;
Implementer(s):
Search NeuronDB for information about:  Neocortex V1 L6 pyramidal corticothalamic cell; GabaA; AMPA; NMDA; I Na,t; I L high threshold; I A; I K; I M; I h; I K,Ca; I_AHP; I_KD;
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ShuEtAl20062007
readme.txt
ampa5.mod *
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 *
2006_Nature.pdf
2006_Nature_supp.pdf
best_full_axon_decay.hoc
best_full_axon_spike_init.hoc
decay_constant.gif
for_decay.m
for_initiation.m
j4a.hoc *
j4a_removedendrite.hoc
j4a_removedendrite1.hoc
j7.hoc *
j8.hoc *
j8_removedendrite.hoc
lcAS3.hoc *
mosinit.hoc
spike_initiation.gif
                            
TITLE transient potassium current (A-current)

COMMENT
	*********************************************
	reference:	Huguenard & McCormick (1992) 
			J.Neurophysiology 68(4), 1373-1383
	found in:	thalamic relay neurons		 	
	*********************************************
	Original by Alain Destexhe
	Rewritten for MyFirstNEURON by Arthur Houweling
ENDCOMMENT

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

NEURON {
	SUFFIX iA
	USEION k READ ek WRITE ik 
        RANGE gkbar, m_inf1, tau_m, h_inf, tau_h1, ik
}

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

PARAMETER {
	v		(mV)
	celsius		(degC)
	dt		(ms)
	ek		(mV)
	gkbar= 0.009	(mho/cm2)
:	gkbar= 0.00345	(mho/cm2)
}

STATE {
	m1 h1
}

ASSIGNED {
	ik		(mA/cm2)
	m_inf1
	tau_m		(ms)
	h_inf
	tau_h1		(ms)
	tadj
}

BREAKPOINT { 
	SOLVE states :METHOD euler
 	ik = gkbar * m1^4*h1 * (v-ek)
}

:DERIVATIVE states { 
:	evaluate_fct(v)
:
:	m1'= (m_inf1-m1) / tau_m
:	h1'= (h_inf-h1) / tau_h1
:}

PROCEDURE states() {
        evaluate_fct(v)

	m1= m1 + (1-exp(-dt/tau_m))*(m_inf1-m1)
	h1= h1 + (1-exp(-dt/tau_h1))*(h_inf-h1)
}

UNITSOFF
INITIAL {
:	tadj = 2.3^((celsius-23)/10)
	tadj = 3^((celsius-23.5)/10)
	evaluate_fct(v)
	m1 = m_inf1
        h1 = h_inf
}

PROCEDURE evaluate_fct(v(mV)) {  LOCAL a,b
	tau_m = 1.0/((exp((v+35.82)/19.69)+exp(-(v+79.69)/12.7))+0.37) / tadj
	m_inf1 = 1.0 / (1+exp(-(v+60)/8.5))
	a = 1.0/((exp((v+46.05)/5)+exp(-(v+238.4)/37.45))) / tadj
	if (v<-63) {
		tau_h1 = a
		}
	else {
		tau_h1 = 19.0/tadj
		}
	h_inf = 1.0/(1+exp((v+78)/6))
}
UNITSON

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