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;
/
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
                            
COMMENT

High threshold Ca2+ channel

2-state kinetics with sigmoidal voltage-dependence

  C<->O

Goldman-Hodgkin-Katz equations

     # MODEL
    |   MODEL AUTHOR  : D.A. McCormick & J. Huguenard
    |   MODEL DATE    : 1992
    |   MODEL REF     : A model of the electrophysiological properties of 
thalamocortical relay neurons. J Neurophysiol, 1992 Oct, 68(4):1384-400.
 
    # EXPERIMENT
    |   EXP AUTHOR    : Kay AR; Wong RK
    |   EXP DATE      : 1987
    |   EXP REF       : Journal of Physiology, 1987 Nov, 392:603-16.
    |   ANIMAL        : guinea-pig
    |   BRAIN REGION  : hippocampus
    |   CELL TYPE     : Ca1 pyramidal
    |   TECHNIQUE     : slices, whole-cell
    |   RECORDING METHOD  : voltage-clamp
    |   TEMPERATURE   : 20-22
 
Reference:

   Destexhe, A., Mainen, Z.F. and Sejnowski, T.J. Synthesis of models for
   excitable membranes, synaptic transmission and neuromodulation using a 
   common kinetic formalism, Journal of Computational Neuroscience 1: 
   195-230, 1994.

  (electronic copy available at http://cns.iaf.cnrs-gif.fr)


ENDCOMMENT

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

NEURON {
	SUFFIX caL3d
	USEION ca READ cai, cao WRITE ica
	RANGE O, C, I
	RANGE a,b
	GLOBAL Ra, Rb, q, th, p
	GLOBAL q10, temp, tadj
}

UNITS {
	F = (faraday) (coulomb)
	R = (k-mole) (joule/degC)
	(mA) = (milliamp)
	(mV) = (millivolt)
	(pS) = (picosiemens)
	(um) = (micron)
	(mM) = (milli/liter)
} 

PARAMETER {
	p    = 0.2e-3  	(cm/s)		: max permeability
	v 		(mV)

	th   = 5	(mV)		: v 1/2 for on/off
	q   = 13	(mV)		: voltage dependence

	: max rates

	Ra   = 1.6	(/ms)		: open (v)
	Rb   = 0.2	(/ms)		: close (v)

	celsius		(degC)
	temp = 22	(degC)		: original temp
	q10  = 3			: temperature sensitivity
} 


ASSIGNED {
	ica 		(mA/cm2)
	cao		(mM)
	cai		(mM)
	a (/ms)	b (/ms)
	tadj
}
 

STATE { C O }

INITIAL { 
	C = 1 
}


BREAKPOINT {
	rates(v)
	SOLVE kstates METHOD sparse
	ica = O * p * ghk(v,cai,cao)
} 


KINETIC kstates {
	~ C <-> O 	(a,b)	
	CONSERVE C+O = 1
}	
	
PROCEDURE rates(v(mV)) {
	TABLE a, b
	DEPEND Ra, Rb, th, celsius, temp, q10
	FROM -100 TO 100 WITH 200

	tadj = q10 ^ ((celsius - temp)/10 (degC))

	a = Ra / (1 + exp(-(v-th)/q)) * tadj
	b = Rb / (1 + exp((v-th)/q)) * tadj
}

: Special gear for calculating the Ca2+ reversal potential
: via Goldman-Hodgkin-Katz eqn.
: [Ca2+]o "cao" and [Ca2+]i "cai" are assumed to be set elsewhere


FUNCTION ghk(v(mV), ci(mM), co(mM)) (0.001 coul/cm3) {
	LOCAL z

	z = (0.001)*2*F*v/(R*(celsius+273.15))
	ghk = (.001)*2*F*(ci*efun(-z) - co*efun(z))
}

FUNCTION efun(z) {
	if (fabs(z) < 1e-4) {
		efun = 1 - z/2
	}else{
		efun = z/(exp(z) - 1)
	}
}





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