CA1 pyramidal neuron: as a 2-layer NN and subthreshold synaptic summation (Poirazi et al 2003)

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Accession:20212
We developed a CA1 pyramidal cell model calibrated with a broad spectrum of in vitro data. Using simultaneous dendritic and somatic recordings, and combining results for two different response measures (peak vs. mean EPSP), two different stimulus formats (single shock vs. 50 Hz trains), and two different spatial integration conditions (within vs. between-branch summation), we found the cell's subthreshold responses to paired inputs are best described as a sum of nonlinear subunit responses, where the subunits correspond to different dendritic branches. In addition to suggesting a new type of experiment and providing testable predictions, our model shows how conclusions regarding synaptic arithmetic can be influenced by an array of seemingly innocuous experimental design choices.
References:
1 . Poirazi P, Brannon T, Mel BW (2003a) Arithmetic of subthreshold synaptic summation in a model CA1 pyramidal cell. Neuron 37:977-987 [PubMed]
2 . Poirazi P, Brannon T, Mel BW (2003b) Pyramidal Neuron as Two-Layer Neural Network. Neuron 37:989-999 [PubMed]
3 . Poirazi P, Brannon T, Mel BW (2003ab-sup) Online Supplement: About the Model Neuron 37 Online:1-20
4 . Polsky A, Mel BW, Schiller J (2004) Computational subunits in thin dendrites of pyramidal cells. Nat Neurosci 7:621-7 [PubMed]
Model Information (Click on a link to find other models with that property)
Model Type: Neuron or other electrically excitable cell;
Brain Region(s)/Organism:
Cell Type(s): Hippocampus CA1 pyramidal cell;
Channel(s): I Na,p; I Na,t; I L high threshold; I T low threshold; I A; I K; I M; I h; I K,Ca; I Calcium;
Gap Junctions:
Receptor(s): GabaA; GabaB; NMDA; Glutamate;
Gene(s):
Transmitter(s):
Simulation Environment: NEURON;
Model Concept(s): Action Potential Initiation; Activity Patterns; Dendritic Action Potentials; Active Dendrites; Influence of Dendritic Geometry; Detailed Neuronal Models; Action Potentials; Depression; Delay;
Implementer(s): Poirazi, Panayiota [poirazi at imbb.forth.gr];
Search NeuronDB for information about:  Hippocampus CA1 pyramidal cell; GabaA; GabaB; NMDA; Glutamate; I Na,p; I Na,t; I L high threshold; I T low threshold; I A; I K; I M; I h; I K,Ca; I Calcium;
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CA1_multi
mechanism
not-currently-used
cad.mod *
cagk.mod *
cal.mod *
calH.mod *
car.mod *
cat.mod *
d3.mod *
gabaa.mod *
gabab.mod *
glutamate.mod *
h.mod *
hha_old.mod *
hha2.mod *
kadist.mod *
kaprox.mod *
kca.mod *
km.mod *
nap.mod *
nmda.mod *
somacar.mod *
mosinit.hoc *
mosinit.hoc.old *
                            
TITLE HH channel that includes both a sodium and a delayed rectifier channel 
: and accounts for sodium conductance attenuation
: Bartlett Mel-modified Hodgkin - Huxley conductances (after Ojvind et al.)
: Terrence Brannon-added attenuation 
: Yiota Poirazi-modified Kdr and Na threshold and time constants
: to make it more stable, 2000, poirazi@LNC.usc.edu
: Used in all BUT somatic and axon sections. The spike threshold is about -50 mV

NEURON {
	SUFFIX hha_old
	USEION na READ ena WRITE ina 
	USEION k READ ek WRITE ik
	NONSPECIFIC_CURRENT il
	RANGE gnabar, gkbar, gl, el
	RANGE ar2, vhalfs
	RANGE inf, fac, tau
	RANGE taus
	RANGE W
	GLOBAL taumin
}

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

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

PARAMETER {   : parameters that can be entered when function is called in cell-setup
        a0r = 0.0003 (ms)
        b0r = 0.0003 (ms)
        zetar = 12    
	zetas = 12   
        gmr = 0.2   
	ar2 = 1.0               :initialized parameter for location-dependent
                                :Na-conductance attenuation, "s", (ar=1 -> zero attenuation)
	taumin = 3   (ms)       :min activation time for "s" attenuation system
        vvs  = 2     (mV)       :slope for "s" attenuation system
        vhalfr = -60 (mV)       :half potential for "s" attenuation system
	W = 0.016    (/mV)      :this 1/61.5 mV
:	gnabar = 0.2 (mho/cm2)  :suggested conductance values
:	gkbar = 0.12 (mho/cm2)
:	gl = 0.0001  (mho/cm2)
        gnabar = 0   (mho/cm2)  :initialized conductances
	gkbar = 0    (mho/cm2)  :actual values set in cell-setup.hoc
	gl = 0       (mho/cm2)
	ena = 60     (mV)       :Na reversal potential (also reset in
	ek = -77     (mV)       :K reversal potential  cell-setup.hoc)
	el = -70.0   (mV)       :steady state 
	celsius = 34 (degC)
	v            (mV)
        dt           (ms)
}

STATE {                         : the unknown parameters to be solved in the DEs
	m h n s
}

ASSIGNED {			: parameters needed to solve DE
	ina (mA/cm2)
	ik (mA/cm2)
	il (mA/cm2)
	inf[4]
	fac[4]
	tau[4]
}

BREAKPOINT {
	SOLVE states
	ina = gnabar*m*m*h*s*(v - ena) :Sodium current
	ik = gkbar*n*n*(v - ek)        :Potassium current
	il = gl*(v - el)               :leak current
}

INITIAL {                       : initialize the following parameter using states()
	states()
	s=1
	ina = gnabar*m*m*h*s*(v - ena)
	ik = gkbar*n*n*(v - ek)
	il = gl*(v - el)
}

PROCEDURE calcg() {
	mhn(v*1(/mV))
	m = m + fac[0]*(inf[0] - m)   :Na activation variable
	h = h + fac[1]*(inf[1] - h)   :Na inactivation variable
	n = n + fac[2]*(inf[2] - n)   :K activation variable
	s = s + fac[3]*(inf[3] - s)   :Na attenuation variable
}	

PROCEDURE states() {	: exact when v held constant
	calcg()
	VERBATIM
	return 0;
	ENDVERBATIM
}


FUNCTION varss(v, i) { :steady state values
	if (i==0) {
		varss = 1 / (1 + exp((v + 40)/(-3))) :Na activation
	}
	else if (i==1) {
		varss = 1 / (1 + exp((v + 45)/(3)))  :Na inactivation
	}
	else if (i==2) {	
		varss = 1 / (1 + exp((v + 42)/(-2))) :K activation

	} else {
                :"s" activation system for spike attenuation - Migliore 96 model
		varss = alpv(v,vhalfr)
       }
}


FUNCTION alpv(v(mV),vh) {    :used in "s" activation system infinity calculation
  alpv = (1+ar2*exp((v-vh)/vvs))/(1+exp((v-vh)/vvs))
}

FUNCTION alpr(v(mV)) {       :used in "s" activation system tau
  alpr = exp(1.e-3*zetar*(v-vhalfr)*9.648e4/(8.315*(273.16+celsius))) 
}

FUNCTION betr(v(mV)) {       :used in "s" activation system tau
  betr = exp(1.e-3*zetar*gmr*(v-vhalfr)*9.648e4/(8.315*(273.16+celsius))) 
}

FUNCTION vartau(v, i) { :estimate tau values
	LOCAL tmp
	if (i==0) {
	   vartau = 0.05      :Na activation tau
	}
	else if (i==1) {
           vartau = 0.5       :Na inactivation tau
        }
	else if (i==2) {
            vartau = 2.2      :K activation tau
       	} else {
	     tmp = betr(v)/(a0r+b0r*alpr(v)) 
	     if (tmp<taumin) {tmp=taumin}
	VERBATIM
	ENDVERBATIM
	     vartau = tmp      :s activation tau
       }
}	

PROCEDURE mhn(v) {
:       TABLE infinity, tau, fac DEPEND dt, celsius FROM -100 TO 100 WITH 200
	FROM i=0 TO 3 {
		tau[i] = vartau(v,i)
		inf[i] = varss(v,i)
		fac[i] = (1 - exp(-dt/tau[i]))
	}
}
















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