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.
Reference:
1 . Poirazi P, Brannon T, Mel BW (2003) Arithmetic of subthreshold synaptic summation in a model CA1 pyramidal cell. Neuron 37:977-87 [PubMed]
2 . Poirazi P, Brannon T, Mel BW (2003) Pyramidal neuron as two-layer neural network. Neuron 37:989-99 [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]
Citations  Citation Browser
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 CaGk
: Calcium activated mAHP K channel.
: From Moczydlowski and Latorre (1983) J. Gen. Physiol. 82

UNITS {
	(molar) = (1/liter)
}

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

INDEPENDENT {t FROM 0 TO 1 WITH 100 (ms)}

NEURON {
	SUFFIX mykca
	USEION ca READ cai
	USEION k READ ek WRITE ik
	RANGE gkbar, ik
	GLOBAL oinf, tau
}

UNITS {
	FARADAY = (faraday)  (kilocoulombs)
	R = 8.313424 (joule/degC)
}

PARAMETER {
	v		(mV)
	dt		(ms)
	ek		(mV)
	celsius = 20	(degC)
	gkbar = 0.01	(mho/cm2)	: Maximum Permeability
	cai = 1e-3	(mM)
	d1 = 0.84
	d2 = 1.0
	k1 = 0.18	(mM)
	k2 = 0.011	(mM)
	bbar = 0.28	(/ms)
	abar = 0.48	(/ms)
}
COMMENT
the preceding two numbers were switched on 8/19/92 in response to a bug
report by Bartlett Mel. In the paper the kinetic scheme is
C <-> CCa (K1)
CCa <-> OCa (beta2,alpha2)
OCa <-> OCa2 (K4)
In this model abar = beta2 and bbar = alpha2 and K4 comes from d2 and k2
I was forcing things into a nomenclature where alpha is the rate from
closed to open. Unfortunately I didn't switch the numbers.
ENDCOMMENT

ASSIGNED {
	ik		(mA/cm2)
	oinf
	tau		(ms)
}

STATE {	o }		: fraction of open channels

BREAKPOINT {
	SOLVE state
	ik = gkbar*o*(v - ek) : potassium current induced by this channel
}

LOCAL fac

:if state_cagk is called from hoc, garbage or segmentation violation will
:result because range variables won't have correct pointer.  This is because
:only BREAKPOINT sets up the correct pointers to range variables.
PROCEDURE state() {	: exact when v held constant; integrates over dt step
	rate(v, cai)
	o = o + fac*(oinf - o)
	VERBATIM
	return 0;
	ENDVERBATIM
}

INITIAL {           : initialize the following parameter using rate()
	rate(v, cai)
	o = oinf
}

FUNCTION alp(v (mV), ca (mM)) (1/ms) { :callable from hoc
	alp = abar/(1 + exp1(k1,d1,v)/ca)
}

FUNCTION bet(v (mV), ca (mM)) (1/ms) { :callable from hoc
	bet = bbar/(1 + ca/exp1(k2,d2,v))
}  

FUNCTION exp1(k (mM), d, v (mV)) (mM) { :callable from hoc
	exp1 = k*exp(-2*d*FARADAY*v/R/(273.15 + celsius))
}

PROCEDURE rate(v (mV), ca (mM)) { :callable from hoc
	LOCAL a
	a = alp(v,ca)
	tau = 1/(a + bet(v, ca)) : estimation of activation tau
	oinf = a*tau             : estimation of activation steady state value
	fac = (1 - exp(-dt/tau))
}