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 Ca R-type channel with medium threshold for activation
: used in distal dendritic regions, together with calH.mod, to help
: the generation of Ca++ spikes in these regions
: uses channel conductance (not permeability)
: written by Yiota Poirazi on 11/13/00 poirazi@LNC.usc.edu

NEURON {
	SUFFIX car
	USEION ca READ eca WRITE ica
        RANGE gcabar, m, h
	RANGE inf, fac, tau
}

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
        v               (mV)
        celsius = 34	(degC)
	dt              (ms)
        gcabar = 0      (mho/cm2) : initialized conductance
	eca = 140       (mV)      : Ca++ reversal potential
        }  

STATE {	m h }            : unknown activation and inactivation parameters to be solved in the DEs  

ASSIGNED {               : parameters needed to solve DE
	ica (mA/cm2)
        inf[2]
	fac[2]
	tau[2]
}

BREAKPOINT {
	SOLVE states
	ica = gcabar*m*m*m*h*(v - eca)
	}

INITIAL {
        m = 0    : initial activation parameter value
	h = 1    : initial inactivation parameter value
	states()
	ica = gcabar*m*m*m*h*(v - eca) : initial Ca++ current value
        }

PROCEDURE calcg() {
	mhn(v*1(/mV))
	m = m + fac[0]*(inf[0] - m)
	h = h + fac[1]*(inf[1] - h)
	}	

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

FUNCTION varss(v, i) {
	if (i==0) {
	    varss = 1 / (1 + exp((v+48.5)/(-3))) : Ca activation
	}
	else if (i==1) {
             varss = 1/ (1 + exp((v+53)/(1)))    : Ca inactivation
	}
}

FUNCTION vartau(v, i) {
	if (i==0) {
           vartau = 50  : activation variable time constant
        }
	else if (i==1) {
           vartau = 5   : inactivation variable time constant
       }
	
}	

PROCEDURE mhn(v) {LOCAL a, b :rest = -70
:	TABLE inf, fac DEPEND dt, celsius FROM -100 TO 100 WITH 200
	FROM i=0 TO 1 {
		tau[i] = vartau(v,i)
		inf[i] = varss(v,i)
		fac[i] = (1 - exp(-dt/tau[i]))
	}
}
















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