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 (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]
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 GLU 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 GLU 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
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VClamp.omod *
                            
TITLE fast HVA calcium current

COMMENT
 fast high-voltage-activated calcium channel model
 Nif/AgTx/CgTx resistant VSCC from rat sensorimotor pyramidal cells
 Based on Lorenzon and Foehring (1995), J. Neurophysiol. 73(4):1430-1442

 Written by Kevin A. Archie, karchie@lnc.usc.edu
 (GHK code taken from Arthur Houweling's MyFirstNEURON models)

$Log: hvaccf.mod,v $
Revision 1.2  2000/09/27 22:45:41  karchie
Incorporated a few minor changes.

Revision 1.1  2000/09/21 17:50:33  karchie
Initial revision

ENDCOMMENT

VERBATIM

extern double nrn_ghk(double, double, double, double);

static const char rcsid[]="$Id: hvaccf.mod,v 1.2 2000/09/27 22:45:41 karchie Exp karchie $";

ENDVERBATIM

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

NEURON {
        SUFFIX ca
        USEION ca READ cai,cao WRITE ica
        RANGE pcabar, ica, m_inf, h_inf
}

UNITS {
        (mA)    = (milliamp)
        (mV)    = (millivolt)
        (mM)    = (milli/liter)
        FARADAY = 96480 (coul)
        R       = 8.314 (volt-coul/degC)
}

PARAMETER {
        v                       (mV)
        celsius                 (degC)
        dt                      (ms)
        cai             = 5.e-05(mM)
        cao             = 2.5   (mM)
        pcabar                  (cm/s)  
        tauM            = 5     (ms)
:        vHalfM          = -22   (mV)
:        slopeM          = 12    (mV)
        vHalfM          = 3   (mV)
        slopeM          = 8.3    (mV)
        tauH            = 0.8   (ms)
:        vHalfH          = -24   (mV)  : given slopeH, 80% inactivation @ -10mV
:        slopeH          = 10    (mV)  : close to slopeM (no data for this)
        vHalfH          = -39   (mV)  : given slopeH, 80% inactivation @ -10mV
        slopeH          = 9.2    (mV)  : close to slopeM (no data for this)
        tBase           = 23.5  (degC) : temperature for which tau is correct
:        mpow            = 2           : power of m in state equation
}

STATE {
        m
        h
}

ASSIGNED {
        ica             (mA/cm2)
        m_inf
        h_inf
}

INITIAL {
        LOCAL tadj

        : adjust rate constants based on temperature.
        : original experiments performed at room temperature
        : assumes that temperature remains constant through the sim
        tadj = 3^((celsius-tBase)/10)   : assume Q10 of 3
        tauM = tauM / tadj
        tauH = tauH / tadj

        : set initial values of state variables.
        rates(v)
        m = m_inf
        h = h_inf
}

BREAKPOINT {
        SOLVE states

:        ica = pcabar * pow(m,mpow) * h * nrn_ghk((v),(cai),(cao),2);
VERBATIM
        ica = pcabar * m * m * h * nrn_ghk((v),(cai),(cao),2);
ENDVERBATIM
}

PROCEDURE states() {
        rates(v)
        m = m + (1-exp(-dt/tauM))*(m_inf-m)
        h = h + (1-exp(-dt/tauH))*(h_inf-h)
}


PROCEDURE rates(v(mV)) {
        m_inf = 1/(1+exp(-(v-vHalfM)/slopeM))
        h_inf = 1/(1+exp((v-vHalfH)/slopeH))
}

FUNCTION ghk( v(mV), ci(mM), co(mM), z)  (millicoul/cm3) {
        LOCAL e, w
        w = v * (.001) * z*FARADAY / (R*(celsius+273.16))
        e = w / (exp(w)-1)
        if (fabs(w)>1e-4) 
          { e = w / (exp(w)-1) }
        else
        : denominator is small -> Taylor series
          { e = 1-w/2 }
        ghk = - (.001) * z*FARADAY * (co-ci*exp(w)) * e
}








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