CA1 pyramidal neuron: synaptically-induced bAP predicts synapse location (Sterratt et al. 2012)

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Accession:144490
This is an adaptation of Poirazi et al.'s (2003) CA1 model that is used to measure BAP-induced voltage and calcium signals in spines after simulated Schaffer collateral synapse stimulation. In the model, the peak calcium concentration is highly correlated with soma-synapse distance under a number of physiologically-realistic suprathreshold stimulation regimes and for a range of dendritic morphologies. There are also simulations demonstrating that peak calcium can be used to set up a synaptic democracy in a homeostatic manner, whereby synapses regulate their synaptic strength on the basis of the difference between peak calcium and a uniform target value.
Reference:
1 . Sterratt DC, Groen MR, Meredith RM, van Ooyen A (2012) Spine calcium transients induced by synaptically-evoked action potentials can predict synapse location and establish synaptic democracy. PLoS Comput Biol 8:e1002545 [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,t; I L high threshold; I T low threshold; I A; I K; I M; I Mixed; I R; I_AHP;
Gap Junctions:
Receptor(s): AMPA; NMDA;
Gene(s):
Transmitter(s):
Simulation Environment: NEURON;
Model Concept(s): Dendritic Action Potentials; Synaptic Plasticity;
Implementer(s): Sterratt, David ; Groen, Martine R [martine.groen at gmail.com];
Search NeuronDB for information about:  Hippocampus CA1 pyramidal cell; AMPA; NMDA; I Na,t; I L high threshold; I T low threshold; I A; I K; I M; I Mixed; I R; I_AHP;
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bpap
CA1_multi
mechanism
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.old *
mosinit.poirazi.hoc *
                            
TITLE K-A channel from Klee Ficker and Heinemann
: modified by Brannon and Yiota Poirazi (poirazi@LNC.usc.edu)
: to account for Hoffman et al 1997 proximal region kinetics
: used only in soma and sections located < 100 microns from the soma

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
        dt              (ms)
	v               (mV)
        ek = -77        (mV)      :K reversal potential  (reset in cell-setup.hoc)
	celsius = 24	(degC)
       	gkabar = 0      (mho/cm2) :initialized conductance
        vhalfn = 11     (mV)      :activation half-potential
        vhalfl = -56    (mV) 	  :inactivation half-potential
        a0n = 0.05      (/ms)     :parameters used
        zetan = -1.5    (1)       :in calculation of
        zetal = 3       (1)       :steady state values
        gmn = 0.55      (1)       :and time constants
        gml = 1         (1)
	lmin = 2        (mS)
	nmin = 0.1      (mS)
	pw = -1         (1)
	tq = -40
	qq = 5
	q10 = 5                   :temperature sensitivity
}


NEURON {
	SUFFIX kap
	USEION k READ ek WRITE ik
        RANGE gkabar,gka
        GLOBAL ninf,linf,taul,taun,lmin
}

STATE {          :the unknown parameters to be solved in the DEs 
	n l
}
 
ASSIGNED {       :parameters needed to solve DE
	ik (mA/cm2)
        ninf
        linf      
        taul
        taun
        gka
}

INITIAL {		:initialize the following parameter using rates()
	rates(v)
	n = ninf
	l = linf
	gka = gkabar*n*l
	ik = gka*(v-ek)
}

BREAKPOINT {
	SOLVE states 
	gka = gkabar*n*l
	ik = gka*(v-ek)
}


FUNCTION alpn(v(mV)) { LOCAL zeta 
  zeta = zetan+pw/(1+exp((v-tq)/qq))
  alpn = exp(1.e-3*zeta*(v-vhalfn)*9.648e4/(8.315*(273.16+celsius))) 
}

FUNCTION betn(v(mV)) { LOCAL zeta
  zeta = zetan+pw/(1+exp((v-tq)/qq))
  betn = exp(1.e-3*zeta*gmn*(v-vhalfn)*9.648e4/(8.315*(273.16+celsius))) 
}

FUNCTION alpl(v(mV)) {
  alpl = exp(1.e-3*zetal*(v-vhalfl)*9.648e4/(8.315*(273.16+celsius))) 
}

FUNCTION betl(v(mV)) {
  betl = exp(1.e-3*zetal*gml*(v-vhalfl)*9.648e4/(8.315*(273.16+celsius))) 
}

LOCAL facn,facl
:if state_borgka 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 states() {     : exact when v held constant; integrates over dt step
        rates(v)
        n = n + facn*(ninf - n)
        l = l + facl*(linf - l)
        VERBATIM
        return 0;
        ENDVERBATIM
}

PROCEDURE rates(v (mV)) {                  :callable from hoc
        LOCAL a,qt
        qt = q10^((celsius-24)/10)         : temprature adjastment factor
        a = alpn(v)
        ninf = 1/(1 + a)                   : activation variable steady state value
        taun = betn(v)/(qt*a0n*(1+a))      : activation variable time constant
	if (taun<nmin) {taun=nmin}         : time constant not allowed to be less than nmin
        facn = (1 - exp(-dt/taun))
        a = alpl(v)
        linf = 1/(1+ a)                    : inactivation variable steady state value
	taul = 0.26*(v+50)                 : inactivation variable time constant
	if (taul<lmin) {taul=lmin}         : time constant not allowed to be less than lmin
        facl = (1 - exp(-dt/taul))
}