Distance-dependent synaptic strength in CA1 pyramidal neurons (Menon et al. 2013)

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Accession:222726
Menon et al. (2013) describes the experimentally-observed variation in synaptic AMPA and NMDA conductance as a function of distance from the soma. This model explores the effect of this variation on somatic EPSPs and dendritic spike initiation, as compared to the case of uniform AMPA and NMDA conductance.
Reference:
1 . Menon V, Musial TF, Liu A, Katz Y, Kath WL, Spruston N, Nicholson DA (2013) Balanced synaptic impact via distance-dependent synapse distribution and complementary expression of AMPARs and NMDARs in hippocampal dendrites. Neuron 80:1451-63 [PubMed]
Model Information (Click on a link to find other models with that property)
Model Type: Neuron or other electrically excitable cell; Synapse;
Brain Region(s)/Organism: Hippocampus;
Cell Type(s): Hippocampus CA1 pyramidal GLU cell;
Channel(s): I A; I K; I Na, slow inactivation;
Gap Junctions:
Receptor(s): AMPA; NMDA;
Gene(s):
Transmitter(s):
Simulation Environment: NEURON;
Model Concept(s): Synaptic Integration;
Implementer(s): Menon, Vilas [vilasmenon2008 at u dot northwestern dot edu];
Search NeuronDB for information about:  Hippocampus CA1 pyramidal GLU cell; AMPA; NMDA; I A; I K; I Na, slow inactivation;
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MenonEtAl2013
README.txt
dv.mod
ih_new.mod
kadist.mod *
kaprox.mod *
kdrca1.mod *
leakcond.mod *
nafast2.mod
naslowcond2.mod
nmda.mod
spines.mod *
synampa.mod *
vmax.mod
vmax2.mod
vmaxlast.mod
vms.mod
code_membrane.hoc
code_objects.hoc
code_point_processes.hoc
code_routine_for_runs.hoc
code_run_multiple_spines_on_branch.hoc
code_run_single_spine.hoc
code_synapse_array_setup.hoc
code_synapse_setup.hoc
mosinit.hoc
ri06.nrn *
simulated_axon.nrn *
spinearraygeom.nrn
spinegeom.nrn
                            
TITLE K-A channel from Klee Ficker and Heinemann
: modified to account for Dax A Current ----------
: M.Migliore Jun 1997

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

}

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

PARAMETER {
        dt (ms)
	v (mV)
        ek  = -90  (mV)           : must be explicitely def. in hoc
	celsius = 24	(degC)
	gbar=.008 (mho/cm2)
        vhalfn=11   (mV)
        vhalfl=-56   (mV)
        a0l=0.05      (/ms)
        a0n=0.05    (/ms)
        zetan=-1.5    (1)
        zetal=3    (1)
        gmn=0.55   (1)
        gml=1   (1)
	lmin=2  (ms)
	nmin=0.1  (ms)
	pw=-1    (1)
	tq=-40  (mV)
	qq=5    (mV)
	q10=5
	qtl=1
        nscale=1
        lscale=1
}


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

STATE {
	n
        l
}

ASSIGNED {
	ik (mA/cm2)
        ninf
        linf      
        taul  (ms)
        taun  (ms)
        gka   (mho/cm2)
        qt
}

INITIAL {
        rates(v)
        n=ninf
        l=linf
        gka = gbar*n*l
	ik = gka*(v-ek)
}        

BREAKPOINT {
	SOLVE states METHOD cnexp
	gka = gbar*n*l
	ik = gka*(v-ek)

}

DERIVATIVE states {
        rates(v)
        n' = (ninf-n)/taun
        l' = (linf-l)/taul
}

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

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

FUNCTION betl(v(mV)) {
  betl = exp(1.e-3*zetal*gml*(v-vhalfl)*9.648e4(degC/mV)/(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(degC))
        a = alpn(v)
        ninf = 1/(1 + a)
        taun = betn(v)/(qt*a0n*(1+a))
	if (taun<nmin) {taun=nmin}
:	taun=nmin
        taun=taun/nscale
        facn = (1 - exp(-dt/taun))
        a = alpl(v)
        linf = 1/(1+ a)
	taul = 0.26(ms/mV)*(v+50)/qtl
	if (taul<lmin/qtl) {taul=lmin/qtl}
        taul=taul/lscale
        facl = (1 - exp(-dt/taul))
}















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