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]
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,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 GLU 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
datastore
pars
plots
poirazi-nmda-car
tests
validation-plots
README.txt
ampa_forti.mod
cacum.mod
cad.mod *
cagk.mod
cal.mod
calH.mod
car.mod
car_mag.mod
cat.mod
d3.mod *
h.mod
hha_old.mod
hha2.mod
kadist.mod
kaprox.mod
kca.mod
km.mod
nap.mod
nmda_andr.mod
somacar.mod
binaverages.m
bpap-cell.hoc
bpap-data.hoc
bpap-dendburst.hoc
bpap-graphics.hoc
bpap-gui.hoc
bpap-gui.ses
bpap-pars.hoc
bpap-record.hoc
bpap-run.hoc
bpap-scaling.hoc
bpap-sims.hoc
bpap-sims-cell1.hoc
bpap-sims-cell2.hoc
bpap-sims-scaling.hoc
bpap-somainj.hoc
bpap-spiketrain.hoc
ca1_mrg_cell1.hoc
ca1_mrg_cell2.hoc
ca1_poirazi.hoc
ChannelBlocker.hoc
CrossingFinder.hoc
epspsizes.hoc
figure-example.R
figures.R
figures-common.R
FileUtils.hoc
FormatFile.hoc
ghk.inc
GraphUtils.hoc
Integrator.hoc
Makefile
mosinit.hoc
NmdaAmpaSpineSynStim.hoc
NmdaAmpaSynStim.hoc
ObjectClass.hoc
plotscalingresults_pergroup1.m
plotscalingresults5.m
PointProcessDistributor.hoc
ReferenceAxis.hoc
removezeros.m
RPlot.hoc
scaling_plots.m
Segment.hoc
SimpleSpine.hoc
Spine.hoc
TreePlot.hoc
TreePlotArray.hoc
triexpsyn.inc
units.inc
utils.hoc
validate-bpap.hoc
VarList.hoc
VCaGraph.hoc
                            
COMMENT

AMPA synapse with two decay time constants based on the exp2syn.mod
mechanism from the NEURON distribution.

We use the time constants measured by Andrasfalvy & Magee (2001) from
patches excised from different parts of the stratum radiatum at
22\degC.  These are in broad agreement with the time constants measured
by Spruston &al (1995), epecially when the age-dependent change in
receptor properties (Hestrin &al., 1992) is taken into account.
Although they are considerably slower than the time constants measured
using whole-cell recordings from hippocampal cells (Hestrin & al., 1990),
this might be accounted for by the more depolarised potentials used in
these recordings.  We corrected the time constants recorded at 22\degC
to 34\degC using a \Qten of 3 (Hestrin & al., 1990).  This gave a
rise time of 1.7\ms and a dual exponential decay comprising a fast
component fast time constant of 67\ms and a slow component with a time
constant of 428\ms in the ratio 0.61 to 0.39. 

References

B K Andr\'asfalvy & J C Magee 2001 "Distance-Dependent Increase in
  AMPA Receptor Number in the Dendrites of Adult Hippocampal CA1
  Pyramidal Neurons" J. Neurosci. 21, 9151-9159

S Hestrin & al. 1990 "Mechanisms Generating the time course of dual
  component excitatory synaptic currents recorded in hippocampal
  slices" Neuron 5, 247-253

S Hestrin 1992 "Developmental regulation of NMDA receptor-mediated
  currents at a central synapse" Nature 357, 686-689

N Spruston & al. 1995 "Dendritic glutamate receptor channels in rat
  hippocampal CA3 and CA1 neurons" J. Physiol. 482, 325-352

ENDCOMMENT

NEURON {
    POINT_PROCESS NmdaSyn
    RANGE  e, g, i, b, ica
    NONSPECIFIC_CURRENT i
    USEION ca READ cai,cao WRITE ica
    GLOBAL total, mg, q10, taurise, taufast, tauslow, taurise_exp, taufast_exp, tauslow_exp, afast, aslow, normfac, T_exp, K0, delta, fracca
}

INCLUDE "units.inc"

PARAMETER {
    : Time constants and afast from Andrasfalvy & Magee 01
    taurise_exp =    6.46 (ms) <1e-9,1e9>    : rise      
    taufast_exp =  252.5  (ms) <1e-9,1e9>    : fast decay
    tauslow_exp = 1660    (ms) <1e-9,1e9>    : slow decay
    afast = 0.61 <0,1>
    e=0	(mV)
    mg	= 1    (mM)		: external magnesium concentration
    fracca= 0.13        : fraction of current that is ca ions; Srupuston &al 95
    z = 2
    celsius = 22	(degC)
    T_exp = 22    (degC)
    q10 = 3       : Hestrin 90
    K0 = 4.1 (mM) : From Spruston &al 95
    delta = 0.8   : From Spruston &al 95
}

ASSIGNED {
    v       (mV)
    i       (nA)
    ica	    (nA) 	
    g       (uS)
    aslow 
    total   (uS)
    cai     (mM)
    cao     (mM)
    taurise (ms)
    taufast (ms)
    tauslow (ms)
    normfac 
    b
}

BREAKPOINT {
    SOLVE state METHOD cnexp
    b = mgblock(v)		: b is the block by magnesium at this voltage
    g = (B + C - A) * b
    i =   g * (1-fracca) * (v - e)
    ica = g * fracca     * ghkg(v,cai,cao,z)
}

INCLUDE "triexpsyn.inc"

INCLUDE "ghk.inc"

FUNCTION mgblock(v(mV)) {
    TABLE 
    DEPEND mg, K0, delta, celsius
    FROM -140 TO 80 WITH 1000
    : From Spruston &al 95
    mgblock = 1/(1+(mg/K0)*exp(-delta*z*FARADAY*v*(0.001)/R/(celsius+273)))
}




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