Differential modulation of pattern and rate in a dopamine neuron model (Canavier and Landry 2006)

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Accession:84612
"A stylized, symmetric, compartmental model of a dopamine neuron in vivo shows how rate and pattern can be modulated either concurrently or differentially. If two or more parameters in the model are varied concurrently, the baseline firing rate and the extent of bursting become decorrelated, which provides an explanation for the lack of a tight correlation in vivo and is consistent with some independence of the mechanisms that generate baseline firing rates versus bursting. ..." See paper for more and details.
Reference:
1 . Canavier CC, Landry RS (2006) An increase in AMPA and a decrease in SK conductance increase burst firing by different mechanisms in a model of a dopamine neuron in vivo. J Neurophysiol 96:2549-63 [PubMed]
Model Information (Click on a link to find other models with that property)
Model Type: Neuron or other electrically excitable cell; Electrogenic pump;
Brain Region(s)/Organism:
Cell Type(s): Substantia nigra pars compacta DA cell;
Channel(s): I L high threshold; I N; I T low threshold; I A; I K; I K,Ca; I Sodium; I Calcium; Na/K pump;
Gap Junctions:
Receptor(s): AMPA; NMDA; Gaba;
Gene(s):
Transmitter(s):
Simulation Environment: NEURON;
Model Concept(s): Activity Patterns; Bursting; Detailed Neuronal Models; Intrinsic plasticity; Calcium dynamics; Sodium pump;
Implementer(s): Kuznetsova, Anna [anna.kuznetsova at utsa.edu];
Search NeuronDB for information about:  Substantia nigra pars compacta DA cell; AMPA; NMDA; Gaba; I L high threshold; I N; I T low threshold; I A; I K; I K,Ca; I Sodium; I Calcium; Na/K pump;
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CanavierLandry2006
in_vitro
README
ampasyn.mod *
cabalan.mod *
cachan.mod *
capump.mod *
hh3.mod *
kca.mod *
leak.mod *
nabalan.mod *
nmdasyn.mod *
pump.mod *
stim.mod *
fig10a.hoc
fig10a.ses
fig10AMPA.dat
fig10b.hoc
fig10b.ses
fig10c.hoc
fig10c.ses
fig10NMDA.dat
fig11b1.hoc
fig11b1.ses
fig11b2.hoc
fig11b2.ses
fig4b1.hoc
fig4b1.ses
fig4b2.hoc
fig4b2.ses
fig4b3.hoc
fig4b3.ses
fig4bAMPA.dat
fig4bNMDA.dat
fig5a.hoc
fig5a.ses
fig5AMPA.dat
fig5b.hoc
fig5b.ses
fig5NMDA.dat
fig9a1.hoc
fig9a1.ses
fig9a2.hoc
fig9a2.ses
fig9a3.hoc
fig9a3.ses
fig9aAMPA.dat
fig9aNMDA.dat
fig9b1.hoc
fig9b1.ses
fig9b2.hoc
fig9b2.ses
fig9b3.hoc
fig9b3.ses
fig9bAMPA.dat
fig9bNMDA.dat
mosinit.hoc
Receptor.cpp
                            
TITLE NMDA receptor as a distributed mechanism
COMMENT
Landry did not multiply the calcium current by z squared,
hence the effective permeability ratio is not 10.6 but 2.65.
(To make this file equivalent to Komendantov's nmda.mod,
(see Komendantov et al. 2004 ModelDB entry)
the 91st line here should be ica = 4*10.6*power*numerca/denom2).
Also Landry used the somatic calcium concentration
to drive the dendritic calcium component of the NMDA current, while
in Komendantov et al. 2004, a constant calcium concentration cai
is used in the dendrites instead. 
Other than there two discrepancies, the description of the current
is identical despite the different formulations.
ENDCOMMENT

UNITS {
        (pA) = (picoamp)
        (molar) = (1/liter)
	(mV) =	(millivolt)
	(mA) =	(milliamp)
	(mM) =	(millimolar)
}


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

NEURON {
	SUFFIX nmda
	USEION ca WRITE ica
	USEION na  READ nai WRITE ina
	USEION k  WRITE ik
	RANGE  ica,ina,ik,inmda,Pbar,mg,km,nai,pr
        GLOBAL pinf
        POINTER caisoma  : will take calcium concentration from the soma
        POINTER nmdasyn  : will transfer "random synaptic dynamics" from a data file
}

UNITS {
	:FARADAY = 96520 (coul)
	:R = 8.3134 (joule/degC)
	FARADAY = (faraday) (coulomb)
	R = (k-mole) (joule/degC)
}

PARAMETER {
        v (mV)
	celsius= 35  	(degC)
	Pbar = 0.23e-6	(cm/s)	: Maximum Permeability PNMDA in Laundry
	cao = 2.0		(mM)
	lamdaca = 0.3 
        lamda = 0.75
        pr = 0.0225
	nao = 145	(mM)
	ki =  140	(mM)
	ko = 2.5	(mM)
        dt (ms)
        q=9 (mV)
        km=50.7 (mM)
        mg = 1.2 (mM)
}

STATE {
         p <1e-4>
}

ASSIGNED { 
	   nai          (mM)
           ica		(mA/cm2)
           ina		(mA/cm2)
           ik		(mA/cm2)
           inmda 	(mA/cm2)
           pinf
           caisoma      (mM)
           nmdasyn      (1)
}

LOCAL arg, power, numerna, numerk, numerca, denom, denom2

BREAKPOINT {
     SOLVE states METHOD cnexp
	pinf = pr + (1.0 - pr)/(1 + (mg/km)*exp(-v/q))
        arg = v*FARADAY /((1000)*R*(celsius+273.15))
	power =  nmdasyn*Pbar*(0.000001)*v*p*FARADAY*FARADAY/(R*(celsius+273.15))
	numerna = lamda*nai - lamda*nao*exp(-arg)
	numerk = lamda*ki - lamda*ko*exp(-arg)
	numerca = caisoma - lamdaca*cao*exp(-2*arg)
	denom = 1 - exp(-arg)
	denom2 = 1 - exp(-2*arg)
	
        ina = power*numerna/denom
	ik = power*numerk/denom
	ica = 10.6*power*numerca/denom2
	inmda = ina + ik + ica


}
UNITSOFF
DERIVATIVE states {
	pinf = pr + (1.0 - pr)/(1 + (mg/km)*exp(-v/q))
	p' = pinf - p 
	}
UNITSON

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