CA1 pyramidal neuron: depolarization block (Bianchi et al. 2012)

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Accession:143719
NEURON files from the paper: On the mechanisms underlying the depolarization block in the spiking dynamics of CA1 pyramidal neurons by D.Bianchi, A. Marasco, A.Limongiello, C.Marchetti, H.Marie,B.Tirozzi, M.Migliore (2012). J Comput. Neurosci. In press. DOI: 10.1007/s10827-012-0383-y. Experimental findings shown that under sustained input current of increasing strength neurons eventually stop firing, entering a depolarization block. We analyze the spiking dynamics of CA1 pyramidal neuron models using the same set of ionic currents on both an accurate morphological reconstruction and on its reduction to a single-compartment. The results show the specic ion channel properties and kinetics that are needed to reproduce the experimental findings, and how their interplay can drastically modulate the neuronal dynamics and the input current range leading to depolarization block.
Reference:
1 . Bianchi D, Marasco A, Limongiello A, Marchetti C, Marie H, Tirozzi B, Migliore M (2012) On the mechanisms underlying the depolarization block in the spiking dynamics of CA1 pyramidal neurons. J Comput Neurosci 33:207-25 [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: Hippocampus;
Cell Type(s): Hippocampus CA1 pyramidal cell;
Channel(s): I Na,t; I A; I K; I M; I h; I K,Ca; I_AHP;
Gap Junctions:
Receptor(s): GabaA; AMPA; NMDA;
Gene(s):
Transmitter(s): Gaba; Glutamate;
Simulation Environment: NEURON; Mathematica;
Model Concept(s): Simplified Models; Depolarization block; Bifurcation;
Implementer(s): Bianchi, Daniela [danielabianchi12 -at- gmail.com]; Limongiello, Alessandro [alessandro.limongiello at unina.it];
Search NeuronDB for information about:  Hippocampus CA1 pyramidal cell; GabaA; AMPA; NMDA; I Na,t; I A; I K; I M; I h; I K,Ca; I_AHP; Gaba; Glutamate;
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Ca1_Bianchi
experiment
cad.mod *
cagk.mod *
cal.mod *
calH.mod *
car.mod *
cat.mod *
d3.mod *
h.mod *
kadist.mod *
kaprox.mod *
kca.mod *
kdr.mod *
km.mod *
na3.mod *
na3dend.mod *
na3notrunk.mod *
nap.mod *
nax.mod *
somacar.mod *
cell-setup.hoc
mosinit.hoc
sessio.ses
Simulation.hoc
                            
TITLE  H-current that uses Na ions

NEURON {
	SUFFIX h
        RANGE  gbar,vhalf, K, taun, ninf, g  
	USEION na READ ena WRITE ina      
:	NONSPECIFIC_CURRENT i
}

UNITS {
	(um) = (micrometer)
	(mA) = (milliamp)
	(uA) = (microamp)
	(mV) = (millivolt)
	(pmho) = (picomho)
	(mmho) = (millimho)
}



PARAMETER {              : parameters that can be entered when function is called in cell-setup
        dt             (ms)
	v              (mV)
        ena    = 50    (mV)
        eh     = -10   (mV)
	K      = 8.5   (mV)
	gbar   = 0     (mho/cm2)  : initialize conductance to zero
	:vhalf  = -90   (mV)       : half potential
      vhalf  = -81   (mV)       : half potential
     

}	


STATE {                : the unknown parameters to be solved in the DEs
	n
}

ASSIGNED {             : parameters needed to solve DE
	ina (mA/cm2)
	ninf
	taun (ms)
	g
}

        


INITIAL {               : initialize the following parameter using states()
	states()	
	n = ninf
	g = gbar*n
	ina = g*(v-eh)
}


BREAKPOINT {
	SOLVE h METHOD derivimplicit
	g = gbar*n
	ina = g*(v-eh)  
}

DERIVATIVE h {
	states()
        n' = (ninf - n)/taun
}

PROCEDURE states() {  
 
 	if (v > -30) {
	   taun = 1
	} else {
           :taun = 2*(1/(exp((v+145)/-17.5)+exp((v+16.8)/16.5)) + 5) :h activation tau
           taun = 5*(1/(exp((v+145)/-17.5)+exp((v+16.8)/16.5)) + 5) :h activation tau


	}  
         ninf = 1 - (1 / (1 + exp((vhalf - v)/K)))                  :steady state value
}




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