Ih levels roles in bursting and regular-spiking subiculum pyramidal neurons (van Welie et al 2006)

 Download zip file   Auto-launch 
Help downloading and running models
Accession:82364
Pyramidal neurons in the subiculum typically display either bursting or regular-spiking behavior. ... Here we report that bursting neurons posses a hyperpolarization-activated cation current (Ih) that is two-fold larger (conductance: 5.3 ± 0.5 nS) than in regularspiking neurons (2.2 ± 0.6 nS), while Ih exhibits similar voltage-dependent and kinetic properties in both classes of neurons. Bursting and regular-spiking neurons display similar morphology. The difference in Ih between the two classes is not responsible for the distinct firing patterns, since neither pharmacological blockade of Ih nor enhancement of Ih using a dynamic clamp affects the qualitative firing patterns. Instead, the difference in Ih between bursting and regular-spiking neurons determines the temporal integration of evoked synaptic input from the CA1 area. In response to 50 Hz stimulation, bursting neurons, with a large Ih, show ~50% less temporal summation than regular-spiking neurons. ... A computer simulation model of a subicular neuron with the properties of either a bursting or a regular-spiking neuron confirmed the pivotal role of Ih in temporal integration of synaptic input. These data suggest that in the subicular network, bursting neurons are better suited to discriminate the content of high frequency input, such as that occurring during gamma oscillations, compared to regular-spiking neurons. See paper for more and details.
Reference:
1 . van Welie I, Remme MW, van Hooft JA, Wadman WJ (2006) Different levels of Ih determine distinct temporal integration in bursting and regular-spiking neurons in rat subiculum. J Physiol 576:203-14 [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):
Channel(s): I h;
Gap Junctions:
Receptor(s): AMPA;
Gene(s):
Transmitter(s):
Simulation Environment: NEURON;
Model Concept(s): Coincidence Detection; Synaptic Integration;
Implementer(s):
Search NeuronDB for information about:  AMPA; I h;
//////////// Subiculum model ///////////////

load_file("nrngui.hoc")
cvode_active(1)

xopen("./S40.hoc")

create bar
bar{
	L = 100
	diam = 7
	insert pas g_pas = 1
	insert hd ghdbar_hd = 0
	pt3dadd(60,-400,0,7)
	pt3dadd(60,-500,0,7)
}

access soma
distance(0,.5)

// parameters

tstop	= 800
dt		= 0.025
celsius = 33.0
Vrest 	= -65
Rm 		= 40000
epas	= -67
Cm    	= 1
RaAll	= 150
RaAx 	= 50
e_hd	= -25
ghd		= 1.2e-5   	// [S/cm2]
h_st	= 1.7		// gradient of Ih density (increase per 100 um)


// Cell setup

proc cell_setup() {
	forsec soma_list {
		insert pas
			e_pas	= epas
			g_pas 	= 1/Rm
			Ra		= RaAll
			cm		= Cm
		insert hd	ghdbar_hd	= 0	vhalfl_hd = -73 kl_hd = -8
	}

	forsec apical_list{
		insert pas
			e_pas	= epas
			g_pas 	= 1/Rm
			Ra		= RaAll
			cm		= Cm
		insert hd	ghdbar_hd 	= 0
		for (x) if (x>0 && x<1) {
			xdist = distance(x)
			if (xdist>500) {xdist=500}
			if (xdist > 100){
					vhalfl_hd(x) = -81 kl_hd = -8
			} else {
					vhalfl_hd(x) = -73 kl_hd = -8
			}
		}
	}
	forsec basal_list{
		insert pas
			e_pas	= epas
			g_pas 	= 1/Rm
			Ra		= RaAll
			cm		= Cm
		insert hd	ghdbar_hd 	= 0
		for (x) if (x>0 && x<1) {
			xdist = 0
			if (xdist > 100){
					vhalfl_hd(x) = -81 kl_hd = -8
			} else {
					vhalfl_hd(x) = -73 kl_hd = -8
			}
		}
	}
	forsec axon_list {
		insert pas
			e_pas	= Vrest
			g_pas 	= 1/Rm
			Ra		= RaAx
			cm		= Cm
	}
    forall {
        v	= Vrest
        if (ismembrane("hd")) {ehd_hd = e_hd}
	}
    qtl_hd = 0.5
}

cell_setup()

proc init(){
	t=0
	finitialize(Vrest)
	cvode.re_init()
}

proc init_rest(){
	init()
	forall {
		if(ismembrane("hd")){
			for(x) if (x>0 && x<1) e_pas(x) = (g_pas(x)*v(x) + i_hd(x))/g_pas(x)
		} else {
			e_pas = Vrest
			g_pas = 1/Rm
		}
	}
	init()
}

proc h_density() {
	soma distance(0,.5)
	forall {
		if(ismembrane("hd")) {
			for (x) if (x>0 && x<1) {
				xdist = distance(x)
				if (xdist>500) {xdist=500}
				ifsec basal_list xdist = 0
				ghdbar_hd(x) = ghd*(1+h_st*xdist/100)
			}
		}
	}
	init_rest()
}

init_rest()

load_file("./add_syns.hoc")


Loading data, please wait...