Space clamp problems in neurons with voltage-gated conductances (Bar-Yehuda and Korngreen 2008)

 Download zip file   Auto-launch 
Help downloading and running models
Accession:110560
" ... using numerical simulations, we show that the distortions of voltage-gated K+ and Ca2+ currents are substantial even in neurons with short dendrites. The simulations also demonstrate that passive cable theory cannot be used to justify voltage-clamping of neurons, due to significant shunting to the reversal potential of the voltage-gated conductance during channel activation. ... "
Reference:
1 . Bar-Yehuda D, Korngreen A (2008) Space-clamp problems when voltage clamping neurons expressing voltage-gated conductances. J Neurophysiol 99:1127-36 [PubMed]
Citations  Citation Browser
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): Neocortex V1 L6 pyramidal corticothalamic cell;
Channel(s): I K; I Calcium;
Gap Junctions:
Receptor(s):
Gene(s):
Transmitter(s):
Simulation Environment: NEURON;
Model Concept(s): Ion Channel Kinetics; Influence of Dendritic Geometry; Detailed Neuronal Models;
Implementer(s): Korngreen, Alon [alon.korngreen at gmail.com];
Search NeuronDB for information about:  Neocortex V1 L6 pyramidal corticothalamic cell; I K; I Calcium;
/
SpaceClampDemo
cells
ReadMe.html
calcium.mod
potassium.mod
calcium.hoc
init.hoc
mosinit.hoc *
potassium.hoc
screenshot.jpg
                            
create soma
access soma

membranecap = 1    /* specific membrane capacitance in uF cm^-2 */
membraneresist = 40000 /* specific membrane resistance in ohm cm^2 */
axialresist = 100     /* axial resistivity in ohm cm */
Vrest = -70               /* resting potential, mV */
ECA=60
Gbar=5
V05=-10
Z=10

objref gplot, vplot, vC,BOX

proc load_cell() {

// $s1 filename

  aspiny = 0
  forall delete_section()
  xopen($s1)
  access soma
	forall {
		nseg*=5
		insert pas
		insert Calcium
		gbar_Calcium=Gbar
	    v12_Calcium=V05
	    vSlope_Calcium=Z
	    tau_Calcium=3
		e_pas = Vrest
		eca= ECA
		g_pas=1/membraneresist 
		Ra=axialresist 
		cm=membranecap
	}
	soma  vC = new SEClamp(0.5)
	vC.amp1=-120
	vC.dur1=15400
	vC.amp2=0
	vC.dur2=1000

	vC.rs=1e-5
 }   




proc DoIt(){

	finitialize(Vrest)
	fcurrent()

	dt=100
	for i=0,149 fadvance()

	dt=10
	for i=0,39 fadvance()

	dt=0.1
	for i=0,99 fadvance()

	dt=0.025
	for j=0,49 for i=0,39 fadvance()

	BOX = new HBox()
	BOX.intercept(1)
	vplot = new PlotShape()
	vplot.variable("v")
	vplot.scale(-10,80)
	vplot.exec_menu("Show Diam")
	vplot.exec_menu("Shape Plot")

	gplot = new PlotShape()
	gplot.variable("gca_Calcium")
	gplot.scale(0,Gbar+0.5)
	gplot.exec_menu("Show Diam")
	gplot.exec_menu("Shape Plot")
	xpanel("Information")
	xlabel("The left graph displays the membrane potential") 
	xlabel("in pseudo color in each compartment of the neuron while")
	xlabel("the right graph displays the activation of the")
	xlabel("voltage-gated conductance also in  pseudo color.")
	xlabel("Change the value of the conductance density in ")
	xlabel("panel or cell type to observe the different decay.")
	xpanel()
	BOX.intercept(0)
	BOX.map()
} 

proc fig1a() {
  load_cell("cells/A0606.hoc")
  DoIt()
}

proc fig1b() {
  load_cell("cells/C050800E2.hoc")  
  DoIt()
}

proc fig1c() {
  load_cell("cells/C230998A-I3.hoc")
  DoIt()
}

proc fig1d() {
  load_cell("cells/j7_L4stellate.hoc") 
  DoIt()
}

xpanel("Simulate")
xvalue("Calcium conductance density", "Gbar")
xbutton("1. L5 Pyramidal Neuron","fig1a()")
xbutton("2. L4 interneuron","fig1b()")
xbutton("3. L2/3 bipolar interneuron ","fig1c()")
xbutton("4. L4 spiny stellate ","fig1d()")
xpanel()