/*----------------------------------------------------------------------------
VOLTAGE-CLAMP SIMULATIONS OF RE CELLS
=====================================
- passive and structural parameters estimated from SimFit
- electrode with adjustable series resistance
- simulations at 36 degC
- calcium diffusion
- Q10=2.5
- hyperpolarized leak of -82 mV; dc current to maintain at -65
** current-clamp in RE cell simplified to 3 compartments **
For more details, see:
Destexhe, A., Contreras, D., Steriade, M., Sejnowski, T.J. and Huguenard,
J.R. In vivo, in vitro and computational analysis of dendritic calcium
currents in thalamic reticular neurons. J. Neurosci. 16: 169-185, 1996.
See also:
http://www.cnl.salk.edu/~alain
http://cns.fmed.ulaval.ca
----------------------------------------------------------------------------*/
//----------------------------------------------------------------------------
// load and define general graphical procedures
//----------------------------------------------------------------------------
// xopen("$(NEURONHOME)/lib/hoc/stdrun.hoc")
load_file("nrngui.hoc")
objectvar g[20] // max 20 graphs
ngraph = 0
proc addgraph() { local ii // define subroutine to add a new graph
// addgraph("variable", minvalue, maxvalue)
ngraph = ngraph+1
ii = ngraph-1
g[ii] = new Graph()
g[ii].size(tstart,tstop,$2,$3)
g[ii].xaxis()
g[ii].yaxis()
g[ii].addvar($s1,1,0)
g[ii].save_name("graphList[0].")
graphList[0].append(g[ii])
}
if(ismenu==0) {
nrnmainmenu() // create main menu
nrncontrolmenu() // create control menu
}
//----------------------------------------------------------------------------
// transient time
//----------------------------------------------------------------------------
trans = 200
print " "
print ">> Transient time of ",trans," ms"
print " "
//----------------------------------------------------------------------------
// create multi-compartment geometry and insert currents
//----------------------------------------------------------------------------
xopen("cells/re3.geo") // read geometry file
corrD = 3.777 // dendritic surface correction (SimFit)
forall { // insert passive current everywhere
insert pas
g_pas = 5e-5 * corrD // (from simfit)
// e_pas = -72.843 // (from simfit)
e_pas = -82 // corrected for liquid junction potential
cm = 1 * corrD // (from simfit)
Ra = 260 // (from simfit)
L = L
}
soma {
g_pas = 5e-5 // (from simfit)
cm = 1 // (from simfit)
insert hh2 // insert fast spikes
ena = 50
ek = -100
vtraub_hh2 = -67 // threshold for spikes is low
gnabar_hh2 = 0.1
gkbar_hh2 = 0.08
}
forall {
insert it2 // T-current everywhere
cai = 2.4e-4
cao = 2
eca = 120
shift_it2 = 0 // no shift of ITs
gcabar_it2 = corrD * 0.0002
qm_it2 = 2.5 // low q10
qh_it2 = 2.5
insert cad // calcium diffusion everywhere
depth_cad = corrD // NEED TO BE RESCALED
kt_cad = 0 // no pump
kd_cad = 1e-4
taur_cad = 5
cainf_cad = 2.4e-4
}
xopen("loc3.oc") // load procedure for localizing T-current
localize(4.5e-5, 4.5e-5, 6.8e-4) // initial distribution of T-current
xopen("leak.oc") // load dc current injection
access soma
add_dc(0.1) // set 0.1 nA dc current to adjust to -65 mV
//----------------------------------------------------------------------------
// insert electrode in the soma
//----------------------------------------------------------------------------
load_file("El.oc") // Electrode with series resistance
access soma
objectvar El // insert electrode
El = new Electrode()
electrodes_present=1
//
// CURRENT-CLAMP MODE
//
soma El.stim.loc(0.5) // put electrode in current-clamp mode
El.stim.del = 100
El.stim.dur = 200
El.stim.amp = -0.3
//----------------------------------------------------------------------------
// setup simulation parameters
//----------------------------------------------------------------------------
Dt = 0.1
npoints = 4000
objectvar Sim // create vector of simulation points
Sim = new Vector(npoints)
dt = 0.1 // must be submultiple of Dt
tstart = trans-100
tstop = trans + npoints * Dt
runStopAt = tstop
steps_per_ms = 1/Dt
celsius = 36
v_init = -70
//----------------------------------------------------------------------------
// add graphs
//----------------------------------------------------------------------------
addgraph("soma.v(0.5)",-120,40)
//addgraph("dend1[3].v(0.5)",-120,40) // for dissociated cell
//addgraph("dend1[3].v(0.5)",-120,40) // for intact cell
//addgraph("dend1[8].v(0.5)",-120,40) // for intact cell
//addgraph("dend1[12].v(0.5)",-120,40) // for intact cell
addgraph("dend1[0].v(0.5)",-120,40) // for simplified cell
addgraph("dend1[1].v(0.5)",-120,40) // for simplified cell
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