/*---------------------------------------------------------------------------- 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 //---------------------------------------------------------------------------- // note load_file command only executed if not executed yet for that file in current session 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