// Simulation and analysis of Spatiotemporal Component of Cl- Gradients in a isolated dendrite // Here simulation of one AMPA Synapses // Here application in a simple Ball and Stick Model // Determination Parameters AMPA ANZAHL_AMPA = 1 //Anzahl der synaptischen Pulse G_AMPA = 0.000305 * 0 //Value from Lombardi et al 2018 E_AMPA = 0 // Reversal Potential of Exp2Syn DECAY_AMPA = 11 AMPA_SYN_LOCATION = 0.5 // Position GABA Synapse for Pulses AMPA_Delay = 198000 // Determine [Cl-]i ----------- Cl_intra = 5 // mM //----- Define run parameters --------------------- tstop = 200000 // Duration slowdown_start = AMPA_Delay - 1000 v_init = -60 // Initial voltage dt_fast = 10 // Step Interval in ms dt_slow = 0.2 // Step Interval in ms // Functions init_changedt and set_changedt -----------------// // // // Event Handler that decreases dt at a given timepoint // // required for fast equilibratin at low temp resolution // // but a high resolution for phases with synaptic events // // ----------------------------------------------------------// objref fih fih = new FInitializeHandler("init_slowchangedt()") proc init_slowchangedt() { printf("\n Init_slowchangedt-ok, Start = %g ms \n",slowdown_start) dt = dt_fast cvode.event(slowdown_start, "set_slowdt()") } proc set_slowdt() { printf("\n Call executed - changed to slow dt \n") dt = dt_slow if (cvode.active()) { cvode.re_init() } else { fcurrent() } } //-- Initialize Graph for Display of [Cli]i in the right scale objectvar Cl_graph Cl_graph = new Graph(0) Cl_graph.size(slowdown_start,tstop,5.76,5.77) Cl_graph.view(slowdown_start, 5.76, tstop - slowdown_start, 0.01, 462, 636, 961.2, 200.8) graphList[0].append(Cl_graph) Cl_graph.addexpr("dend.cli( 0.5 )", 1, 1, 0.8, 0.9, 2) //----- Insert synapses ------------------------- objref ampasyn dend { // insert AMPA synapse ampasyn = new Exp2Syn(AMPA_SYN_LOCATION) ampasyn.tau1 = 0.1 ampasyn.tau2 = DECAY_AMPA ampasyn.e = E_AMPA } // Definition of synaptic Stimuli objref stimAMPApuls //Pulssequenz AMPA stimAMPApuls = new NetStim(AMPA_SYN_LOCATION) stimAMPApuls.number = ANZAHL_AMPA // Linkage of synaptic Inputs objref synpulseampa // Update Cl- homeostasis in all compartments ---------------------------------------------- forsec all { cli0_cldif_CA3_NKCC1_HCO3 = Cl_intra cli_Start_cldif_CA3_NKCC1_HCO3 = Cl_intra cli_cldif_CA3_NKCC1_HCO3 = Cl_intra } //-- Stimulate AMPA -------------------------------------------------------------- dend { stimAMPApuls.start = AMPA_Delay synpulseampa = new NetCon(stimAMPApuls, ampasyn, 0, 0, G_AMPA) } // Run Simulation -------------------------------------------------------- run()