Rat LGN Thalamocortical Neuron (Connelly et al 2015, 2016)

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Accession:223891
" ... Here, combining data from fluorescence-targeted dendritic recordings and Ca2+ imaging from low-threshold spiking cells in rat brain slices with computational modeling, the cellular mechanism responsible for LTS (Low Threshold Spike) generation is established. ..." " ... Using dendritic recording, 2-photon glutamate uncaging, and computational modeling, we investigated how rat dorsal lateral geniculate nucleus thalamocortical neurons integrate excitatory corticothalamic feedback. ..."
References:
1 . Connelly WM, Crunelli V, Errington AC (2016) Passive Synaptic Normalization and Input Synchrony-Dependent Amplification of Cortical Feedback in Thalamocortical Neuron Dendrites. J Neurosci 36:3735-54 [PubMed]
2 . Connelly WM, Crunelli V, Errington AC (2015) The Global Spike: Conserved Dendritic Properties Enable Unique Ca2+ Spike Generation in Low-Threshold Spiking Neurons. J Neurosci 35:15505-22 [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: Thalamus;
Cell Type(s): Thalamus geniculate nucleus/lateral principal GLU cell;
Channel(s): I T low threshold; I Calcium; I h;
Gap Junctions:
Receptor(s): NMDA; AMPA;
Gene(s):
Transmitter(s): Glutamate;
Simulation Environment: NEURON;
Model Concept(s): Dendritic Action Potentials; Detailed Neuronal Models; Action Potentials; Active Dendrites; Action Potential Initiation; Calcium dynamics;
Implementer(s): Connelly, William [connelly.bill at gmail.com];
Search NeuronDB for information about:  Thalamus geniculate nucleus/lateral principal GLU cell; AMPA; NMDA; I T low threshold; I h; I Calcium; Glutamate;
load_file("nrngui.hoc")
xopen("rlgntc5-10-95.geo")
xopen("proc.hoc")


celsius = 34
dt = 0.02
steps_per_ms = 1/dt
tstop = 7000
v_init = -70


gcabarfixed = 1
g_pas_fixed = 1
g_hbar_fixed = 1


// Not actually conductance, but permeability
Gbar_cat_soma = 0.00007
Gbar_cat_proximal = 0.00007 
Gbar_cat_distal = 0.00007

E_pas = -79
G_pas_soma = 1.5e-5
G_pas_prox = 8e-6
G_pas_dist = 1.4e-6

Ghbar_htc_soma = 1.5e-05
Ghbar_htc_prox = 0
Ghbar_htc_dist = 0

AxialRes = 170
C = 0.7
Cprox = 0.7
Cdist = 0.7
Gbar_ican = 2.5e-4

forsec whole_cell { 			// insert passive and Ih current everywhere
	insert pas
	e_pas=E_pas

	insert htc
	eh_htc=-45
 
  insert irk          // insert IRK
  gkbar_irk = 0.00002
  shift_irk = 15

	Ra = AxialRes
	cm = C

	nseg=3
}

objref distalsForStim
distalsForStim = new Vector()
distalsForStim.append(38, 45, 52, 61, 30, 124,74,118,185,107,151,157,161,25,31,49,13)

for (n=0; n<=15; n+=1) { 
  dend[distalsForStim.x[n]] {
    nseg=9
  }
}

soma {
	insert hh2		// insert fast spikes
	ena = 50
	ek = -100
	vtraub_hh2 = -52
	gnabar_hh2 = 0.05
	gkbar_hh2 = 0.05
}
if (g_pas_fixed==1) {
  forsec whole_cell { g_pas = G_pas_soma }
} else {
  localizepas(G_pas_soma,G_pas_soma,G_pas_dist)
}

if (g_hbar_fixed==1) {
  forsec whole_cell { ghbar_htc = Ghbar_htc_soma }
} else {
  localizehtc(Ghbar_htc_soma,Ghbar_htc_soma,Ghbar_htc_dist) 
}

  
forsec whole_cell {

	insert itGHK
	cai = 2.4e-4 
	cao = 2 
	eca = 120 
	shift_itGHK = -12	// shift for LJP
	qm_itGHK = 5
	qh_itGHK = 4

	insert cad		// calcium diffusion everywhere
	depth_cad = 0.1 
	kt_cad = 0		// no pump
	kd_cad = 1e-4
	taur_cad = 5
	cainf_cad = 2.4e-4
	
	insert ican
	
}

if (gcabarfixed==1) {
  forsec whole_cell {pcabar_itGHK = Gbar_cat_soma}
} else{
  localizeca(Gbar_cat_soma,Gbar_cat_proximal,Gbar_cat_distal)
}

proc init() {
  soma { cm = C }
  forsec proximals { cm = Cprox }
  forsec distals { cm = Cdist }

  forsec whole_cell {
    e_pas = E_pas
    Ra = AxialRes

    gbar_ican = Gbar_ican
  }
  if (g_pas_fixed==1) {
    forsec whole_cell { g_pas = G_pas_soma }
  } else {
  localizepas(G_pas_soma,G_pas_soma,G_pas_dist)
  }
  if (g_hbar_fixed==1) {
    forsec whole_cell {ghbar_htc = Ghbar_htc_soma }
  } else {
    localizehtc(Ghbar_htc_soma,Ghbar_htc_soma,Ghbar_htc_dist) 
  } 
  if (gcabarfixed==1) {
    forsec whole_cell {pcabar_itGHK = Gbar_cat_soma}
  } else {
    localizeca(Gbar_cat_soma,Gbar_cat_proximal,Gbar_cat_distal)
  }
  finitialize(v_init)
  if (cvode.active()) {
    cvode.re_init()
  } else {
    fcurrent()
  }
  frecord_init()
}


objref somastim
soma somastim = new IClamp(0.5)
somastim.del = 2000
somastim.dur = 500
somastim.amp = -0.1

objref dendstim
dend[38] dendstim = new IClamp(1)
dendstim.del = 5500
dendstim.dur = 500
dendstim.amp = 0.02

objref spstim
soma spstim = new IClamp(0.5)
spstim.del = 0
spstim.dur = 0
spstim.amp = 0


addgraph("soma.v(0.5)",-90,-40, 1500, 3000)		// soma


//Begin VariableTimeStep
objectvar ocbox_
ocbox_ = NumericalMethodPanel[0]
object_push(ocbox_)

atol_ = 0.001
CVode[0].atol(atol_)
restore(301, 1)
object_pop()
ocbox_.map("VariableTimeStep", 361, 451, 216.9, 120.6)
objref ocbox_
//End VariableTimeStep

xopen("analysisProc.hoc")

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