DRt neuron model (Sousa et al., 2014)

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Accession:151949
Despite the importance and significant clinical impact of understanding information processing in the nociceptive system, the functional properties of neurons in many parts of this system are still unknown. In this work we performed whole-cell patch-clamp recording in rat brainstem blocks to characterize the electrophysiological properties of neurons in the dorsal reticular nucleus (DRt), a region known to be involved in pronociceptive modulation. We also compared properties of DRt neurons with those in the adjacent parvicellular reticular nucleus (PCRt) and in neighboring regions outside the reticular formation. We found that neurons in the DRt and PCRt had similar electrophysiological properties and exhibited mostly tonic-like firing patterns, whereas neurons outside the reticular formation showed a larger diversity of firing-patterns. The dominance of tonic neurons in the DRt supports previous conclusions that these neurons encode stimulus intensity through their firing frequency.
Reference:
1 . Sousa M, Szucs P, Lima D, Aguiar P (2014) The pronociceptive dorsal reticular nucleus contains mostly tonic neurons and shows a high prevalence of spontaneous activity in block preparation. J Neurophysiol 111:1507-18 [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:
Cell Type(s): Hodgkin-Huxley neuron;
Channel(s): I Na,t; I K; I K,Ca; I Calcium;
Gap Junctions:
Receptor(s):
Gene(s):
Transmitter(s):
Simulation Environment: NEURON;
Model Concept(s): Activity Patterns;
Implementer(s): Aguiar, Paulo [pauloaguiar at fc.up.pt];
Search NeuronDB for information about:  I Na,t; I K; I K,Ca; I Calcium;
/*
* Explore the possible membrane currents and their parameters giving rise to the after-hyperpolarization variability observed experimentally in
* current clamp experiment: start at -20 pA, steps of 10 pA, current step in Trace T [pA] =>  -20 + 10*(T-1)
*
* Created by Mafalda Sousa [mafsousa@ibmc.up.pt]
*/


// create a DRt tonic neuron
load_file("DRt_tonic_neuron.hoc")
load_file("AHP_profile.ses")

tstop = 850
celsius = 25  
cac_iKCa = 0.001

objectvar scene_vector_[5], v1, v2, v3, v4

v1 = new Vector()
v2 = new Vector()
v3 = new Vector()
v4 = new Vector()


// insert current-clamp electrode 
objref stim
stim = new IClamp(0.5)
stim.del = 95
stim.dur = 500 

// fitting trace 1
stim.amp = 0.67
vtraub_HH2 = -65
soma.cai_tau_CaIntraCellDyn = 10
soma.gbar_iKCa = 0.02
beta_iKCa = 0.003
taumin_iKCa = 6

objref g1
g1 = new Graph(0)
g1.size(0,800,-80,40)
scene_vector_[1] = g1
{g1.view(0, -80, 800, 120, 412, 27, 300.6, 184.6)}
graphList[0].append(g1)
g1.save_name("graphList[0].")
v1.record(&soma.v(0.5))
run()
v1.line(g1,0.025)

g1 = scene_vector_[1]
{g1.view(370, -80, 200, 120, 841, 30, 100.8, 180.1)}

//fitting trace 2

stim.amp = 0.37
vtraub_HH2 = -65
soma.cai_tau_CaIntraCellDyn = 10
soma.gbar_iKCa = 0.0006
beta_iKCa = 0.05
taumin_iKCa = 1

objref g2
g2 = new Graph(0)
g2.size(0,800,-80,40)
scene_vector_[2] = g2
{g2.view(0, -80, 800, 120, 1022, 26, 300.6, 181.9)}
graphList[1].append(g2)
g2.save_name("graphList[1].")
v2.record(&soma.v(0.5))
run()
v2.line(g2,0.025)

g2 = scene_vector_[2]
{g2.view(180, -80, 90, 120, 1449, 27, 100.8, 179.2)}

//fitting trace 3

stim.amp = 0.34
vtraub_HH2 = -65
soma.cai_tau_CaIntraCellDyn = 5
soma.gbar_iKCa = 0.009
beta_iKCa = 0.005
taumin_iKCa = 7

objref g3
g3 = new Graph(0)
g3.size(0,800,-80,40)
scene_vector_[3] = g3
{g3.view(0, -80, 800, 120, 412, 360, 300.6, 200.8)}
graphList[2].append(g3)
g3.save_name("graphList[2].")
v3.record(&soma.v(0.5))
run()
v3.line(g3,0.025)

g3 = scene_vector_[3]
{g3.view(410, -80, 85, 120, 838, 361, 100.8, 201.7)}

//fitting trace 4

stim.amp = 0.664
vtraub_HH2 = -55
soma.cai_tau_CaIntraCellDyn = 4
soma.gbar_iKCa = 0.001
beta_iKCa = 0.004
taumin_iKCa = 3

objref g4
g4 = new Graph(0)
g4.size(0,800,-80,40)
scene_vector_[4] = g4
{g4.view(0, -80, 800, 120, 1022, 362, 300.6, 198.1)}
graphList[3].append(g4)
g4.save_name("graphList[3].")
v4.record(&soma.v(0.5))
run()
v4.line(g4,0.025)

g4 = scene_vector_[4]
{g4.view(390, -80, 90, 120, 1450, 362, 100.8, 199.9)}

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