Determinants of the intracellular and extracellular waveforms in DA neurons (Lopez-Jury et al 2018)

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To systematically address the contribution of AIS, dendritic and somatic compartments to shaping the two-component action potentials (APs), we modeled APs of male mouse and rat dopaminergic neurons. A parsimonious two-domain model, with high (AIS) and lower (dendro-somatic) Na+ conductance, reproduced the notch in the temporal derivatives, but not in the extracellular APs, regardless of morphology. The notch was only revealed when somatic active currents were reduced, constraining the model to three domains. Thus, an initial AIS spike is followed by an actively generated spike by the axon-bearing dendrite (ABD), in turn followed mostly passively by the soma. Larger AISs and thinner ABD (but not soma-to-AIS distance) accentuate the AIS component.
1 . López-Jury L, Meza RC, Brown MTC, Henny P, Canavier CC (2018) Morphological and Biophysical Determinants of the Intracellular and Extracellular Waveforms in Nigral Dopaminergic Neurons: A Computational Study. J Neurosci 38:8295-8310 [PubMed]
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Model Information (Click on a link to find other models with that property)
Model Type: Extracellular; Dendrite; Neuron or other electrically excitable cell;
Brain Region(s)/Organism: Basal ganglia;
Cell Type(s): Substantia nigra pars compacta DA cell;
Channel(s): I Calcium; I K,Ca; Na/K pump; I L high threshold; I T low threshold; I A; I N; I Na,t; I K;
Gap Junctions:
Simulation Environment: NEURON;
Model Concept(s): Action Potential Initiation; Pacemaking mechanism; Temporal Pattern Generation; Oscillations; Extracellular Fields;
Implementer(s): Lopez-Jury, Luciana [lucianalopezjury at]; Canavier, CC;
Search NeuronDB for information about:  Substantia nigra pars compacta DA cell; I Na,t; I L high threshold; I N; I T low threshold; I A; I K; I K,Ca; I Calcium; Na/K pump;
cabal.mod *
nabalan.mod *
newcachan.mod *
newkca.mod *
pump.mod *
anatscale.hoc *
field.hoc *
fixnseg.hoc *
interpxyz.hoc *
setpointers.hoc *
// $Id: msgic.hoc,v 1.4 2008/12/03 03:29:41 ted Exp ted $
objref vbox
vbox = new VBox()
xlabel("Monopolar extracellular recording of a dopaminergic neuron with a spontaneous")
xlabel("pacemaking activity.")
xlabel("The recorded potential vrec is computed from er_extra, which is calculated from")
xlabel("transmembrane current and the transfer resistances between the segments and the")
xlabel("recording electrode.  This calculation does not involve vext or e_extracellular")
xlabel("at all, and space plots of the latter remain unchanged during the simulation.")
xlabel("The location of the monopolar extracellular recording electrode is shown by the red")
xlabel("dot in the Shape Plot. Note that there is no current injection in the model.")
xlabel("The IClamp shown by the blue dot in PointProcess Manager window is set to")
xlabel("zero nA.")
xlabel("After any change to cell geometry or nseg, be sure to invoke setpointers().")
xlabel("Think of this as attaching the current generated by each segment to its")
xlabel("corresponding transfer resistance.")
xlabel("All voltages are in millivolts except for ex_xtra and vrec, which are in microvolts.")
vbox.intercept(0)  //ends intercept mode"Notes", 100, 100, -1, 500)  //draw the box and its contents