Functional structure of mitral cell dendritic tuft (Djurisic et al. 2008)

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The computational modeling component of Djurisic et al. 2008 addressed two primary questions: whether amplification by active currents is necessary to explain the relatively mild attenuation suffered by tuft EPSPs spreading along the primary dendrite to the soma; what accounts for the relatively uniform peak EPSP amplitude throughout the tuft. These simulations show that passive spread from tuft to soma is sufficient to yield the low attenuation of tuft EPSPs, and that random distribution of a biologically plausible number of excitatory synapses throughout the tuft can produce the experimentally observed uniformity of depolarization.
1 . Djurisic M, Popovic M, Carnevale N, Zecevic D (2008) Functional structure of the mitral cell dendritic tuft in the rat olfactory bulb. J Neurosci 28:4057-68 [PubMed]
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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: Olfactory bulb;
Cell Type(s): Olfactory bulb main mitral GLU cell;
Channel(s): I K; I Sodium;
Gap Junctions:
Simulation Environment: NEURON;
Model Concept(s): Dendritic Action Potentials; Active Dendrites; Synaptic Integration; Olfaction;
Implementer(s): Carnevale, Ted [Ted.Carnevale at];
Search NeuronDB for information about:  Olfactory bulb main mitral GLU cell; I K; I Sodium;
// $Id: instrument_spiketuft.hoc,v 1.1 2007/03/11 04:38:42 ted Exp ted $

// based on instrument_probetuft.hoc

// this assumes that geometry will not be changed
// otherwise, it would be necessary to calculate distance in proc init()

soma {
  area(0.5)  // force initialization of geometry
  distance(0, 0.5)  // origin is mid-soma
  // origin needs to be default (i.e. 0) for ready comparison with Impedance tool GUI
  distance()  // origin is soma(0)

forsec tuft {
  insert monx
  for (x,0) dist_monx(x) = distance(x)  // avoid 0 & 1 ends; otherwise overwrites adjacent internal nodes

// we've given up on RangeVarPlots of peak amplitude, 
// so call the distance tuftorigin rather than rvporigin
apic[1] {
//  insert monx
//  for (x,0) dist_monx(x) = distance(x)
//  rvporigin = distance(1) // use apic[1](1) as origin of RangeVarPlot of vmax_monx
  tuftorigin = distance(1) // use apic[1](1) as origin of tuft for scatterplots

// <<>> is this needed for init_spiketuft.hoc?
// create a List of SectionRefs that point to terminal branches in tuft
objref tempref, terminalreflist
terminalreflist = new List()
forsec tuft {
  tempref = new SectionRef()
  if (tempref.nchild() == 0) {
//    tempref.sec print secname()  // for development/diagnostic purposes only
objref tempref