CA1 pyramidal neuron: depolarization block (Bianchi et al. 2012)

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Accession:143719
NEURON files from the paper: On the mechanisms underlying the depolarization block in the spiking dynamics of CA1 pyramidal neurons by D.Bianchi, A. Marasco, A.Limongiello, C.Marchetti, H.Marie,B.Tirozzi, M.Migliore (2012). J Comput. Neurosci. In press. DOI: 10.1007/s10827-012-0383-y. Experimental findings shown that under sustained input current of increasing strength neurons eventually stop firing, entering a depolarization block. We analyze the spiking dynamics of CA1 pyramidal neuron models using the same set of ionic currents on both an accurate morphological reconstruction and on its reduction to a single-compartment. The results show the specic ion channel properties and kinetics that are needed to reproduce the experimental findings, and how their interplay can drastically modulate the neuronal dynamics and the input current range leading to depolarization block.
Reference:
1 . Bianchi D, Marasco A, Limongiello A, Marchetti C, Marie H, Tirozzi B, Migliore M (2012) On the mechanisms underlying the depolarization block in the spiking dynamics of CA1 pyramidal neurons. J Comput Neurosci 33:207-25 [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: Hippocampus;
Cell Type(s): Hippocampus CA1 pyramidal GLU cell;
Channel(s): I Na,t; I A; I K; I M; I h; I K,Ca; I_AHP;
Gap Junctions:
Receptor(s): GabaA; AMPA; NMDA;
Gene(s):
Transmitter(s): Gaba; Glutamate;
Simulation Environment: NEURON; Mathematica;
Model Concept(s): Simplified Models; Depolarization block; Bifurcation;
Implementer(s): Bianchi, Daniela [danielabianchi12 -at- gmail.com]; Limongiello, Alessandro [alessandro.limongiello at unina.it];
Search NeuronDB for information about:  Hippocampus CA1 pyramidal GLU cell; GabaA; AMPA; NMDA; I Na,t; I A; I K; I M; I h; I K,Ca; I_AHP; Gaba; Glutamate;
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Ca1_Bianchi
lib
basic-graphics.hoc *
current-balance.hoc *
cut-sections.hoc *
map-segments-to-3d.hoc *
vector-distance.hoc *
                            
// Given a reference point (ie, soma), an apex point, and a point of
// interest, (POI), this function returns the distance from the reference point to
// the POI. These three points are vectors with x,y,z as their values
// written by Terrence Brannon, last modified by Yiota Poirazi, July 2001, poirazi@LNC.usc.edu

objref RP, POI, APEX

proc pvec() {
  printf("%s: \t", $s1)
  $o2.printf("%f ")
}

proc pvecs() {
  pvec("RP", RP)
  pvec("APEX",APEX)
  pvec("POI",POI)
}

proc clear_vecs() {
  RP=new Vector()
  APEX=new Vector()
  POI=new Vector()
}

objref vhold
vhold=new Vector()

func vector_distance() { local adjustment
//  print "func vector_distance() {"

  clear_vecs()
  
  RP=$o1.c
  APEX=$o2.c
  POI=$o3.c
  adjustment = $4

//  pvecs()

  // Subtract Psoma: Qapex = Papex - Psoma. Therefore Qsoma=0,0,0

  APEX.sub(RP)
  POI.sub(RP)
    RP.sub(RP)

//    pvecs()

  // Normalize Qapex, Creating Uapex

  vhold=APEX.c
  vhold.mul(vhold)
  APEX_BAR=sqrt(vhold.sum())

//  printf("APEX_BAR: %f\n", APEX_BAR)

  APEX.div(APEX_BAR)

//  pvec("UAPEX", APEX)

  // Find length of projection of Qdend onto Uapex

  H = POI.dot(APEX) + adjustment
  
  H=abs(H)

  return(H)
}

objref fvd_vec
strdef fvd_str
func find_vector_distance() {

  fvd_vec=new Vector()
  sprint(fvd_str, "access %s", $s1)
  execute1(fvd_str)
  
  vcreate2(fvd_vec,0)
  
  return(vector_distance(vRP,vAPEX,fvd_vec,adjustment))
}

func find_vector_distance_precise() {

  fvd_vec=new Vector()
  sprint(fvd_str, "access %s", $s1)
  execute1(fvd_str)
  
  vcreate3(fvd_vec,$2)
  
  return(vector_distance(vRP,vAPEX,fvd_vec,adjustment))
}

proc vcreate() {
  $o1.append(x3d(0))
  $o1.append(y3d(0))
  $o1.append(z3d(0))
}

proc vcreate2() {
  $o1.append(x3d($2))
  $o1.append(y3d($2))
  $o1.append(z3d($2))
}

proc vcreate3() {
  $o1.append(x_d3($2))
  $o1.append(y_d3($2))
  $o1.append(z_d3($2))
}

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