Amyloid-beta effects on release probability and integration at CA3-CA1 synapses (Romani et al. 2013)

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Accession:147757
The role of amyloid beta (Aß) in brain function and in the pathogenesis of Alzheimer’s disease remains elusive. Recent publications reported that an increase in Aß concentration perturbs presynaptic release in hippocampal neurons, in particular by increasing release probability of CA3-CA1 synapses. The model predics how this alteration can affect synaptic plasticity and signal integration. The results suggest that the perturbation of release probability induced by increased Aß can significantly alter the spike probability of CA1 pyramidal neurons and thus contribute to abnormal hippocampal function during Alzheimer’s disease.
Reference:
1 . Romani A, Marchetti C, Bianchi D, Leinekugel X, Poirazi P, Migliore M, Marie H (2013) Computational modeling of the effects of amyloid-beta on release probability at hippocampal synapses. Front Comput Neurosci 7:1 [PubMed]
Model Information (Click on a link to find other models with that property)
Model Type: Neuron or other electrically excitable cell; Synapse;
Brain Region(s)/Organism: Hippocampus;
Cell Type(s): Hippocampus CA1 pyramidal cell;
Channel(s): I Na,t; I A; I K; I M; I h; I Calcium; I_AHP;
Gap Junctions:
Receptor(s): AMPA;
Gene(s):
Transmitter(s): Glutamate;
Simulation Environment: NEURON;
Model Concept(s): Synaptic Plasticity; Short-term Synaptic Plasticity; Facilitation; Depression; Synaptic Integration; Aging/Alzheimer`s;
Implementer(s): Bianchi, Daniela [danielabianchi12 -at- gmail.com]; Romani, Armando [romani.armando -at- gmail.com];
Search NeuronDB for information about:  Hippocampus CA1 pyramidal cell; AMPA; I Na,t; I A; I K; I M; I h; I Calcium; I_AHP; Glutamate;
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RomaniEtAl2013
lib
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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