Amyloid beta (IA block) effects on a model CA1 pyramidal cell (Morse et al. 2010)

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Accession:87284
The model simulations provide evidence oblique dendrites in CA1 pyramidal neurons are susceptible to hyper-excitability by amyloid beta block of the transient K+ channel, IA. See paper for details.
Reference:
1 . Morse TM, Carnevale NT, Mutalik PG, Migliore M, Shepherd GM (2010) Abnormal Excitability of Oblique Dendrites Implicated in Early Alzheimer's: A Computational Study. Front Neural Circuits [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): Hippocampus CA1 pyramidal GLU cell;
Channel(s): I Na,t; I L high threshold; I N; I T low threshold; I A; I K; I h; I K,Ca;
Gap Junctions:
Receptor(s):
Gene(s):
Transmitter(s):
Simulation Environment: NEURON;
Model Concept(s): Dendritic Action Potentials; Active Dendrites; Detailed Neuronal Models; Pathophysiology; Aging/Alzheimer`s;
Implementer(s): Carnevale, Ted [Ted.Carnevale at Yale.edu]; Morse, Tom [Tom.Morse at Yale.edu];
Search NeuronDB for information about:  Hippocampus CA1 pyramidal GLU cell; I Na,t; I L high threshold; I N; I T low threshold; I A; I K; I h; I K,Ca;
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CA1_abeta
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readme.html
cacumm.mod
cagk.mod *
cal2.mod *
can2.mod *
cat.mod *
distr.mod *
h.mod
ipulse2.mod *
kadist.mod
kaprox.mod
kdrca1.mod
na3n.mod
naxn.mod *
zcaquant.mod
aBeta.hoc
add_ca.hoc
bAP_peak_vecs.hoc
c91662.ses
C91662_Link.txt
cond_report.hoc
control_boxes.hoc
distribute_currents.hoc
fig1.jpg
fig2.jpg
fig2A_c91662.hoc
fig3.jpg
fig3.ses
fig4.jpg
fig4.ses
fig5.jpg
fig6b.jpg
figs.hoc
find_averages.hoc
fixnseg.hoc
GaspiriniEtAl2007Fig1Stimulation.ses
generate_conc_graph.hoc
gka_averager.hoc
graph_na3_kinetics.hoc
init_and_run_and_graph.hoc
leaky_distal.hoc
maxica.hoc
maxica.ses.20100525
mosinit.hoc
na3_shifter.hoc
ntc_additions.hoc
oblique_application.hoc
oblique_scaled_ka.hoc
obliques_primary_tuft.hoc
paper_fig_buttons.hoc
sectiontest.hoc
shrink_obliques.hoc
SubBranch.hoc
trigger_and_start.hoc
wait_for_go.hoc
                            
// create subset that contains only the apicals and the soma

objref atree
atree = new SectionList()
soma atree.append()
apic[0] atree.subtree()

// show just the elements of the set in a Shape
objref atreesh
atreesh = new Shape(0)
atreesh.size(-10,740,-429.402,319.402)
atreesh.view(-10, -429.402, 750, 748.804, 7, 105, 200.64, 200.32)
atreesh.observe(atree)

// build subsets that contain cal+can and car+cat
// note the model no longer uses uses this type of ca distrib.
// however this portion of the code still needs to be cleaned up.

objref calcan, carcat
calcan = new SectionList()
carcat = new SectionList()
forsec atree {
  if (ismembrane("cal")) {
    calcan.append()
  } else {
    // these are nonoverlapping, so . . .
    carcat.append()
  }
}

forsec atree {
  insert caquant
  for (x,0) svr_caquant(x) = 1/depth_cacum(x)
}

mode_caquant = 1 // measure peak ica and cai

proc xrun() {
  finitialize(v_init)
  mode_caquant = 1 // measure peak ica and cai
  run() // don't bother with runm()--does lots of stuff not
        // relevant to these figs
  // note:  the use of different slightly different initializations
  // for example, the one from init() in init_and_run....hoc, can
  // lead to especially different half widths of the ica spike as the
  // AP backpropagates into the distal dendrites.  However the basic
  // result that the max calcium peak occurs in the obliques 
  // proximal to the branch from the trunk remains unchanged in both the
  // control and aBeta cases (as long as there is significant propagation
  // into that proximal portion of the oblique).

  mode_caquant = 2
  run()

  /*
  Sets up plots of max ica, cai, max cai, ica halfwidth,
  surface/vol ratio, approx q entry by ca, and predicted max cai.
  Also sets up a List of the cmax range var plots
  and a List of the SectionLists that define the spatial coverage
  of each RangeVarPlot.
  */
  load_file("maxica.hoc")

}


// apply abeta before calling the following procs

// show recording sites
MARKSIZE = 4 // size of marks.  4 is good for small Shapes
proc show_recording_sites() {
  // markpoints.hoc presumes maxica.hoc has been loaded
  load_file("maxica.hoc")
  load_file("markpoints.hoc") // to mark points on a shape plot
  domarks(atreesh, MARKSIZE) // atreesh or shlist.o(i) where i=0-3 (tuft, dist, intermed, prox)
}

// show time axis plots of v, i, can caimax
// these would look better if tstop were 15 ms
// throw away after generating plots
proc vicaplots() { local tsave
  xopen("proxplots.ses")
  xopen("intermedplots.ses")
  xopen("distplots.ses")
  xopen("tuftplots.ses")
  xrun()
}

proc myshapes() { local ii
  load_file("maxica.hoc")
  pathshapes()
  atreesh.exec_menu("View Axis")
  // shlist is empty when this proc is first parsed
  // so we can't do this:
//  for ii=0,shlist.count()-1 shlist.o(ii).exec_menu("View Axis")
  // but we can get away with this:
  execute("for ii=0,shlist.count()-1 shlist.o(ii).exec_menu(\"View Axis\")")
}

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