Spike repolarization in axon collaterals (Foust et al. 2011)

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Accession:143442
Voltage sensing dye experiments and simulations characterize the location and re-polarizing function of Kv1 channels in cortical neurons. "... (the papers) results indicate that action potential-induced synaptic transmission may operate through a mix of analog–digital transmission owing to the properties of Kv1 channels in axon collaterals and presynaptic boutons."
Reference:
1 . Foust AJ, Yu Y, Popovic M, Zecevic D, McCormick DA (2011) Somatic membrane potential and Kv1 channels control spike repolarization in cortical axon collaterals and presynaptic boutons. J Neurosci 31:15490-8 [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): Neocortex L5/6 pyramidal GLU cell; Neocortex L2/3 pyramidal GLU cell;
Channel(s): I Na,t; I K; I_KD;
Gap Junctions:
Receptor(s):
Gene(s):
Transmitter(s):
Simulation Environment: NEURON;
Model Concept(s): Action Potentials;
Implementer(s):
Search NeuronDB for information about:  Neocortex L5/6 pyramidal GLU cell; Neocortex L2/3 pyramidal GLU cell; I Na,t; I K; I_KD;
// from test4, but have collatoral
load_file("nrngui.hoc")

// --------------------------------------------------------------
// redefine some things in stdrun.hoc
// --------------------------------------------------------------
objref st, st1, st2, st3, st4, st5, st6, st7, st8, st9, st10, st11, st12 //DC current stimuli

dc0= 0.06//0.06//0.025 //0.12 //0
dc = 0.14//0.14//0.04 //.22
tp=5
nk=1000 // gk/nk,  increase gk, destroy the sub-dep increased sp duration phonomenon
gkd= 0.006*1//0.006*50 //0.006*10
//gkd= 0.006*30 //0.006*10
tstart = 0
tstop = 120//10100 //6050 //10100
//dt = 0.1/1
dt = 0.01/1
steps_per_ms = 1/dt

// Create the neuron
rm = 30000
v_init    = -70
celsius   = 37
Ek = -90   //-90 might affect the axon spike phase slope value low, and less noisy, increase to be -85?
           //   maybe not, still need check
Ena = 60 //50
ra = 150
c_m = 0.8 // the optimal value, both increase and decrease will decrease slope value
           //however, small C value will have high dv/dt value
xn = 1
gna = 2000*2   //2.5
gk = gna/4


ndend=1  // increase this will increase kink slope
create ais, myelin1, cnod, node1, myelin2, node2,myelin3

ais {
    L=20
    nseg=5
    diam = 1.2 // weeken the biphase, but looks closer to the real data
}
node1 {
    L=2
    nseg=1
    diam = 1.2 // weeken the biphase, but looks closer to the real data
}

node2 {
    L=2
    nseg=1
    diam = 1.2 // weeken the biphase, but looks closer to the real data
}
myelin1{
     L=80
     nseg = 10
     diam = 1.4       // .5?  nodes are thinner than axon
      }
myelin2{
     L=200
     nseg = L/20
     diam = 1.4       // .5?  nodes are thinner than axon
      }
myelin3{
     L=200
     nseg = L/20
     diam = 1.4       // .5?  nodes are thinner than axon
      }
cnod{
     L=500
     nseg = L/5
     diam = 0.5       // .5?  nodes are thinner than axon
      }
   connect myelin1(0), ais(1)
   connect node1(0), myelin1(1)
   connect cnod(0), node1(0.5)
   connect myelin2(0), node1(1)
   connect node2(0), myelin2(1)
   connect myelin3(0), node2(1)

   
proc init_cell() {
      forall {
              insert pas
              Ra = ra
              cm = c_m
              g_pas = 1/rm //10/rm
              e_pas = v_init
              }
         node1.g_pas=0.02
         node2.g_pas=0.02
         myelin1.cm=0.04
         myelin2.cm=0.04
         myelin3.cm=0.04
          
      forall insert na             
             ais.gbar_na = gna  //gna
             node1.gbar_na = gna*0.7 //2  //gna
             node2.gbar_na = gna*0.7 //2  //gna
             cnod.gbar_na = gna/3  //gna
             myelin1.gbar_na = 10
             myelin2.gbar_na = 10
             myelin3.gbar_na = 10

// insert Id current in the node only
             ais { insert kd  gkbar_kd  = 2.5*gkd }
             node1 { insert kd  gkbar_kd  = 1.2*gkd }
             cnod { insert kd  gkbar_kd  = 1*gkd }
             node2 { insert kd  gkbar_kd  = 1.2*gkd }
     
      forall insert kv
             ais.gbar_kv = 20//6//20//0.1 //gk/nk  //gk/2000
             node1.gbar_kv = 3  //gk/2000
             node2.gbar_kv = 3  //gk/2000
             cnod.gbar_kv = 10//gk/(nk)     //gk/2  //gk/2000
             myelin1.gbar_kv=0
             myelin2.gbar_kv=0
             myelin3.gbar_kv=0
   
     
      forall if(ismembrane("k_ion")) ek = Ek
      forall if(ismembrane("na_ion")) {
                ena = Ena
                // seems to be necessary for 3d cells to shift Na kinetics -5 mV
                vshift_na = -20 //-20  //-15
                                      }
}             
                      
init_cell()
//nrnmainmenu()
//nrncontrolmenu()
access ais

// --------------------------------------------------------------
// stimulus
// --------------------------------------------------------------

  st=new IClamp(.5)
  st.dur = 5000
  st.del = 5
  st.amp = .0

  st1=new IClamp(.5)
  st1.dur = 5000
  st1.del = 5
  st1.amp = .0

  st2=new IClamp(.5)
  st2.dur = 5000
  st2.del = 5
  st2.amp = .0
  
  st3=new IClamp(.5)
  st3.dur = 5000
  st3.del = 5
  st3.amp = .0

  st4=new IClamp(.5)
  st4.dur = 5000
  st4.del = 5
  st4.amp = .0

  st5=new IClamp(.5)
  st5.dur = 5000
  st5.del = 5
  st5.amp = .0

  st6=new IClamp(.5)
  st6.dur = 5000
  st6.del = 5
  st6.amp = .0

  st7=new IClamp(.5)
  st7.dur = 5000
  st7.del = 5
  st7.amp = .0

  st8=new IClamp(.5)
  st8.dur = 5000
  st8.del = 5
  st8.amp = .0

  st9=new IClamp(.5)
  st9.dur = 5000
  st9.del = 5
  st9.amp = .0

  st10=new IClamp(.5)
  st10.dur = 5000
  st10.del = 5
  st10.amp = .0

  st11=new IClamp(.5)
  st11.dur = 5000
  st11.del = 5
  st11.amp = .0

  st12=new IClamp(.5)
  st12.dur = 5000
  st12.del = 5
  st12.amp = .0

proc set_stim() {
  st.loc($1)  st.amp = $2   st.del = $3   st.dur = $4
}

proc set_stim1() {
  st1.loc($1)  st1.amp = $2   st1.del = $3   st1.dur = $4
}

proc set_stim2() {
  st2.loc($1)  st2.amp = $2   st2.del = $3   st2.dur = $4
}

proc set_stim3() {
  st3.loc($1)  st3.amp = $2   st3.del = $3   st3.dur = $4
}

proc set_stim4() {
  st4.loc($1)  st4.amp = $2   st4.del = $3   st4.dur = $4
}
proc set_stim5() {
  st5.loc($1)  st5.amp = $2   st5.del = $3   st5.dur = $4
}
proc set_stim6() {
  st6.loc($1)  st6.amp = $2   st6.del = $3   st6.dur = $4
}
proc set_stim7() {
  st7.loc($1)  st7.amp = $2   st7.del = $3   st7.dur = $4
}
proc set_stim8() {
  st8.loc($1)  st8.amp = $2   st8.del = $3   st8.dur = $4
}
proc set_stim9() {
  st9.loc($1)  st9.amp = $2   st9.del = $3   st9.dur = $4
}
proc set_stim10() {
  st10.loc($1)  st10.amp = $2   st10.del = $3   st10.dur = $4
}
proc set_stim11() {
  st11.loc($1)  st11.amp = $2   st11.del = $3   st11.dur = $4
}
proc set_stim12() {
  st12.loc($1)  st12.amp = $2   st12.del = $3   st12.dur = $4
}


objref rect, recv, rec_somaic, rec_axonv
objref rec_axon1, rec_axon2, rec_axon3, rec_axon4, rec_axon5 , rec_axon6, rec_axon7, rec_axon8, rec_axon9, rec_axon10 
objref rec_caxon1, rec_caxon2, rec_caxon3, rec_caxon4, rec_caxon5 , rec_caxon6, rec_caxon7, rec_caxon8, rec_caxon9, rec_caxon10 
objref rec_axonid,rec_axonina, rec_axonik
rect = new Vector()
recv = new Vector()

rec_axonid=new Vector()
rec_axonina=new Vector()
rec_axonik=new Vector()

rec_axon1=new Vector()
rec_axon2=new Vector()
rec_axon3=new Vector()
rec_axon4=new Vector()
rec_axon5=new Vector()
rec_axon6=new Vector()
rec_axon7=new Vector()
rec_axon8=new Vector()
rec_axon9=new Vector()
rec_axon10=new Vector()

rec_caxon1=new Vector()
rec_caxon2=new Vector()
rec_caxon3=new Vector()
rec_caxon4=new Vector()
rec_caxon5=new Vector()
rec_caxon6=new Vector()
rec_caxon7=new Vector()
rec_caxon8=new Vector()
rec_caxon9=new Vector()
rec_caxon10=new Vector()

objref savdata //used for saving file
savdata = new File()  //savdata is a file pointer
savdata.wopen("AIS_uniform_withmyelin090211AISkv20_new.dat")  //open a file with a defined name to save data

objref savdata1 //used for saving file
savdata1 = new File()  //savdata is a file pointer
savdata1.wopen("AIS_uniform_withmyelin090211AISkv20_new_co.dat")  //open a file with a defined name to save data

ais set_stim(0.,dc0,0,11000)
proc node_inj() {
   ais set_stim1(0.,dc,20,tp)
  ais set_stim2(0.,dc,500,tp)
  ais set_stim3(0.,dc,1000,tp)
  ais set_stim4(0.,dc,2000,tp)
  ais set_stim5(0.,dc,3000,tp)
  ais set_stim6(0.,dc,4000,tp)
  ais set_stim7(0.,dc,5000,tp)
  ais set_stim8(0.,dc,6000,tp)
  ais set_stim9(0.,dc,7000,tp)
  ais set_stim10(0.,dc,8000,tp)
  ais set_stim11(0.,dc,9000,tp)
  ais set_stim12(0.,dc,10000,tp)
    

recv.record(&ais.v(0.1))   //put value of soma.v to recv
rect.record(&t)             //put value of t to rect 
rec_axon1.record(&ais.v(1))
rec_axon2.record(&myelin1.v(0.1))
rec_axon3.record(&myelin1.v(0.3))
rec_axon4.record(&myelin1.v(0.5))
rec_axon5.record(&myelin1.v(0.7))
rec_axon6.record(&myelin1.v(0.9))
rec_axon7.record(&node1.v(0.5))
rec_axon8.record(&myelin2.v(0.5))
rec_axon9.record(&node2.v(0.3))
rec_axon10.record(&myelin2.v(0.5))

rec_caxon1.record(&cnod.v(0.05))
rec_caxon2.record(&cnod.v(0.1))
rec_caxon3.record(&cnod.v(0.15))
rec_caxon4.record(&cnod.v(0.2))
rec_caxon5.record(&cnod.v(0.25))
rec_caxon6.record(&cnod.v(0.3))
rec_caxon7.record(&cnod.v(0.35))
rec_caxon8.record(&cnod.v(0.4))
rec_caxon9.record(&cnod.v(0.6))
rec_caxon10.record(&cnod.v(8))

run() // this is the right position

for i=0,rect.size()-1 {
savdata.printf("%g %g %g %g %g %g %g %g %g %g %g\n", rect.x(i), recv.x(i), rec_axon1.x(i), rec_axon2.x(i), rec_axon3.x(i), rec_axon4.x(i), rec_axon5.x(i), rec_axon6.x(i), rec_axon7.x(i), rec_axon8.x(i), rec_axon9.x(i))
savdata1.printf("%g %g %g %g %g %g %g %g %g %g %g\n", rect.x(i), rec_caxon1.x(i), rec_caxon2.x(i), rec_caxon3.x(i), rec_caxon4.x(i), rec_caxon5.x(i), rec_caxon6.x(i), rec_caxon7.x(i), rec_caxon8.x(i), rec_caxon9.x(i), rec_caxon10.x(i))
}
savdata.close()
savdata1.close()
}


//------------------figure area--------------------------------------------------
access ais

proc figv() { local wd,ht
    graphItem = new Graph(0)
   wd=300 ht=200
    graphItem.save_name("graphList[0].")
    graphList[0].append(graphItem)
    graphItem.view(0,-80,tstop,140,300,200,wd,ht)
  }

proc figsyn() { local wd,ht
    graphItem = new Graph(0)
   wd=300 ht=200
    graphItem.save_name("graphList[0].")
    graphList[0].append(graphItem)
   graphItem.view(0,-5,tstop,10,300,200,wd,ht)
  }

proc figina() { local wd,ht
    graphItem = new Graph(0)
   wd=300 ht=200
    graphItem.save_name("graphList[0].")
    graphList[0].append(graphItem)
   graphItem.view(0,-20,tstop,22,300,200,wd,ht)
  }

proc figid() { local wd,ht
    graphItem = new Graph(0)
   wd=300 ht=200
    graphItem.save_name("graphList[0].")
    graphList[0].append(graphItem)
   graphItem.view(0,0,tstop,40,300,200,wd,ht)
  }

objref vbox 
vbox=new VBox()
vbox.intercept(1)

figina()
graphItem.addvar("ais.ina(0.1)",2,1)

figid()
graphItem.addvar("ais.ik_kd(0.1)",2,1)
//graphItem.addvar("node.ik_kf(0.9)",3,1)
//graphItem.addvar("node.ik_ks(0.9)",7,1)
//graphItem.addvar("node.i_hd(0.9)",1,1)


//graphItem.addvar("node.ik_kasup(0.9)",3,1)

vbox.intercept(0)
vbox.map("current",0,0,500, 700)

objref vbox1
vbox1=new VBox()
vbox1.intercept(1)
figsyn()
graphItem.addvar("myelin2.v(0.5)",2,1)

figv()
graphItem.addvar("ais.v(.1)",2,1)

vbox1.intercept(0)
vbox1.map("mv",700, 0, 500, 700)


objref vbox2 
vbox2=new VBox()
vbox2.intercept(1)
xpanel("Stuart & Sakmann")
xvalue("stim amp","st.amp")
xbutton("inject node","node_inj()")
xpanel()


nrnmainmenu()
nrncontrolmenu()
vbox2.intercept(0)
vbox2.map("mv",1600, 0, 500, 600)

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