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/* net_dd_imodel.hoc */
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objref interneuron[nIN] // the "network" of interneurons (n = nIN)
begintemplate Interneuron // template of an interneuron
//names of variables
public soma_interneuron, old_v, drv_interneuron, syn_II, syn_EI, \
switch_syn_II, switch_syn_EI, set_syn, change_Imu_interneuron, \
pre_list_II, pre_list_EI, connect_pre_II, is_connected_II, disconnect_cell_II, \
connect_pre_EI, disconnect_cell_EI, index_IN, indicing_IN, connect_gap, \
disconnect_gaps, switch_gaps, currents, bgdrive, inj_input, injvec,\
signinput
external n_d_interneuron,n_L_interneuron,n_seg_interneuron,\
ARes_interneuron,MCap_interneuron,Rm_interneuron, Vrest_interneuron,\
Syn_II_rise, SynE_II, max_ddcon_II, Syn_II_N, nIN,\
Syn_EI_rise, Syn_EI_decay, SynE_EI, Ek_interneuron, shift_interneuron,\
SynDel, SynADel, SynG_II, GapR, tauvec_II, temiinj_IN, iinj_time, inj_step,\
Imu_interneuron, tstop, BGSyn_rise_IN, BGSyn_decay_IN, tINinj_on,\
IN_SIGNSyn_rise, IN_SIGNSyn_decay
objref syn_II[50], syn_EI, pre_list_II, pre_list_EI,\
drv_interneuron, net_c_interneuron, net_c_principalneuron, gaps[8],\
bgsyn, bgdrive_list, inj_IN, injvec, signsyn, signinput_list
create soma_interneuron
proc init() {
pre_list_II = new List()
pre_list_EI = new List()
bgdrive_list = new List()
signinput_list = new List()
soma_interneuron {
//geometry
diam = n_d_interneuron L=n_L_interneuron nseg=n_seg_interneuron
f_surf = area(0.5)/100000 // area(0.5) = 100 um^2 (PI*diam^2)
//cable parameters
Ra = ARes_interneuron cm=MCap_interneuron v=Vrest_interneuron
old_v = Vrest_interneuron
//modified HH conductances
insert hh_net // this determines the membrane mechanisms
gl_hh_net = 1/Rm_interneuron
el_hh_net = Vrest_interneuron
egk_hh_net = Ek_interneuron
sh_hh_net = shift_interneuron
// postsynaptic currents: IPSC
for i = 0,Syn_II_N-1 {
syn_II[i] = new Exp2Syn(0.5)
syn_II[i].tau1 = Syn_II_rise
syn_II[i].tau2 = tauvec_II.x[i*(max_ddcon_II/Syn_II_N)]
syn_II[i].e = SynE_II
}
// postsynaptic currents: EPSC
syn_EI = new Exp2Syn(0.5)
syn_EI.tau1 = Syn_EI_rise
syn_EI.tau2 = Syn_EI_decay
syn_EI.e = SynE_EI
// excitatory synapses for background drive
bgsyn = new Exp2Syn(0.5)
bgsyn.tau1 = BGSyn_rise_IN
bgsyn.tau2 = BGSyn_decay_IN
bgsyn.e = 0
// excitatory synapses for synaptic input signal
signsyn = new Exp2Syn(0.5)
signsyn.tau1 = IN_SIGNSyn_rise
signsyn.tau2 = IN_SIGNSyn_decay
signsyn.e = 0
// IClamps - a) for constant drive
drv_interneuron = new IClamp(0.5)
drv_interneuron.del = 0
drv_interneuron.dur = tstop
drv_interneuron.amp = Imu_interneuron*f_surf // nA
// excitatory curent injection - the density param. 'Imu' [uA/cm^2] should be converted
// to the injected current 'amp' [nA] using the factor 'fsurf' derived from the
// surface area [um^2] and the conversion of the units
// IClamps - b) for shaped input
inj_IN = new IClamp(0.5)
inj_IN.del = 0
inj_IN.dur = tstop
// Gaps
for i=0,7 { // connect to 8 neighbours L and R 4
gaps[i] = new gap(0.5)
gaps[i].r = GapR
setpointer gaps[i].vgap,v(0.5)
}
n_gaps=0
}
}
proc indicing_IN() {
index_IN = $1
}
// ****GAPs****
proc connect_gap() {
// $o1 arg is the other Cell
setpointer gaps[n_gaps].vgap, $o1.soma_interneuron.v(0.5)
n_gaps +=1
}
proc disconnect_gaps() {
for i=0,7 {
setpointer gaps[i].vgap, soma_interneuron.v(0.5)
}
n_gaps=0
}
proc switch_gaps() {local i,r
if ($1==0) {r=1000000000} else {r=$1}
for i=0,7 {gaps[i].r = r }
}
// ****IPSCs****
proc connect_pre_II() {local f, axdel, strength
// $o1 arg is the **PRESynaptic** Cell, $2 is the distance between the cells, $3 gsyn, $4 distance for the tau-Vector
axdel=$2*SynADel // in ms distance between cells 50 um
// AP propagation .25 m/s => 0.2 ms for one interval
strength = $3*f_surf // synaptic strength calculate using the surface factor
synno = int(($4*Syn_II_N)/(max_ddcon_II+1))
$o1.soma_interneuron pre_list_II.append( new NetCon(&v(1),syn_II[synno],-20,SynDel+axdel,strength))
// list.append() adds new items to the list
// NetCon: (presynaptic variable, target, thresh, delay, weight)
// the last argument is the 'weight' with a range of [0-1] where 1 corresponds to 1 uS peak
// conversion: 'SynG' [mS/cm^2] to 'weight' [uS] using the factor 'fsurf' derived from the
// surface area [um^2] and the conversion of the units
// connect_pre_II() is executed on top of the postsynaptic cell-object (object.connect_pre_II()).
// Every cell in the network has an own pre_list for every type of connections that
// is made on it. These lists contain all the NetCon-objects of this synapse type
// which have the respective cell as a target cell. In the brackets the first argument
// gives the presynaptic cell of which the soma is used as the source of the
// NetCon-object
}
proc disconnect_cell_II() {
pre_list_II.remove_all()
}
func is_connected_II() {local i,c // check if connected
c = 0
for i = 0,pre_list_II.count()-1 {
net_c_interneuron = pre_list_II.object(i) // get netCon object from list
if ($o1 == net_c_interneuron.precell()) {c=1}
}
return c
}
proc switch_syn_II() {local i // check if connected
for i = 0,Syn_II_N-1 {
syn_II[i].tau1 = Syn_II_rise // to make sure changes in syn params
syn_II[i].tau2 = tauvec_II.x[i*(max_ddcon_II/Syn_II_N)]
syn_II[i].e = SynE_II
}
for i = 0,pre_list_II.count()-1 {
net_c_interneuron = pre_list_II.object(i) // get netCon object from list
net_c_interneuron.active($1)
}
}
// ****EPSCs****
proc connect_pre_EI() {local f, axdel, strength
// $o1 arg is the **PRSynEaptic** Cell, $2 is the distance between the cells, $3 gsyn
axdel=$2*SynADel // in ms distance between cells 50 um
// AP propagation .25 m/s => 0.2 ms for one interval
strength = $3*f_surf // synaptic strength calculate using the surface factor
$o1.soma_principalneuron pre_list_EI.append( new NetCon(&v(1),syn_EI,0,SynDel+axdel,strength))
// list.append() adds new items to the list
// NetCon: (presynaptic variable, target, thresh, delay, weight)
// the last argument is the 'weight' with a range of [0-1] where 1 corresponds to 1 uS peak
// conversion: 'SynG' [mS/cm^2] to 'weight' [uS] using the factor 'fsurf' derived from the
// surface area [um^2] and the conversion of the units
}
proc disconnect_cell_EI() {
pre_list_EI.remove_all()
}
proc switch_syn_EI() {local i // check if connected
syn_EI.tau1 = Syn_EI_rise // to make sure changes in syn params
// take place in the network
syn_EI.tau2 = Syn_EI_decay
syn_EI.e = SynE_EI
for i = 0,pre_list_EI.count()-1 {
net_c_principalneuron = pre_list_EI.object(i) // get netCon object from list
net_c_principalneuron.active($1)
}
}
// ****Constant excitatory drive****
proc change_Imu_interneuron() {
if (numarg()<1) {
drv_interneuron.amp = Imu_interneuron*f_surf
} else {
drv_interneuron.amp = $1*f_surf
}
}
// ****Background synaptic drive****
proc bgdrive() {
strength = $2*f_surf
bgdrive_list.append( new NetCon($o1,bgsyn,10,0,strength) )
}
// ****Shaped input****
proc inj_input() {
injvec = new Vector(tstop/inj_step)
// $1 is the multiplicative factor that depends on the spatial position of the cell in the net!
injvec = temiinj_IN.c.mul(f_surf*$1)
// $2 is a variability factor determined by spainput_on_sd
for i = tINinj_on/inj_step,$2/inj_step {
injvec.x[i-1] = 0
}
injvec.play(&inj_IN.amp,iinj_time,1)
}
proc signinput() {
strength = $2*f_surf
signinput_list.append( new NetCon($o1,signsyn,10,0,strength) )
}
endtemplate Interneuron
