/*-----------------------------------------------------
Model used in the article by Michalikova et al. (2016)
to explore the generation of spikelets in cortical pyramidal neurons.
The model was adapted from Hu et al. (2009).
The following script simulates a layer V pyramidal cell stimulated with
fluctuating synaptic input that results in somatic APs and spikelets.
To run this script, first compile the .mod files (e.g. with "nrnivmodl"),
then open this script in GUI ("nrngui Spikelets_Main.hoc").
Press "Init & Run" to start the simulation. The graph shows voltage traces
at the soma (black) and at the AIS (red). Somatic spikelets correspond to
APs at the AIS.
---------------------------------------------------- */
/* -----------------------------------------------------
Layer V Cortical Pyramidal Cell
Based on Yu Yuguo ( May 1, 2008)
----------------------------------------------------- */
objref somatodendritic, dendritic
// --------------------------------------------------
// Parameter Settings
// --------------------------------------------------
/* Global */
dt = 0.01
celsius = 37
steps_per_ms = 1/dt
tstop = 10000
v_init = -70
/* Others */
axonOnSoma=1
/* Passive membrane */
ra = 150
global_ra = ra
rm = 30000 // g_pas=1/rm
c_m = 0.5
cm_myelin = 0.02
g_pas_node = 0.02
/* Active channels */
// Nav
Ena = 60
gna12_soma = 80
gna12_dend = 80
gna12_ais_max = 3200 // Nav1.2
gna16_ais_max = 3200 // Nav1.6
gna16_nakeaxon= 300
gna12_myelin=20 // Nav1.2 at myelins
gna16_node = 3200 // Nav1.6 at node
vhalf_na12 = -30
vhalf_na16 = -43
vhalf_na = -30
// Kv
Ek = -90
gkv_soma = 20
gkv_dend = 10
gkv_axon = 1000
// Km
gkm = .3
gkm_soma = gkm
// Kca
gkca = 3
gkca_soma = gkca
// Ca
Eca=140
gca = .3
gca_soma = gca
/* MM: downscale gNa */
scale_gna_soma = 0.8 //factor to scale gbar_na in soma
scale_gna_dend = 0.6 //factor to scale gbar_na in dendrites
scale_gna12_hillais = 0.8 //factor to scale the na12 conductance in hill and ais
// ------------------------------------------------
// Cell Geometry
// ------------------------------------------------
/* Clean up */
forall delete_section()
/* Soma and Dendrites */
load_file("morphology/P_Soma_Dendrites.hoc")
// build a sectionlist for soma and dendrites
somatodendritic = new SectionList()
forall {
if (L/nseg>40) {
nseg = L/40 + 1
} // make sure no segments exceed 40 uM length. Note, soma.nseg remains 10.
somatodendritic.append() // soma and dendrites are all included
}
// build a sectionlist for dendrites only
dendritic = new SectionList()
forsec somatodendritic dendritic.append()
soma dendritic.remove() // remove soma for pure dendritic sectionlist
/* Axon - MM: diameters corrected to avoid a discontinuity */
load_file("morphology/P_Axon_corrected.hoc")
create_axon()
/* Spines */
aspiny = 0 // 0 for spiny
if (!aspiny) {
load_file ("morphology/P_Spines.hoc")
add_spines(dendritic,spine_dens)
}
distance(0,axonOnSoma) // set the point where axon seated on soma as the origin
// ----------------------------------------------------
// Insert Density Mechanisms
// ----------------------------------------------------
load_file ("P_DensityMech.hoc")
// Install passive membrane properties
install_passive()
// Install active channels
install_channels()
// -------------------------------------------------------------------
// MM: insert fluctuating synaptic conductance from Destexhe et al. (2001)
// -------------------------------------------------------------------
objref fl
soma fl = new Gfluct2(0.5)
/* MM: load the session */
xopen("Gfluct_session.ses")
| 
