/*
Alzheimers axon study to determine the effect of dystrophic structures
on AP propagation.
Detect the following phenomena in the axon: transmission of an AP from
one side of the dysmorphic structure to the other was seen to either
be
1) delayed
2) made into a double spike, or persistent firing
3) blocked
To detect these we will run models under varying settings. After
initiating an AP at one end of the axon, detect APs at the other end
defined by exceding 0 mV (arbitrary) in simulations that run for 10
seconds.
This GUI version of the code reproduces Extended Data Figure 2a and
contains other related studies.
*/
func diam_as_func_of_area() {
return $1/(PI*5) // pass the area and assume the length is 5 um to find diam
}
dystrophy_active=1 // can be false (0) for sealed dystrophy, -1 for passive dystrophy and +1 for active dystrophy
forsec "axon" {
gbar_nax = intrinsic_factor * gbar_nax_orig
gkdrbar_kdr = intrinsic_factor * gkdrbar_kdr_orig
}
////////////////////////
///
/// create the simulations morphology
///
////////////////////////
load_file("simple_axon.hoc")
objref vbox
vbox= new VBox()
vbox.intercept(1)
load_file("dystrophy_shape.ses")
load_file("runctrl_plus_graph2.ses") // vbox.intercept(0) happens in here
dys_shape_graph.exec_menu("Show Diam")
////////////////////////
///
/// set up the axon stimulation and recording of the AP times
///
////////////////////////
objref ic, ic_amp_vec
axon ic = new IClamp(0)
// it was noted that in simulations that get blasted with a short large current
// clamp pulse, that they are similar at latter time points so simple way to insure
// that an AP occurs is to stimulte little diam axons with the same amount needed
// for big diam axons when iterating over axon sizes. For examining fixed axon size
// and creating paper figures it is OK to adjust current clamp amplitude to one that
// produces an AP at one end of the axon without artifacts (without a short time
// large transient voltage)
ic.del=100 // new method plays a vec into amp, instead of del 1
load_file("IClamp_GUI.ses")
// parameters of one IClamp pulse delivered to start AP at one end of axon:
ic_amp=0.02
ic_dur=1
ic_del=100
vbox.intercept(0)
vbox.map("PAAS over left green, right end purple V vs t", 350, 200, 400, 500)
objref pre_spike, post_spike // pre and post refer to before and after the dystrophy
objref pre_netcon, post_netcon, nil
pre_spike = new Vector(0)
post_spike = new Vector()
// default v threshold is 0 mV for event (AP) detection
axon pre_netcon = new NetCon(&v(0), nil)
axon post_netcon = new NetCon(&v(1), nil)
pre_netcon.record(pre_spike)
post_netcon.record(post_spike)
// store the max conductance densities to take fractions thereof later
axon {
gbar_nax_orig = gbar_nax
gkdrbar_kdr_orig = gkdrbar_kdr
}
objref axon_0_trace, axon_p5_trace, axon_1_trace, can_trace
/*
// Paul Yuan selection row 581 in results matrix (22205)
sphereDiam = 107.5
ChannelStrength = 0.5
AxonDiam = 0.25
stickDiam = 3.8 // thick stick batch
dystrophy_active = 1
*/
// special_id = 22205
// special_id 19177 equivalent to below example
/* sphereDiam = 52.5
ChannelStrength = 0.3
AxonDiam = 0.15
stickDiam = 3.8 // thick stick batch
dystrophy_active = 1
*/
objref axon_0_trace, axon_p5_trace, axon_1_trace, can_trace
strdef APinputTimesFilename
strdef APoutputTimesFilename
strdef folder
load_file("write_vec.hoc")
sphereDiam = 29
// if (sphereDiam==0) {sphereDiam=1e-6}
ChannelStrength = 0.3
AxonDiam = 0.15
stickDiam = 3.8 // allows to simulate multiple PAAS's with one large one
dystrophy_active = 1 // 1 active, 0 sealed, -1 passive (leak) channel(s) in PAAAS
////////////////////////
///
/// make channels appropriate for this processor id
///
////////////////////////
//assign the CanDiam based on the equiv sphereDiam
Stick { CanLength = L } // handy to have CanLength
// start with
// 4*PI*sphereR^2 = CanDiam*PI*CanLength
// divide both sides by PI * CanLength and switch sides to get
CanDiam = 4 * (sphereDiam/2)^2 / CanLength
Can { diam = CanDiam }
// print "setting axon params"
axon {
gbar_nax = gbar_nax_orig * ChannelStrength
gkdrbar_kdr = gkdrbar_kdr_orig * ChannelStrength
diam = AxonDiam
}
// print "set axon params"
if (dystrophy_active) {
// actually either active or passive here
Can {
if (dystrophy_active==-1) {
gbar_nax = 0
gkdrbar_kdr = 0
g_pas=3.16228e-05 // for passive only
} else {
gbar_nax = gbar_nax_orig * ChannelStrength
gkdrbar_kdr = gkdrbar_kdr_orig * ChannelStrength
g_pas=3.16228e-05
}
}
Stick {
if (dystrophy_active==-1) {
gbar_nax = 0
gkdrbar_kdr = 0
g_pas=3.16228e-05 // for passive only
} else {
gbar_nax = gbar_nax_orig * ChannelStrength
gkdrbar_kdr = gkdrbar_kdr_orig * ChannelStrength
g_pas=3.16228e-05 // for passive only
}
}
} else {
Can {
gbar_nax = 0
gkdrbar_kdr = 0
g_pas = 0
}
Stick {
gbar_nax = 0
gkdrbar_kdr = 0
g_pas = 0
}
}
// Stick { diam = AxonDiam } // if wanted to share the axon diameter
Stick { diam = stickDiam }
////////////////////////
///
/// setup recordings of voltage traces
///
////////////////////////
axon_0_trace = new Vector()
axon_p5_trace = new Vector()
axon_1_trace = new Vector()
can_trace = new Vector()
axon_0_trace.record(&axon.v(0))
axon_p5_trace.record(&axon.v(0.5))
axon_1_trace.record(&axon.v(1))
can_trace.record(&Can.v(0.5))
////////////////////////
///
/// run the simulation
///
////////////////////////
tstop=150 // run shorter for GUI than the usual 10000
init()
run()
////////////////////////
///
/// store the result
///
////////////////////////
if (dystrophy_active==-1) { folder = "passive/" }
if (dystrophy_active==0) { folder = "sealed/" }
if (dystrophy_active==1) { folder = "active/" }
sprint(APinputTimesFilename,"%ssphereDiam_%g_ChannelStrength_%g_AxonDiam_%g_InputAPtimes_%g_stickDiam.dat",folder,sphereDiam, ChannelStrength, AxonDiam, stickDiam)
sprint(APoutputTimesFilename,"%ssphereDiam_%g_ChannelStrength_%g_AxonDiam_%g_OutputAPtimes_%g_stickDiam.dat",folder,sphereDiam, ChannelStrength, AxonDiam, stickDiam)
// print APinputTimesFilename, ", " , APoutputTimesFilename
write_vec(APinputTimesFilename, pre_spike)
write_vec(APoutputTimesFilename, post_spike)
// store these vectors of recorded voltages with unique filenames related to the parameter settings
// Voltage vectors: axon_0_trace, axon_p5_trace, axon_1_trace, can_trace
strdef axon_0_trace_filename, axon_p5_trace_filename, axon_1_trace_filename, can_trace_filename
sprint(axon_0_trace_filename,"%saxon_0_trace_%g_%g_%g_%g.dat",folder, sphereDiam, ChannelStrength, AxonDiam, stickDiam)
sprint(axon_p5_trace_filename,"%saxon_p5_trace_%g_%g_%g_%g.dat",folder, sphereDiam, ChannelStrength, AxonDiam, stickDiam)
sprint(axon_1_trace_filename,"%saxon_1_trace_%g_%g_%g_%g.dat",folder, sphereDiam, ChannelStrength, AxonDiam, stickDiam)
sprint(can_trace_filename, "%scan_trace_%g_%g_%g_%g.dat",folder, sphereDiam, ChannelStrength, AxonDiam, stickDiam)
// do instead of don't write all these traces - too much
write_vec(axon_0_trace_filename,axon_0_trace)
write_vec(axon_p5_trace_filename,axon_p5_trace)
write_vec(axon_1_trace_filename,axon_1_trace)
write_vec(can_trace_filename,can_trace)
objref t_vec
t_vec=new Vector(tstop/dt)
t_vec=new Vector(tstop/dt-1)
t_vec.indgen(0 , tstop-dt, dt)
write_vec("active/t_vec.dat",t_vec)
// procedures for visualization of PAAS (in the code called Can as in tomato soup can)
// switch to "square" NEURON shape plot visualization, closer to spherical representation
// PAAS2square() and PAAS2hammerhead() are sister functions that transform the Can morphology
// for visualization purposes (PAAS2square is especailly for visualization while the other
// morphology was used to iterate over a single parameter (diam) in earlier simulations).
proc PAAS2square() {
Can { diameter=sqrt(diam*L)
old_diam = diam
old_L = L
diam=diameter
L=diameter
}
}
// Elongated representation convenient for changing size of dystrophy and
// although looks like the hammer in a a hammerhead shark, is euivalent mathematically
// to sphere of the same area (true only for a nseg=1, i.e. a single compartment).
// Can verify equivalence by running a simulation, executing PAAS2square(), and then
// rerunning the simulation to see v trajectory is the same as before.
// Switch back to original representation with PAAS2hammerhead()
proc PAAS2hammerhead() {
Can {diam=old_diam L=old_L}
}
// pass sphereDiam to have CanDiam returned
// 4*PI*sphereR^2 = CanDiam*PI*CanLength
// divide both sides by PI * CanLength and switch sides to get
// CanDiam = 4 * (sphereDiam/2)^2 / CanLength
// SphereDiam2CanDiam and CanDiam2SphereDiam are sister functions
func SphereDiam2CanDiam() {
// retrieve current Can L
Can current_Can_L = L
sphereDiam = $1
CanDiam = 4 * (sphereDiam/2)^2 / current_Can_L
return CanDiam
}
// pass a CanDiam to find SphereDiam
func CanDiam2SphereDiam() {
// retrieve current Can L
Can current_Can_L = L
tmp_CanDiam = $1
// start with
// 4*PI*sphereR^2 = CanDiam*PI*CanLength
// 4*sphereR^2 = CanDiam*CanLength
// sphereR^2 = CanDiam*CanLength/4
sphereR = sqrt(tmp_CanDiam * current_Can_L/4)
return 2*sphereR
}
// PWManager[0].hide(5)
PAAS2square()