www.neuron.yale.edu

Code: Select all

// Test Fano factor

objref syn, sti , con, Vec, Gra, Vec1
create soma
insert pas
Vec = new Vector()
syn = new Exp2Syn(0.5)
sti = new NetStim(0.5)
sti.interval = 100
sti.start 	 = 10
sti.number   = 500000
sti.noise     = 1
con  = new NetCon(sti,syn)
con.weight=1
con.record(Vec)  // record all events of synaptic release 

tstop = 55000
run()

Vec1 = new Vector()
for i=1,(Vec.size()-1){  // getting only the difference between each synaptic event
	Vec1.append(Vec.x[i] - Vec.x[i-1])
}

Vec1.var()/Vec1.mean()

Code: Select all

rand_sm = poissrnd(1650,1,70);
var(rand_sm)/mean(rand_sm)

Code: Select all

// Test Fano factor

objref syn, sti , con, Vec, Vec1, hist
create soma
insert pas
Vec = new Vector()
syn = new Exp2Syn(0.5)
sti = new NetStim(0.5)
sti.interval = 100
sti.start 	 = 10
sti.number   = 500000
sti.noise     = 1

con  = new NetCon(sti,syn)
con.weight=1
con.record(Vec)


tstop = 35000
timewindow = 250 // Should work for any time window!
run()

Vec1 = new Vector()
for i=1,(Vec.size()-1){
	Vec1.append(Vec.x[i] - Vec.x[i-1])
}

hist = Vec.histogram(0,tstop,20)
hist.var()/hist.mean()  //This is the Fano factor --> Should be 1 for possion...

Vec1.stdev()/Vec1.mean() //Should be 1 for possion...

Code: Select all

objref sti
sti = new NetStim()
sti.interval = 100
sti.start = 10
sti.number = 1e9 // no need to limit this
sti.noise = 1

objref con, nil, vec
con  = new NetCon(sti,nil)
vec = new Vector()
con.record(vec)

tstop = 35000
cvode_active(1)
run()

objref isivec, hist

proc analyze() {
  isivec = new Vector()
  isivec.deriv(vec,1,1) // Euler deriv with dx == 1 yields vector of ISIs
  print "mean ISI ", isivec.mean(), "based on ", isivec.size(), "samples"
  print "ISI stdev ", isivec.stdev()
  print "stdev/mean ", isivec.stdev()/isivec.mean()
  print " "
  hist = vec.histogram(0,tstop,20)
  print "estimate from spike counts over 20 ms intervals: ", hist.var()/hist.mean()
}

analyze()