ran_test.hoc

NSNUM = 5 // how many NetStims to create
MAXSTREAM = 1000 // max # events in a NetStim's stream
  // before it begins to repeat values already generated
  // by a different stream.
  // set to 0 and all NetStims will produce identical streams

ISI = 10 // default NetStim parameters
NUM = 50
START = 1
NOISE = 0

TSTOP = 20 // length of simulation

load_file("nrngui.hoc")
load_file("ranstream.hoc")

///// model setup

objref nslist, rslist
nslist = new List()
rslist = new List()

proc makenetstims() { local i  localobj ns, rs
  nslist = new List()
  rslist = new List()
  random_stream_offset_ = MAXSTREAM
  for i = 0, $1-1 {
    ns = new NetStim()
    nslist.append(ns)
    rs = new RandomStream(i)
    rslist.append(rs)
    ns.noiseFromRandom(rs.r)
    rs.r.negexp(1) // must specify negexp distribution with mean = 1
    rs.start()
  }
}

makenetstims(NSNUM)

proc setparams() { local i
  for i = 0,nslist.count()-1 {
    nslist.o(i).interval = ISI
    nslist.o(i).number = NUM
    nslist.o(i).start = START
    nslist.o(i).noise = NOISE
  }
}

setparams() // default is deterministic spike times (NOISE = 0)

///// instrumentation

objref tvec, idvec, nil
tvec = new Vector()
idvec = new Vector()

proc instrumentation() { local i  localobj nc
  tvec = new Vector()
  idvec = new Vector()
  for i = 0,nslist.count()-1 {
    nc = new NetCon(nslist.o(i), nil)
    nc.record(tvec, idvec, i)
  }
}

instrumentation()

///// simulation control

// spike times will be at 0.5*ISI + sample from negexp that has mean 0.5*ISI
NOISE = 0.5
setparams()

tstop = TSTOP

proc restart() { local i
  for i = 0, rslist.count()-1 rslist.o(i).start()
}

objref g

proc myrun() {
  run()
  // make a raster plot of spike times
  idvec.add(1) // so cell i spikes are marked at y = i+1
  objref g
  g = new Graph(0)
  g.size(0,tstop,0,NSNUM)
  g.view(0, 0, tstop, NSNUM, 47, 109, 300.48, 200.32)
  idvec.mark(g, tvec, "|", 10, 2, 1)
  // print out spike times
  print " time         cell"
  for i=0, tvec.size-1 printf("%7.3f \t%d\n", tvec.x(i), idvec.x(i))
}

/////

print "============================================================"
print "Control:  all have interval 10, number 50, start 10, noise 1"
print "============================================================"

myrun()

print " "
print "Take a good look at the graph.  The marks at y = 1"
print "indicate the spikes generated by NetStim[0]."
print "When ready for next test, type"
print "test()"
print "at the oc> prompt, then press Return"
print " "

proc test() {
  print "============================================================"
  print "Test:  NetStim 0 (i.e. cell 1) interval 1, number 3"
  print "============================================================"

  nslist.o(0).interval = 1
  nslist.o(0).number = 3
  restart() // restore each generator to the start of its stream

  myrun()

  print " "
  print "Note that only the marks at y = 1 changed location in time."
  print "Compare the NetStim spike times in this run"
  print "against the spike times from the control run."
  print "Note that only the spikes from \"cell 1\" (NetStim[0]) are different."
}