: $Id: netstim.mod,v 1.1.1.1 2001/01/01 20:30:37 hines Exp $
: modified in such a way that the first event will never be before start
: M.Migliore Dec.2001
: modified in such a way to have the first event at start
: M.Migliore Sep. 2003
NEURON {
POINT_PROCESS NetStims
RANGE y
RANGE interval, number, start
RANGE noise
}
PARAMETER {
interval = 10 (ms) <1e-9,1e9>: time between spikes (msec)
number = 10 <0,1e9> : number of spikes
start = 50 (ms) : start of first spike
noise = 0 <0,1> : amount of randomeaness (0.0 - 1.0)
}
ASSIGNED {
y
event (ms)
on
end (ms)
}
PROCEDURE seed(x) {
set_seed(x)
}
INITIAL {
on = 0
y = 0
if (noise < 0) {
noise = 0
}
if (noise > 1) {
noise = 1
}
if (start >= 0 && number > 0) {
: first spike occurs at start
event = start
net_send(event, 3)
}
}
PROCEDURE init_sequence(t(ms)) {
if (number > 0) {
on = 1
event = t
end = t + 1e-6 + invl(interval)*(number-1)
}
}
FUNCTION invl(mean (ms)) (ms) {
if (mean <= 0.) {
mean = .01 (ms) : I would worry if it were 0.
}
if (noise == 0) {
invl = mean
}else{
invl = (1. - noise)*mean + noise*mean*exprand(1)
}
}
PROCEDURE event_time() {
if (number > 0) {
event = event + invl(interval)
}
if (event > end) {
on = 0
}
}
NET_RECEIVE (w) {
if (flag == 0) { : external event
if (w > 0 && on == 0) { : turn on spike sequence
init_sequence(t)
net_send(0, 1)
}else if (w < 0 && on == 1) { : turn off spiking
on = 0
}
}
if (flag == 3) { : from INITIAL
if (on == 0) {
init_sequence(t)
net_send(0, 1)
}
}
if (flag == 1 && on == 1) {
y = 2
net_event(t)
event_time()
if (on == 1) {
net_send(event - t, 1)
}
net_send(.1, 2)
}
if (flag == 2) {
y = 0
}
}
COMMENT
Presynaptic spike generator
---------------------------
This mechanism has been written to be able to use synapses in a single
neuron receiving various types of presynaptic trains. This is a "fake"
presynaptic compartment containing a spike generator. The trains
of spikes can be either periodic or noisy (Poisson-distributed)
Parameters;
noise: between 0 (no noise-periodic) and 1 (fully noisy)
interval: mean time between spikes (ms)
number: mean number of spikes
Written by Z. Mainen, modified by A. Destexhe, The Salk Institute
Modified by Michael Hines for use with CVode
The intrinsic bursting parameters have been removed since
generators can stimulate other generators to create complicated bursting
patterns with independent statistics (see below)
Modified by Michael Hines to use logical event style with NET_RECEIVE
This stimulator can also be triggered by an input event.
If the stimulator is in the on=0 state and receives a positive weight
event, then the stimulator changes to the on=1 state and goes through
its entire spike sequence before changing to the on=0 state. During
that time it ignores any positive weight events. If, in the on=1 state,
the stimulator receives a negative weight event, the stimulator will
change to the off state. In the off state, it will ignore negative weight
events. A change to the on state immediately fires the first spike of
its sequence.
ENDCOMMENT