: thetastim.mod derived from:
: $Id: netstim.mod 2212 2008-09-08 14:32:26Z hines $
: comments at end
NEURON {
ARTIFICIAL_CELL ThetaStim_reject
RANGE outer_interval, outer_number, outer_start
RANGE outer_noise
RANGE interval, number, start
RANGE noise
THREADSAFE : only true if every instance has its own distinct Random
POINTER donotuse
}
PARAMETER {
outer_interval = 1000 (ms) <1e-9,1e9>: time between spikes (msec)
outer_number = 10 <0,1e9> : number of spikes (independent of noise)
outer_start = 50 (ms) : start of first spike
outer_noise = 0 <0,1> : amount of randomness (0.0 - 1.0)
interval = 10 (ms) <1e-9,1e9>: time between spikes (msec)
number = 10 <0,1e9> : number of spikes (independent of noise)
: start = 50 (ms) : start of first spike
noise = 0 <0,1> : amount of randomness (0.0 - 1.0)
}
ASSIGNED {
outer_event (ms)
outer_on
outer_ispike
event (ms)
on
ispike
donotuse
: note that outer_start is a parameter (not assigned during integration)
start : start used to be a parameter however now gets assigned
}
PROCEDURE seed(x) {
set_seed(x)
}
INITIAL {
on = 0 : off
ispike = 0
if (outer_noise < 0) {
outer_noise = 0
}
if (outer_noise > 1) {
outer_noise = 1
}
if (noise < 0) {
noise = 0
}
if (noise > 1) {
noise = 1
}
if ((outer_start >= 0 && outer_number > 0) && (number > 0)) {
outer_on = 1
: randomize the first spike so on average it occurs at
: start + noise*interval
outer_event = outer_start + invl(outer_interval) - outer_interval*(1. - outer_noise)
: but not earlier than 0
if (outer_event < 0) {
event = 0
}
net_send(outer_event, 4) // flag=4 starts a net_send to send flag=3 to start the spikes
}
}
PROCEDURE outer_init_sequence(t(ms)) {
if (outer_number > 0) {
outer_on = 1
outer_event = 0
outer_ispike = 0
}
}
PROCEDURE init_sequence(t(ms)) {
if (number > 0) {
on = 1
event = 0
ispike = 0
}
}
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*erand()
}
}
VERBATIM
double nrn_random_pick(void* r);
void* nrn_random_arg(int argpos);
ENDVERBATIM
FUNCTION erand() {
VERBATIM
if (_p_donotuse) {
/*
:Supports separate independent but reproducible streams for
: each instance. However, the corresponding hoc Random
: distribution MUST be set to Random.negexp(1)
*/
_lerand = nrn_random_pick(_p_donotuse);
}else{
/* only can be used in main thread */
if (_nt != nrn_threads) {
hoc_execerror("multithread random in ThetaStim"," only via hoc Random");
}
ENDVERBATIM
: the old standby. Cannot use if reproducible parallel sim
: independent of nhost or which host this instance is on
: is desired, since each instance on this cpu draws from
: the same stream
erand = exprand(1)
VERBATIM
}
ENDVERBATIM
}
PROCEDURE noiseFromRandom() {
VERBATIM
{
void** pv = (void**)(&_p_donotuse);
if (ifarg(1)) {
*pv = nrn_random_arg(1);
}else{
*pv = (void*)0;
}
}
ENDVERBATIM
}
PROCEDURE next_invl() {
if (number > 0) {
event = invl(interval)
}
if (ispike >= number) {
on = 0
}
}
NET_RECEIVE (w) {
if (flag == 0) { : external event
if (w > 0 && on == 0) { : turn on spike sequence
: but not if a netsend is on the queue
init_sequence(t)
: randomize the first spike so on average it occurs at
: noise*interval (most likely interval is always 0)
next_invl()
event = event - interval*(1. - noise)
net_send(event, 1)
}else if (w < 0) { : turn off spiking definitively
on = 0
}
}
if (flag == 4) { : from INITIAL or outer event
if (start >= 0 && number > 0) {
on = 1
: randomize the first spike so on average it occurs at
: start + noise*interval
event = start + invl(interval) - interval*(1. - noise)
: but not earlier than 0
if (event < 0) {
event = 0
}
net_send(event, 3) // flag=4 starts a net_send to send flag=3 to start the spikes
}
}
if (flag == 3) { : to initialize the inner spikes
if (on == 1) { : but ignore if turned off by external event
init_sequence(t)
net_send(0, 1)
}
}
if (flag == 1 && on == 1) {
ispike = ispike + 1
net_event(t)
next_invl()
if (on == 1) {
net_send(event, 1)
}
}
}
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: number of spikes (independent of noise)
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 (no net_send events on queue)
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 an on!=0 state,
the stimulator receives a negative weight event, the stimulator will
change to the on==0 state. In the on==0 state, it will ignore any ariving
net_send events. A change to the on==1 state immediately fires the first spike of
its sequence.
Modified by Tom Morse to be ThetaStim which is essentially two NetStim's
where the outter NetStim triggers the inner NetStim to make what is
traditionally called a theta stimulation (i.e. a stimulation pattern where
a burst of spikes is repeated at regular intervals. An example of this would
be three pulses at 50 Hz (corresponds to a period of 20 ms) repeated every
200 ms (which corresponds to a frequency of 5 Hz): this would be pulses at
t=0, 20, 40, 200, 220, 240, ... ms)
ENDCOMMENT