: \$Id: netstim.mod 1887 2007-11-19 12:34:00Z hines \$ : comments at end : Modified from NetStim so that spikes are Gaussian distributed around : regular spike times (BPG 14-1-09) : Spikes outside regular interval are moved to just inside the interval : (this will distort the distribution, so noise level should be chosen : so that this does not happen very often!!) NEURON { ARTIFICIAL_CELL RegnStim RANGE interval, number, start RANGE noise POINTER donotuse } PARAMETER { 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 { event (ms) on ispike tspike : regular spike time donotuse } PROCEDURE seed(x) { set_seed(x) } INITIAL { on = 0 : off tspike = start ispike = 0 if (noise < 0) { noise = 0 } if (noise > 1) { noise = 1 } if (start >= 0 && number > 0) { on = 1 : randomize the first spike event = start + noise*interval*erand() : but not earlier than 0 if (event < 0) { event = 0 } net_send(event, 3) } } 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() invl = tspike + mean + noise*mean*erand() - t if (invl <= 0) { invl = .01 (ms) : reset to small interval } : if (t+invl >= tspike+mean) { : invl = tspike + mean - t - .01 : } } tspike = tspike + mean } 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.normal(0, 1) (BPG) */ _lerand = nrn_random_pick(_p_donotuse); }else{ 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 = normrand(0, 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 == 3) { : from INITIAL 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. ENDCOMMENT