: \$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 NEURON { POINT_PROCESS NetStimm 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) { : randomize the first spike so on average it occurs at start+interval event = start + invl(interval) 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