Fig. 1.

Dynamic synapses alter the distribution of interrelease intervals (IRI) of one vesicle produced by a Poisson spike train. a1–a2 Histogram of IRIs for static synapses is exponential ($p_0=0.5$). b1–b2 Histogram of IRIs for a facilitating synapse is more sharply peaked than exponential (with a CV greater than one) ($p_0=0.1$, $f_F=0.5$, ${\tau }_F=500\text{ ms}$). c1–c2 Histogram of IRIs for a probabilistic depressing synapse has a dip at low intervals (producing a CV less than one) ($p_0=0.5$, ${\tau }_D=250\text{ ms}$). a1, b1, c1 Presynaptic Poisson spike train of 2 Hz. a2, b2, c2 Presynaptic Poisson spike train of 50 Hz