Fig. 3

a Mean synaptic transmission, $〈s〉$ and b variance of synaptic transmission,$〈s^2〉-{〈s〉}^2$, arising from presynaptic Poisson trains throughprobabilistic synapses. c Variance in synaptic transmission as a function ofthe mean transmission. Solid curves are analytic solutions (blue, middlecurve for static, a= Eq. (23), b= Eq. (24), c= Eq. (25);green, upper curve for facilitating, a from Eqs. (20) and (31),b from Eqs. (22) and (31), c from a &b; andred, lower curve for depressing synapses, a= Eq. (26), b fromEqs. (4), (22), (25) and (27), c from a &b). Blackdots are corresponding results from simulations produced by 30,000 sec ofPoisson input spike trains through saturating synapses