Fig. 4.
Simulated HSD as a result of vesicle depletion when strong and weak synapses differ in the release probability of individual vesicles. During each simulation,Pves and Nsiteremained constant. A, Univesicular release.B, Limited multivesicular release (as in Fig.3C,D). Pves inA was selected to achieve aPsite of 0.25 and 0.75 forPves Low and PvesHigh, respectively, with six releasable vesicles; the samePves values were used in B. Average initial number of quanta released were: for A, 11.0 for Pves Low and 29.7 forPves High; and for B, 11.6 for Pves Low and 37.6 forPves High. Strong synapses underwent HSD at a faster rate than weak synapses [repeated measure ANOVA testing interaction between vesicle number and trial number: (A) F(14,145) = 43, p < 0.001; (B)F(14,145) = 54, p< 0.001]. Sampling interval was 0.01 msec.