TABLE 2.

Distribution of synaptic vesicles and exocytosis by population

	Docked-not-Tethered	Docked-and-Tethered	Tethered	Outlier
Experimental vesicle counts	81 ± 37	43 ± 8	357 ± 42	1,997 ± 320
Simulated vesicle counts	91 ± 31	39 ± 11	361 ± 38	1,914 ± 615
Colocalized with channels	9 ± 6	19 ± 7	0	0
Simulated exocytosis
Vesicles	9.3 ± 6.4	19.8 ± 6.9	1.3 ± 1.4	0.1 ± 0.4
% of population	10 ± 7	52 ± 18	0.39 ± 0.46	0.01 ± 0.02
% of colocalized	98 ± 5	98 ± 3

All values are means ± SD of 250 trials, except experimental vesicle count variations, which are SE. Experimental vesicle counts from Lenzi et al. (2002), where they used the nomenclature: Outlying, docked; Synaptic body associated, docked; Synaptic body associated, not docked; Outlying, not docked. We modified their anatomical nomenclature in an effort to better reflect each group's functional significance in our active-zone simulations, specifically contrasting the two groups that dominate exocytosis: docked-not-tethered versus docked-and-tethered vesicles. Colocalized vesicles were 5–8 nm from the nearest calcium channel (see methods). Simulated exocytosis was driven by 10 ms of maximal calcium influx. Percentage exocytosis computed on a trial-by-trial basis then averaged across trials.