Fig. 6: Relative distribution of synchronous and asynchronous release events in the active zone.

a Hierarchical cluster analysis of vesicular exocytosis sites. (i) Distributions of clustered events (clustering diameter threshold 100 nm, see Methods) in a representative wild type bouton (same as in Fig. 5a–d) and a Syt1^−/− bouton. (ii) Distributions of number of events per cluster. (iii) Dependences of mixed clusters fraction (containing both synchronous and asynchronous events) on the number of events per cluster. (iv) Increase of synchronous events fraction with cluster size in wild type synapses. Dashed lines, linear regression. Solid lines 95% confidence intervals. (ii)–(iv) pooled data from m = 799 clusters from n = 106 boutons in wild type and m = 553 clusters from n = 64 boutons in Syt1^−/− neurons. b Comparison of convex hull areas circumventing synchronous or asynchronous events. (i) Representative boutons (the same as shown in a). (ii) Relationship between the release areas and the number of fitted events in all analysed boutons. Dashed lines, linear regression. Solid lines, 95% confidence intervals. c Illustration of the reshuffling analysis used to compare spatial distributions of synchronous and asynchronous events within individual synapses (representative reshuffled versions of the wild type bouton shown in (a), see text for details). d Comparison of the normalised areas for synchronous and asynchronous events in wild type and Syt1^−/− synapses. Data points and box-and-whisker plots: centre, median; notch 95% confidence interval for median; box, 25th–75th percentiles; whiskers, the most extreme data points not considered outliers (within 1.5 times the interquartile range from the bottom or the top of the box). ** p < 0.01, *** p < 0.001, two-tailed Mann–Whitney U test (for exact p values see SourceData.xlsx file).