Fig. 2: Localizing release events at Schaffer collateral boutons.
From: Vesicular release probability sets the strength of individual Schaffer collateral synapses
a Rapid frame scans (62.5 Hz) show increase in iGluSnFR fluorescence (green) after stimulation (single trial, single AP triggered between frame #2 and #3). Scale bar: 1 µm. b The center position and amplitude (color scale) of Gaussian fits to the change in green fluorescence are plotted with respect to the bouton outline (red line). Failure trials and random changes in baseline fluorescence show no local clustering. c For calibration purposes, green fluorescent microspheres (0.17 µm) were imaged next to boutons. d To quantify the spatial distribution of release events at each bouton, an ellipse was fit to contain 95% of success locations. Both short and long axis of the ellipse were significantly smaller (short axis, two-sided Wilcoxon test, p = 0.04, long axis, two-sided Wilcoxon test, p = 0.001, n = 12 boutons) under high Ca2+ conditions (short axis: 0.21 ± 0.03 µm; long axis: 0.41 ± 0.06 µm) compared to 1 mM [Ca2+]e (short axis: 0.28 ± 0.01 µm; long axis: 0.56 ± 0.06 µm). For comparison, microsphere localization precision (0.05 ± 0.01 μm) and xy-size of the point spread function (PSF) are also shown (gray bars, mean ± SEM). Source data are provided as a Source Data file.
