Fig. 4. Spatial distribution of docked vesicles. SB-associated (yellow) and outlying (green) vesicles are shown at three synapses (A, B, synapse 1; C,D, synapse 3; E, synapse 2) in relation to the plasma membrane (gray), the SB (blue), and the presynaptic density (pink). Arrow pairs inA/B and C/D denote the same vesicle in both views of the same synapse. A, C,E, View through the mostly transparent plasma membrane of vesicles docked at it. Asterisks in Cand E show the locations of omega-shaped invaginations in the presynaptic membrane. Scale bar (applies to A,C, E), 100 nm. B, View of docked vesicles and the closed pole of the SB. D, Another tomogram of the synapse shown in C, revealing docked vesicles far from the SB, which is truncated by two edges of the volume. F, Nonsynaptic region of a hair cell showing vesicles in the hair cell cytoplasm (pale green) and those docked (dark blue) at the plasma membrane (red). Mitochondrial outer membranes (purple) are flat where truncated by the edge of the volume and reveal the wedge shape of this reconstruction.