Table 1.

Summary of quantitative presynaptic data

Presynaptic data	Brain	Cell culture
Active zone	0.039  ± 0.022 μm2	0.027  ± 0.019 μm2
PSD	0.043  ± 0.031 μm2	0.028  ± 0.020 μm2
Docked vesicle number	10.3  ± 5.6	4.6  ± 3.0
Area per docked vesicle	62  × 62 nm	77  × 77 nm
Bouton volume	0.086  ± 0.049 μm3	0.122  ± 0.106 μm3
Spine volume	0.038  ± 0.036 μm3
Total number of vesicles	270  ± 176	195  ± 154
Outer vesicle diameter	35.2  ± 3.4 nm

The left column summarizes values for mouse brain synapses as given in the text. The right column gives corresponding values for rat hippocampal neurons in culture; some entries do not appear in the text but are included here for completeness.