Figure 8.

The relationship between the volume of presynaptic vesicle fields and number postsynaptic contacts at individual boutons. The volume is calculated by multiplying the cumulative imaged area of the vesicle field across successive sections by the section thickness (70 nm). Grey dots indicate that the bouton contained primarily small presynaptic vesicles; black dots indicate that the bouton contained both small presynaptic vesicles and large intensely stained dense core vesicles; open circles indicate that the bouton contained both small presynaptic vesicles and large low density vesicles. At all data points only the volume of the small presynaptic vesicle field was calculated.