Table 1.

Comparison of all quantitative synaptic data from piriform cortex and hippocampus

Variable	Hippocampus	Piriform cortex
	CA1	Layer 1a	Layer 1b
Active zone	0.039 ± 0.022 μm2	0.095 ± 0.101 μm2	0.097 ± 0.087 μm2
Postsynaptic density	0.043 ± 0.031 μm2	0.096 ± 0.105 μm2	0.100 ± 0.087 μm2
Docked vesicle number	10.3 ± 5.6	16.4 ± 17.1	26.8 ± 23.8
Area per docked vesicle	62 × 62 nm	79 × 79 nm	62 × 62 nm
Bouton volume	0.086 ± 0.049 μm3	0.367 ± 0.378 μm3	0.208 ± 0.137 μm3
Total number of vesicles	270 ± 176	354 ± 436.5	656 ± 423.7
Spine volume	0.038 ± 0.036 μm3	0.129 ± 0.174 μm3	0.071 ± 0.073 μm3
Total synaptic vesicle density	3,139/μm3	927 ± 446/μm3	3,192 ± 889/μm3
One synapse per bouton	90%  (64)	81%  (22)	82%  (23)
Two synapses per bouton	8%  (6)	19%  (5)	11%  (3)
Three synapses per bouton	2%  (1)	0	4%  (1)
Four synapses per bouton	0	0	4%  (1)
Number of shaft synapses		16%  (6)	6%  (2)
Two synapses per spine	0	3%  (1)	3%  (1)
Two active zones per synapse	0	3%  (1)	6%  (2)
Total number boutons	71	27	28
Total number synapses	79	38	36

The first eight rows list the average values and the corresponding standard deviations for indicated quantities. Remaining rows give the percentage for different types of synapses (with the numbers in parentheses).