Table 1. Synaptic junction lengths.

	Synaptic vesicles (+)	Synaptic vesicles (—)
BDNF(+/+)	373.8 ± 8.4 (256)	290.4 ± 9.1 (146)
BDNF(+/—)	337.3 ± 7.4 (279)*	299.0 ± 8.8 (151)
BDNF(—/—)	343.0 ± 8.1 (228)*	308.5 ± 7.8 (165)

The difference in synaptic junction lengths among BDNF genotypes. The synaptic contact size was estimated as described in Supporting Methods. We defined the vesicle containing (+) and not containing (—) synapses according to the number (more than four and less than three, respectively) of synaptic vesicles appeared at the proximal region of postsynaptic density, as shown in Fig. 1A. The number in parentheses is the synaptic number examined. The data are shown as average length (nm) ± SEM. Significance was shown by the asterisk when P < 0.05 by using the Mann—Whitney U test.