Fig. 3.

Quantification of morphologic properties of adult-born mossy fiber boutons. Quantification of average bouton perimeter (A), normalized spine density (B), normalized density of synaptic contacts per bouton onto dendritic spines (C), and number of synaptic contacts per spine (D) at 1.5, 2, 4, 8, and 16 wpi and of unlabeled control boutons (C). This demonstrates that bouton perimeter and spine density are the same as controls by 4 wpi, whereas spinous synaptic contact density and the number of synaptic contacts per spine are the same as controls by 8 wpi. Thus, it takes ≈8 weeks for adult-born mossy fiber boutons to reach morphologic maturity. Values represent mean ± SEM. **P < 0.01; *P < 0.05. See Methods for normalization procedure and refer to Table S1 for raw numbers.