A fixed-width section model gave a 1.50-fold density rise from mouse mossy fiber counts and did not determine rat functional pool growth

We tested how thin-section vesicle counts can be compared with a functional pool at a mossy fiber bouton. We used released data from Kim et al. (2024). For a flat membrane with constant mean docking density, a sampling strip gives a count proportional to its width and surface density. This relation also holds for clustered points. All 308 released mouse profile values gave a 1.50-fold rise in the condition mean. Functional pool-decrement estimates from eight rat pairs gave a 2.24-fold ratio of means. The squared profile fold was 2.25, but this close match does not follow from section sampling. In a representative bouton model with equal sampling width and quantal amplitude, the two means leave a 1.49-fold factor in total active-zone area times functional availability. Two explicit models fit both means with different changes in area and availability. Exact integration and simulations checked the sampling relation. We provide a reusable conversion calculation, source archive, extracted data, proof, figures, and repeat steps. This is an exploratory method study. The cohorts, species, and temperatures differ. The release lacks profile-to-mouse identifiers. The 1.49-fold factor is a conditional aggregate comparison, not a measured biological change. The source study already discusses area changes and differences between docked and functional pools.

mossy fiber · synaptic vesicle · stereology · structure and function · active zone · functional pool · sampling geometry