section thickness 21 μm) through the dentate gyrus of the hippocampus counterstained with Nuclear Fast Red was saved in strict anatomical order for quantitative analysis. Granule cell layer volume was estimated using StereoInvestigator software that employs the Cavalieri method (West and Andersen, 1980; West et al., 1991). The average density of granule cells was found by examinations from all portions of the granule cell layer. Over 400 cells were counted at 630× with an oil objective (N/A 1.4), a 10 μm × 10 μm × 2 μm counting grid, and a 2 μm top and bottom guard zone. The total number of cells was determined by multiplying the average density of cells (cells/μm3) by the total volume of the granule cell layer (West et al., 1991). Granule cell layer volume and cell number estimates were made by an observer blind to the study.
