Quantitative analysis to obtain unbiased estimates of the total number of granule cells was performed on a Zeiss Axiophot Microscope equipped with MicroBrightField Stereo Investigator software (MicroBrightField), a three-axis Mac 5000 motorized stage (Ludl Electronics Products), a digital charge-coupled device ZVS video camera (Zeiss), a PCI color frame grabber, and computer workstation. All contours were drawn at low magnification using a Zeiss Plan-Apochromat 10× objective N/A 0.32, and the contours were realigned at high magnification using a Zeiss Plan Apochromat 63× oil objective N/A 1.4. The total number of granule cells was calculated by an unbiased stereological estimation in which the average density of the granule cells was multiplied by total volume of the granule cell layer of the hippocampal dentate gyrus (Donovan et al., 2006). Every 18th section (eight sections from each rat; cut section thickness 40 μm; measured 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
