Confocal imaging and quantification

Images were acquired using a Leica TCS SP5 Confocal Microscope. Z-stacks of the DG were obtained (step size: 1 µm) using sequential scanning to prevent bleed-through between fluorophores. Six or more Z-stacks of equal thickness and equivalent rostrocaudal position were quantified for each sample. For viral injection experiments, only sections with confirmed infection in the DG were quantified. Stereological cell counting was performed using ImageJ software. For per volume quantification, cell counts were normalized to the volume of the DG granule cell layer. All imaging and quantification was performed blinded to experimental condition.