Confocal images of neurons in CA1 pyramidal layer cell layer of the hippocampus at 100× magnification. 5-bromo-2-deoxyuridine (BrdU) immunofluorescence was combined with immunostaining for the neuronal marker, NeuN, at 3 weeks (PN21). (A) Confocal image showing NeuN+ cells. (B) Confocal image showing BrdU+ cells. (C) Merged image of both BrdU+/NeuN+ cells. (D) Graph representing total proportion of BrdU+/NeuN+ cells in CA1. Scale bars = 10 μm.