Changes in the numbers of olfactory neurons or in neuroblast migration to the olfactory bulb can affect abilities to discriminate odors or establish new odor-related memories. Studying female mice, Shingo et al. show that the hormone prolactin induces increased production of olfactory cell precursors. The prolactin-induced changes were apparent during pregnancy and also just after mating. Odor discrimination contributes to recognition of mates and offspring. These insights into prolactin-regulated neurogenesis may provide a physiological basis for understanding certain complex, seemingly social, behaviors. T. Shingo, C. Gregg, E. Enwere, H. Fujikawa, R. Hassam, C. Geary, J. C. Cross, S. Weiss, Pregnancy-stimulated neurogenesis in the adult female forebrain mediated by prolactin. Science 299 , 117-120 (2003). [Abstract] [Full Text]