This confocal image shows a coronal slice of the entire olfactory bulb from a mouse in which EGFP (green) was expressed in calretinin-expressing (CR+) periglomerular (PG) cells, the most abundant interneurons in the glomerular layer, and a tdTomato-expressing plasmid (red) had been electroporated into the dorsal subventricular zone at birth to label newborn neurons. Blue DAPI labeling shows nuclei. New work suggests that postnatally generated CR+ PG cells continuously supply the olfactory bulb with a large pool of neurons that have unconventional properties. For more information, see the article by Benito et al. (Pages 9870–9882).