Olfactory epithelium. This image shows a vertical projection of a stack of confocal images taken from a transgenic mouse, in which green fluorescent protein (GFP) is expressed in all ciliated olfactory sensory neurons. GFP brightly labels the olfactory neuronal cell bodies (OCB), their apical dendrites (AD), and terminal knobs (TK). Staining does not extend into the sensory cilia, which remain invisible in this preparation. Basally to the olfactory neuronal cell bodies is the unstained layer of basal stem cells (LBC), from which degenerating neurons are constantly regenerated. The olfactory axons grow in bundles (AB) through the basal lamina (BL), and then fasciculate to form the tracts of the olfactory nerve, which projects into the brain. (Rebecca Elsaesser and Jacques Paysan, unpublished).