Nerve cells that reside in the olfactory sensory organs and are the primary cells for the detection and transduction of olfactory signals to the brain. In mammalian species, the dendrites of these neurons contain cilia (q.v.), on which reside odorant receptors. The binding of an odorant (q.v.) to a receptor causes intracellular biochemical changes which result in the generation of an electrical impulse that travels along the axon (q.v.) of the olfactory neuron to the olfactory bulb, where the signal is transferred to additional nerve cells for transport to the brain. In rodents and in Drosophila, each olfactory receptor neuron is highly specific, in that it expresses only one odorant receptor gene (q.v.), but multiple neurons collectively produce a pattern of neuronal activation, which is interpreted by the brain into distinct odors that are perceived by the organism. Also called olfactory sensory neuron. See anosmia, dendrite, odorant receptor.
Subjects: Genetics and Genomics.