An Enduring Sensory Map

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Science  01 Dec 2000:
Vol. 290, Issue 5497, pp. 1655
DOI: 10.1126/science.290.5497.1655b

The ability to sense and process olfactory information is central to the feeding, predatory, and mating behavior of most organisms. Mice have two million olfactory sensory neurons, and each expresses only one of a thousand different odorant receptor genes. Neurons expressing a given receptor project axons to two of 1800 discrete synaptic structures, or glomeruli, within the olfactory bulb. This pattern of projections provides a precise two-dimensional map of receptor activation in the brain, and it is established within the first two weeks of life.

In adult organisms, olfactory neurons die and are replaced, yet the ability to perceive specific odors persists for a lifetime. To explore how the integrity of the olfactory map is maintained, Gogos et al. used a genetic approach to kill groups of neurons expressing a particular odorant receptor gene. The synapses in the olfactory system reformed with precision after this neuronal ablation. Thus, the determinants governing the establishment of the olfactory map during development persist throughout life, and the target selection that occurs during regeneration is likely to recapitulate developmental events. — PAK

Cell103, 609 (2000).

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