The modulation of lifespan by perceptual systems.

Could the mere perception of food availability reverse the beneficial effects of diet restriction, which robustly increases lifespan and reduces aging-related disease in many species? We had noted from previous work in Drosophila that the effects of dietary restriction were fast acting, completely reversible, and largely independent of the energetic content of the food. Indeed, some characteristic of the diet seemed to be "sensed" by the flies independent of their tendency to eat it. We quickly realized that the Drosophila olfactory system, with its well-understood architecture and associated set of genetic tools, was the ideal model to test our hypothesis. Subsequent work resulted in the identification of particular odorants and populations of sensory neurons with potent effects on lifespan, obesity, and metabolism.