Vanessa Ruta in Phys.Org:
As animals explore their environment, they learn to master it. By discovering what sounds tend to precede predatorial attack, for example, or what smells predict dinner, they develop a kind of biological clairvoyance—a way to anticipate what’s coming next, based on what has already transpired. Now, Rockefeller scientists have found that an animal’s education relies not only on what experiences it acquires, but also on when it acquires them. Studying fruit flies, the researchers showed that a single odor can become either appealing or disgusting to an animal, depending on when the smell is encountered relative to a reward. The study, described in a report in Cell, also reveals that animals can quickly revise these memories, and shows how this process unfolds on a cellular level—insights that likely pertain not just to flies, but to learning across the animal kingdom.
Memory, at its most fundamental level, amounts to a series of associations: Ring a bell before feeding a dog, and eventually the dog will learn to salivate at the sound of the bell alone. “In this case, the bell comes before the food and is therefore predictive of reward,” says Annie Handler, a graduate fellow in the lab of Vanessa Ruta, the Gabrielle H. Reem and Herbert J. Kayden Associate Professor. “But we suspected that there isn’t just one order of events that animals find significant. They should also be able extract meaning from cues that follow a reward.”