You can bring a fly to water…but is it rewarding for it to drink?

I needed a bit of food, but do i find this red stuff rewarding?

University of Florida

Scott Waddell, at Oxford's Centre for Neural Circuits and Behavior, is interested in Big Ideas like memory and motivation—and not necessarily in thirsty flies. But in trying to understand the former, he has spent a lot of time studying the latter.

Reward systems depend on both obtaining a resource and learning to appreciate it. Drinking water is rewarding to thirsty animals, but only because the act of drinking impacts the nervous system and controls water-seeking behavior. How it manages to do so has been largely unexplored.

In the case of flies, thirst completely rewires behavior. Water-sated flies avoid water; only those that have been deprived for at least six hours gravitate towards it. Waddell's group demonstrated that a specific subset of dopamine-using neurons are required for thirst to induce flies to value water, and that this valuation depends on the flies' sensing of water vapor.