Yuki Oka, an assistant professor of biology and Chen Scholar at Caltech, wanted to better understand how the brain processes satiation and pleasure signals related to drinking. He was curious for example why, after you have exercised on a hot day, a cool glass of water will quench your thirst immediately—even before your body has had a chance to absorb the water. In a new paper, Oka shows that thirst satiation is governed by two independent pathways in the mammalian body and brain. These pathways work together to help keep animals properly rehydrated.