Posted on by Dr. Francis Collins
Whether it’s Rockefeller Center, the White House, or somewhere else across the land, ‘tis the season to gather with neighbors for a communal holiday tree-lighting ceremony. But this festive image has more do with those cups of cider in everyone’s hands than admiring the perfect Douglas fir. What looks like lights and branches are actually components of a high-resolution map from a part of the brain that controls thirst.
The map, drawn up from mouse studies, shows that when thirst arises, neurons activate a gene called c-fos (red)—lighting up the tree—indicating it’s time for a drink. In response, other neurons (green) direct additional parts of the brain to compensate by managing internal water levels. In a mouse that’s no longer thirsty, the tree would look almost all green.
This wiring map comes from a part of the brain called the hypothalamus, which is best known for its role in hunger, thirst, and energy balance. Thanks to powerful molecular tools from NIH’s Brain Research through Advancing Innovative Technologies (BRAIN) Initiative, Yuki Oka of the California Institute of Technology, Pasadena, and his team were able to draw detailed maps of the tree-shaped region, called the median preoptic nucleus (MnPO).
Using a technique called optogenetics, Oka’s team, led by Vineet Augustine, could selectively turn on genes in the MnPO . By doing so, they could control a mouse’s thirst and trace the precise control pathways responsible for drinking or not.
This holiday season, as you gather with loved ones, take a moment to savor the beautiful complexity of biology and the gift of human health. Happy holidays to all of you, and peace and joy into the new year!
 Hierarchical neural architecture underlying thirst regulation. Augustine V, Gokce SK, Lee S, Wang B, Davidson TJ, Reimann F, Gribble F, Deisseroth K, Lois C, Oka Y. Nature. 2018 Mar 8;555(7695):204-209.
Oka Lab, California Institute of Technology, Pasadena
The BRAIN Initiative (NIH)
NIH Support: National Institute of Neurological Disorders and Stroke