by Guanhua Sun, Tomoyuki Mano, Shoi Shi, Alvin Li, Koji L Ode, Alex Rosi-Andersen, Erica Pedron, Steven A. Brown, Hiroki R Ueda, Konstantinos Kompotis, Daniel B. Forger The mouse brain’s activity changes drastically over a day despite being generated from the same neurons and physical connectivity. To better understand this, we develop an experimental-computational pipeline to determine which neurons and networks are most active at different times of the day. We genetically mark active neurons