Neuroscientists have for the first time shown individual mouse brain cells being switched on during learning and later reactivated during memory recall. We store episodic memories about events in our lives in a part of a brain called the hippocampus, said Brian Wiltgen, now an assistant professor at the Center for Neuroscience and department of psychology at UC Davis. (Most of the work was conducted while Wiltgen was working at the University of Virginia.)