In the brainstem's rostral ventrolateral medulla, a small cluster of cells called C1 neurons has been found to reliably kindle anxiety-like states in mice — a discovery that quietly challenges the assumption that fear and dread require the full orchestra of the brain to play at once. Researchers at the University of Nebraska, publishing in Neuron, used a novel pairing of genetic tools to isolate these neurons with unprecedented precision, switching them on and off with light to observe how profoundly a single cell type can shape an animal's relationship with open space, threat, and safety. The