A brain circuit to control alcohol intake Most people are exposed to alcohol at some point in their lives, but only a small fraction will develop a compulsive drinking disorder. Siciliano et al. first established a behavioral measure to assess how predisposition interacts with experience to produce compulsive drinking in a subset of mice (see the Perspective by Nixon and Mangieri). In search of the underlying neurobiological mechanism, they discovered that a discrete circuit between the medial prefrontal cortex and brainstem is central for the development of compulsive drinking. This circuit serves as both a biomarker for the development of compulsive drinking and a driver of its expression. It can bidirectionally control compulsive behavior by mitigating or mimicking punishment signals. Science , this issue p. 1008 ; see also p. 947