For many people battling addictions, seeing drug paraphernalia—or even places associated with past use—can ignite cravings that make relapse more likely. Associating environmental cues with pleasurable experiences is a basic form of learning, but some researchers think such associations can “hijack” behavior, contributing to problems such as addiction and eating disorders.

Researchers led by neuroscientist Shelly Flagel of the University of Michigan have found a brain circuit that may control this hijacking; rats that exhibit a type of compulsive behavior show different brain connectivity and activity than those that do not, and manipulation of the circuit altered their behavior. These findings may help researchers understand why some individuals are more susceptible to impulse-control disorders. “This is technically a really excellent study,” says neuroscientist Jeff Dalley of the University of Cambridge, who was not involved in the work.

In the study, published last September in eLife, researchers showed rats an inert lever shortly before delivering a tasty treat via a chute, then sorted them into groups based on their responses. All rats learned to associate the lever with the treat, but some—dubbed “goal trackers”—began to approach the food chute directly after seeing the lever, whereas inherent “sign trackers” kept compulsively returning to the lever itself.

Read the full article at Scientific American.