Drug cravings can be brought on by many factors, such as the sight of drugs, drug availability and lack of self-control. Now, researchers have uncovered some of the neural mechanisms involved in cigarette craving . Two brain areas, the orbitofrontal cortex and the prefrontal cortex, interact to turn cravings on or off depending on whether drugs are available, the study reports today (Jan. 28) in the journal the Proceedings of the National Academy of Sciences.