PFC activation to relevant cues has also been reported in behavioural addictions. For example, young males who played internet games for over 30 hours a week showed BOLD activations in OFC, ACC, medial PFC and DLPFC when viewing pictures of the game, and these activations were correlated with the urge to play39. Similarly, compared to control subjects, pathological gamblers watching gambling videos showed increased activation in right DLPFC and inferior frontal gyrus40, and this activation correlated with the urge to gamble41. By contrast, another study in pathological gamblers showed reduced left ventromedial PFC BOLD responses to winning versus losing in a gambling-like task, and the size of the reduction was correlated with the severity of the gambling addiction, as assessed with a gambling questionnaire42. The opposite directions of the activity changes (hyperactivations versus hypoactivations as compared to controls) may be driven by the ROI (for example, ventromedial PFC task-related deactivations are often seen and have been attributed to the role of the ‘default brain’ network43), differences in craving (craving was reported in REFS 39–41 but not REF. 42), task differences or methodological factors, which are summarized at the end of this section.
