These results were reported in the left DLPFC, left medial frontal gyrus and right subcallosal gyrus (Brodmann area 34) in young cigarette smokers27, and in bilateral DLPFC and ACC in short-term28 and long-term29 abstinent alcoholics. Similar increases were reported in studies (including PET FDG studies) of cocaine-addicted individuals watching cocaine-related videos30 and of heavy smokers watching cigarette-related videos while handling a cigarette31. Often, there are no differences between addicted and non-addicted individuals in valence or arousal ratings, or even in autonomic reactions (for example, skin conductance responses) to the drug-related cues29, which suggests that neuroimaging measures are more sensitive in detecting group differences in conditioned responses to drug-related cues. Importantly, cue-induced PFC responses were correlated with craving31 and severity of drug use27, and predicted both subsequent performance on a primed emotion recognition task32 and drug use 3 months later29, indicating that these measures have clinical relevance. As no PFC activation was elicited by drug-related masked cues33 (which activated subcortical regions instead34), these effects may only be induced when drug-related cues are consciously perceived, but this needs to be studied further.
