is most active. Support for such a concept comes from rodent studies that distinguish between approach and consumption (Czachowski & Samson, 1999), and where dopaminergic manipulation affects approach more than consumption (Czachowski et al., 2002; Czachowski, Chappell, & Samson, 2001). Moreover, genetic selection for drinking can affect appetitive and consumptive features differently (Czachowski & Samson, 2002). In humans, stimulus-provoked craving (appetitive drive) is also higher in individuals with the A118G variant of the OPRM1 (μ-opiod receptor) gene (van den Wildenberg et al., 2007). Similarly, subjects who tasted alcohol during fMRI had greater vmPFC fMRI activation if they possessed the DRD4 VNTR dopamine receptor gene variant or the A118G OPRM1 polymorphism (Filbey et al., 2008a). In our subjects, however, there were no overt group differences in craving.
