Advances in imaging technology have provided the field with an opportunity to refine and expand the conceptualization of phenotypes that lend themselves to the identification of genetic variations that influence the etiology of alcohol and drug dependence. For example, there have been a number of studies that have utilized functional magnetic resonance imaging (fMRI) technology to investigate craving for alcohol by examining the hemodynamic response of brain structures after exposure to alcohol cues.67-69 Specifically, one study has found that alcoholrelated stimuli increased activation in the prefrontal cortex and anterior thalamus,67 whereas another study noted activation in the prefrontal cortex and anterior limbic areas.68 Furthermore, a study utilizing alcohol odor as an alcohol cue found significant increases in activation of the cerebellum and amygdala in alcoholics, but not controls.69 These differences, however, were not observed after treatment and no evidence of a correlation between brain activation and subjective craving was presented.
