Garavan H, Pankiewicz J, Bloom A, Cho J K, Sperry L, Ross T J, Salmeron B J, Risinger R, Kelley D, Stein E A
Department of Psychiatry and Behavioral Medicine, Medical College of Wisconsin, Milwaukee 53226, USA.
Am J Psychiatry. 2000 Nov;157(11):1789-98. doi: 10.1176/appi.ajp.157.11.1789.
Cocaine-related cues have been hypothesized to perpetuate drug abuse by inducing a craving response that prompts drug-seeking behavior. However, the mechanisms, underlying neuroanatomy, and specificity of this neuroanatomy are not yet fully understood.
To address these issues, experienced cocaine users (N=17) and comparison subjects (N=14) underwent functional magnetic resonance imaging while viewing three separate films that portrayed 1 ) individuals smoking crack cocaine, 2) outdoor nature scenes, and 3) explicit sexual content. Candidate craving sites were identified as those that showed significant activation in the cocaine users when viewing the cocaine film. These sites were then required to show significantly greater activation when contrasted with comparison subjects viewing the cocaine film (population specificity) and cocaine users viewing the nature film (content specificity).
Brain regions that satisfied these criteria were largely left lateralized and included the frontal lobe (medial and middle frontal gyri, bilateral inferior frontal gyrus), parietal lobe (bilateral inferior parietal lobule), insula, and limbic lobe (anterior and posterior cingulate gyrus). Of the 13 regions identified as putative craving sites, just three (anterior cingulate, right inferior parietal lobule, and the caudate/lateral dorsal nucleus) showed significantly greater activation during the cocaine film than during the sex film in the cocaine users, which suggests that cocaine cues activated similar neuroanatomical substrates as naturally evocative stimuli in the cocaine users. Finally, contrary to the effects of the cocaine film, cocaine users showed a smaller response than the comparison subjects to the sex film.
These data suggest that cocaine craving is not associated with a dedicated and unique neuroanatomical circuitry; instead, unique to the cocaine user is the ability of learned, drug-related cues to produce brain activation comparable to that seen with nondrug evocative stimuli in healthy comparison subjects.
可卡因相关线索被认为会通过引发渴望反应来促使觅药行为，从而使药物滥用持续存在。然而，其潜在机制、相关神经解剖结构以及这种神经解剖结构的特异性尚未完全明确。
为解决这些问题，有经验的可卡因使用者（N = 17）和对照受试者（N = 14）在观看三部不同影片时接受功能磁共振成像检查，这三部影片分别描绘了：1）吸食快克可卡因的个体；2）户外自然场景；3）露骨的性内容。候选渴望部位被确定为那些在可卡因使用者观看可卡因影片时显示出显著激活的部位。然后要求这些部位在与观看可卡因影片的对照受试者（群体特异性）以及观看自然影片的可卡因使用者（内容特异性）进行对比时，显示出显著更强的激活。
满足这些标准的脑区大多位于左侧，包括额叶（内侧和额中回、双侧额下回）、顶叶（双侧顶下小叶）、岛叶和边缘叶（前扣带回和后扣带回）。在被确定为假定渴望部位的13个区域中，只有三个（前扣带回、右侧顶下小叶以及尾状核/外侧背核）在可卡因使用者观看可卡因影片时的激活程度显著高于观看性影片时，这表明可卡因线索在可卡因使用者中激活了与自然唤起刺激类似的神经解剖学底物。最后，与可卡因影片的效果相反，可卡因使用者对性影片的反应比对照受试者小。
这些数据表明，可卡因渴望并非与专门且独特的神经解剖回路相关；相反，可卡因使用者独有的能力是，习得的与药物相关的线索能够产生与健康对照受试者中非药物唤起刺激所见相当的脑激活。
