Division of Clinical Neuroscience and Behavioral Research, National Institute on Drug Abuse,National Institutes of Health, Bethesda, MD 20892, USA.
Hum Brain Mapp. 2012 Sep;33(9):2174-88. doi: 10.1002/hbm.21351.
Aberrant sensitivity of incentive neurocircuitry to nondrug rewards has been suggested as either a risk factor for or consequence of drug addiction. Using functional magnetic resonance imaging, we tested whether alcohol-dependent patients (ADP: n = 29) showed altered recruitment of ventral striatal (VS) incentive neurocircuitry compared to controls (n = 23) by: (1) cues to respond for monetary rewards, (2) post-response anticipation of rewards, or (3) delivery of rewards. Using an instrumental task with two-stage presentation of reward-predictive information, subjects saw cues signaling opportunities to win $0, $1, or $10 for responding to a target. Following this response, subjects were notified whether their success would be indicated by a lexical notification (“Hit?”) or by delivery of a monetary reward (“Win?”). After a variable interval, subjects then viewed the trial outcome. We found no significant group differences in voxelwise activation by task contrasts, or in signal change extracted from VS. Both ADP and controls showed significant VS and other limbic recruitment by pre-response reward anticipation. In addition, controls also showed VS recruitment by post-response reward-anticipation, and ADP had appreciable subthreshold VS activation. Both groups also showed similar mesolimbic responses to reward deliveries. Across all subjects, a questionnaire measure of “hot” impulsivity correlated with VS recruitment by post-response anticipation of low rewards and with VS recruitment by delivery of low rewards. These findings indicate that incentive-motivational processing of nondrug rewards is substantially maintained in recovering alcoholics, and that reward-elicited VS recruitment correlates more with individual differences in trait impulsivity irrespective of addiction.
奖赏神经回路对非药物奖赏的异常敏感，被认为是成瘾的风险因素或结果。我们使用功能磁共振成像，通过以下三种方式测试酒精依赖患者（ADP：n = 29）与对照组（n = 23）相比，是否存在腹侧纹状体（VS）奖赏神经回路募集的改变：（1）响应货币奖励的线索，（2）响应后对奖励的预期，或（3）奖励的传递。使用具有两阶段呈现奖励预测信息的工具任务，被试看到线索，表示有机会通过响应目标赢得 0 美元、1 美元或 10 美元。在这次响应之后，被试会被告知他们的成功是通过词汇通知（“Hit？”）还是通过货币奖励的传递（“Win？”）来指示。在一个可变的间隔后，被试会查看试验结果。我们没有发现任务对比中脑区激活或 VS 信号变化存在显著的组间差异。ADP 和对照组在预响应奖励预期时都显示出 VS 和其他边缘系统的显著募集。此外，对照组在响应后奖励预期时也显示出 VS 募集，而 ADP 则显示出明显的亚阈值 VS 激活。两组都显示出类似的中脑边缘对奖励传递的反应。在所有被试中，“热”冲动性的问卷测量与低奖励响应后预期时的 VS 募集以及低奖励传递时的 VS 募集呈正相关。这些发现表明，非药物奖赏的激励动机加工在康复中的酗酒者中得到了很大的维持，并且奖励引起的 VS 募集与个体特质冲动性的差异更相关，而与成瘾无关。
