Department of Systems Neuroscience, University Medical Center Hamburg-Eppendorf, 20246 Hamburg, Germany, Department of Clinical Psychology, Psychotherapy and Health Psychology, Institute of Psychology, University of Salzburg, 5020 Salzburg, Austria, Department of Psychology, Stanford University, Stanford, California 94305, and Helen Wills Neuroscience Institute, University of California, Berkeley, California 94720.
J Neurosci. 2014 Mar 26;34(13):4750-5. doi: 10.1523/JNEUROSCI.5020-13.2014.
Impulsive behavior such as steep temporal discounting is a hallmark of addiction and is associated with relapse. In pathological gamblers, discounting may be further increased by the presence of gambling-related cues in the environment, but the extent to which the gambling relatedness of task settings affects reward responses in gambling addiction is debated. In the present study, human problem gamblers made choices between immediate rewards and individually tailored larger-but-later rewards while visual gambling-related scenes were presented in the background. N = 17 participants were scanned using fMRI, whereas N = 5 additional participants completed a behavioral version of the task. Postscan craving ratings were acquired for each image, and behavioral and neuroimaging data were analyzed separately for high- and low-craving trials (median split analysis). Discounting was steeper for high versus low craving trials. Neuroimaging revealed a positive correlation with model-based subjective value in midbrain and striatum in low-craving trials that was reversed in high-craving trials. These findings reveal a modulation of striatal reward responses in gamblers by addiction-related cues, and highlight a potentially important mechanism that may contribute to relapse. Cue-induced changes in striatal delayed reward signals may lead to increased discounting of future rewards, which might in turn affect the likelihood of relapse.
冲动行为，如陡峭的时间折扣，是成瘾的一个标志，与复发有关。在病态赌徒中，环境中存在与赌博相关的线索可能会进一步增加折扣，但是任务环境中与赌博的相关性对赌博成瘾的奖励反应的影响程度存在争议。在本研究中，人类问题赌徒在即时奖励和个性化的更大但更晚的奖励之间做出选择，同时在背景中呈现视觉上与赌博相关的场景。N = 17 名参与者接受 fMRI 扫描，而 N = 5 名额外的参与者完成了任务的行为版本。对每张图像进行了扫描后的渴望评分，并分别对高渴望和低渴望试验（中位数分割分析）进行了行为和神经影像学数据分析。高渴望试验的折扣率高于低渴望试验。神经影像学显示，在低渴望试验中，中脑和纹状体与基于模型的主观价值呈正相关，而在高渴望试验中则相反。这些发现揭示了成瘾相关线索对赌徒纹状体奖励反应的调节作用，并强调了可能导致复发的一个重要机制。线索引起的延迟奖励信号变化可能导致对未来奖励的折扣增加，这反过来可能影响复发的可能性。
