Assessing Cue-Induced Brain Response as a Function of Abstinence Duration in Heroin-Dependent Individuals: An Event-Related fMRI Study

The brain activity induced by heroin-related cues may play a role in the maintenance of heroin dependence. Whether the reinforcement or processing biases construct an everlasting feature of heroin addiction remains to be resolved. We used an event-related fMRI paradigm to measure brain activation in response to heroin cue-related pictures versus neutral pictures as the control condition in heroin-dependent patients undergoing short-term and long-term abstinence. The self-reported craving scores were significantly increased after cue exposure in the short-term abstinent patients (t = 3.000, P = 0.008), but no increase was found in the long-term abstinent patients (t = 1.510, P = 0.149). However, no significant differences in cue-induced craving changes were found between the two groups (t = 1.193, P = 0.850). Comparing between the long-term abstinence and short-term abstinence groups, significant decreases in brain activation were detected in the bilateral anterior cingulated cortex, left medial prefrontal cortex, caudate, middle occipital gyrus, inferior parietal lobule and right precuneus. Among all of the heroin dependent patients, the abstinence duration was negatively correlated with brain activation in the left medial prefrontal cortex and left inferior parietal lobule. These findings suggest that long-term abstinence may be useful for heroin-dependent patients to diminish their saliency value of heroin-related cues and possibly lower the relapse vulnerability to some extent.海洛因相关线索诱发的脑活动可能在海洛因依赖的维持中发挥作用。目前尚不清楚强化偏向与加工偏向是否构成海洛因成瘾的持久特征，这一问题仍有待解决。我们采用事件相关功能磁共振成像（event-related fMRI）范式，对接受短期戒断与长期戒断的海洛因依赖患者，在海洛因线索相关图片相较于中性对照图片时的脑激活情况进行了测量。自我报告的渴求评分在线索暴露后的短期戒断患者中显著升高（t=3.000，P=0.008），但在长期戒断患者中未出现升高（t=1.510，P=0.149）。然而，两组间线索诱发的渴求变化未发现显著差异（t=1.193，P=0.850）。对比长期戒断组与短期戒断组，双侧前扣带回皮层、左侧内侧前额叶皮层、尾状核、枕中回、顶下小叶以及右侧楔前叶的脑激活水平出现显著降低。在所有海洛因依赖患者中，戒断时长与左侧内侧前额叶皮层及左侧顶下小叶的脑激活水平呈负相关。上述研究结果表明，长期戒断或可帮助海洛因依赖患者降低海洛因相关线索的显著性价值，并在一定程度上降低复发易感性。