Gambling disorder is a behavioral addiction associated with impairments in value-based decision-making and behavioral flexibility and might be linked to changes in the dopamine system. Maximizing long-term rewards requires a flexible trade-off between the exploitation of known options and the exploration of novel options for information gain. This exploration-exploitation trade-off is thought to depend on dopamine neurotransmission. We hypothesized that human gamblers would show a reduction in directed (uncertainty-based) exploration, accompanied by changes in brain activity in a fronto-parietal exploration-related network. Twenty-three frequent, non-treatment seeking gamblers and twenty-three healthy matched controls (all male) performed a four-armed bandit task during functional magnetic resonance-imaging. Computational modeling using hierarchical Bayesian parameter estimation revealed signatures of directed exploration, random exploration, and perseveration in both groups. Gamblers showed a reduction in directed exploration, whereas random exploration and perseveration were similar between groups. Neuroimaging revealed no evidence for group differences in neural representations of basic task variables (expected value, prediction errors). Our hypothesis of reduced frontal pole recruitment in gamblers was not supported. Exploratory analyses revealed that during directed exploration, gamblers showed reduced parietal cortex and substantia-nigra / ventral-tegmental-area activity. Cross-validated classification analyses revealed that connectivity in an exploration-related network was predictive of group status, suggesting that connectivity patterns might be more predictive of problem gambling than univariate effects. Findings reveal specific reductions in strategic exploration gamblers that might be linked to altered processing in a fronto-parietal network and/or changes in dopamine neurotransmission implicated in gambling disorder.

中文翻译：

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赌博障碍强化学习过程中的衰减定向探索

赌博性疾病是一种行为上瘾，与基于价值的决策制定和行为灵活性受损有关，可能与多巴胺系统的变化有关。要最大限度地提高长期回报，就需要在利用已知期权和探索新颖期权之间进行灵活的权衡，以获取信息。人们认为这种探索与开发的取舍取决于多巴胺的神经传递。我们假设人类赌徒将表现出定向（基于不确定性）探索的减少，并伴随额顶探索相关网络中大脑活动的变化。在功能性磁共振成像过程中，二十三名频繁的，不接受治疗的赌徒和二十三名健康的匹配对照者（均为男性）执行了四臂匪徒的任务。使用分层贝叶斯参数估计的计算模型揭示了两组的定向勘探，随机勘探和坚持的特征。赌徒的定向探索减少，而各组之间的随机探索和坚持则相似。神经影像学显示没有证据表明基本任务变量的神经表征（预期值，预测误差）存在群体差异。我们关于减少赌徒额极招募的假设没有得到支持。探索性分析表明，在定向探索过程中，赌徒的大脑顶叶皮层和黑质/腹侧被膜区活动减少。交叉验证的分类分析表明，与勘探相关的网络中的连通性可预测群体状态，提示连通性模式可能比单变量效应更能预测问题赌博。研究结果揭示了战略探索赌徒的具体减少，这可能与额顶网络中加工过程的改变和/或与赌博疾病有关的多巴胺神经传递的改变有关。