Department of Psychiatry and Psychotherapy, Technische Universität Dresden, Germany.
Neuroimaging Center, Technische Universität Dresden, Germany.
Addict Biol. 2018 Jan;23(1):379-393. doi: 10.1111/adb.12490. Epub 2017 Jan 23.
Alcohol dependence is a mental disorder that has been associated with an imbalance in behavioral control favoring model-free habitual over model-based goal-directed strategies. It is as yet unknown, however, whether such an imbalance reflects a predisposing vulnerability or results as a consequence of repeated and/or excessive alcohol exposure. We, therefore, examined the association of alcohol consumption with model-based goal-directed and model-free habitual control in 188 18-year-old social drinkers in a two-step sequential decision-making task while undergoing functional magnetic resonance imaging before prolonged alcohol misuse could have led to severe neurobiological adaptations. Behaviorally, participants showed a mixture of model-free and model-based decision-making as observed previously. Measures of impulsivity were positively related to alcohol consumption. In contrast, neither model-free nor model-based decision weights nor the trade-off between them were associated with alcohol consumption. There were also no significant associations between alcohol consumption and neural correlates of model-free or model-based decision quantities in either ventral striatum or ventromedial prefrontal cortex. Exploratory whole-brain functional magnetic resonance imaging analyses with a lenient threshold revealed early onset of drinking to be associated with an enhanced representation of model-free reward prediction errors in the posterior putamen. These results suggest that an imbalance between model-based goal-directed and model-free habitual control might rather not be a trait marker of alcohol intake per se.
酒精依赖是一种精神障碍，与行为控制失衡有关，这种失衡有利于无模型的习惯性策略，而不利于基于模型的目标导向策略。然而，目前尚不清楚这种失衡是反映了一种易感性倾向，还是由于反复和/或过度饮酒暴露所致。因此，我们在一项两步连续决策任务中，在功能磁共振成像的同时，检查了 188 名 18 岁的社交饮酒者的酒精消费与基于模型的目标导向和无模型习惯控制之间的关系，在这种任务中，参与者在经历长时间的滥用酒精可能导致严重的神经生物学适应之前，他们的饮酒量适中。行为上，参与者表现出混合的无模型和基于模型的决策，如前所述。冲动性测量与酒精消费呈正相关。相比之下，无模型或基于模型的决策权重，以及它们之间的权衡，都与酒精消费无关。在腹侧纹状体或腹内侧前额叶皮层中，酒精消费与无模型或基于模型决策量的神经相关物之间也没有显著关联。使用宽松阈值的全脑功能磁共振成像分析显示，饮酒的早期发作与后纹状体中无模型奖励预测误差的增强表示有关。这些结果表明，基于模型的目标导向和无模型习惯控制之间的失衡可能不是酒精摄入本身的特征性标记。
