Yamamoto Dorothy J, Woo Choong-Wan, Wager Tor D, Regner Michael F, Tanabe Jody
Department of Radiology, University of Colorado Anschutz Medical Campus, 12700 E, 19th Avenue Mail Stop C278, Aurora, CO, 80045, USA.
Department of Psychology and Neuroscience, University of Colorado Boulder, Boulder, CO, 80309, USA.
Drug Alcohol Depend. 2015 Apr 1;149:10-7. doi: 10.1016/j.drugalcdep.2014.12.026. Epub 2015 Feb 16.
Alterations in frontal and striatal function are hypothesized to underlie risky decision making in drug users, but how these regions interact to affect behavior is incompletely understood. We used mediation analysis to investigate how prefrontal cortex and ventral striatum together influence risk avoidance in abstinent drug users.
Thirty-seven abstinent substance-dependent individuals (SDI) and 43 controls underwent fMRI while performing a decision-making task involving risk and reward. Analyses of a priori regions-of-interest tested whether activity in dorsolateral prefrontal cortex (DLPFC) and ventral striatum (VST) explained group differences in risk avoidance. Whole-brain analysis was conducted to identify brain regions influencing the negative VST-risk avoidance relationship.
Right DLPFC (RDLPFC) positively mediated the group-risk avoidance relationship (p < 0.05); RDLPFC activity was higher in SDI and predicted higher risk avoidance across groups, controlling for SDI vs.
Conversely, VST activity negatively influenced risk avoidance (p < 0.05); it was higher in SDI, and predicted lower risk avoidance. Whole-brain analysis revealed that, across group, RDLPFC and left temporal-parietal junction positively (p ≤ 0.001) while right thalamus and left middle frontal gyrus negatively (p < 0.005) mediated the VST activity-risk avoidance relationship.
RDLPFC activity mediated less risky decision making while VST mediated more risky decision making across drug users and controls. These results suggest a dual pathway underlying decision making, which, if imbalanced, may adversely influence choices involving risk. Modeling contributions of multiple brain systems to behavior through mediation analysis could lead to a better understanding of mechanisms of behavior and suggest neuromodulatory treatments for addiction.
额叶和纹状体功能改变被认为是吸毒者冒险决策的基础，但这些区域如何相互作用以影响行为尚不完全清楚。我们使用中介分析来研究前额叶皮质和腹侧纹状体如何共同影响戒毒者的风险规避。
37名戒毒的物质依赖个体（SDI）和43名对照者在进行涉及风险和奖励的决策任务时接受功能磁共振成像（fMRI）检查。对预先设定的感兴趣区域进行分析，以检验背外侧前额叶皮质（DLPFC）和腹侧纹状体（VST）的活动是否能解释风险规避方面的组间差异。进行全脑分析以确定影响VST与风险规避之间负相关关系的脑区。
右侧DLPFC（RDLPFC）正向介导了组与风险规避之间的关系（p < 0.05）；SDI组的RDLPFC活动更高，并预测了各组更高的风险规避，同时控制了SDI与对照组的差异。相反，VST活动对风险规避有负面影响（p < 0.05）；SDI组的VST活动更高，并预测了更低的风险规避。全脑分析显示，在各组中，RDLPFC和左侧颞顶叶交界处正向（p ≤ 0.001），而右侧丘脑和左侧额中回负向（p < 0.005）介导了VST活动与风险规避之间的关系。
在吸毒者和对照者中，RDLPFC活动介导了风险较低的决策，而VST介导了风险较高的决策。这些结果表明决策存在双重途径，如果失衡，可能会对涉及风险的选择产生不利影响。通过中介分析对多个脑系统对行为的贡献进行建模，可能有助于更好地理解行为机制，并为成瘾提出神经调节治疗方法。
