调控方式影响跨期选择的神经基础:内侧前额叶的中介作用  

The neural basis of the effect of regulatory mode on intertemporal choice:the mediating role of mPFC

作　　者：郭逸群[1] 冯廷勇[1,2] 

机构地区：[1]西南大学心理学与社会发展研究中心,重庆400715 [2]西南大学心理学部认知与人格教育部重点实验室,重庆400715

出　　处：《科学通报》2016年第32期3498-3508,共11页Chinese Science Bulletin

基　　金：重庆市人文社会科学重点研究基地重点项目(16SKB007);中央高校基本科研业务费专项(SWU1609321);国家自然科学基金(31271117;31571128);中央高校基本科研业务经费创新团队项目(SWU1509392)资助

摘　　要：跨期选择(intertemporal choice)是指个体对发生在不同时间点的成本与收益进行权衡,进而做出的各种判断和选择.先前的研究表明,个体在长久生活中所形成的调控方式("评估"和"行动"定向)会对跨期选择产生影响,然而调控方式影响跨期选择的认知神经机制依然不清楚.为此,本研究试图采用功能性磁共振成像(f MRI)技术考察调控方式影响跨期选择的神经基础.行为结果发现,"评估"定向者比"行动"定向者表现出更小的延迟折扣率;被试的"评估"定向得分和延迟折扣率成负相关,而"行动"定向得分和延迟折扣率呈正相关.脑成像的结果发现,表征延迟奖赏主观价值的内侧前额叶的激活水平与"评估"定向得分成显著的正相关,而与"行动"定向得分存在显著的负相关;进一步的中介分析表明,表征主观价值的内侧前额叶在调控方式与延迟折扣之间存在显著的部分中介效应.这些结果说明,调控方式对跨期选择的影响可能是通过改变延迟奖赏的主观价值来实现的,而表征主观价值的内侧前额叶则是其神经基础.Decisions that involve tradeoffs between outcomes that occur at different points in time are called intertemporal choice. A consistent finding regarding intertemporal choice is that delayed outcomes are discounted relative to immediate ones. The extent of preference for delayed rewards is captured by delay discounting rate, which expresses that the subjective value of a delayed reward declines as a function of delay. It is generally thought that people are fairly stable in their intertemporal preference, and it has been suggested that they may have a genetic component. Previous studies have shown that the chronic regulatory mode orientation can affect intertemporal choice. Steeper delay discounting is related to lower assessment orientation, while related to higher locomotion orientation. However, the cognitive and neural mechanism of the effect of regulatory mode on intertemporal choice is still unclear. Recent neuroimaging studies have identified a valuation network （such as ventral striatum, posterior cingulate cortex, and medial prefrontal cortex） in delay discounting, which is the neural computation and representation of the subjective values of rewards. Thus, we investigated the role of the valuation network in the relation between regulatory mode and delay discounting. In the present study, we used functional magnetic resonance imaging （fMRI） to investigate the neural basis of this effect. We used two different approaches to examine the link between regulatory mode and delay discounting. First, we split participants into two groups of assessors and locomotors according to relative strength of regulatory orientations, and compared the difference between the two groups. We found that locomotors showed a steeper delay discounting than assessors. Our second approach examined this effect in a continuous rather than a categorical manner. Correlation results showed that delay discounting was negatively correlated with assessment scores, but positively correlated with locomotion scores. These behavioral f

关 键 词：跨期选择 调控方式 评估定向 行动定向 内侧前额叶 功能性磁共振成像(fMRI) 

分 类 号：B842[哲学宗教—基础心理学] R338[哲学宗教—心理学]