School of Psychological and Cognitive Sciences and Beijing Key Laboratory of Behavior and Mental Health, Peking University, Beijing 100871, China; Center for Brain and Cognitive Sciences, Peking University, Beijing 100871, China.
School of Psychological and Cognitive Sciences and Beijing Key Laboratory of Behavior and Mental Health, Peking University, Beijing 100871, China.
Neuroimage. 2016 Dec;143:343-352. doi: 10.1016/j.neuroimage.2016.09.006. Epub 2016 Sep 6.
In intertemporal choice (ITC), people discount future rewards in proportion to the time delay until reward receipt. Despite recent non-invasive brain stimulation studies suggesting a general causal link between dorsolateral prefrontal cortex (dlPFC) activity and ITC impulsivity, results regarding the functional specificity of dlPFC are mixed. We used high-definition transcranial direct current stimulation (HD-tDCS) to map changes in causal impulsivity through bi-directional modulation of left and right dlPFC during ITC. Model-free and model-based analyses demonstrated that anodal and cathodal stimulation of left dlPFC, but not right dlPFC, decreased and increased impulsivity, respectively. Critically, an individual differences analysis revealed that modulation of impulsivity was contingent on participants' baseline impulsivity. Overall, our results might reconcile the discrepancies in the existing literature and suggest a baseline-dependent role for left dlPFC during ITC.
在跨期选择 (ITC) 中，人们会根据获得奖励之前的时间延迟来按比例贴现未来奖励。尽管最近的非侵入性脑刺激研究表明背外侧前额叶皮层 (dlPFC) 的活动与 ITC 冲动性之间存在一般的因果关系，但关于 dlPFC 的功能特异性的结果却存在分歧。我们使用高清晰度经颅直流电刺激 (HD-tDCS) 通过在 ITC 期间对左、右 dlPFC 进行双向调制来映射因果冲动性的变化。无模型和基于模型的分析表明，左 dlPFC 的阳极和阴极刺激分别降低和增加了冲动性，而右 dlPFC 则没有。至关重要的是，个体差异分析表明，冲动性的调节取决于参与者的基线冲动性。总的来说，我们的结果可能调和了现有文献中的差异，并表明在 ITC 期间左 dlPFC 存在依赖于基线的作用。
