Kohno Milky, Morales Angelica M, Guttman Zoe, London Edythe D
Dept. of Psychiatry & Biobehavioral Sciences, University of California Los Angeles, Los Angeles, CA 90095, USA.
Neuroscience Interdepartmental Program, University of California Los Angeles, Los Angeles, CA 90095, USA.
Neuroimage. 2017 Apr 1;149:15-22. doi: 10.1016/j.neuroimage.2017.01.058. Epub 2017 Jan 25.
The ability to evaluate the balance between risk and reward and to adjust behavior accordingly is fundamental to adaptive decision-making. Although brain-imaging studies consistently have shown involvement of the dorsolateral prefrontal cortex, anterior insula and striatum during risky decision-making, activation in a neural network formed by these regions has not been linked to structural connectivity. Therefore, in this study, white-matter connectivity was measured with diffusion-weighted imaging in 40 healthy research participants who performed the Balloon Analogue Risk Task, a test of risky decision-making, during fMRI. Fractional anisotropy within a network that includes white-matter pathways connecting four regions (the prefrontal cortex, insula and midbrain to the striatum) was positively correlated with the number of risky choices and total amount earned on the task, and with the parametric modulation of activation in regions within the network to the level of risk during choice selection. Furthermore, analysis using a mixed model demonstrated how relationships of the parametric modulation of activation in each of the four aforementioned regions are related to risk probabilities, and how previous trial outcomes and task progression influence the choice to take risk. The present findings provide the first direct evidence that white-matter integrity is linked to function within previously identified components of a network that is activated during risky decision-making, and demonstrate that the integrity of white-matter tracts is critical in consolidating and processing signals between cortical and striatal circuits during the decision-making process.
评估风险与回报之间的平衡并据此调整行为的能力是适应性决策的基础。尽管脑成像研究一直表明，在风险决策过程中背外侧前额叶皮层、前岛叶和纹状体均有参与，但由这些区域构成的神经网络中的激活与结构连通性并无关联。因此，在本研究中，对40名健康研究参与者进行了扩散加权成像以测量白质连通性，这些参与者在功能磁共振成像（fMRI）期间执行了气球模拟风险任务（一项风险决策测试）。在一个包含连接四个区域（前额叶皮层、岛叶、中脑与纹状体）的白质通路的网络内，分数各向异性与风险选择的数量、任务中赚取的总金额以及网络内各区域激活对选择过程中风险水平的参数调制呈正相关。此外，使用混合模型的分析表明了上述四个区域中每个区域激活的参数调制与风险概率之间的关系，以及先前的试验结果和任务进展如何影响冒险选择。本研究结果提供了首个直接证据，表明白质完整性与在风险决策过程中被激活的先前确定的网络组件内的功能相关联，并表明白质束的完整性在决策过程中巩固和处理皮质与纹状体回路之间的信号方面至关重要。
