Greening Steven G, Mitchell Derek G V
Department of Psychology, Louisiana State University, Baton Rouge, Louisiana, USA.
Department of Psychiatry, Schulich School of Medicine and Dentistry, University of Western Ontario, London, Ontario, Canada.
Hum Brain Mapp. 2015 Dec;36(12):4819-30. doi: 10.1002/hbm.22952. Epub 2015 Sep 10.
In this study we demonstrate that the pattern of an amygdala-centric network contributes to individual differences in trait anxiety. Individual differences in trait anxiety were predicted using maximum likelihood estimates of amygdala structural connectivity to multiple brain targets derived from diffusion-tensor imaging (DTI) and probabilistic tractography on 72 participants. The prediction was performed using a stratified sixfold cross validation procedure using a regularized least square regression model. The analysis revealed a reliable network of regions predicting individual differences in trait anxiety. Higher trait anxiety was associated with stronger connections between the amygdala and dorsal anterior cingulate cortex, an area implicated in the generation of emotional reactions, and inferior temporal gyrus and paracentral lobule, areas associated with perceptual and sensory processing. In contrast, higher trait anxiety was associated with weaker connections between amygdala and regions implicated in extinction learning such as medial orbitofrontal cortex, and memory encoding and environmental context recognition, including posterior cingulate cortex and parahippocampal gyrus. Thus, trait anxiety is not only associated with reduced amygdala connectivity with prefrontal areas associated with emotion modulation, but also enhanced connectivity with sensory areas. This work provides novel anatomical insight into potential mechanisms behind information processing biases observed in disorders of emotion.
在本研究中，我们证明了以杏仁核为中心的网络模式导致了特质焦虑的个体差异。我们使用扩散张量成像（DTI）和概率纤维束成像技术，对72名参与者的杏仁核与多个脑区目标的结构连接性进行最大似然估计，以此预测特质焦虑的个体差异。预测采用分层六重交叉验证程序，并使用正则化最小二乘回归模型。分析揭示了一个可靠的脑区网络，可预测特质焦虑的个体差异。特质焦虑程度较高与杏仁核与背侧前扣带回皮质（一个与情绪反应产生有关的区域）、颞下回和中央旁小叶（与感知和感觉处理相关的区域）之间更强的连接有关。相反，特质焦虑程度较高与杏仁核与涉及消退学习的区域（如内侧眶额皮质）以及与记忆编码和环境背景识别相关的区域（包括后扣带回皮质和海马旁回）之间较弱的连接有关。因此，特质焦虑不仅与杏仁核与与情绪调节相关的前额叶区域的连接减少有关，还与与感觉区域的连接增强有关。这项工作为在情绪障碍中观察到的信息处理偏差背后的潜在机制提供了新的解剖学见解。
