The prefrontal cortex and limbic system are important components of the neural circuit that underlies stress and anxiety. These brain regions are connected by white matter tracts that support neural communication including the cingulum, uncinate fasciculus, and the fornix/stria-terminalis. Determining the relationship between stress reactivity and these white matter tracts may provide new insight into factors that underlie stress susceptibility and resilience. Therefore, the present study investigated sex differences in the relationship between stress reactivity and generalized fractional anisotropy (GFA) of the white matter tracts that link the prefrontal cortex and limbic system. Diffusion weighted images were collected and deterministic tractography was completed in 104 young adults (55 men, 49 women; mean age = 18.87 SEM = 0.08). Participants also completed self-report questionnaires (e.g., Trait Anxiety) and donated saliva (later assayed for cortisol) before, during, and after the Trier Social Stress Test. Results revealed that stress reactivity (area under the curve increase in cortisol) and GFA of the cingulum bundle varied by sex. Specifically, men demonstrated greater cortisol reactivity and greater GFA within the cingulum than women. Further, an interaction between sex, stress reactivity, and cingulum GFA was observed in which men demonstrated a positive relationship while women demonstrated a negative relationship between GFA and cortisol reactivity. Finally, trait anxiety was positively associated with the GFA of the fornix/stria terminalis – the white matter pathways that connect the hippocampus/amygdala to the hypothalamus. These findings advance our understanding of factors that underlie individual differences in stress reactivity.

前额叶皮层和边缘系统是构成压力和焦虑的神经回路的重要组成部分。这些大脑区域由支持神经交流的白质束连接，包括扣带、钩束和穹窿/终纹。确定压力反应性和这些白质束之间的关系可能会为了解压力易感性和恢复力的潜在因素提供新的见解。因此，本研究调查了连接前额叶皮层和边缘系统的白质束的压力反应性和广义分数各向异性 (GFA) 之间关系的性别差异。收集了扩散加权图像，并在 104 名年轻人（55 名男性，49 名女性；平均年龄 = 18.87 SEM = 0.08）中完成了确定性纤维束成像。参与者还在特里尔社会压力测试之前、期间和之后完成了自我报告问卷（例如，特质焦虑）并捐赠了唾液（后来检测了皮质醇）。结果显示，扣带束的应激反应性（皮质醇曲线下面积增加）和 GFA 因性别而异。具体而言，男性在扣带回中表现出比女性更高的皮质醇反应性和更大的 GFA。此外，观察到性别、压力反应和扣带回 GFA 之间的相互作用，其中男性表现出正相关关系，而女性表现出 GFA 和皮质醇反应性之间的负相关关系。最后，特质焦虑与穹窿/终纹的 GFA 呈正相关——连接海马/杏仁核和下丘脑的白质通路。