Alterations in white matter integrity have been demonstrated in a number of psychiatric disorders involving emotional disruptions. One such pathway – the uncinate fasciculus – connects the orbitofrontal cortex (OFC) to the medial temporal lobes (MTL) and has been associated with early life adversity, maltreatment, anxiety, and depression. While it is purported to play a role in episodic memory and discrimination, its exact function remains poorly understood. We have previously described the role of the amygdala and dentate (DG)/CA3 fields of the hippocampus in the mnemonic discrimination of emotional experiences (i.e. emotional pattern separation). However, how this computation may be modulated by connectivity with the orbitofrontal cortex remains unknown. Here we asked if the uncinate fasciculus plays a role in influencing MTL subregional activity during emotional pattern separation. By combining diffusion imaging with high-resolution fMRI, we found that reduced integrity of the UF is related to elevated BOLD fMRI activation of the DG/CA3 subregions of the hippocampus during emotional lure discrimination. We additionally report that higher levels of DG/CA3 activity are associated with poorer memory performance, suggesting that greater activation in this network (possibly driven by CA3 recurrent collaterals) is associated with memory errors. Based on this work we suggest that the UF is one pathway that may allow the OFC to exert control on this network and improve discrimination of emotional experiences, although further work is necessary to fully evaluate this possibility. This work provides novel insight into the role of prefrontal interactions with the MTL, particularly in the context of emotional memory.

白质完整性的改变已在许多涉及情绪紊乱的精神障碍中得到证实。一种这样的途径——钩状束——将眶额皮质 (OFC) 连接到内侧颞叶 (MTL)，并与早年的逆境、虐待、焦虑和抑郁有关。虽然据称它在情景记忆和辨别方面发挥作用，但其确切功能仍然知之甚少。我们之前已经描述了海马的杏仁核和齿状核 (DG)/CA3 场在情绪体验的助记识别（即情绪模式分离）中的作用。然而，如何通过与眶额皮层的连接来调节这种计算仍然未知。在这里，我们询问钩状束是否在情感模式分离过程中影响 MTL 子区域活动中起作用。通过将扩散成像与高分辨率 fMRI 相结合，我们发现 UF 完整性的降低与情绪诱惑歧视期间海马 DG/CA3 亚区的 BOLD fMRI 激活升高有关。我们还报告说，较高水平的 DG/CA3 活动与较差的记忆性能相关，这表明该网络中更大的激活（可能由 CA3 循环侧支驱动）与记忆错误相关。基于这项工作，我们建议 UF 是一种可能允许 OFC 对该网络施加控制并改善对情绪体验的歧视的途径，尽管需要进一步的工作来充分评估这种可能性。