Emotional memories are better remembered than neutral ones, but the mechanisms leading to this memory bias are not well understood in humans yet. Based on animal research, it is suggested that the memory-enhancing effect of emotion is based on central noradrenergic release, which is triggered by afferent vagal nerve activation. To test the causal link between vagus nerve activation and emotional memory in humans, we applied continuous noninvasive transcutaneous auricular vagus nerve stimulation (taVNS) during exposure to emotional arousing and neutral scenes and tested subsequent, long-term recognition memory after 1 week. We found that taVNS, compared with sham, increased recollection-based memory performance for emotional, but not neutral, material. These findings were complemented by larger recollection-related brain potentials (parietal ERP Old/New effect) during retrieval of emotional scenes encoded under taVNS, compared with sham. Furthermore, brain potentials recorded during encoding also revealed that taVNS facilitated early attentional discrimination between emotional and neutral scenes. Extending animal research, our behavioral and neural findings confirm a modulatory influence of the vagus nerve in emotional memory formation in humans.

SIGNIFICANCE STATEMENT Emotionally relevant information elicits stronger and more enduring memories than nonrelevant information. Animal research has shown that this memory-enhancing effect of emotion is related to the noradrenergic activation in the brain, which is triggered by afferent fibers of the vagus nerve (VN). In the current study, we show that noninvasive transcutaneous auricular VN stimulation enhances recollection-based memory formation specifically for emotionally relevant information as indicated by behavioral and electrophysiological indices. These human findings give novel insights into the mechanisms underlying the establishment of emotional episodic memories by confirming the causal link between the VN and memory formation which may help understand the neural mechanisms underlying disorders associated with altered memory functions and develop treatment options.

情绪记忆比中性记忆更容易记住，但导致这种记忆偏差的机制在人类中尚不清楚。基于动物研究，建议情绪的记忆增强作用基于中枢去甲肾上腺素能释放，这是由传入迷走神经激活触发的。为了测试人类迷走神经激活和情绪记忆之间的因果关系，我们在暴露于情绪唤醒和中性场景期间应用连续无创经皮耳部迷走神经刺激 (taVNS)，并在 1 周后测试了随后的长期识别记忆。我们发现，与假手术相比，tavns 增加了基于回忆的情感记忆性能，但不是中性材料。与假手术相比，在检索 taVNS 下编码的情绪场景期间，更大的回忆相关脑电位（顶叶 ERP 旧/新效应）补充了这些发现。此外，在编码过程中记录的大脑电位还表明 tavns 促进了情绪和中性场景之间的早期注意区分。扩展动物研究，我们的行为和神经研究结果证实了迷走神经在人类情绪记忆形成中的调节作用。

意义声明与情绪相关的信息比不相关的信息能引发更强烈、更持久的记忆。动物研究表明，情绪的这种记忆增强作用与大脑中的去甲肾上腺素能激活有关，这是由迷走神经 (VN) 的传入纤维触发的。在当前的研究中，我们表明无创经皮耳廓 VN 刺激增强了基于回忆的记忆形成，专门针对行为和电生理指标所指示的情绪相关信息。