According to the Polyvagal theory, the vagus nerve is the key phylogenetic substrate that supports efficient emotion recognition for promoting safety and survival. Previous studies showed that the vagus nerve affects people’s ability to recognize emotions based on eye regions and whole facial images, but not static bodies. The purpose of this study was to verify whether the previously suggested causal link between vagal activity and emotion recognition can be generalized to situations in which emotions must be inferred from images of whole moving bodies. We employed transcutaneous vagus nerve stimulation (tVNS), a noninvasive brain stimulation technique that stimulates the vagus nerve by a mild electrical stimulation to the auricular branch of the vagus, located in the anterior protuberance of the outer ear. In two sessions, participants received active or sham tVNS before and while performing three emotion recognition tasks, aimed at indexing their ability to recognize emotions from static or moving bodily expressions by actors. Active tVNS, compared to sham stimulation, enhanced the recognition of anger but reduced the ability to recognize sadness, regardless of the type of stimulus (static vs. moving). Convergent with the idea of hierarchical involvement of the vagus in establishing safety, as put forward by the Polyvagal theory, we argue that our findings may be explained by vagus-evoked differential adjustment strategies to emotional expressions. Taken together, our findings fit with an evolutionary perspective on the vagus nerve and its involvement in emotion recognition for the benefit of survival.

根据多迷走神经理论，迷走神经是支持有效情绪识别以促进安全和生存的关键系统发育基质。先前的研究表明，迷走神经会影响人们基于眼睛区域和整个面部图像识别情绪的能力，而不是静态身体。本研究的目的是验证之前提出的迷走神经活动和情绪识别之间的因果关系是否可以推广到必须从整个运动身体的图像中推断出情绪的情况。我们采用经皮迷走神经刺激 (tVNS)，这是一种非侵入性脑刺激技术，通过对位于外耳前部突起的迷走神经耳支的轻度电刺激来刺激迷走神经。在两次会议中，参与者在执行三项情绪识别任务之前和期间接受了主动或假 tVNS，旨在衡量他们从演员的静态或移动身体表情中识别情绪的能力。与假刺激相比，主动 tVNS 增强了对愤怒的识别，但降低了识别悲伤的能力，无论刺激的类型如何（静态与移动）。正如多迷走神经理论所提出的那样，与迷走神经在建立安全性中的等级参与的想法一致，我们认为我们的研究结果可以用迷走神经诱发的情绪表达差异调整策略来解释。总而言之，我们的研究结果符合关于迷走神经的进化观点及其参与情绪识别以利于生存。