Background: The vagus nerve plays an important role in the regulation of food intake. Modulating vagal activity via electrical stimulation (VNS) in patients and animal studies caused changes in food intake, energy metabolism, and body weight. However, the moderating impact of cognitive processes on VNS effects on eating behavior has not been investigated so far. Hypothesis: We hypothesized that transcutaneous VNS (tVNS) affects food intake by altering cognitive functions relevant to the processing of food-related information. Methods: Using a repeated-measurement design, we applied tVNS and a sham stimulation for 2 h on two different days in normal-weight subjects. We recorded standard scalp EEG while subjects watched food and object pictures presented in an oddball task. We analyzed the event-related potentials (ERPs) P1, P2, N2, and LPP and also examined the amount of consumed food and eating duration in a free-choice test meal. Results: Significant differences between stimulations were observed for the P1, P2, and N2 amplitudes. However, we found no tVNS-dependent modulation of food intake nor a specific food-related stimulation effect on the ERPs. Further analyses revealed a negative relationship between P2 amplitude and food intake for the sham stimulation. Significant effects are additionally confirmed by Bayesian statistics. Conclusion: Our study demonstrates tVNS’ impact on visual processing. Since the effects were similar between food and object stimuli, a general effect on visual perceptual processing can be assumed. More detailed investigations of these effects and their relationship with food intake and metabolism seem reasonable for future studies.

中文翻译：

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短期经皮迷走神经刺激 (tVNS) 对食物线索大脑处理的影响：电生理研究

背景：迷走神经在调节食物摄入中起重要作用。在患者和动物研究中通过电刺激 (VNS) 调节迷走神经活动导致食物摄入、能量代谢和体重发生变化。然而，迄今为止尚未研究认知过程对 VNS 对饮食行为的影响的调节作用。假设：我们假设经皮 VNS (tVNS) 通过改变与食物相关信息处理相关的认知功能来影响食物摄入。方法：使用重复测量设计，我们在两个不同的日子在正常体重的受试者中应用 tVNS 和假刺激 2 小时。我们记录了标准的头皮脑电图，同时受试者观看了一项奇怪任务中呈现的食物和物体图片。我们分析了事件相关电位 (ERP) P1、P2、N2、和 LPP，还检查了自由选择测试餐中消耗的食物量和进食时间。结果：观察到 P1、P2 和 N2 振幅的刺激之间存在显着差异。然而，我们没有发现 tVNS 依赖的食物摄入调节，也没有发现特定的食物相关刺激对 ERP 的影响。进一步的分析揭示了 P2 幅度与假刺激的食物摄入量之间存在负相关关系。贝叶斯统计进一步证实了显着影响。结论：我们的研究证明了 tVNS 对视觉处理的影响。由于食物和物体刺激之间的效果相似，因此可以假设对视觉感知处理有一般影响。对这些影响及其与食物摄入和代谢的关系进行更详细的研究对于未来的研究似乎是合理的。