Ludwig Mareike, Pereira Calida, Keute Marius, Düzel Emrah, Betts Matthew J, Hämmerer Dorothea
Institute of Cognitive Neurology and Dementia Research, Otto-von-Guericke University Magdeburg, Magdeburg, Germany.
CBBS Center for Behavioral Brain Sciences, Magdeburg, Germany.
bioRxiv. 2024 Jul 29:2024.07.27.605407. doi: 10.1101/2024.07.27.605407.
The efficacy of transcutaneous auricular vagus nerve stimulation (taVNS) as a non-invasive method to modulate physiological markers of noradrenergic activity of the Locus Coeruleus (LC), such as pupil dilation, is increasingly more discussed. However, taVNS studies show high heterogeneity of stimulation effects. Therefore, a taVNS setup was established here to test different frequencies ( and ) and intensities ( and ) during phasic stimulation () with time-synchronous recording of pupil dilation in younger adults. Specifically, phasic real taVNS and higher intensity led to increased pupil dilation, which is consistent with phasic invasive VNS studies in animals. The results also suggest that the influence of intensity on pupil dilation may be stronger than that of frequency. However, there was an attenuation of taVNS-induced pupil dilation when differences in perception of sensations were considered. Specifically, pupil dilation during phasic stimulation increased with perceived stimulation intensity. The extent to which the effect of taVNS induces pupil dilation and the involvement of sensory perception in the stimulation process are discussed here and require more extensive research. Additionally, it is crucial to strive for comparable stimulation sensations during systematic parameter testing in order to investigate possible effects of phasic taVNS on pupil dilation in more detail.
经皮耳迷走神经刺激（taVNS）作为一种调节蓝斑（LC）去甲肾上腺素能活动生理指标（如瞳孔扩张）的非侵入性方法，其疗效受到越来越多的讨论。然而，taVNS研究显示出刺激效果的高度异质性。因此，在此建立了一个taVNS装置，用于在年轻成年人的相位刺激（）期间测试不同频率（和）和强度（和），并同步记录瞳孔扩张情况。具体而言，相位真实taVNS和更高强度导致瞳孔扩张增加，这与动物的相位侵入性VNS研究一致。结果还表明，强度对瞳孔扩张的影响可能比频率更强。然而，当考虑感觉感知差异时，taVNS诱导的瞳孔扩张会减弱。具体来说，相位刺激期间的瞳孔扩张随着感知到的刺激强度增加而增加。本文讨论了taVNS诱导瞳孔扩张的程度以及感觉感知在刺激过程中的参与情况，这需要更广泛的研究。此外，在系统参数测试期间争取可比的刺激感觉至关重要，以便更详细地研究相位taVNS对瞳孔扩张的可能影响。
