No modulation of pupil size and event-related pupil response by transcutaneous auricular vagus nerve stimulation (taVNS)

摘要: Transcutaneous auricular vagus nerve stimulation (taVNS) bears therapeutic potential for a wide range of medical conditions. However, previous studies have found substantial interindividual variability in responsiveness to taVNS, and no reliable predictive biomarker success has been developed so far. In this study, we investigate pupil size event-related response as candidate biomarkers. Both measures direct physiological link the activity locus coeruleus (LC), brainstem structure main source norepinephrine brain. LC activation is considered one key mechanisms action therefore, expected clear increase pupillary under taVNS compared sham (placebo) stimulation, such that it could serve prospective predictor individual clinical effects future studies. We studied resting responses target stimuli an auditory oddball task 33 healthy young volunteers. observed stronger than standard stimuli. contrary our hypothesis, neither nor behavioral performance were modulated by taVNS. discuss explanations negative finding its implications investigation development