Transauricular Vagal Nerve Stimulation and Interoception

The study is exploring whether, and for how long, taVNS may modulate deep muscular pressure pain thresholds, heartbeat, and thermal perception (Ethics Region Nord Jylland Denmark, N-20230022). To achieve this, 20 healthy subjects will complete a randomized, active control, crossover study. The main intervention is left concha taVNS (NEMOS, CerboMed GmbH, Erlangen, Germany) for 20 minutes (200µs duration, 20Hz, at a personalized intensity). This will be compared to an active control of identical electrical stimulation to the left earlobe. A blinding assessment inquiring which stimulation is supposed to be therapeutic will be collected. Main outcomes are pressure pain thresholds and temporal summation of pain responses acquired via cuff-pressure algometer (Cortex Technology, Aalborg University, Denmark) placed at the calf. Heartbeat perception, assessed via the heartbeat counting task, and thermal perception, assessed using a QST thermal grid, are also primary outcomes. Secondary outcomes are conditioned pain modulation, resting state electroencephalography, electrocardiography, and pupillary light reflexes.