Frequency Effects of Transcutaneous Trigeminal Nerve Stimulation (eTNS) on Brain and Autonomic Function

This study aims to investigate how different frequencies of transcutaneous Trigeminal Nerve Stimulation (eTNS) affect brain activity and the autonomic nervous system in healthy individuals. Participants will undergo a 3T functional magnetic resonance imaging (fMRI) scan while receiving three different types of nerve stimulation: 2Hz eTNS, 120Hz eTNS, and a sham (inactive) stimulation. The order of these stimulations will be randomly assigned. During the brain scan, researchers will simultaneously monitor the participants' breathing and heart rhythms (using a finger sensor). The main goal is to understand how changing the frequency of eTNS influences the connection between the brain's networks and the body's unconscious physiological responses.