This study explores the use of transcutaneous auricular vagus nerve stimulation (taVNS), a new form of neuromodulation which stimulates the ear. 24 healthy subjects without a past medical or psychiatric history will be recruited to participate in a phone screen followed by 1 lab visit. During the lab visit, subjects will participate twice in a validated stress induction technique called the cold pressor test, while concurrently receiving either active or sham taVNS. The cold pressor test consists of subjects placing their feet in an ice bath for a short period of time. Researchers will measure participant's body's responses (heart rate and blood pressure), while they receive taVNS (ear stimulation) and participate in the cold pressor test. Assessments of mood, anxiety, and stress will be collected at the beginning and end of the visit.
In a second trial, we will recruit up to 20 subjects (ages 18-65) to participate in a 1-visit randomized, controlled, crossover trial investigating the acute effects of taVNS on anxiety in subjects with a history of generalized anxiety disorder. Each subject will attend 1 visit, where they will receive 4 different taVNS settings (low-, medium-, and high- frequency active taVNS and sham stimulation). There will not be any anxiety provocation during this portion of the protocol. Subjects will complete visual analog scales related to anxiety while receiving the 4 different stimulation conditions.