<qa>  What is the name of the three interventions at Visit 2?This study will comprise 2 clinic visits. At Visit 1, participants will be randomly assigned to receive manual acupuncture; electro-acupuncture, which passes an electrical current through the needles; or some type of sensory stimulation. At Visit 2, participants will again be randomly assigned to receive one of the three interventions. As participants receive their assigned intervention, they will undergo functional magnetic resonance imaging fMRI brain scans. Participants will also have their heart rate monitored during the brain scans. 