Effect of Stimulation on the Vagus Nerve

"Electrical stimulation of the vagus nerve around the external ear using a transcutaneous device. Electrical current will be increased in intensity based on subject feedback of a scale 0-10.~Electrical stimulation will be delivered for 2 minutes once the subject reports the maximum comfortable intensity."

"Subjects will be asked to do the following in order to stimulate the vagus nerve:~* Cough 6 to 8 forceful coughs~* Have an ice cold wash cloth placed on their face for 10 seconds.~* Carotid massage~* Gagging: a tongue depressor is briefly inserted into the back of the mouth touching the bag of the throat.~* Valsalva maneuver: Subjects will be asked to bear down as if having a bowel movement. They will be asked to blow through a mouthpiece that is hooked to a device that measures how hard they are blowing. Alternatively, we can have them blow through the barrel of a 10 ml syringe for 15-20 seconds.~* Eating: Subjects will be asked to drink water and/or Ensure that has 220 calories after fasting overnight."