Balance, Autonomic Response, and Sensory Modulation to Dosage of Mechanical Vagal Stimulation in Healthy Adults

The stimulation consists of a combination of normal neck movements, performed in a comfortable supine position, which can selectively stimulate the VN. In particular. The participant will be stimulated supine on a comfortable massage/treatment bed with the experimenter standing at the cranial short side of the bed. All the neck movements will be gently performed with a combination of upper cervical flexion and contralateral lateral flexion to load the intracranial portion of the vagus nerve. The ipsilateral neck rotation will be combined to load the cervical tract of the nerve. Keeping the participant's head in the final movements combination the upper abdomen will be gently moved caudally to load the thoracic tract and intermittent gentle impulses 1 each second will be administered. The stimulation will be provided for 2 consecutive minutes for each side, only once for the experiment duration.

The stimulation consists of a combination of normal neck movements, performed in a comfortable supine position, which can selectively stimulate the VN. In particular. The participant will be stimulated supine on a comfortable massage/treatment bed with the experimenter standing at the cranial short side of the bed. All the neck movements will be gently performed with a combination of upper cervical flexion and contralateral lateral flexion to load the intracranial portion of the vagus nerve. The ipsilateral neck rotation will be combined to load the cervical tract of the nerve. Keeping the participant's head in the final movements combination the upper abdomen will be gently moved caudally to load the thoracic tract and intermittent gentle impulses 1 each second will be administered. The stimulation will be provided for 3 sessions of 2 minutes, with 2 minutes of rest for each side. stimulation will be provided only once for the experiment duration.

The stimulation consists of a combination of normal neck movements, performed in a comfortable supine position, which can selectively stimulate the VN. In particular. The participant will be stimulated supine on a comfortable massage/treatment bed with the experimenter standing at the cranial short side of the bed. All the neck movements will be gently performed with a combination of upper cervical flexion and contralateral lateral flexion to load the intracranial portion of the vagus nerve. The ipsilateral neck rotation will be combined to load the cervical tract of the nerve. Keeping the participant's head in the final movements combination the upper abdomen will be gently moved caudally to load the thoracic tract and intermittent gentle impulses 1 each second will be administered. The stimulation will be provided for 8 consecutive minutes for each side, only once for the experiment duration.

Participants will be treated with a fake vagus stimulation by letting the operator hold the neck of the participant in one hand and placing the other hand on the abdomen without any stretch on the vagus nerve