Brain-Stomach Circuits in Chronic Nausea

Inclusion Criteria: * Adults between ages 21-60 years old, with and without CNVS diagnosis per self-report. Exclusion Criteria: * body mass index (BMI) \> 30 * pregnancy or intention to become pregnant * past or present chemotherapy * diagnosis of gastric (stomach) cancer * any kind of gastric (stomach) surgery * current use of GLP-1 receptor agonists (e.g. Ozempic, Trulicity) * medications which significantly lower seizure thresholds (e.g. bupropion (Wellbutrin), fluoxetine (Prozac), or tramadol (Ultram)) * implantable devices, such as a pacemakers or nerve stimulators * history of head injury that required hospitalization, metal in the skull, or neurologic disease such as stroke, history of seizures or history of syncope (fainting or passing out) * neurodegenerative disease (Multiple Sclerosis, Parkinson's or Alzheimer's Disease) * ongoing psychosis or altered cognitive status status (e.g. hearing sounds or seeing visions that are not there, or feeling confused or suffering from memory lapses) * history of cardiovascular (i.e., heart attack), pulmonary (i.e., need for supplemental oxygen), or endocrine disease (e.g. diabetes) * current enrollment in another study using Transcranial Magnetic Stimulation (TMS) * current use of drugs such as amphetamines, methamphetamine, Ecstasy, Ketamine, Angel Dust/PCP, cocaine, or drinking 3 or more alcoholic drinks per day * For healthy subjects only: chronic history of gastrointestinal symptoms (e.g., nausea, indigestion, bloating, abdominal pain) * For CNVS subjects only: diagnosis of gastric motility disorder (e.g. gastroparesis/slow stomach emptying) or history of bowel obstruction (i.e., chronic partial small bowel obstruction)