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)