Inclusion Criteria  Must meet one of the following categories:  Gastroparesis  Meets diagnostic criteria for gastroparesis:  Evidence of delayed gastric emptying documented with a standard 2 hour or 4 hour gastric emptying scintigraphy exam Absence of mechanical obstruction Exhibits cardinal symptoms of early satiety, post-prandial fullness, nausea, vomiting, bloating, and upper abdominal pain  Gastrointestinal cardinal symptom index (GCSI) score > 0 (i.e., the presence of at least mild severity of >1 of 3 symptoms of nausea/vomiting, postprandial fullness/early satiety, and/or bloating).  Functional Dyspepsia  Meets Rome IV diagnostic criteria for functional dyspepsia:  Criteria fulfilled for the last 3 months with symptom onset at least six months prior to diagnosis No evidence of organic, systemic, or metabolic disease that is likely to explain the symptoms on routine investigations (including at upper endoscopy) Meet criteria for Epigastric pain syndrome and/or Postprandial distress syndrome  Epigastric Pain Syndrome At least 1 of the following symptoms at least 1 day per week  Bothersome epigastric pain Bothersome epigastric burning  Postprandial Distress Syndrome At least 1 of the following symptoms at least 3 days per week  Bothersome postprandial fullness Bothersome early satiation  G-POEM  The G-POEM procedure must have been performed at least 4 weeks prior to screening. GCSI score is < 3 which correlates to mild or less symptom severity. Controls  None of the above conditions  Exclusion Criteria:  Another active disorder or treatment which could explain or contribute to symptoms in the opinion of the Investigator (including but not limited to gastric malignancy, neurological disorder, or heavy doses of strong anticholinergics). Gastrectomy, fundoplication, vagotomy, bariatric surgery, post-surgical cause of gastroparesis, or gastric stimulation device surgically implanted within the last year. Prior G-POEM procedure for gastroparesis is allowed for the group of post-G-POEM study subjects. Dysphagia, swallowing disorder Suspected bowel obstruction or perforation Gastric or parenteral feeding within 4 weeks of screening Pregnancy or nursing History of an eating disorder within 2 years of screening Recent history (within six months of screening) of Alcohol Use Disorder or Substance Use Disorder as defined in DSM-5. Uncontrolled thyroid disease Unstable cardiac, respiratory, hepatic or renal disease Evidence of uncontrolled blood glucose (including HbA1C >9 or metabolic crisis in past 60 days). Use of prohibited medication or medication with anti-nausea, antiemetic, neuromodulating, or prokinetic effect within 2 weeks of the screening visit EXCEPT when administered on a stable daily dosing schedule (stable for at least 1 month prior to the screening visit). Use of as needed or daily opioids within the past 1 month. Pyloric injection of neurotoxins (e.g. botulinum type A or B) within 3 months of the Screening visit. Altered mental status (e.g., hepatic encephalopathy) that limits the ability to swallow a capsule Expected to have Magnetic Resonance Imaging (MRI) examination within 30 days. No reliable contact information - no phone, no permanent address. Pacemaker or ICD Inability to avoid using the bathroom for urination and/or bowel movements for the duration of the study. Metal Implant (ie metal hip arthroplasty, surgical mesh, coronary or arterial stent) Prior bowel surgery Severe claustrophobia Any other reason as determined by the Investigator which may lead to an unfavorable risk-benefit of study participation, may interfere with study compliance, or may confound study results.