Elucidating Mechanisms That Underlie the Symptomatology of Functional Dyspepsia Using Novel Techniques and Its Therapeutic Validation Using Neuromodulators

Inclusion Criteria (Healthy): * Age 18 and above, up to 65 years old * No current GI symptoms (as assessed by history taking during screening and based on the investigators' collective judgement) * No previous GI illness (as determined by clinically significant findings from medical history taking and vital signs) * No chronic medical illness e.g., chronic neurological, cardiovascular, pulmonary, endoscirne and hematological disorders, as well as psychiatric disorders Exclusion Criteria (Healthy): * BMI of less than 18.50 and more than 29.99 * Had undergone any abdominal surgery except appendicectomy, tubal ligation, or Caesarean section * Females that are pregnant, expecting to become pregnant during the study period, or breastfeeding * Aversion to test meals * Use of medications that may alter gastrointestinal function and motility * Contraindication for MRI examination e.g., cardiac pacemaker, ferromagnetic implants, claustrophobia Inclusion Criteria (FD patients): * Age 18 and above, up to 65 years old * Satisfy the diagnosis of FD as per Rome IV criteria * Absence of organic disorders that explain dyspepsia in patients such as autoimmune disease, inflammatory disease or brain trauma * No other chronic medical illnesses (including chronic neurological, cardiovascular, pulmonary, endocrine and hematological disorders) and psychiatric disorders Exclusion Criteria (FD patients): * Positive Helicobacter pylori test * Presence of esophagitis, gastric atrophy, heartburn as predominant symptom, history of peptic ulcer or major abdominal surgery * Medications that potentially affects gastrointestinal motility or sensitivity (eg: acid suppressant, prokinetics, corticosteroids, NSAIDs and analgesics apart from paracetamol) * Aversion to test meals * Recent trauma to the abdomen * Patients on antipsychotic or antidepressant in the last 6 weeks * Contraindication for MRI examination e.g., cardiac pacemaker, ferromagnetic implants, claustrophobia