Immune Cell Study in Neurologic Diseases

Inclusion Criteria: * Age 18 and up ONE of the following: * Recommended to under a screening colonoscopy (+/- upper endoscopy) as part of standard of care. This includes healthy individuals as well as those with neurologic and/or autoimmune diseases. OR * Willing to undergo research colonoscopy (+/- upper endoscopy) for research Exclusion Criteria: * Currently pregnant. Women of childbearing potential would perform a point of care urine pregnancy test prior to colonoscopy/endoscopy. * Known or suspected, chronic inflammatory gastrointestinal disease (e.g. inflammatory bowel disease) * Known, acute or chronic infections * Systemic antibiotic (PO or IV) use within 3 months of colonoscopy * Systemic corticosteroid use (equivalent of prednisone 10 mg per day or higher for \>5 days) within 2 weeks of colonoscopy * Malignancy, diagnosed or treated within the last 5 years * Probiotic use within 2 weeks of procedure * History of major GI surgery (e.g. colon resection, gastric bypass) * Bleeding disorder, or on anticoagulant medication * Other medical condition that, in the judgement of the investigator, would lead to higher-than-expected risks of biopsy * Allergy to MAC anesthesia or other drugs used pursuant to standard of care for biospecimen collection