Neurophysiological Effects on tPCS and tDCS on Healthy Subjects and on Patients With Chronic Visceral Pain

PART 1: 48 healthy subjects will be selected to take part in this study. All healthy subjects will need to meet all of the following inclusion criteria and none of the following exclusion criteria: Inclusion criteria: * Provide informed consent to participate in the study * Age 18 - 60 years Exclusion criteria: * History of alcohol or substance abuse within the last 6 months as self-reported * Severe depression (with a score of \>30 in the Beck Depression Inventory)\* * History of seizures during the last two years or diagnosis of epilepsy * History of neurological or psychiatric illness * Unstable medical conditions such as uncontrolled diabetes mellitus, uncompensated cardiac pathology, heart failure, kidney insufficiency or chronic obstructive pulmonary disease, acute thrombosis * History of head injury resulting in more than a momentary loss of consciousness during the last two years * History of unexplained fainting spells or loss of consciousness as self-reported during the last two years * Contraindication to tPCS or tDCS * Metallic brain implants * Implanted brain electronic medical devices * Pregnancy * Use of neuropsychotropic drugs within the past two weeks as self reported Part 2: 18 patients with Chronic Visceral Pain will take part in this experiment. All subjects must meet the following criteria: Inclusion criteria: * Provide informed consent to participate in the study * Age 18 - 60 years * Abdominal or pelvic pain for ≥ 3 days per week for at least 3 months (average VAS scale score of 4/10 or greater at time of enrollment) as self reported * Diagnosis of chronic visceral pain (e.g. Chronic Pancreatitis or Chronic Pelvic Pain) as confirmed by medical records or a letter from their physician * If taking pain medications, stable doses are required for at two weeks prior to initiation of the study Exclusion criteria: * History of alcohol or substance abuse within the last 6 months as self-reported * Severe depression (with a score of \>30 in the Beck Depression Inventory)\* * Epilepsy * Unstable medical conditions such as uncontrolled diabetes mellitus, uncompensated cardiac pathology, heart failure, kidney insufficiency or chronic obstructive pulmonary disease, acute thrombosis * History of head injury resulting in more than a momentary loss of consciousness during the last two years * History of unexplained fainting spells or loss of consciousness as self-reported during the last two years * Contraindication to tPCS or tDCS * Metallic brain implants * Implanted brain electronic medical devices * Pregnancy or trying to become pregnant during the next month * Use of carbamazepine oxcarbazepine, phenytoin, pramipexole (Mirapex), or cavergoline (Dostinex) within the past 6 months as self-reported