Psychology of Reward and Punishment: Functional and Molecular Brain Imaging and Monoaminergic Correlates

Who cannot join

• Potential participants for either experimental group will be excluded from participation in this study according to the following criteria:
• Current drug use: Subjects may smoke regular cigarettes, use moderate amounts of alcohol and caffeine, or smoke an occasional marijuana cigarette. Moderate alcohol use is defined as for men, less than ten drinks and for women less than 7 drinks of liquor (1.5 oz) or the equivalent beer (12 oz) or wine (5 oz) per week. Moderate caffeine use is defined as less than 500 mg of caffeine per day, where one 5-oz serving of coffee and 2 12-oz servings of caffeinated soft drinks or tea each contain 100 mg. Occasional marijuana use is defined as less than or equal to 2 cigarettes/month. Participants may not use alcohol or marijuana for at least 24 hours prior to scanning, but will be allowed to smoke regular cigarettes according to their normal usage pattern. Participants who do not meet these guidelines for current drug use will not be allowed to participate in this study.
• Current or Past Medication Use: Volunteers may not currently use chronic (defined as daily for more than 10/14 days in the last month) prescription or over the counter medications that might interfere with the imaging signal (PET or MRI) or which may interact adversely with any of the substances being given in this protocol. This will include, but not be limited to, anti-hypertensive, anti-allergy, and pain medications. In addition, the use of psychotropic medications, particularly antidepressants or antipsychotic medication, will be exclusionary. Past use of antidepressant medication will be evaluated on a case by case basis; however, use of MAOI's within 14 days of AMPH administration will be exclusionary due to the possibility of precipitating hypertensive crisis. Over the counter or prescription medications may be used on an occasional basis (for example, for the treatment of self-limited conditions, such as occasional headache, musculoskeletal discomfort, allergic symptoms or pain), but medications which can interact with AMPH such as Vitamin C, L-glutamine, sodium bicarbonate, and sodium phosphate will be exclusionary. In addition, current use of over-the-counter estrogen-like compounds will be exclusionary for female participants. Subjects who have previously had significant exposure to medications that act on the DA system (antipsychotics, psychostimulants) will also be excluded from the study.
• CNS disease: History of known structural brain abnormalities (e.g. neoplasm, subarachnoid cysts), cerebrovascular disease, infectious disease (e.g. abscess), history of head trauma (defined as documented loss of consciousness > 5 min or injury requiring hospitalization), history of seizures as an adult, sleep apnea, or tic disorder will all be exclusionary.
• Cardiovascular, pulmonary, or systemic disease: Repeated (measured on three separate occasions) diastolic blood pressure > 90 mm Hg, or systolic blood pressure > 135 mm Hg, known arrhythmia, symptomatic or known coronary artery disease; history of endocarditis, cerebral embolism, obstructive pulmonary disease, asthma, active tuberculosis, known endocrine disease (derangements in adrenal, thyroid, bone or reproductive function), known chronic renal or hepatic dysfunction, known HIV seropositive, known current autoimmune disease involving the CNS, glaucoma, allergy to amphetamine, dextroamphetamine or known hypersensitivity to sympathomimetic amines.
• Female participants who are currently pregnant or nursing will not be allowed to participate in this study. Female subjects will be given a serum pregnancy test a maximum of 24 hours prior to each PET session and a urine pregnancy test on the day of each fMRI session.