Dopaminergic Modulation of Brain Activation Using Simultaneous PET/Pharmacological MRI

  • End date
    Dec 31, 2025
  • participants needed
  • sponsor
    National Institute on Alcohol Abuse and Alcoholism (NIAAA)
Updated on 22 July 2021



Dopamine (DA) is a chemical signal in the brain linked to learning, memory, and habits. Stimulant drugs like methylphenidate can increase DA in the brain. Researchers want to measure DA with and without this drug. They want to learn how methylphenidate and brain dopamine affect body responses, mood, and thinking.


To better understand the role of dopamine in the brain and the effects of methylphenidate.


Adults ages 18-55 who have used alcohol or stimulant drugs but have no drug dependence.


Participants will be screened with:

  • Physical exam
  • Question about medical, psychiatric, and alcohol and drug use history
  • Questions to see if it s safe to have a PET/MRI scan
  • Blood and urine tests
  • Breath test for alcohol

Participants will have 3 or 4 study visits. At each visit they will have:

  • Urine and breath tested for alcohol and drugs
  • A thin plastic tube (catheter) inserted in each arm by needle
  • A small amount of radioactive chemical injected through the catheter.
  • PET/MRI scan. Participants will lie still on a table that slides in and out of a metal cylinder surrounded by a strong magnetic field. Their vital signs will be monitored. They will get earmuffs for loud noises. Before the scan, participants will get the study drug or placebo through the catheter. They may also get a sugar pill (placebo). They will get a small meal and have blood drawn.
  • Tests of memory, attention, and thinking.

Participants will wear an activity monitor on the wrist for one week.


  • Objectives: The overarching goal of this study is to assess the dynamic association between dopamine (DA) D2 receptor (D2R) occupancymeasured by positron emission tomography (PET) with [11C]raclopride and brain activity inferred by pharmacological magnetic resonance imaging (phMRI) in the human brain, and to assess the relative sensitivity and specificity of the neurovascular coupling for slow (oral) versus rapid (intravenous, IV) stimulant methylphenidate (MP) delivery. Secondary objectives are to assess the associations between behavioral measures (heart and respiration rates and blood pressure, motor and sleep parameters, and neuropsychological testing variables), D2R occupancy and fMRI signals.
    • Study population: 10 healthy males and 10 healthy females 18-55 years old will be included.
    • Design: Double-blind. Participants will undergo simultaneous PET/phMRI, to evaluate dynamic changes in D2R occupancy by DA with [11C]raclopride and in bloodoxygenationlevel dependent (BOLD) signals, under MP or placebo (PL). The participants will be scanned on 3 different occasions: 1) oral-MP (60 mg) and iv PL (3 cc saline), 2) oral-PL and iv-MP (0.25 mg/kg in 3 cc sterile water) and 3) oral PL and iv PL, which will be carried in different study days with at least 48 hours between them and their order will be randomized across subjects. Participants and researchers will be blind to the nature of the stimulant drug (MP/PL).
    • Outcome parameters: The scale factor between the distribution volume ratio (DVR) and the BOLD signal in the dorsal and ventral striatum for the slow and fast MP challenges.

Condition Normal Physiology
Treatment Oral placebo, IV placebo, Oral Methylphenidate, IV Methylphenidate, Oral Methylphenidate followed by IV placebo, Oral placebo followed by IV Methylphenidate, Oral Placebo followed by IV Placebo
Clinical Study IdentifierNCT03326245
SponsorNational Institute on Alcohol Abuse and Alcoholism (NIAAA)
Last Modified on22 July 2021


Yes No Not Sure

Inclusion Criteria

Healthy Volunteer Participants
Males or females between 18 and 55 years of age
Ability to provide written informed consent
Willing to abstain from drug use on scheduled testing days
Have or had any prior experience with alcohol use or stimulant drugs including cocaine, methylphenidate, amphetamine or methamphetamine, diet pills (prescription or over the counter), caffeine, and others but did not have a substance use disorder

Exclusion Criteria

Pregnant or breastfeeding. Females of childbearing potential must have negative urine pregnancy test and not be currently breastfeeding. Postmenopausal or surgically sterile (tubal ligation or hysterectomy) females satisfy these criteria
Unwilling or unable to refrain from use within 24 hours of scheduled study procedures: psychoactive medications or medication that may affect study results (e.g., antibiotics (must finish course at least 24 hours prior to a scheduled procedure), antidiarrheal preparations, anti-inflammatory drugs [systemic corticosteroids are exclusionary], anti-nausea, cough/cold preparations) (self-report, medical history). The following medications are allowable for entry on this study: analgesics (non-narcotic); antacids; antiasthma agents that are not systemic corticosteroids; antifungal agents for topical use; antihistamines (non-sedating); H2-Blockers/PPI (proton pump inhibitors); laxatives. The use of antihyperlipidemics and/or diuretics are permitted if they have been taken for at least 1 month before procedure visits and dose has been stabilized. The episodic use of benzodiazepines such as alprazolam (Xanax), diazepam (Valium) and lorazepam (Ativan), will not exclude participants from this study unless they have been taken within the last 24 hours prior to the study
The following current chronically used medications are exclusionary from the study: stimulant or stimulant-like medications (amphetamine, methylphenidate, modafinil); analgesics containing narcotics; anorexics (sibuteramine); antianginal agents; antiarrhythmics; antiasthma agents that are systemic corticosteroids; antibiotics; anticholinergics; anticoagulants; anticonvulsants; antidepressants; antidiarrheal preparations; antifungal agents (systemic); antihistamines (sedating); antihypertensives; anti-inflammatory drugs (systemic); antineoplastics; antiobesity; antipsychotics; antivirals (except for treatment of HSV with agents without CNS activity, e.g. acyclovir, ganciclovir, famciclovir, valacyclovir); anxiolytics (benzodiazepine or barbiturates); hormones (exceptions: thyroid hormone replacement, oral contraceptives, and estrogen replacement therapy); insulin; lithium; muscle relaxants; psychotropic drugs not otherwise specified (nos) including herbal products (no drugs with psychomotor effects or with anxiolytics, stimulant, antipsychotic, or sedative properties); sedatives/hypnotics. Note that nicotine and/or caffeine use will not exclude participants
Current or past DSM-IV or DSM-5 diagnosis of a psychiatric disorder as determined by history and clinical exam including substance use disorder (except for nicotine/caffeine), alcohol use disorder (or alcohol dependence, if assessed using DSM-IV) anxiety disorder or panic attacks. Past history of a mental disorder as defined by DSM-IV or DSM-5 will be excluded only if it required hospitalization (any length), or chronic medication management (more than 4 weeks), and that could impact brain function at the time of the study
Those with a binge drinking history every month continuously for the last 10 years will also be excluded. Binge drinkers are those who being female consume 4 or more drinks and males consume 5 or more drinks in one occasion at least once a month
Major medical problems that can impact brain function at the time of the scan (including but not limited to HIV; glaucoma, central nervous system including seizures and psychosis; cardiovascular including hypertension and arrhythmias; metabolic, autoimmune, endocrine) as determined by history and clinical exam
Any clinically significant laboratory finding as determined during the screening procedures
Have had previous radiation exposure (from X-rays, PET scans, or other exposure) that, with the exposure from this study, would exceed NIH annual research limits
Head trauma with loss of consciousness for more than 30 minutes
Presence of ferromagnetic objects in the body that are contraindicated for PET/phMRI of the head (pacemakers or other implanted electrical devices, brain stimulators, some types of dental implants, aneurysm clips, metallic prostheses, permanent eyeliner, implanted delivery pump, or shrapnel fragments), fear of enclosed spaces, or other standard contraindication to MRI/MRS (elf-report checklist)
Cannot lie comfortably flat on back for up to 2 hours in the PET/phMRI scanner
Body weight > 204 kg (> 450 lbs)
Allergy to methylphenidate
Clinically significant EKG abnormalities. Clinically significant findings on EKG will be assessed by the Medical Advisory Investigator on the study or through a cardiology consult. EKG reviews are documented in CRIS
History of glaucoma as determined by medical history
NIH employees who are study investigators, as well as their superiors, subordinates and immediate family members (adult children, spouses, parents, siblings)
Subjects will not be excluded from enrollment in this study if their urine test is positive for drugs. However, if they test positive on scheduled study procedure days involving study imaging and neuropsychological testing, the procedures will be postponed and rescheduled. We will allow for up to 3 rescheduled study days that were the result of positive urine drug screens. If the drug test is positive on the third rescheduled visit, the participant will be withdrawn from the study
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