Effects of Caffeine on Reinforcement Learning in Healthy Adults Using PET/MRI

Description

This research study aims to determine whether and how caffeine intake affects learning process through reward feedback compared to placebo. The data acquired from this study would improve our understanding on the consequence and mechanism of caffeine intake in the aspect of learning process. Participants will perform a reinforcement learning task (i.e. Probabilistic Selection Task) and a motor inhibition task (i.e. Go/NoGo task) in a brain scan. The scan will be done with the Siemens Biograph mMR positron emission tomography (PET)/ magnetic resonance imaging (MRI) 3 Tesla scanner. The PET allows us to see the changes in the "reward signals" - dopamine - in the brain using a radioactive dye called \[11C\]Raclopride. The MRI, on the other hand, enables us to take detailed pictures of the brain activities during cognitive tasks using a high-powered magnet. Reviewing these pictures will help us understand the influence of caffeine on reward signals and brain activities during the learning process.

Conditions

Healthy, Caffeine, Adenosine, Dopamine D2/3 Receptor Availability

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Study Overview

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Study Details

Study overview

This research study aims to determine whether and how caffeine intake affects learning process through reward feedback compared to placebo. The data acquired from this study would improve our understanding on the consequence and mechanism of caffeine intake in the aspect of learning process. Participants will perform a reinforcement learning task (i.e. Probabilistic Selection Task) and a motor inhibition task (i.e. Go/NoGo task) in a brain scan. The scan will be done with the Siemens Biograph mMR positron emission tomography (PET)/ magnetic resonance imaging (MRI) 3 Tesla scanner. The PET allows us to see the changes in the "reward signals" - dopamine - in the brain using a radioactive dye called \[11C\]Raclopride. The MRI, on the other hand, enables us to take detailed pictures of the brain activities during cognitive tasks using a high-powered magnet. Reviewing these pictures will help us understand the influence of caffeine on reward signals and brain activities during the learning process.

Measure Striatal Adenosine-dopamine Receptors Interactions: from Molecule to Behaviors

Effects of Caffeine on Reinforcement Learning in Healthy Adults Using PET/MRI

Condition
Healthy
Intervention / Treatment

-

Contacts and Locations

Charlestown

Athinoula A. Martinos Center for Biomedical Imaging, Charlestown, Massachusetts, United States, 02129

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

For general information about clinical research, read Learn About Studies.

Eligibility Criteria

  • * Age ≥ 18 and ≤ 45.
  • * Habitual caffeine intake ≥ 100 mg and ≤ 450 mg daily.
  • * Non-smokers.
  • * Clinically healthy.
  • * Have normal vision or corrected to normal vision.
  • * Pregnant or lactating women.
  • * Women using hormonal contraceptives.
  • * BMI \< 18.5 or \> 29.9
  • * Sleep disturbance or extreme chronotype.
  • * Urine test positive on one of the following substances: benzoylecgonine, morphine, d-Methamphetamine, d-Amphetamine, Benzodiazepines, Secobarbital, Methadone, Buprenorphine Glucuronide, Nortriptyline, MDMA, Oxycodone, PCP, Propoxyphene, and Cannabis/THC
  • * Diagnosis of depression, anxiety, psychosis, or neurologic disorders in the last 5 years.
  • * Heart or cardiovascular diseases.
  • * Diabetes or other metabolic diseases.
  • * Under chronic medications, for instance, painkiller and steroid.
  • * Allergy to lactose (main ingredient of blank control dose)
  • * Incapable to operate the tasks or comprehend the study information in English.
  • * Metallic foreign bodies such as cardiac pacemakers, perfusion pumps, aneurysm clips, metallic tattoos anywhere on the body, tattoos near the eye.
  • * Pre-existing medical conditions including a likelihood of developing seizures or claustrophobic reactions
  • * Inability to lie flat on scanner bed for about 90 min as assessed by physical examination and medical history (e.g. arthritis)
  • * Recent exposure to radiation (i.e., PET from other research studies) that, when combined with this study, would be above the allowable limits
  • * Pregnancy or breastfeeding: A negative serum or urine pregnancy test is required on the day of the PET procedure
  • * Body weight of \> 300 lbs (weight limit of the MRI scanner table)

Ages Eligible for Study

18 Years to 45 Years

Sexes Eligible for Study

ALL

Accepts Healthy Volunteers

Yes

Collaborators and Investigators

Hsiao-Ying Wey,

Study Record Dates

2026-12-31