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Caffeine's Effects on Learning and Brain Chemistry

This study is looking at how caffeine affects learning based on rewards, compared to a placebo (a sugar pill). Researchers want to understand how caffeine changes "reward signals" in the brain, specifically dopamine D2/D3 receptors, which are important for learning. You might be able to join if you are a healthy adult between 18 and 45 years old, usually drink 100-450 mg of caffeine daily, and don't smoke. The study will measure dopamine D2/D3 receptor availability and how caffeine affects a learning task during a PET/fMRI scan. The study is currently unclear on its recruitment status and plans to enroll 12 participants.

Study design
This is an interventional study with 12 planned participants. It compares the effects of caffeine (200 mg) to a placebo.
What's involved
You would take either caffeine or a placebo, then perform learning tasks during a PET/fMRI brain scan on the study day.
Compensation
Not stated in the trial record.
Follow-up
Measurements are taken during the PET/fMRI scan on the study day, implying no long-term follow-up.

AI-generated from the public study record. Only the study team can confirm whether you're eligible — confirm details with them before making decisions.

NCT06763172

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

Recruiting
PHASE4Ages 18–45InterventionalBasic science
Hsiao-Ying Wey
~12 participants
Updated 2025-01-09 on ClinicalTrials.gov
What's tested:Caffeine (200 mg)Placebo

At a glance

Recruiting sites
1 of 1 listed site is recruiting right now
RecruitingSuspended, closed, or not yet open
What they're measuring
Dopamine D2/D3 receptor availability
Measured over During the PET/fMRI scan on the study day
+1 more outcome measured

Conditions

Healthy
Caffeine
Adenosine
Dopamine D2/3 Receptor Availability

Explore related trials

Healthy

Where it's being run

1 sites across 1 states
Massachusetts1

Who to contact

Hsiao-Ying Wey, PhD
[email protected]
6177241384
Email the study team

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Do you actually qualify for this trial?

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Eligibility criteria

Inclusion

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.

Exclusion

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)

What this trial measures

  • Dopamine D2/D3 receptor availabilityDuring the PET/fMRI scan on the study day

    Dopamine D2/D3 receptor availability will be measured and indexed by the \[11C\]Raclopride nondisplaceable binding potential (BPND).

  • Effects of caffeine on reinforcement learning assessed by Probabilistic Selection Task (PST) in fMRIDuring the PET/fMRI scan on the study day

    Reinforcement learning and the associated brain activity will be measured using PST in a fMRI scan. The reinforcement learning is indexed by the accuracy of the task performance on the behavioral level and the hemodynamic response to reward feedback on the neural level.