Effects of caffeine on learning in healthy adults using brain imaging

Is this trial a fit for you?

A plain-English reading of the study's rules. Only the study team can confirm whether you qualify.

What this trial studies

This research investigates how caffeine intake influences the learning process through reward feedback in healthy adults. Participants will engage in reinforcement learning and motor inhibition tasks while undergoing brain scans using PET and MRI technology. The study aims to elucidate the mechanisms by which caffeine affects dopamine signaling and cognitive functions related to learning. By comparing the effects of caffeine to a placebo, the researchers hope to gain insights into the role of adenosine and dopamine interactions in reinforcement learning.

Why it matters

Who can join: the full rules

Inclusion 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.

Exclusion Criteria:

* 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.

General MRI and PET safety exclusion criteria for all subjects:

* 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)

Where it's running

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

Study contacts

• Study coordinator: Hsiao-Ying Wey, PhD
• Email: hsiaoying.wey@mgh.harvard.edu
• Phone: 6177241384

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How to take part

1. Review the eligibility criteria above with your treating physician.
2. Check the official listing on ClinicalTrials.gov for the latest contact details and recruitment status.
3. Contact the study coordinator or principal investigator to ask for pre-screening. Pre-screening is free and never obligates you to enroll.