Coffee break for the brain: study probes Caffeine's effect on brain oxygen

Copied word for word from the study's registry entry, so the wording is the study team's rather than ours.

Inclusion Criteria: * Males and Females 25-35 years old * BMI between 18.5 kg/m2 and 29.9 kg/m2 * Conditions for study procedure compliance: * Willing and able to sign an informed consent form * Fluent in English (self-reported C1 or C2 English level) * Have reliable cortical oxygenation signal for subsequent analysis (based on the real-time computation of a parameter reflecting the quality of the signal, which may be influenced by variations in hair thickness) * Dominant right-handed * Have normal or corrected-to-normal vision * Willing and able to comply with the protocol requirements Exclusion Criteria: * Conditions that may affect cortical oxygenation: * Have a past or current neural, cerebrovascular, cardiovascular, or respiratory disease (based on anamnesis) * Have a past or current kidney disease or condition (based on anamnesis) * Measured hypo- or hyper-tension (verified by evaluating Blood Pressure, BP, measure against medical norms at screening) * Self-reported, suspected or diagnosed migraine (based on anamnesis) * Have a mild or clinical form of insomnia (verified by thresholding rated insomnia severity index, ISI, at or above 8) or being a night shift worker (based on anamnesis) * Regular smoker, regularly is being defined as more than 2 cigarettes per week * Participating in vigorous physical activity defined as requiring more than 6 metabolic equivalents (e.g., hiking, jogging at 10 km/h or more, carrying of heavy loads, bicycling fast at 23 km/h or more, basketball, soccer, and tennis single), greater than 4 times 45 minutes per week * Conditions that may affect cognition or mental fatigue: * Have a current psychiatric disorder or have a self-reported, suspected or diagnosed anxiety or depression (based on anamnesis) * Taking illicit drugs for e.g., cannabis, heroin, and cocaine * Have an average alcohol consumption defined as greater than 2 standard drinks per day over a week for males, and greater than 1 standard drink per day over a week for females. One standard drink contains 10-12 g of ethanol. Examples of standard drinks are one beer can (300 ml), one glass of wine (100 ml) or one glass of schnaps (30 ml). * Pregnant (verified by a pregnancy test in urine dipstick format provided by the study's site) or seeking to become pregnant or breast feeding (based on anamnesis) * Conditions that may interact with the IP mechanism: * Have food allergies and intolerances (based on anamnesis) * Have a high usual consumption of caffeine-based beverages and foods (verified by thresholding the daily consumption of caffeine as determined by the Caffeine Consumption Questionnaire, CCQ, at or above 600mg) * Body mass below 60kg (associated with a dosing of more than 3mg caffeine per 1kg of body mass) * Currently taking Sildenafil (based on anamnesis) * Self-reported, suspected or diagnosed with acute inflammatory diseases e.g., herpes simplex virus, allergies, or asthma (based on anamnesis) * Have a hierarchal or family relationship with any of the research team members. * Currently participating in an interventional study.