Clinical Research Directory

Inclusion Criteria: 1. Voluntary written informed consent of the participant or their legally authorized representative has been obtained prior to any screening procedures 2. Proficiency in English and/or Dutch 3. Access to a -18°C freezer (i.e. ordinary household freezer) 4. Male participants 5. Age 18-45 years 6. BMI 18.5-25 kg/m2 Exclusion Criteria: 1. Participant has a history of previous or current neurological, psychiatric, gastrointestinal or endocrine disorder 2. Any disorder, which in the Investigator's opinion might jeopardise the participant's safety or compliance with the protocol (as assessed by medical staff on the research team) 3. Any prior or concomitant treatment(s) that might jeopardise the participant's safety or that would compromise the integrity of the study 4. Participation in an interventional Trial with an investigational medicinal product (IMP) or device 5. Current or recent (3-month) medication use (especially antibiotics, cardiovascular drugs, steroids, non-steroid anti-inflammatory drugs, centrally effective drugs) 6. Current or recent (1-month) infection (e.g. common cold, influenza, COVID-19, etc.) 7. Recent (1-month) vaccination (e.g. flu shot, SARS-COV-2 vaccine, etc) 8. Smoking 9. Night-shift work 10. Adherence to special diets (e.g. vegan, vegetarian, weight-loss, lactose-free, gluten- free, etc.) 11. Use of pre- or probiotics within one month preceding the study 12. Previous experience with any of the tasks used in the study (not including questionnaires) 13. Neuroimaging contraindications 14. If the participant invokes that he does not want to be informed of eventual pathology that might be found during imaging (invokes the "right not to know")