Short-Chain Fatty Acids in Lypopolysaccharide-Induced Inflammation and Executive Function

Inclusion Criteria: * Voluntary written informed consent obtained prior to any study procedure * Healthy, with no gastrointestinal or psychological complaints * Age 18-45 years * BMI 18.5-27 kg/m2 * Proficiency in English and/or Dutch Exclusion Criteria: * History of previous or current neurological disorder (e.g., epilepsy, multiple sclerosis, migraine with aura) * History of previous or current psychiatric disorder (e.g., depression, anxiety disorders, bipolar disorder, schizophrenia) * History of previous or current gastrointestinal disorder (e.g., Crohn's disease, ulcerative colitis, irritable bowel syndrome) * History of previous or current endocrine disorder (e.g., diabetes, thyroid disorders, polycystic ovary syndrome) * History of immune system disorder, including inflammatory, autoimmune, or severe allergic conditions (e.g., rheumatoid arthritis, lupus, celiac disease, or severe allergies such as anaphylaxis) * History of neuropsychiatric disorder (e.g., ADHD, autism spectrum disorder, learning disorder, Tourette's syndrome) * History of major head trauma (e.g., concussion with loss of consciousness or long-term symptoms) * History of severe infection (e.g., sepsis, pneumonia requiring hospitalization, meningitis, endocarditis, or other systemic infection requiring hospitalization, intravenous antibiotics, or intensive care) * One or more diagnoses based on the Mini International Neuropsychiatric Interview (MINI) * One or more diagnoses based on ROME-IV criteria for gastrointestinal disorders * Any disorder that, in the investigator's opinion, might jeopardise the participant's safety or compliance with the protocol * Any prior or concomitant treatment that might jeopardise the participant's safety or compromise the integrity of the study * Participation in an interventional trial with an investigational medicinal product (IMP) or device * Current or recent (past month) prescribed medication use, with particular attention to cardiovascular drugs, steroids, NSAIDs, and centrally-acting drugs (excluding isolated over-the-counter use such as ibuprofen or paracetamol, and hormonal contraceptives in women) * Use of psychotropic medication within the past year (e.g., antidepressants, anxiolytics, antipsychotics) * Use of antibiotics within three months preceding the study * Use of pre- or probiotics within one month preceding the study * Current or recent (past month) infection (e.g., common cold, influenza, COVID-19) * Recent (past month) vaccination * Pregnant or lactating women * Previous or current substance or alcohol dependence or abuse (\>2 units/day or \>14 units/week) * Smoking * Night-shift work * Adherence to special diets (e.g., vegan, vegetarian, weight-loss, lactose-free, gluten-free) * Previous experience with or knowledge of any of the cognitive tasks used in the study (questionnaires excluded) * C-reactive protein higher than 0.5mg/dL on the day of the injection. * Colour vision deficiency or colour-blindness