Effects of Methylphenidate and Sulpiride on Brain and Cognition: An exploratory PET, Pharmaco-fMRI Study

INTERVENTION: Participants will take part in an intake screening, and if included, they will complete a battery of computerized tests after administration of methylphenidate / sulpiride / placebo, in and outside an fMRI scanner, at three separate occasions. Participants will also take part in one F‐DOPA PET scan session where entacapone and carbidopa will be administered prior to PET scanning. On the days preceding testing, subjects will have to adhere to some simple restrictions with respect to medication, alcohol and drug intake. CONDITION: Dopamine, Working Memory, Cognition ; ; PRIMARY OUTCOME: Effects of methylphenidate and sulpiride on brain activity and/or behavioural performance on a battery of computerized tasks:; ; 1. Working memory performance; ; 2. Mental motivation (mental effort discounting task) ; ; 3. Reward learning (Reversal learning task); ; 4. Motor motivation (monetary incentive delay task); ; ; ; Baseline personality questionnaires: ; ; • The Beck Depression Inventory (Beck, Ward, Mendelson, Mock, & Erbaugh, 1961);; ; • Positive and negative affect scale (Watson et al., 1988); ; • The BIS/BAS (Behavioural Inhibition Scale/Behavioural Activation (BIS/BAS) Scale (Carver & White, 1994); ; ; • The Barratt Impulsiveness Scale (Patton, Stanford, & Barratt, 1995);; ; • Need for Cognition Scale (Cacioppo, Pettz, and Kao, 1984) ; ; • Kaufman Domains of Creativity Scale (Kaufman, 2012); ; ; ; Baseline assessment of executive function; ; ‐ Listening span (Daneman and Carpenter, 1980); ; ; ‐ Digit Span (Wechsler 2008);; ; ‐ Dutch Adult reading test (NLV ‐ Schmand et al., 1991);; ; ‐ WAIS IV Dutch Adult intelligence scale (Wechsler, 1997); ; ; ; ; Baseline assessment of physiological function; ; ‐ Eye blink rate (Groman et al., 2014) SECONDARY OUTCOME: Effects of methylphenidate and sulpiride on behavioural performance on a battery of computerized tasks: ; ; 5. Reinforcement learning (Probabilistic selection (RL) task) ; 6‐8. Creativity tasks ; ; ; ; Baseline assessment of instrumental behaviour ; ; 1. Motivational influences on instrumental behaviour (Pavlovian‐instrumental transfer) ; ; ; ; Methylphenidate and sulpiride‐induced changes in mood and physiological measures ; ; ‐ Positive Affect Negative Affect (PANAS; Watson et al., 1988); ; ; ‐ Mood rating scale (Bond & Lader, 1974); ; ; ‐ Changes in blood pressure, heart rate and body temperature; ; ; ‐ Medical symptoms visual analogue rating scale. INCLUSION CRITERIA: 1. Healthy volunteers; 2. Age 18 ‐ 45 years; 3. Predominantly right‐handed 4. Normal or corrected‐to‐normal vision; 5. Normal uncorrected hearing; 6. Willingness and ability to give written informed consent and willingness and ability to understand the nature and content, to participate and to comply with the study requirements.