NCT04384562

Studying the Role of Brain Molecules for Decision Making

• Status: Completed
• Phase: N/A
• Study type: Interventional
• Enrollment: 160 (actual)
• Sponsor: University of Zurich · Academic / Other
• Sex: All
• Age: 18 Years – 35 Years
• Healthy volunteers: Accepted

Summary

The aim of the present project is to elucidate the neuropharmacological mechanisms underlying value (choice preference) and attention (choice randomness) processing in humans. More specifically, the investigators test whether dopaminergic, noradrenergic and cholinergic interventions affect neural and behavioral processing of valuation and attention during decision-making. The investigators do this by up-regulating dopaminergic, noradrenergic or cholinergic neurotransmission pharmacologically through administration of methylphenidate, reboxetine, or nicotine. We test the hypothesis that methylphenidate, reboxetine, or nicotine reduce choice randomness and that this effect is underpinned by an effect on attention and/or value processing.

Detailed description

To simultaneously assess and dissociate choice preference and randomness in stable environments, the investigators plan to use two tasks: (1) a variant of the RISKGARP task, a well-established risky decision-making task and (2) a modified Becker-DeGroot-Marshak task that measures choice preference and the width of preference representations with the range of willingness to pay procedure (range-WTP). Note that wider representations should result in more choice randomness. The investigators will assess choice randomness also by repeating the same decision questions several times within each task and by relating the preferences measured by the RISKGARP task to those measured by the range-BDM task by using the same options in both tasks. To assess the impact of changing environments and learning on choice preference and randomness, participants will perform two established exploration/exploitation tasks. One (3) is a foraging task that has been combined with different pharmacological manipulations and the other (4) is a variant of the four-armed bandit task, which allows distinguishing value- or information-based exploration from random choice. Blood and saliva samples may be taken. Blood samples may be used to determine levels of the administrated substances and to assess genetic variation. Saliva samples may be used to determine cortisol and testosterone levels.

Conditions

• Decision Making
• Healthy

Interventions

Type	Name	Description
DRUG	Methylphenidate	A 20 mg methylphenidate (Ritalin®) is administered only once for the dopamine reuptake inhibitor group.
DRUG	Reboxetine	A 4 mg reboxetine (Edronax®) is administered only once for the noradrenaline reuptake inhibitor group.
DRUG	Nicotine gum	A 2 mg nicotine (Nicorette®) gum is administered only once for the cholinergic receptor agonist group.
DRUG	Placebo pill	A placebo pill is administered only once.
DRUG	Placebo gum	A placebo gum is administered only once.

Timeline

• Start date: 2020-12-17
• Primary completion: 2021-12-13
• Completion: 2021-12-13
• First posted: 2020-05-12
• Last updated: 2024-05-08

Locations

1 site across 1 country: Switzerland