Contribution of L-Tyrosine to Human Decision Making in Stressful Situations

Summary

L-tyrosine is a chemical precursor of dopamine. Under specific conditions, tyrosine administration can increase brain dopamine levels and therefore several studies have explored whether tyrosine supplementation can have a beneficial effect on cognitive and behavioural performance that is dependent on dopaminergic function. However, the effects of tyrosine supplementation are mixed: some studies show positive effects while others do not. Stress leads to an increase in dopaminergic activity and turnover in the brain, resulting in a decrease in brain dopamine levels. We propose to study the contribution of tyrosine to decision making and more particularly to the processes of response selection (mediated by the prefrontal cortex and under the influence of the dopaminergic system) in stressful situations.

Conditions

• Stress, Psychological

Interventions

BIOLOGICAL

Blood collection

A blood sample will be collected before and after treatment administration

DRUG

L-Tyrosine 500 Mg

The participants will be administered 4 capsules of L-Tyrosine 500 mg per oral route

DRUG

Placebo

The participants will be administered 4 capsules of Lactose 500 mg (placebo) per oral route

BEHAVIORAL

Cognitive tasks

The participants will perform cognitive decision-making tasks: Simon task and masking task after treatment administration

OTHER

Stress exposure

Unpleasant but not painful skin stimulations will be administered to the participants at variable intervals on the left leg during the cognitive tasks

BEHAVIORAL

Anxiety scale

Spielberger's State Trait Anxiety Inventory (STAI) will be filled by the participants before and after cognitive tasks

DEVICE

Electromyography (EMG)

Electromyography measurements will be performed during cognitive tasks.

DEVICE

Electroencephalography (EEG)

Electroencephalography measurements will be performed during cognitive tasks.

Sponsors & Collaborators

• Direction Centrale du Service de Santé des Armées

  lead OTHER

Study Design

Allocation

RANDOMIZED

Purpose

PREVENTION

Masking

TRIPLE

Model

CROSSOVER

Eligibility

Min Age

18 Years

Max Age

65 Years

Sex

ALL

Healthy Volunteers

Yes

Timeline & Regulatory

Start

2021-11-18

Primary Completion

2022-04-07

Completion

2022-04-07

Countries

• France

Study Locations