Mod of Cognitive Flexibility by tDCS, Tyrosine Polymorphisms in the COMT Gene

April 2, 2019 updated by: Sheffield Hallam University

Modulation of Cognitive Flexibility by Transcranial Direct Current Stimulation, Tyrosine Administration and Polymorphisms in the COMT Gene

The current study would examine whether increases in endogenous dopaminergic activity via tyrosine and the (presumed) excitation of these by anodal tDCS of the dlPFC could causally be related to cognitive flexibility as measured by task switching and reversal learning.

Additionally, the study will test whether the Val158Met-polymorphism in the catechol- O-methyltransferase (COMT) gene could also predict the effect of TYR supplementation, as this gene is involved in DA degradation in the prefrontal cortex.

Study Overview

Status

Unknown

Conditions

Intervention / Treatment

Study Type

Interventional

Enrollment (Anticipated)

32

Phase

  • Not Applicable

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Locations

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Ages Eligible for Study

18 years to 30 years (Adult)

Accepts Healthy Volunteers

No

Genders Eligible for Study

All

Description

Inclusion Criteria:

  • • Either male or female

    • Between 18 and 30 years
    • You are in good health
    • You agree to fast overnight prior to testing

Exclusion Criteria:

  • • Are suffering from cardiac, hepatic, renal, neurological disorders

    • Damaged or diseased skin on your face and scalp, or a sensitive scalp
    • A history of alcohol or drug addiction, or severe psychiatric illness
    • Drug treatment which may lower seizure threshold (i.e. epilepsy)
    • Pregnancy
    • Sleep deprivation (less than 6 hours a day)
    • A history of migraine or headaches
    • A history of taking antidepressants
    • A history of taking tyrosine supplements

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

  • Primary Purpose: Basic Science
  • Allocation: Randomized
  • Interventional Model: Crossover Assignment
  • Masking: Double

Arms and Interventions

Participant Group / Arm
Intervention / Treatment
Other: tDCS sham + placebo
tDCS= transcranial direct current stimulation drugs= placebo (cellulose [2 grams])
Combination product: tdcs (sham/anodal) + drug (placebo/tyrosine)

tDCS= A DC Stimulator Plus (neuroConn, Germany) with one 5 cm x 7 cm rubber electrode (anode) and a 10 cm x 10 cm (cathode; reference electrode), encased in saline soaked sponges will be used. The anode will be positioned over the left dlPFC, centered on F3 in the 10e20 electroencephalography (EEG) system, while the cathode on the contralateral supraorbital ridge (Fp2).Current will be delivered at 1.5mA for 20 min plus 30 s fade in/fade out periods.For sham stimulation, the current will be faded in over 30 s, at 1.5mA and then will be switched off.

Drugs= 2.0 g of L-Tyrosine and 2.0 g of the placebo microcrystalline cellulose will be dissolved in 400ml of orange juice as per previously published protocols.
Experimental: tDCS sham + tyrosine
tDCS= transcranial direct current stimulation drugs= tyrosine (2 grams)
Combination product: tdcs (sham/anodal) + drug (placebo/tyrosine)

tDCS= A DC Stimulator Plus (neuroConn, Germany) with one 5 cm x 7 cm rubber electrode (anode) and a 10 cm x 10 cm (cathode; reference electrode), encased in saline soaked sponges will be used. The anode will be positioned over the left dlPFC, centered on F3 in the 10e20 electroencephalography (EEG) system, while the cathode on the contralateral supraorbital ridge (Fp2).Current will be delivered at 1.5mA for 20 min plus 30 s fade in/fade out periods.For sham stimulation, the current will be faded in over 30 s, at 1.5mA and then will be switched off.

Drugs= 2.0 g of L-Tyrosine and 2.0 g of the placebo microcrystalline cellulose will be dissolved in 400ml of orange juice as per previously published protocols.
Experimental: tDCS anodal + placebo
tDCS= anodal transcranial direct current stimulation of the dorsolateral prefrontal cortex drugs= placebo (cellulose [2 grams])
Combination product: tdcs (sham/anodal) + drug (placebo/tyrosine)

tDCS= A DC Stimulator Plus (neuroConn, Germany) with one 5 cm x 7 cm rubber electrode (anode) and a 10 cm x 10 cm (cathode; reference electrode), encased in saline soaked sponges will be used. The anode will be positioned over the left dlPFC, centered on F3 in the 10e20 electroencephalography (EEG) system, while the cathode on the contralateral supraorbital ridge (Fp2).Current will be delivered at 1.5mA for 20 min plus 30 s fade in/fade out periods.For sham stimulation, the current will be faded in over 30 s, at 1.5mA and then will be switched off.

Drugs= 2.0 g of L-Tyrosine and 2.0 g of the placebo microcrystalline cellulose will be dissolved in 400ml of orange juice as per previously published protocols.
Experimental: tDCS anodal +tyrosine
tDCS= anodal transcranial direct current stimulation of the dorsolateral prefrontal cortex drugs= tyrosine (2 grams)
Combination product: tdcs (sham/anodal) + drug (placebo/tyrosine)

tDCS= A DC Stimulator Plus (neuroConn, Germany) with one 5 cm x 7 cm rubber electrode (anode) and a 10 cm x 10 cm (cathode; reference electrode), encased in saline soaked sponges will be used. The anode will be positioned over the left dlPFC, centered on F3 in the 10e20 electroencephalography (EEG) system, while the cathode on the contralateral supraorbital ridge (Fp2).Current will be delivered at 1.5mA for 20 min plus 30 s fade in/fade out periods.For sham stimulation, the current will be faded in over 30 s, at 1.5mA and then will be switched off.

Drugs= 2.0 g of L-Tyrosine and 2.0 g of the placebo microcrystalline cellulose will be dissolved in 400ml of orange juice as per previously published protocols.

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Wisconsin Card Sorting Test (WCST) performance
Time Frame: Measured twice in each session (4 arms): at time 0 and 80 minutes into testing.
Measuring change in perseverative errors in the WCST
Measured twice in each session (4 arms): at time 0 and 80 minutes into testing.
Probabilistic Reversal Learning (PRL) performance
Time Frame: Measured twice in each session (4 arms): at time 0 and 80 minutes into testing.
Measuring change in reversal errors in the WCST
Measured twice in each session (4 arms): at time 0 and 80 minutes into testing.
Flanker Task performance
Time Frame: Measured twice in each session (4 arms): at time 0 and 80 minutes into testing.
Measuring change in conflict cost (defined as the difference in reaction time between congruent and incongruent responses)
Measured twice in each session (4 arms): at time 0 and 80 minutes into testing.

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

Sheffield Hallam University

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Actual)

February 18, 2019

Primary Completion (Anticipated)

September 30, 2019

Study Completion (Anticipated)

September 30, 2019

Study Registration Dates

First Submitted

February 11, 2019

First Submitted That Met QC Criteria

February 15, 2019

First Posted (Actual)

February 19, 2019

Study Record Updates

Last Update Posted (Actual)

April 4, 2019

Last Update Submitted That Met QC Criteria

April 2, 2019

Last Verified

April 1, 2019

More Information

Terms related to this study

Other Study ID Numbers

  • SheffieldHallamAquili2019

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

No

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

No

Studies a U.S. FDA-regulated device product

No

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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