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

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

Official title:

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

Clinical Trial Details — Status: Recruiting

Administrative data

• NCT number: NCT03845920
• Other study ID #: SheffieldHallamAquili2019
• Status: Recruiting
• Phase: N/A
• Start date: February 18, 2019
• Est. completion date: September 30, 2019

Study information

• Verified date: April 2019
• Source: Sheffield Hallam University
• Contact: Luca Aquili, Ph.D.
• Phone: + 44 (0) 114 225
• Email: luca.aquili[@]shu.ac.uk
• Is FDA regulated: No
• Study type: Interventional

Clinical Trial Summary

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.

Recruitment information / eligibility

• Status: Recruiting
• Enrollment: 32
• Est. completion date: September 30, 2019
• Est. primary completion date: September 30, 2019
• Accepts healthy volunteers: Accepts Healthy Volunteers
• Gender: All
• Age group: 18 Years to 30 Years

Eligibility

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

Related Conditions & MeSH terms

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

Intervention

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.

Locations

Country	Name	City	State
United Kingdom	Psychology labs	Sheffield	South Yorkshire

Sponsors (1)

Lead Sponsor	Collaborator
Sheffield Hallam University

Country where clinical trial is conducted

United Kingdom, 

Outcome

Type	Measure	Description	Time frame	Safety issue
Primary	Wisconsin Card Sorting Test (WCST) performance	Measuring change in perseverative errors in the WCST	Measured twice in each session (4 arms): at time 0 and 80 minutes into testing.
Primary	Probabilistic Reversal Learning (PRL) performance	Measuring change in reversal errors in the WCST	Measured twice in each session (4 arms): at time 0 and 80 minutes into testing.
Primary	Flanker Task performance	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.