Mod of Cognitive Flexibility by tDCS, Tyrosine 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.