The Effects of Naturally-Occurring Interactions of Dopamine Vs. Serotonin Levels on Reinforcement Learning in Healthy Individuals
Haneen H. Sharabati
Mohammad M. Herzallah
Al-Quds University, Deanship of Scientific Research
Background: The neuromodulators dopamine and serotonin play key roles in reinforcement learning. While dopamine modulates positive feedback processing, serotonin facilitates aversive learning and behavioral inhibition. The dopamine transporter (DAT), coded by the DAT1 gene, regulates synaptic dopamine levels in the brain is. DAT1 exhibits a naturally-occurring variable number of tandem repeats polymorphism (VNTR) in its 3’ untranslated region (3’-UTR). Similarly, the serotonin transporter (SERT) controls synaptic serotonin levels in the brain. SERT is coded by the SLC6A4 gene that has a polyadenylation polymorphism influencing the balance of two polyadenylation forms of SERT in the brain (STPP).