title: Serotonin Transporter Genetic Variation is Differentially Associated with Reflexive- and Reflective-Optimal Learning.
abstract: Learning to respond optimally under a broad array of environmental conditions is a critical brain function that requires engaging the cognitive systems that are optimal for solving the task at hand. Serotonin is implicated in learning and decision-making, but the specific functions of serotonin in system-level cognitive control remain unclear. Across 3 studies, we examined the influence of a polymorphism within the promoter region of the serotonin transporter gene (5-HTTLPR polymorphism in SLC6A4) on participants' ability to engage the task appropriate cognitive system when the reflexive (Experiments 1 and 2) or the reflective (Experiment 3) system was optimal. Critically, we utilized a learning task for which all aspects remain fixed with only the nature of the optimal cognitive processing system varying across experiments. Using large community samples, Experiments 1 and 2 (screened for psychiatric diagnosis) found that 5-HTTLPR S/LG allele homozygotes, with putatively lower serotonin transport functionality, outperformed LA allele homozygotes in a reflexive-optimal learning task. Experiment 3 used a large community sample, also screened for psychiatric diagnosis, and found that 5-HTTLPR LA homozygotes, with putatively higher serotonin transport functionality, outperformed S/LG allele homozygotes in a reflective-optimal learning task.
authors.affiliation: Department of Psychology and Institute for Mental Health Research, University of Texas at Austin, Austin, TX 78712, USA.
authors.forename: W Todd
authors.initials: WT
authors.lastname: Maddox
authors.affiliation: Department of Psychology, Yale University, New Haven, CT 06520, USA.
authors.forename: Marissa A
authors.initials: MA
authors.lastname: Gorlick
authors.affiliation: Department of Psychology and Institute for Mental Health Research, University of Texas at Austin, Austin, TX 78712, USA.
authors.forename: Seth
authors.initials: S
authors.lastname: Koslov
authors.affiliation: Psychiatry and Human Behavior, Providence Veterans Affairs Medical Center, Providence, RI, USA.
authors.forename: John E
authors.initials: JE
authors.lastname: McGeary
authors.affiliation: Rhode Island Hospital & Brown University, Providence, RI, USA.
authors.forename: Valerie S
authors.initials: VS
authors.lastname: Knopik
authors.affiliation: Department of Psychology and Institute for Mental Health Research, University of Texas at Austin, Austin, TX 78712, USA.
authors.forename: Christopher G
authors.initials: CG
authors.lastname: Beevers
mesh_terms: D000483:Alleles; D003071:Cognition / Q000502:physiology; D003657:Decision Making; D005260:Female; D005787:Gene Frequency; D005838:Genotype; D006801:Humans; D007858:Learning / Q000502:physiology*; D059032:Learning Curve; D008297:Male; D017072:Neostriatum / Q000502:physiology; D011110:Polymorphism, Genetic; D017397:Prefrontal Cortex / Q000502:physiology; D011597:Psychomotor Performance; D012701:Serotonin / Q000502:physiology; D050486:Serotonin Plasma Membrane Transport Proteins / Q000235:genetics*; D055815:Young Adult
chemical_list: C493230:SLC6A4 protein, human; D050486:Serotonin Plasma Membrane Transport Proteins; D012701:Serotonin
keywords: category learning; decision-making; hypothesis-testing; prefrontal cortex; procedural learning; striatum