title: The C957T polymorphism in the dopamine receptor D₂ gene modulates domain-general category learning.
abstract: Adaptive learning from reward and punishment is vital for human survival. Striatal and frontal dopaminergic activities are associated with adaptive learning. For example, the C957T single nucleotide polymorphism of the dopamine receptor D2 (DRD2) gene alters striatal D2 receptor availability and affects individuals' adaptive learning ability. Specifically, individuals with the T/T genotype, which is associated with higher striatal D2 availability, show enhanced learning from negative outcomes. Prior work examining DRD2 genetic variability has focused primarily on frontally mediated reflective learning that is under effortful, conscious control. However, less is known about a more automatic, striatally mediated reflexive learning. Here we examined the extent to which this polymorphism differentially influences reflective and reflexive learning across visual and auditory modalities. We employed rule-based (RB) and information-integration (II) category learning paradigms that target reflective and reflexive learning, respectively. Results revealed an advantage in II category learning but poorer RB category learning in T/T homozygotes. The pattern of results was consistent across sensory modalities. These findings suggest that this DRD2 polymorphism exerts opposite influences on domain-general frontally mediated reflective learning and striatally mediated reflexive learning.
authors.affiliation: Department of Communication Sciences & Disorders, The University of Texas at Austin, Austin, Texas;
authors.forename: Zilong
authors.initials: Z
authors.lastname: Xie
authors.affiliation: Department of Psychology, The University of Texas at Austin, Austin, Texas;
authors.forename: W Todd
authors.initials: WT
authors.lastname: Maddox
authors.affiliation: Division of Behavioral Genetics, Rhode Island Hospital, Providence, Rhode Island; Brown University, Providence, Rhode Island; and Psychologist, Providence Veterans Affairs Medical Center, Providence, Rhode Island.
authors.forename: John E
authors.initials: JE
authors.lastname: McGeary
authors.affiliation: Department of Communication Sciences & Disorders, The University of Texas at Austin, Austin, Texas; bchandra@utexas.edu.
authors.forename: Bharath
authors.initials: B
authors.lastname: Chandrasekaran
mesh_terms: D000161:Acoustic Stimulation; D000293:Adolescent; D000328:Adult; D000704:Analysis of Variance; D001245:Association Learning / Q000502:physiology*; D001307:Auditory Perception / Q000235:genetics; D003210:Concept Formation / Q000502:physiology*; D005260:Female; D005838:Genotype; D006801:Humans; D008297:Male; D010775:Photic Stimulation; D020641:Polymorphism, Single Nucleotide / Q000502:physiology*; D017448:Receptors, Dopamine D2 / Q000235:genetics*; D014796:Visual Perception / Q000235:genetics; D055815:Young Adult
chemical_list: D017448:Receptors, Dopamine D2
keywords: D2 receptor availability; information-integration learning; rule-based learning; single-nucleotide polymorphism