Association of COMT val158met and DRD2 G>T genetic polymorphisms with individual differences in motor learning and performance in female young adults.
Individuals learn new skills at different rates. Given the involvement of corticostriatal pathways in some types of learning, variations in dopaminergic transmission may contribute to these individual differences. Genetic polymorphisms of the catechol-O-methyltransferase (COMT) enzyme and dopamine receptor D2 (DRD2) genes partially determine cortical and striatal dopamine availability, respectively. Individuals who are homozygous for the COMT methionine (met) allele show reduced cortical COMT enzymatic activity, resulting in increased dopamine levels in the prefrontal cortex as opposed to individuals who are carriers of the valine (val) allele. DRD2 G-allele homozygotes benefit from a higher striatal dopamine level compared with T-allele carriers. We hypothesized that individuals who are homozygous for COMT met and DRD2 G alleles would show higher rates of motor learning. Seventy-two young healthy females (20 ± 1.9 yr) performed a sensorimotor adaptation task and a motor sequence learning task. A nonparametric mixed model ANOVA revealed that the COMT val-val group demonstrated poorer performance in the sequence learning task compared with the met-met group and showed a learning deficit in the visuomotor adaptation task compared with both met-met and val-met groups. The DRD2 TT group showed poorer performance in the sequence learning task compared with the GT group, but there was no difference between DRD2 genotype groups in adaptation rate. Although these results did not entirely come out as one might predict based on the known contribution of corticostriatal pathways to motor sequence learning, they support the role of genetic polymorphisms of COMT val158met (rs4680) and DRD2 G>T (rs 1076560) in explaining individual differences in motor performance and motor learning, dependent on task type.
School of Kinesiology, University of Michigan, Ann Arbor, Michigan;
Fatemeh
F
Noohi
Nate B
NB
Boyden
Youngbin
Y
Kwak
Jennifer
J
Humfleet
David T
DT
Burke
Martijn L T M
ML
Müller
Nico I
NI
Bohnen
Rachael D
RD
Seidler
D000223:Adaptation, Psychological; D016022:Case-Control Studies; D002394:Catechol O-Methyltransferase / Q000235:genetics*; D005260:Female; D056726:Genetic Association Studies; D006801:Humans; D007858:Learning; D009048:Motor Skills; D020125:Mutation, Missense; D020641:Polymorphism, Single Nucleotide; D017448:Receptors, Dopamine D2 / Q000235:genetics*; D013647:Task Performance and Analysis; D055815:Young Adult
C581293:DRD2 protein, human; D017448:Receptors, Dopamine D2; C588010:COMT protein, human; D002394:Catechol O-Methyltransferase
COMT; DRD2; individual differences; sequence learning; visuomotor adaptation