Search Dopaminergic control of attentional flexibility: inhibition of return is associated with the dopamine transporter gene (DAT1)

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doi:10.3389/fnhum.2010.00053

Abstract

Genetic variability related to the dopamine (DA) transporter gene (DAT1) has received increasing attention as a possible modulator of human cognition. The 9-repeat allele of the DAT1 gene is presumably associated with higher striatal DA levels than the 10-repeat allele, which might support inhibitory control functions. We investigated the impact of the DAT1 gene on the inhibition of return (IOR) effect, which refers to the fact that people are slower to detect a target if it appears in a previously attended location. 140 healthy adults, genotyped for the DAT1 gene, performed an IOR task with stimulus-onset asynchronies (SOAs) between attention cue and target of 150–1200 ms. Nine-repeat carriers showed more pronounced IOR effect than 10/10 homozygous at short SOAs but both groups of subjects eventually reached the same magnitude of IOR. Our findings support the idea that striatal DA levels promote IOR, presumably by biasing the interplay between prefrontal and striatal networks towards greater cognitive flexibility.

Highlights

In the regulation of human cognition dopamine (DA) plays a key role, mainly through regulating the interplay between the prefrontal cortex (PFC) and the striatum
The 9-repeat allele of the DAT1 gene has been associated with higher DA levels in the striatum relative to the 10-repeat allele
9-repeat carriers showed an inhibition of return (IOR) that was comparable to that obtained in 10/10 homozygous individuals with respect to its maximum size, but they reached it at shorter stimulus-onset asynchronies (SOAs) already

Summary

Introduction

In the regulation of human cognition dopamine (DA) plays a key role, mainly through regulating the interplay between the prefrontal cortex (PFC) and the striatum. Genetic variations in the dopamine transporter gene (DAT1) and the COMT gene (Val158Met polymorphism) have received increasing attention as possible modulators of cognitive control functions (Cools, 2008; Cools and D’Esposito, 2009). The 9-repeat allele of the DAT1 gene has been associated with higher DA levels in the striatum relative to the 10-repeat allele. Bertolino et al (2006) have observed similar effects on neuronal activity of the 10-repeat allele of the DAT1 gene and the Met allele of the COMT gene (associated with high prefrontal DA levels): the brain-activation patterns of subjects with putatively low striatal DA levels resembled that seen in subjects with putatively high prefrontal DA levels

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