Open Access Highly Accessed Research article

ADHD candidate gene (DRD4 exon III) affects inhibitory control in a healthy sample

Ulrike M Krämer12, Nuria Rojo3, Rebecca Schüle4, Toni Cunillera5, Ludger Schöls4, Josep Marco-Pallarés13, David Cucurell3, Estela Camara3, Antoni Rodriguez-Fornells36 and Thomas F Münte17*

Author Affiliations

1 Dept. of Neuropsychology, Otto-von-Guericke-University, Magdeburg, Germany

2 Helen Wills Neuroscience Institute, University of California, Berkeley, USA

3 Dept. of Physiological Sciences II, University of Barcelona, Barcelona, Spain

4 Hertie-Institute for Clinical Brain Research, University of Tübingen, Tübingen, Germany

5 Dept. Psicologia Bàsica, University of Barcelona, Barcelona, Spain

6 Institució Catalana de Recerca i Estudis Avançats (ICREA), Barcelona, Spain

7 Center for Behavioral Brain Sciences, Magdeburg, Germany

For all author emails, please log on.

BMC Neuroscience 2009, 10:150  doi:10.1186/1471-2202-10-150

Published: 20 December 2009

Abstract

Dopamine is believed to be a key neurotransmitter in the development of attention-deficit/hyperactivity disorder (ADHD). Several recent studies point to an association of the dopamine D4 receptor (DRD4) gene and this condition. More specifically, the 7 repeat variant of a variable number of tandem repeats (VNTR) polymorphism in exon III of this gene is suggested to bear a higher risk for ADHD. In the present study, we investigated the role of this polymorphism in the modulation of neurophysiological correlates of response inhibition (Go/Nogo task) in a healthy, high-functioning sample.

Homozygous 7 repeat carriers showed a tendency for more accurate behavior in the Go/Nogo task compared to homozygous 4 repeat carriers. Moreover, 7 repeat carriers presented an increased nogo-related theta band response together with a reduced go-related beta decrease.

These data point to improved cognitive functions and prefrontal control in the 7 repeat carriers, probably due to the D4 receptor's modulatory role in prefrontal areas. The results are discussed with respect to previous behavioral data on this polymorphism and animal studies on the impact of the D4 receptor on cognitive functions.