Dept, of Neuropsychology, Otto-von-Guericke-University, Magdeburg, Germany.
BMC Neurosci. 2009 Dec 20;10:150. doi: 10.1186/1471-2202-10-150.
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.
多巴胺被认为是注意力缺陷/多动障碍（ADHD）发展的关键神经递质。最近的几项研究指出多巴胺 D4 受体（DRD4）基因与这种情况有关。更具体地说，该基因外显子 III 中的可变数量串联重复（VNTR）多态性的 7 重复变体被认为对 ADHD 具有更高的风险。在本研究中，我们研究了这种多态性在调节健康、高功能样本的反应抑制神经生理学相关性（Go/Nogo 任务）中的作用。
与纯合子 4 重复携带者相比，纯合子 7 重复携带者在 Go/Nogo 任务中的行为表现出更准确的趋势。此外，7 重复携带者表现出与 nogo 相关的 theta 波段反应增加，同时与 go 相关的 beta 减少。
这些数据表明 7 重复携带者的认知功能和前额叶控制得到改善，这可能是由于 D4 受体在前额区域的调节作用。结果与该多态性的先前行为数据和 D4 受体对认知功能影响的动物研究进行了讨论。
