Department of Neuropsychology, Otto-von-Guericke University, Universitätsplatz 2, 39106 Magdeburg, Germany.
Neuroimage. 2010 Nov 15;53(3):962-9. doi: 10.1016/j.neuroimage.2010.02.012. Epub 2010 Feb 12.
Humans are faced with the dilemma to maintain a stable cognitive set on the one hand and to be able to redirect and switch attention to novel stimuli of potential importance. The dopaminergic system has been implicated in the balance between these two antagonistic constraints and in particular in novelty processing. Here we studied the impact of two polymorphisms affecting dopaminergic functioning (COMT Val108/158Met and DRD4 SNP -521) on neurophysiological correlates of novelty processing. Recording event-related potentials (ERPs) and oscillatory activity in a modified oddball task that featured infrequent but task-irrelevant novel sounds in addition to frequent standard and rare target tones, we examined participants homozygous for the Met or Val variant of COMT as well as homozygous for the C or T variant of DRD4. We found effects mainly on the P3a component to novel stimuli. A greater P3a amplitude was found for the COMT-ValVal group relative to MetMet. There was a tendency for DRD4-TT participants to show greater P3a amplitude and shorter P3a latency. Finally, DRD4-TT and COMT-ValVal participants showed the greatest increase of theta-power to novel stimuli. By contrast, the P3b component to target stimuli showed little influence of the studied polymorphism. Individual differences in dopaminergic genes explain part of the interindividual variance in the neural correlates of novelty but not target processing.
人类面临着维持稳定认知定势的困境，同时又要能够重新引导和转移注意力，关注潜在重要的新刺激。多巴胺能系统被认为在这两种拮抗约束之间的平衡中起作用，特别是在新奇处理中。在这里，我们研究了两种影响多巴胺能功能的多态性（COMT Val108/158Met 和 DRD4 SNP-521）对新奇处理的神经生理相关性的影响。在一项经过修改的Oddball 任务中记录事件相关电位（ERP）和振荡活动，该任务除了常见的标准音和罕见的靶音外，还包含罕见但与任务无关的新声音。我们检查了 COMT 中 COMT-Val 或 Val158Met 变体纯合子以及 DRD4 中 C 或 T 变体纯合子的参与者。我们发现，新奇刺激的 P3a 成分主要受到影响。与 MetMet 相比，COMT-ValVal 组的 P3a 振幅更大。DRD4-TT 参与者的 P3a 振幅更大，潜伏期更短。最后，DRD4-TT 和 COMT-ValVal 参与者对新奇刺激的θ功率增加最大。相比之下，对靶刺激的 P3b 成分受研究多态性的影响很小。多巴胺能基因的个体差异解释了新奇处理神经相关性的个体间变异性的一部分，但不能解释目标处理的变异性。
