Ko Ji Hyun, Ptito Alain, Monchi Oury, Cho Sang Soo, Van Eimeren Thilo, Pellecchia Giovanna, Ballanger Benedicte, Rusjan Pablo, Houle Sylvain, Strafella Antonio P
PET Imaging Centre, Centre for Addiction and Mental Health, University of Toronto, Toronto, Canada.
Neuroimage. 2009 Jun;46(2):516-21. doi: 10.1016/j.neuroimage.2009.02.031. Epub 2009 Mar 3.
There is clear evidence that the prefrontal cortex is strongly involved in executive processes and that dopamine can influence performance on working memory tasks. Although, some studies have emphasized the role of striatal dopamine in executive functions, the role played by prefrontal dopamine during executive tasks is unknown. In order to investigate cortical dopamine transmission during executive function, we used D(2)-dopamine receptor ligand [(11)C]FLB 457 PET in healthy subjects while performing the Montreal Card Sorting Task (MCST). During the retrieval with shift task of the MCST, the subjects had to match each test card to one of the reference cards based on a classification rule (color, shape or number) determined by comparing the previously viewed cue card and the current test card. A reduction in [(11)C]FLB 457 binding potential in the right dorsal anterior cingulate cortex (ACC) was observed when subjects performed the active task compared to the control task. These findings may suggest that right dorsal ACC dopamine neurotransmission increases significantly during the performance of certain executive processes, e.g., conflict monitoring, in keeping with previous evidence from fMRI studies showing ACC activation during similar tasks. These results may provide some insights on the origin of cognitive deficits underlying certain neurological disorders associated with dopamine dysfunction, such as Parkinson's disease and schizophrenia.
有明确证据表明前额叶皮质强烈参与执行过程，且多巴胺可影响工作记忆任务的表现。尽管一些研究强调纹状体多巴胺在执行功能中的作用，但前额叶多巴胺在执行任务期间所起的作用尚不清楚。为了研究执行功能期间皮质多巴胺传递情况，我们在健康受试者执行蒙特利尔卡片分类任务（MCST）时，使用D(2)-多巴胺受体配体[(11)C]FLB 457进行正电子发射断层扫描（PET）。在MCST的检索与转换任务期间，受试者必须根据通过比较先前查看的提示卡和当前测试卡所确定的分类规则（颜色、形状或数字），将每张测试卡与一张参考卡进行匹配。与对照任务相比，当受试者执行主动任务时，观察到右侧背侧前扣带回皮质（ACC）中[(11)C]FLB 457结合潜能降低。这些发现可能表明，在某些执行过程（如冲突监测）执行期间，右侧背侧ACC多巴胺神经传递显著增加，这与先前功能磁共振成像（fMRI）研究的证据一致，这些研究表明在类似任务期间ACC会被激活。这些结果可能为某些与多巴胺功能障碍相关的神经疾病（如帕金森病和精神分裂症）所潜在的认知缺陷的起源提供一些见解。
