The neural basis of executive function of working memory

工作记忆是指在认知功能中同时进行信息存储和加工的即时脑过程，本研究利用功能磁共振成像（fMRI）技术，从工作记忆容量差异的角度探讨了执行功能的神经基础。采用阅读广度测验和听力广度测验探讨被试的执行控制过程。两个主题组被选中：那些与大的工作记忆容量，标记高跨度主题（HSS）根据阅读跨度测试，和那些与小的工作记忆容量，标记低跨度主题（LSS）。与对照组相比，主要在两个区域发现明显的激活：前扣带回皮质（ACC）、左背外侧前额叶皮质（DLPFC）。对于两组来说，ACC和DLPFC的fMRI信号强度增加，在LST条件下。在ACC和DLPFC区域也发现了组间差异。行为数据还显示， 关于我们 HSS组的各项指标均优于LSS组。此外，ACC和DLPFC之间的信号变化的交叉相关性在HSS中高于LSS，表明ACC和DLPFC之间的网络系统在HSS中比在LSS中更活跃。这些结果表明，执行功能，即，注意控制系统，特别是注意集中在HSS比LSS更活跃。此外，研究结果证实，尽管在特定于模态的缓冲区中存在差异，但在先前的LST（听力广度测试）任务中，中央执行功能的神经基础是共同的。HSS的执行功能的优势将表现为上级的注意控制系统：即，集中注意力和抑制注意力。由于有效的激活和抑制过程是必需的，并且在语言处理中非常关键，HSS的有效注意控制系统促进了他们的语言理解任务，如在行为数据中观察到的。少

Working memory refers to the immediate brain processes involved in the simultaneous storage and processing of information in cognitive function.In the present research, using fMRI, neural bases of the executive function were investigated with respect to differences in working memory capacity. To explore the executive control processes, Reading span test (RST) and Listening span test (LST) were performed. Two subject groups were selected : those with large working memory capacities, labeled high-span subjects (HSS) according to the reading span test, and those with small working memory capacities, labeled low-span subjects (LSS). Significant activation was found mainly in two regions in comparison with the control : anterior cingulate cortex (ACC), left dorsolateral prefrontal cortex (DLPFC). For both groups, the fMRI signal intensity increased in ACC and DLPFC during the RST and LST condition. A group difference was also found in the ACC and DLPFC region. Behavioral data also showed th … More at the performance was better in HSS than in LSS. Moreover, the cross correlation of signal change between ACC and DLPFC was higher in HSS than in LSS, indicating that the network system between ACC and DLPFC was more activated in HSS compared to that of LSS. These results suggest that the executive function, i.e., attention controlling system especially focusing of attention is more active in HSS than in LSS. Moreover, the results confirmed that the neural basis for the central executive function was common in both RST and previous LST (listening span test) tasks despite differences in modality-specific buffers.The advantage of executive function of HSS would take the form of a superior attention controlling system : i.e., focusing attention and inhibition of attention. Since effective activation and inhibition processes are required and highly crucial in the language processing, the HSS's efficient attention controlling system facilitates their language comprehension tasks as observed in behavioral data. Less