The neural basis of executive function of working memory

工作记忆是指大脑在认知功能中同时存储和加工信息的即时过程。本研究利用功能磁共振成像（fMRI）研究了执行功能的神经基础与工作记忆容量的差异。为了探究执行控制过程，我们进行了阅读广度测试（RST）和听力广度测试（LST）。选择两组被试：工作记忆容量大的被试根据阅读广度测试标记为高跨度被试（HSS），工作记忆容量小的被试标记为低跨度被试（LSS）。与对照组相比，主要在前扣带皮层（ACC）和左背外侧前额叶皮层（DLPFC）两个区域被显著激活。两组在RST和LST条件下，ACC和DLPFC的fMRI信号强度均增加。ACC和DLPFC区域也存在组间差异。行为学数据还显示，高强度刺激组比低强度刺激组表现更好。此外，ACC与DLPFC之间信号变化的相互关系在HSS中高于LSS，表明ACC与DLPFC之间的网络系统在HSS中比LSS更活跃。这些结果表明，HSS的执行功能，即注意控制系统，特别是注意力集中，比LSS更活跃。此外，研究结果证实，尽管模态特异性缓冲存在差异，但中枢执行功能的神经基础在RST和之前的LST（听广度测试）任务中是共同的。HSS的执行功能优势表现为优越的注意控制系统，即集中注意和抑制注意。由于有效的激活和抑制过程在语言加工过程中是必需的，并且是至关重要的，因此从行为数据中可以看出，HSS有效的注意控制系统有助于他们完成语言理解任务。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