工作记忆中整合物体和位置信息时的前额叶激活  

Prefrontal activation for integration of object and location in working memory

作　　者：张燕贞[1] Xia ZHAo Ai-Ling LIN Jia-Hong GAO 张学新[1] 

机构地区：[1]汕头大学医学院广东省医学分子影像重点实验室,广东汕头515041 [2]美国得克萨斯州立大学圣安东尼奥健康科学中心影像研究中心,得克萨斯,美国

出　　处：《中国医学影像技术》2007年第6期837-840,共4页Chinese Journal of Medical Imaging Technology

基　　金：国家自然科学基金面上项目青年科学基金(30200068);国家自然科学基金重大国际合作项目(30420120048);国家自然科学基金面上项目(30570606)资助

摘　　要：目的利用功能磁共振成像(fMRI)技术研究了情节缓存中信息整合过程的脑机制。方法8名正常被试在MR扫描中执行工作记忆任务,“组合”(bound)条件下物体出现在外周某个位置,“未组合”(unbound)条件下,同时呈现一个位于中心的物体和一个在外周某个位置的十字,让被试将物体想象到十字所在位置,要求被试判断再次出现的物体是否在曾经见过的位置(“组合”条件)或曾经想象过的位置(“未组合”条件)。结果“未组合”条件相对于知觉“组合”条件,在双侧额中回/额下回、顶叶和小脑等区域出现了显著激活;“组合”条件相对于"未组合”条件没有任何激活。结论本研究表明前额叶皮层在没有知觉表征情况下建立新的整合表征中具有重要作用。现有研究已证明前额叶皮层在建构和保持整合信息中的作用,本文进一步的研究提示它可能是情节缓存中信息整合的神经基础。Objective To explore the neural basis of the information integration process that is critical to the episodic buffer using functional magnetic resonance imaging （fMRI）. Methods Eight normal subjects were instructed to perform a working memory task while being scanned with a 1.9 T MRI scanner. In the bound condition, subjects saw three displays in sequence, each with one object at a periphery location. While in the unbound condition, one central object and one peripheral cross were simultaneously presented, subjects were told to first picture the object in the location marked by tbe cross, and then to remember the object location pairing as in the bound condition. Subjects were to determine if the probe object occu pied its original location （in the bound condition） or its imaginary location （in the unbound condition）. Results Regions in bilateral middle / inferior frontal gyrus, parietal cortex and cerebellum were found activated when participants constructed coherent representations of object and location that were perceptually unbound, relative to when these information were perceptually bound. Meanwhile, there were no activation for the bound condition versus unbound condition. Conclusion Resuits demonstrate a clear involvement of prefrontal cortex in the creation of new cognitive representations that are not perceptually given. With existing evidence identifying prefrontal cortex in chunking and maintaining integrated representations, this study further characterizes the neural basis of information integration process in the episodic buffer.

关 键 词：情节缓存 工作记忆 整合 前额叶皮层 磁共振成像 功能性 

分 类 号：R445.2[医药卫生—影像医学与核医学]