正常人工作记忆不同认知成分的fMRI研究

An fMRI study for different cognition components of working memory in normal subjects

目的:采用事件相关功能磁共振成像(ER-fMRI)探讨工作记忆(working memory,WM)不同认知成分即编码、维持和提取的脑神经机制。方法:16名正常受试者接受了Sternberg项目认知任务(sternberg item recognition task,SIRT)的功能磁共振成像。采用低、高负荷任务。结果:编码期左侧PMA、左枕叶、左顶叶、双侧DLPFC及颞叶激活;维持期为双侧DLPFC、左侧VLPFC、双侧PMA、左顶叶、左枕叶及颞叶后部、左颞叶;提取期为辅助运动区/扣带、双PMA、左DLPFC、左VLPFC、左IPL及左颞叶。随负载增加编码期激活增加脑区为左侧PMA、枕叶及DLPFC;维持期为双侧PMA、左侧VLPFC、左IPL及左枕叶;提取期为SMA/CMA、左PMA及DLPFC。结论:不同的WM认知成分具有不同的功能脑区,同一脑区可具有不同认知功能。

Objective：Tiffs study investigated neural mechanism associated with the temporally separated encoding, maintenance and retrieval process of working memory （WM） using event-related fMRI （ER-tMRI）. Methods： Sixteen healthy subjects completed a low, high load version of the Sternberg Item Recognition Task during ER-fMRI. Results： Eencodlng phase revealed significant activation in a distributed network of regions including left PMA, left occipital lobe, left parietal lobe, bilateral DLPFC, and temporal lobe. For high load level, activation of left PMA, occipital lobe and DLPFC increased. Our findings of significant activation during maintenance phase were in bilateral DLPFC, left VLPFC, bilateral PMA, left parietal lobe, left occipital lobe / posterior part of temporal lobe and left tem- poral lobe. Brain regions, including bilateral PMA, left VLPFC, left IPL and occipital lobe showed increased activation for high load level. Retrieval phase revealed significant activation in SMA/CMA, bilateral PMA, left DLPFC, left VLPFC, left IPL and left temporal lobe. Retrieval related activity in SMA/CMA, left PMA and DLPFC was load related.Conclusion：Distinct neural functional regions are identified in different cognitive process of WM. Identical brain region maybe possesses different congnition function.