The influence of working memory load on phase specific patterns of cortical activity
The influence of working memory load on phase specific patterns of cortical activity
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DOI：
10.1016/j.cogbrainres.2004.06.014
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发表时间：
2004-11-01
期刊：
影响因子：
--
通讯作者：
Ngan, ETC
中科院分区：
文献类型：
--
作者：
Cairo, TA;Liddle, PF;Ngan, ETC
本研究探讨了与工作记忆任务的编码、维持和提取相关联的大脑皮层活动模式。18名健康受试者完成了Sternberg项目识别任务的可变负荷版本。为每个任务阶段确定了显示平均活动的大脑区域。此外，还确定了显示活动随负荷线性增加的大脑区域，以进行编码和检索。尽管以前的fMRI研究使用了事件相关设计来分离特定阶段的活动，但这项研究的不同之处在于，设计和分析方法得到了优化，以确保感兴趣条件之间的低多重共线性：中间阶段(维持)的持续时间是不同的，并且针对编码和检索阶段选择性地对负载进行建模。脑部区域显示。各阶段负荷的平均活跃度结合在一起，涵盖了先前研究中确定的没有尝试分离特定阶段活跃度的区域。编码与广泛的负荷依赖活动相关，其中双侧枕区和顶后区的活动最强烈。恢复与更多的选择性负荷依赖活动有关，主要是在前部辅助运动区和右侧小脑后部。这项研究中采用的分析策略可以用来进一步描绘在有WM干扰的临床人群中最严重的WM阶段。(C)2004爱思唯尔B.V.保留所有权利。
This study investigated patterns of cortical activity associated with the temporally separated encoding, maintenance and retrieval phases of a working memory (WM) task. Eighteen healthy subjects completed a variable load version of the Sternberg Item Recognition Task. Brain regions showing activity on average across load were determined for each task phase. In addition, brain regions showing activity that increased linearly with load were determined for encoding and retrieval. Although previous fMRI studies have used event-related designs to isolate phase specific activity, this study differed in that design and analysis methods were optimized to ensure low multicollinearity between the conditions of interest: the duration of the intermediate phase (maintenance) was varied and load was selectively modeled for the encoding and retrieval phases. The brain areas showing. activity on average across load for each phase combine to encompass regions identified in previous studies that have not attempted to separate phase specific activity. Encoding is associated with extensive load dependent activity, with the most robust activity in bilateral occipital and posterior parietal regions. Retrieval is associated with more selective load dependent activity, primarily in the anterior supplementary motor region and the right posterior cerebellum. The analysis strategies employed in this study could be used to further delineate the phases of WM that are most severely compromised in clinical populations with WM disturbances. (C) 2004 Elsevier B.V. All rights reserved.