An event-related fMRI study of the neural networks underlying the encoding, maintenance, and retrieval phase in a delayed-match-to-sample task
An event-related fMRI study of the neural networks underlying the encoding, maintenance, and retrieval phase in a delayed-match-to-sample task
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DOI：
10.1016/j.cogbrainres.2004.10.010
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发表时间：
2005-05-01
期刊：
影响因子：
--
通讯作者：
Stern, Y
中科院分区：
文献类型：
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作者：
Habeck, C;Rakitin, BC;Stern, Y
超过工作记忆 (WM) 有限容量的记忆负载已被证明会扩大参与工作记忆的前额叶区域，并揭示出显着的个体表现差异。我们在事件相关的功能磁共振成像研究中使用了延迟匹配样本（DMS）任务来绘制与超容量负荷相关的扩展区域激活的完整范围。将 6 个字母的研究数组与 1 个和 3 个字母的数组进行比较。该任务包括单独的编码、保留和检索 fMRI 时期。对所有任务时期的数据应用全脑空间协方差分析，以识别相关区域激活的模式，其表达在逐个受试者的基础上在 3 个记忆负荷水平上单调增加。这种与负载相关的激活模式存在于所有任务阶段。最令人感兴趣的是在维持阶段获得的激活模式：随着记忆负荷的增加激活不仅在外侧前额叶皮层（BA 9,44）中发现，而且在顶叶（BA 7,40）、前扣带回（BA 32）和小脑中也发现。枕颞叶 (BA 19,39) 和内侧前额叶皮层 (BA 9,10) 的激活减少。受试者模式表达从 1 项增加到 6 项与相应的反应音调增加呈正相关 (p < 0.05)，与 NARTIQ 呈负相关 (p < 0.05)，这表明反应较快且 NARTIQ 较高的人必须较少增加受试者对记忆负荷相关激活模式的表达，并且在认知任务中效率更高。因此，我们的方法不仅重现了其他 WM 研究的结果，而且还解决了任务期间外侧 PFC 与大脑其他部分之间相互作用的问题，以保留要记住的信息。还讨论了编码和检索阶段的负载相关激活模式及其与行为的关系。 (c) 2004 Elsevier B.V. 保留所有权利。
Memory loads exceeding the limited capacity of working memory (WM) have been shown to expand the prefrontal areas that participate in WM and have revealed substantial individual differences in performance. We used a delayed-match-to-sample (DMS) task in an event-related fMRI study to map the full extent of the expanded regional activations associated with supracapacity loads. A 6-letter study array was compared to arrays of 1 and 3 letters. The task comprised separate encoding, retention, and retrieval fMRI epochs. A brain-wide spatial covariance analysis was applied to the data of all task epochs to identify patterns of correlated regional activations whose expression increased monotonically across 3 memory-load levels on a subject-by-subject basis. Such load-related activation patterns were in all task phases. Of greatest interest is the activation pattern that was obtained during the maintenance phase: increasing activation with memory load was found not only in the lateral PFC (BA 9,44) but also in the parietal lobe (BA 7,40), anterior cingulate (BA 32), and cerebellum. Decreasing activation was found in the occipito-temporal lobe (BA 19,39) as well as the medial prefrontal cortex (BA 9,10). Subject increases in pattern expression from 1 to 6 items were positively correlated with the corresponding reaction tune increases (p < 0.05) and negatively correlated with NARTIQ (p < 0.05), indicating that people who were faster in their responses and had higher NARTIQ had to increase their subject expression of the memory-load-related activation pattern less and were more efficient at the cognitive task. Our method thus not only reproduced findings of other WM studies but also addressed the issue of interactions between lateral PFC and other parts of the brain during the task, for the retention of the to-be-remembered information. The load-related activation patterns from encoding and retrieval phase and their relationship to behavior are also discussed. (c) 2004 Elsevier B.V. All rights reserved.