Is Neocortical-Hippocampal Connectivity a Better Predictor of Subsequent Recollection than Local Increases in Hippocampal Activity? New Insights on the Role of Priming
Is Neocortical-Hippocampal Connectivity a Better Predictor of Subsequent Recollection than Local Increases in Hippocampal Activity? New Insights on the Role of Priming
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DOI：
10.1162/jocn.2010.21454
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发表时间：
2011-02-01
影响因子：
3.2
通讯作者：
Eustache, Francis
中科院分区：
文献类型：
--
作者：
Gagnepain, Pierre;Henson, Richard;Eustache, Francis
在记忆编码过程中，海马体活动的增加被认为反映了不同类型的信息结合成独特的情节已经被证明与随后对这些情节的回忆有关。重复启动被认为能诱导更有效的刺激感知处理通常与新皮层活动减少有关，通常被认为能减少情景记忆的编码。在这里，我们使用功能磁共振成像比较活动，启动和未启动的听觉单词在分散注意力的声音作为一个功能的参与者随后是否回忆的单词的声音协会，或只有一个熟悉的感觉，在随后的惊喜识别任务的话。在行为水平上，启动增加了随后回忆的发生率。在神经元水平上，启动降低了上级颞回（STG）的活动，但也逆转了传统的编码相关海马活动的增加与随后的回忆相对于随后的熟悉。为了解释这种互动模式，进一步分析使用动态因果模型显示，增加连接从左STG到左海马体特定的话，后来回忆。这些研究结果表明，成功的情节编码是不完全由本地海马活动，而不是强调增加功能的新皮质-海马耦合的重要性。这种耦合可能是一个更好的预测随后的回忆比局部海马变化本身的方向。我们建议，启动的后果之一是“释放”注意力资源从处理一个项目在嘈杂的背景下，从而使更多的注意编码的情况下。
During memory encoding, increased hippocampal activity-thought to reflect the binding of different types of information into unique episodes-has been shown to correlate with subsequent recollection of those episodes. Repetition priming-thought to induce more efficient perceptual processing of stimuli-is normally associated with decreased neocortical activity and is often assumed to reduce encoding into episodic memory. Here, we used fMRI to compare activity to primed and unprimed auditory words in the presence of distracting sounds as a function of whether participants subsequently recollected the word-sound associations or only had a feeling of familiarity with the word in a subsequent surprise recognition task. At the behavioral level, priming increased the incidence of subsequent recollection. At the neuronal level, priming reduced activity in the superior temporal gyrus (STG) but also reversed the traditional increase in encoding-related hippocampal activity associated with subsequent recollection relative to subsequent familiarity. To explain this interaction pattern, further analyses using dynamic causal modeling showed an increase in connectivity from left STG to left hippocampus specific to words that were later recollected. These findings show that successful episodic encoding is not determined solely by local hippocampal activity and emphasize instead the importance of increased functional neocortical-hippocampal coupling. Such coupling might be a better predictor of subsequent recollection than the direction of local hippocampal changes per se. We propose that one consequence of priming is to "free up" attentional resources from processing an item in a noisy context, thereby allowing greater attention to encoding of that context.