Transient and sustained activity in a distributed neural system for human working memory
Transient and sustained activity in a distributed neural system for human working memory
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DOI：
10.1038/386608a0
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发表时间：
1997-04-10
期刊：
影响因子：
64.8
通讯作者：
Haxby, JV
中科院分区：
文献类型：
--
作者：
Courtney, SM;Ungerleider, BG;Haxby, JV
工作记忆涉及对信息的短期保持，以便它可用于进一步处理。在视觉工作记忆任务中，受试者在短暂的延迟中保留对刺激的记忆，这需要刺激的感知编码和随后在刺激从视图中移除后对其表示的维持。这些任务激活视觉和前额叶皮层的多个区域（1-9）。为了描述这些区域在感知和工作记忆维持中的作用，我们使用功能性磁共振成像（fMRI）来获得与面部工作记忆任务的不同组成部分相关的神经活动的动态测量-对视觉刺激的非选择性瞬时反应，对面部的选择性瞬时反应和对记忆延迟的持续反应。腹侧物体视觉通路中的三个枕颞区对刺激的反应大多是短暂的，表明它们在知觉处理中的主导作用，而三个前额叶区在记忆延迟中表现出持续的活动，表明它们在工作记忆中的主导作用。然而，这种区别并不是绝对的。此外，视觉领域表现出不同程度的选择性，和前额区表现出不同的强度的持续活动，揭示了一个连续的功能专业化，从枕叶到多个前额区，关于每个区域的相对贡献知觉和记忆处理。
Working memory involves the short-term maintenance of an active representation of information so that it is available for further processing. Visual working memory tasks, in which subjects retain the memory of a stimulus over brief delays, require both the perceptual encoding of the stimulus and the subsequent maintenance of its representation after the stimulus is removed from view. Such tasks activate multiple areas in visual and prefrontal cortices(1-9). To delineate the roles these areas play in perception and working memory maintenance, we used functional magnetic resonance imaging (fMRI) to obtain dynamic measures of neural activity related to different components of a face working memory task-non-selective transient responses to visual stimuli, selective transient responses to faces, and sustained responses over memory delays. Three occipitotemporal areas in the ventral object vision pathway had mostly transient responses to stimuli, indicating their predominant role in perceptual processing, whereas three prefrontal areas demonstrated sustained activity over memory delays, indicating their predominant role in working memory. This distinction, however, was not absolute. Additionally, the visual areas demonstrated different degrees of selectivity, and the prefrontal areas demonstrated different strengths of sustained activity, revealing a continuum of functional specialization, from occipital through multiple prefrontal areas, regarding each area's relative contribution to perceptual and mnemonic processing.