Decoding complex flow-field patterns in visual working memory
Decoding complex flow-field patterns in visual working memory
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DOI：
10.1016/j.neuroimage.2014.01.025
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发表时间：
2014-05-01
期刊：
影响因子：
5.7
通讯作者：
Haynes, John-Dylan
中科院分区：
文献类型：
--
作者：
Christophel, Thomas B.;Haynes, John-Dylan
视觉工作记忆的研究已经有了很长的历史。虽然早期的研究集中在外侧前额叶皮质在存储感觉信息中的作用，但这一点受到了人类研究的挑战，这些研究直接评估了知觉内容的编码，指出视觉和顶叶区域在存储过程中的作用。在之前的一项研究中，我们使用模式分类来研究复杂视觉颜色模式在延迟期的存储。这揭示了这种内容在早期视觉和顶脑区域的编码。在这里，我们的目的是调查视觉和顶叶皮质的参与是否也可以观察到其他类型的复杂的视觉空间模式刺激。具体地说，我们使用功能磁共振成像和多变量分类相结合的方法来研究由随机点运动轨迹的空间模式定义的复杂流场刺激的保留。受试者接受了记忆这些刺激的精确空间布局的训练，并在较长的延迟时间内保留了这些信息。我们使用多变量解码方法来识别大脑区域，在这些区域中，活动的空间模式编码了记忆中的刺激。在运动敏感视区MT+和顶叶后皮质可以观察到内容特异性记忆信号，这可能以一种通道无关的方式编码空间信息。有趣的是，我们还在躯体感觉皮层中发现了有关记忆视觉刺激的信息，这表明可能是跨模式对记忆的贡献。因此，我们的发现表明，视觉知觉的工作记忆存储可能分布在单通道、多通道甚至跨通道的大脑区域。(C)2014 Elsevier Inc.保留所有权利。
There has been a long history of research on visual working memory. Whereas early studies have focused on the role of lateral prefrontal cortex in the storage of sensory information, this has been challenged by research in humans that has directly assessed the encoding of perceptual contents, pointing towards a role of visual and parietal regions during storage. In a previous study we used pattern classification to investigate the storage of complex visual color patterns across delay periods. This revealed coding of such contents in early visual and parietal brain regions. Here we aim to investigate whether the involvement of visual and parietal cortex is also observable for other types of complex, visuo-spatial pattern stimuli. Specifically, we used a combination of fMRI and multivariate classification to investigate the retention of complex flow-field stimuli defined by the spatial patterning of motion trajectories of random dots. Subjects were trained to memorize the precise spatial layout of these stimuli and to retain this information during an extended delay. We used a multivariate decoding approach to identify brain regions where spatial patterns of activity encoded the memorized stimuli. Content-specific memory signals were observable in motion sensitive visual area MT+ and in posterior parietal cortex that might encode spatial information in a modality independent manner. Interestingly, we also found information about the memorized visual stimulus in somatosensory cortex, suggesting a potential crossmodal contribution to memory. Our findings thus indicate that working memory storage of visual percepts might be distributed across unimodal, multimodal and even crossmodal brain regions. (C) 2014 Elsevier Inc. All rights reserved.