Neural sources of visual working memory maintenance in human parietal and ventral extrastriate visual cortex
Neural sources of visual working memory maintenance in human parietal and ventral extrastriate visual cortex
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DOI：
10.1016/j.neuroimage.2015.01.059
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发表时间：
2015-04-15
期刊：
影响因子：
5.7
通讯作者：
Hopf, Jens-Max
中科院分区：
文献类型：
--
作者：
Becke, Andreas;Mueller, Notger;Hopf, Jens-Max
维持视觉工作记忆中的信息是可靠的指标对侧延迟活动（CDA）-持续调制的事件相关电位（ERP）与地形最大后头皮区域对侧的记忆输入。根据头皮地形，假设CDA反映了顶叶皮层的神经活动，但从未确定潜在电活动的精确皮层起源。在这里，我们结合联合收割机ERP记录与脑磁图为基础的源定位，以表征皮层电流源产生的CDA。观察者对样本任务进行线索延迟匹配，其中颜色或颜色点的相对位置必须在记忆中保持。在保留间隔的磁活动的详细的源定位分析显示，CDA（mCDA）的磁模拟产生的顶叶皮层中的电流源。重要的是，我们发现mCDA还接收腹侧纹外皮质中电流源的贡献，这些电流源显示出与顶叶来源相似的时间过程。的磁响应的基础上，ERP数据的正向建模显示，腹侧源有非最佳的预测，这些来源，因此隐藏在ERP重叠领域与顶叶投影。目前的观察表明，视觉工作记忆的维持，如CDA索引，涉及顶叶皮层区域以及腹侧纹外区，其中编码的记忆内容的感觉表征。(C)2015爱思唯尔公司All rights reserved.
Maintaining information in visual working memory is reliably indexed by the contralateral delay activity (CDA) - a sustained modulation of the event-related potential (ERP) with a topographical maximum over posterior scalp regions contralateral to the memorized input. Based on scalp topography, it is hypothesized that the CDA reflects neural activity in the parietal cortex, but the precise cortical origin of underlying electric activity was never determined. Here we combine ERP recordings with magnetoencephalography based source localization to characterize the cortical current sources generating the CDA. Observers performed a cued delayed match to sample task where either the color or the relative position of colored dots had to be maintained in memory. A detailed source-localization analysis of the magnetic activity in the retention interval revealed that the magnetic analog of the CDA (mCDA) is generated by current sources in the parietal cortex. Importantly, we find that the mCDA also receives contribution from current sources in the ventral extrastriate cortex that display a time-course similar to the parietal sources. On the basis of the magnetic responses, forward modeling of ERP data reveals that the ventral sources have non-optimal projections and that these sources are therefore concealed in the ERP by overlapping fields with parietal projections. The present observations indicate that visual working memory maintenance, as indexed by the CDA, involves the parietal cortical regions as well as the ventral extrastriate regions, which code the sensory representation of the memorized content. (C) 2015 Elsevier Inc. All rights reserved.