Distinct Neural Substrates for Maintaining Locations and Spatial Relations in Working Memory.
Distinct Neural Substrates for Maintaining Locations and Spatial Relations in Working Memory.
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DOI：
10.3389/fnhum.2016.00594
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发表时间：
2016
影响因子：
2.9
通讯作者：
Courtney SM
中科院分区：
文献类型：
--
作者：
Blacker KJ;Courtney SM
先前的工作已经证明了工作记忆（WM）中两种类型的空间信息的维护之间的区别：空间位置和空间关系。虽然大量工作研究了空间位置等基于感觉的信息的神经机制，但人们对 WM 中如何维持空间关系知之甚少。在两个实验中，我们使用功能磁共振成像来研究早期视觉皮层在 WM 空间关系维持中的参与情况。在这两个实验中，我们发现，与单一空间位置相比，WM 中保持单一空间关系时，视觉皮层中象限特异性 BOLD 活动较少。此外，在这两个实验中，我们发现了一组一致的大脑区域，这些区域在位置与关系的维护过程中被不同程度地激活。与关系相比，维持一个位置与典型空间 WM 区域（如后顶叶皮层和前额叶区域）的更大活动相关。与位置相比，维持关系与海马旁回和楔前叶/压后皮层的更大活动相关。此外，在实验 2 中，我们操纵了 WM 负载，并进行了参与者必须维持三个空间位置或关系的试验。在这种高负载条件下，对位置与关系敏感的区域与低负载下有些不同。我们还确定了对专门用于位置或关系维护的负载敏感的区域，以及对更普遍的负载敏感的重叠区域。这些结果表明，WM 维护空间位置和关系的神经基质彼此不同，并且这些不同类型的空间信息的神经表征随负载而变化。
Previous work has demonstrated a distinction between maintenance of two types of spatial information in working memory (WM): spatial locations and spatial relations. While a body of work has investigated the neural mechanisms of sensory-based information like spatial locations, little is known about how spatial relations are maintained in WM. In two experiments, we used fMRI to investigate the involvement of early visual cortex in the maintenance of spatial relations in WM. In both experiments, we found less quadrant-specific BOLD activity in visual cortex when a single spatial relation, compared to a single spatial location, was held in WM. Also across both experiments, we found a consistent set of brain regions that were differentially activated during maintenance of locations vs. relations. Maintaining a location, compared to a relation, was associated with greater activity in typical spatial WM regions like posterior parietal cortex and prefrontal regions. Whereas maintaining a relation, compared to a location, was associated with greater activity in the parahippocampal gyrus and precuneus/retrosplenial cortex. Further, in Experiment 2 we manipulated WM load and included trials where participants had to maintain three spatial locations or relations. Under this high load condition, the regions sensitive to locations vs. relations were somewhat different than under low load. We also identified regions that were sensitive to load specifically for location or relation maintenance, as well as overlapping regions sensitive to load more generally. These results suggest that the neural substrates underlying WM maintenance of spatial locations and relations are distinct from one another and that the neural representations of these distinct types of spatial information change with load.