Astle Duncan E, Scerif Gaia, Kuo Bo-Cheng, Nobre Anna C
University of Oxford Oxford, UK.
Front Hum Neurosci. 2009 Apr 27;3:6. doi: 10.3389/neuro.09.006.2009. eCollection 2009.
Our representation of the visual world can be modulated by spatially specific attentional biases that depend flexibly on task goals. We compared searching for task-relevant features in perceived versus remembered objects. When searching perceptual input, selected task-relevant and suppressed task-irrelevant features elicited contrasting spatiotopic ERP effects, despite them being perceptually identical. This was also true when participants searched a memory array, suggesting that memory had retained the spatial organization of the original perceptual input and that this representation could be modulated in a spatially specific fashion. However, task-relevant selection and task-irrelevant suppression effects were of the opposite polarity when searching remembered compared to perceived objects. We suggest that this surprising result stems from the nature of feature- and object-based representations when stored in visual short-term memory. When stored, features are integrated into objects, meaning that the spatially specific selection mechanisms must operate upon objects rather than specific feature-level representations.
我们对视觉世界的表征会受到空间特异性注意偏差的调节，这种偏差灵活地取决于任务目标。我们比较了在感知到的物体与记忆中的物体中搜索与任务相关的特征。当搜索感知输入时，尽管所选的与任务相关的特征和被抑制的与任务无关的特征在感知上是相同的，但它们会引发对比鲜明的空间拓扑ERP效应。当参与者搜索记忆阵列时也是如此，这表明记忆保留了原始感知输入的空间组织，并且这种表征可以以空间特异性的方式进行调节。然而，与搜索感知到的物体相比，搜索记忆中的物体时，与任务相关的选择和与任务无关的抑制效应具有相反的极性。我们认为，这一惊人结果源于存储在视觉短期记忆中的基于特征和物体的表征的性质。存储时，特征会整合到物体中，这意味着空间特异性选择机制必须作用于物体而非特定的特征水平表征。
