Eye Movements Help Link Different Views in Scene-Selective Cortex
Eye Movements Help Link Different Views in Scene-Selective Cortex
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DOI：
10.1093/cercor/bhr357
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发表时间：
2011-09-01
期刊：
影响因子：
3.7
通讯作者：
Chun, Marvin M.
中科院分区：
文献类型：
--
作者：
Golomb, Julie D.;Albrecht, Alice R.;Chun, Marvin M.
视觉的关键是识别物体并确定其在环境中的位置。虽然最初的视觉表征必须是视位（以眼睛为中心），但与现实世界的交互需要空间位（绝对）位置信息。我们询问更高层次的人类视觉皮层（对稳定的物体识别和行动很重要）是否包含有关视网膜和/或空间位置的物体位置信息。使用功能磁共振成像多变量模式分析技术，我们在每个腹侧、背侧和早期视觉区域测试中发现了物体类别和物体位置的信息，复制了之前的报告。通过操纵固定位置和刺激位置，我们测试了这些位置表征是视网膜位还是空间位。至关重要的是，所有的位置信息都是纯粹的视网膜定位信息。当位置信息与任务无关时，甚至当空间位（而非视网膜位）刺激位置被明确强调时，这种模式仍然存在。我们还对整个扫描体积进行了“探照灯”分析，以探索额外的皮层，但再次发现主要是视网膜病变表征。缺乏明确的空间位表征表明，空间位对象的位置可能是间接计算的，并且随着每次眼球运动而不断重建。因此，尽管我们的主观印象是视觉信息是空间位的，但即使在更高层次的视觉皮层中，物体位置仍然以视网膜位坐标表示。为了探索日常世界中的视觉场景，我们不断地移动我们的眼睛，然而大多数关于场景处理的神经研究都是在眼睛固定的情况下进行的。这种先前的人类研究表明，海马体旁区（PPA）以一种高度特定的方式代表场景，可以区分全景场景的不同但重叠的视图。使用功能磁共振成像（fMRI）适应性来测量对变化的敏感性，我们询问了当在一个稳定的场景中活跃的眼球运动产生不同的视点时，这种特异性是如何受到影响的。当受试者在一个静止的空间主题场景中进行一系列扫视时，PPA适应了连续的视图，但当眼睛保持固定且场景在背景中转换时，PPA不适应，这表明主动视觉可能为PPA提供了重要的线索，使其随着时间的推移将不同的视图整合为“相同”。当场景与眼睛同步移动时，在不同的视图中保留视网膜定位信息时，适应性也很强。这些数据表明，视网膜位置的物理相似性是基本的，但视觉系统也可能利用动眼肌线索和/或全局空间位置信息，在不同视图中生成更多生态相关的场景表示。
The crux of vision is to identify objects and determine their locations in the environment. Although initial visual representations are necessarily retinotopic (eye centered), interaction with the real world requires spatiotopic (absolute) location information. We asked whether higher level human visual cortex-important for stable object recognition and action-contains information about retinotopic and/or spatiotopic object position. Using functional magnetic resonance imaging multivariate pattern analysis techniques, we found information about both object category and object location in each of the ventral, dorsal, and early visual regions tested, replicating previous reports. By manipulating fixation position and stimulus position, we then tested whether these location representations were retinotopic or spatiotopic. Crucially, all location information was purely retinotopic. This pattern persisted when location information was irrelevant to the task, and even when spatiotopic (not retinotopic) stimulus position was explicitly emphasized. We also conducted a "searchlight" analysis across our entire scanned volume to explore additional cortex but again found predominantly retinotopic representations. The lack of explicit spatiotopic representations suggests that spatiotopic object position may instead be computed indirectly and continually reconstructed with each eye movement. Thus, despite our subjective impression that visual information is spatiotopic, even in higher level visual cortex, object location continues to be represented in retinotopic coordinates.To explore visual scenes in the everyday world, we constantly move our eyes, yet most neural studies of scene processing are conducted with the eyes held fixated. Such prior work in humans suggests that the parahippocampal place area (PPA) represents scenes in a highly specific manner that can differentiate between different but overlapping views of a panoramic scene. Using functional magnetic resonance imaging (fMRI) adaptation to measure sensitivity to change, we asked how this specificity is affected when active eye movements across a stable scene generate retinotopically different views. The PPA adapted to successive views when subjects made a series of saccades across a stationary spatiotopic scene but not when the eyes remained fixed and a scene translated in the background, suggesting that active vision may provide important cues for the PPA to integrate different views over time as the "same." Adaptation was also robust when retinotopic information was preserved across views when the scene moved in tandem with the eyes. These data suggest that retinotopic physical similarity is fundamental, but the visual system may also utilize oculomotor cues and/or global spatiotopic information to generate more ecologically relevant representations of scenes across different views.