Nishimoto Shinji, Huth Alexander G, Bilenko Natalia Y, Gallant Jack L
Helen Wills Neuroscience Institute, University of California, Berkeley, CA, USACenter for Information and Neural Networks, NICT and Osaka University, Osaka,
Helen Wills Neuroscience Institute, University of California, Berkeley, CA, USA.
J Vis. 2017 Jan 1;17(1):11. doi: 10.1167/17.1.11.
During natural vision, humans make frequent eye movements but perceive a stable visual world. It is therefore likely that the human visual system contains representations of the visual world that are invariant to eye movements. Here we present an experiment designed to identify visual areas that might contain eye-movement-invariant representations. We used functional MRI to record brain activity from four human subjects who watched natural movies. In one condition subjects were required to fixate steadily, and in the other they were allowed to freely make voluntary eye movements. The movies used in each condition were identical. We reasoned that the brain activity recorded in a visual area that is invariant to eye movement should be similar under fixation and free viewing conditions. In contrast, activity in a visual area that is sensitive to eye movement should differ between fixation and free viewing. We therefore measured the similarity of brain activity across repeated presentations of the same movie within the fixation condition, and separately between the fixation and free viewing conditions. The ratio of these measures was used to determine which brain areas are most likely to contain eye movement-invariant representations. We found that voxels located in early visual areas are strongly affected by eye movements, while voxels in ventral temporal areas are only weakly affected by eye movements. These results suggest that the ventral temporal visual areas contain a stable representation of the visual world that is invariant to eye movements made during natural vision.
在自然视觉过程中，人类频繁进行眼球运动，但却能感知到一个稳定的视觉世界。因此，人类视觉系统很可能包含对眼球运动具有不变性的视觉世界表征。在此，我们展示一项旨在识别可能包含眼球运动不变性表征的视觉区域的实验。我们使用功能磁共振成像来记录四名观看自然电影的人类受试者的大脑活动。在一种情况下，受试者被要求稳定注视，而在另一种情况下，他们被允许自由进行随意的眼球运动。每种情况下使用的电影都是相同的。我们推断，在对眼球运动具有不变性的视觉区域中记录到的大脑活动，在注视和自由观看条件下应该是相似的。相反，对眼球运动敏感的视觉区域的活动在注视和自由观看之间应该有所不同。因此，我们测量了在注视条件下同一部电影重复呈现时大脑活动的相似性，以及分别在注视和自由观看条件之间的相似性。这些测量值的比率被用于确定哪些脑区最有可能包含眼球运动不变性表征。我们发现，位于早期视觉区域的体素受眼球运动的影响很大，而腹侧颞叶区域的体素受眼球运动的影响较小。这些结果表明，腹侧颞叶视觉区域包含一个对自然视觉过程中所做的眼球运动具有不变性的视觉世界稳定表征。
