Relating retinotopic and object-selective responses in human lateral occipital cortex
Relating retinotopic and object-selective responses in human lateral occipital cortex
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DOI：
10.1152/jn.01383.2007
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发表时间：
2008-07-01
影响因子：
2.5
通讯作者：
Grill-Spector, Kalanit
中科院分区：
文献类型：
--
作者：
Sayres, Rory;Grill-Spector, Kalanit
人侧枕叶皮质视网膜病变与对象选择性之间的关系是什么？我们使用功能磁共振成像(FMRI)来检查LO对视网膜位置和类别的敏感性，LO是一个位于MT后面的对象选择性区域，沿皮质外侧表面。六名受试者参加了相位编码视网膜映射实验和区块设计实验，在这些实验中，来自六个不同类别的物体被呈现在视野中的六个不同位置。我们使用标准的非物体视网膜定位图刺激在LO中发现了实质性的位置调制；这种调制超出了视野图LO-1和LO-2的界限。此外，LO表现出明显的低视野偏差：更多的LO体素代表较低的对侧视野，且呈现在注视下方的物体的平均LO反应高于呈现在注视上方的对象。然而，视网膜定位刺激和物体产生的偏心效应是不同的。虽然在视网膜定位实验中，LO体素喜欢位于中心凹外的一系列偏心，但LO对中心凹呈现的物体的反应最强。最后，我们发现位置比类别对平均LO响应以及跨体素的分布响应都有更强的影响。总之，这些结果表明视网膜位置对LO的神经反应有很强的影响，并表明这些位置效应可能是通过视网膜组织来解释的。
What is the relationship between retinotopy and object selectivity in human lateral occipital (LO) cortex? We used functional magnetic resonance imaging (fMRI) to examine sensitivity to retinal position and category in LO, an object-selective region positioned posterior to MT along the lateral cortical surface. Six subjects participated in phase-encoded retinotopic mapping experiments as well as blockdesign experiments in which objects from six different categories were presented at six distinct positions in the visual field. We found substantial position modulation in LO using standard nonobject retinotopic mapping stimuli; this modulation extended beyond the boundaries of visual field maps LO-1 and LO-2. Further, LO showed a pronounced lower visual field bias: more LO voxels represented the lower contralateral visual field, and the mean LO response was higher to objects presented below fixation than above fixation. However, eccentricity effects produced by retinotopic mapping stimuli and objects differed. Whereas LO voxels preferred a range of eccentricities lying mostly outside the fovea in the retinotopic mapping experiment, LO responses were strongest to foveally presented objects. Finally, we found a stronger effect of position than category on both the mean LO response, as well as the distributed response across voxels. Overall these results demonstrate that retinal position exhibits strong effects on neural response in LO and indicates that these position effects may be explained by retinotopic organization.