OBJECT-RELATED ACTIVITY REVEALED BY FUNCTIONAL MAGNETIC-RESONANCE-IMAGING IN HUMAN OCCIPITAL CORTEX
OBJECT-RELATED ACTIVITY REVEALED BY FUNCTIONAL MAGNETIC-RESONANCE-IMAGING IN HUMAN OCCIPITAL CORTEX
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DOI：
10.1073/pnas.92.18.8135
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发表时间：
1995-08-29
影响因子：
11.1
通讯作者：
TOOTELL, RBH
中科院分区：
文献类型：
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作者：
MALACH, R;REPPAS, JB;TOOTELL, RBH
利用功能磁共振成像技术研究了人类视皮层从局部特征分析到物体识别的整合过程。在这里，我们报告的证据对象相关的激活。这种激活位于枕叶的外侧-后侧，正好邻接运动敏感区MT/V5的后侧，在称为外侧枕叶复合体（LO）的区域中，与大范围的纹理图案相比，LO显示出对物体图像的优先激活。这种激活不是由物体与纹理图像的傅立叶空间频率内容的全局差异引起的，由于与功率谱匹配但相位随机化的纹理相比，物体图像产生增强的LO激活，因此对物体的优先激活也不能用眼球运动的不同模式来解释：当受试者注视物体时和当他们用眼睛扫描物体时观察到类似的激活水平，额外的操作，如空间频率滤波和视觉大小的4倍变化并不影响LO激活，这些结果表明，对物体的增强反应不是低水平视觉处理的表现，一个引人注目的证据表明，LO中的活动与物体的可检测性是唯一相关的，这是由“林肯”错觉产生的，在这种错觉中，数字化成大块的物体的模糊反而增加了它们的可识别性。这种模糊导致LO激活的显著增强。尽管对物体的优先激活，但LO似乎并不参与识别过程的最后“语义”阶段。著名的面孔、普通的物体和不熟悉的三维抽象雕塑）也会以类似的程度激活它。因此，这些结果证明了人类视觉皮层中导致物体识别的处理阶段链中的中间环节。
The stages of integration leading from local feature analysis to object recognition were explored in human visual cortex by using the technique of functional magnetic resonance imaging. Here we report evidence for object-related activation. Such activation was located at the lateral-posterior aspect of the occipital lobe, just abutting the posterior aspect of the motion-sensitive area MT/V5, in a region termed the lateral occipital complex (LO), LO showed preferential activation to images of objects, compared to a wide range of texture patterns, This activation was not caused by a global difference in the Fourier spatial frequency content of objects versus texture images, since object images produced enhanced LO activation compared to textures matched in power spectra but randomized in phase, The preferential activation to objects also could not be explained by different patterns of eye movements: similar levels of activation were observed when subjects fixated on the objects and when they scanned the objects with their eyes, Additional manipulations such as spatial frequency filtering and a 4-fold change in visual size did not affect LO activation, These results suggest that the enhanced responses to objects were not a manifestation of low-level visual processing, A striking demonstration that activity in LO is uniquely correlated to object detectability was produced by the ''Lincoln'' illusion, in which blurring of objects digitized into large blocks paradoxically increases their recognizability. Such blurring led to significant enhancement of LO activation, Despite the preferential activation to objects, LO did not seem to be involved in the final, ''semantic,'' stages of the recognition process, Thus, objects varying widely in their recognizability (e.g., famous faces, common objects, and unfamiliar three-dimensional abstract sculptures) activated it to a similar degree. These results are thus evidence for an intermediate link in the chain of processing stages leading to object recognition in human visual cortex.