V4 lesions in macaques affect both single- and multiple-viewpoint shape discriminations
V4 lesions in macaques affect both single- and multiple-viewpoint shape discriminations
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DOI：
10.1017/s0952523898152112
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发表时间：
1998-03-01
影响因子：
1.9
通讯作者：
Pham, HA
中科院分区：
文献类型：
--
作者：
Merigan, WH;Pham, HA
通过测试猕猴V4病变对从不同视角视觉区分三维（3D）物体图像的能力的影响，研究了皮质区V4在复杂形状辨别中的作用。刺激成对出现在离中央凹约4度的左下或下光视野象限中，猴子在每次试验中判断两个视图是相同还是不同的对象。改变对象相似性以确定阈值形状差异。V4病变引起了深刻的，retinotopic，显然是永久性的中断歧视。无论图像是代表单个还是多个视角。在V4受损的部分视野中，猴子只有在物体的形状与对照位置相比差异更大时才能区分物体。这些损伤的影响几乎是相同的歧视，已经学习之前，病变被放置和那些学习之后。在以前的研究中，V4病变提高对比度阈值约2倍，但对照观察表明，这不是形状歧视的破坏的基础。操纵线索的形状表明，在控制位置，猴子保持良好的形状歧视，尽管各种刺激的变化，而在V4病变区，他们的表现很容易被打乱。这一发现表明，V4可能通过促进使用多种视觉线索来支持视觉形状辨别。然而，事实上，单视点和多视点的歧视受到类似的影响，这表明中断是不是特定的3D形状的歧视，但可能适用于各种微妙的歧视。
The role of cortical area V4 in complex shape discriminations was studied by testing the effects of V4 lesions in macaques on the ability to visually discriminate between images of three-dimensional (3D) objects from different viewpoints. Stimuli were presented in pairs in the lower left or lower light visual field quadrants about 4 deg from the fovea, and the monkeys judged on each trial whether the two views were of the same or of different objects. Object similarity was varied to determine a threshold shape difference. V4 lesions caused profound, retinotopic, and apparently permanent disruptions of discrimination. regardless of whether the images represented single or multiple viewpoints. In V4 lesioned portions of the visual field, monkeys could discriminate objects only when they differed much more grossly in shape than was true in control locations. These effects of the lesion were virtually identical for discriminations that had been learned before lesions were placed and for those learned afterwards. As in previous studies, V4 lesions elevated contrast thresholds by approximately a factor of two, but control observations showed that this was not the basis of the disruption of shape discrimination. Manipulation of cues to shape showed that in control locations, monkeys maintained excellent shape discrimination despite a variety of stimulus alterations, whereas in V4 lesioned areas their performance was easily disrupted. This finding suggests that V4 may support visual shape discriminations by facilitating the use of multiple visual cues. However, the fact that single-viewpoint and multiple-viewpoint discriminations were similarly affected indicates that the disruption was not specific to 3D shape discrimination, but may apply re a variety of subtle discriminations.