PSYCHOPHYSICAL AND PHYSIOLOGICAL EVIDENCE FOR VIEWER-CENTERED OBJECT REPRESENTATIONS IN THE PRIMATE
PSYCHOPHYSICAL AND PHYSIOLOGICAL EVIDENCE FOR VIEWER-CENTERED OBJECT REPRESENTATIONS IN THE PRIMATE
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DOI：
10.1093/cercor/5.3.270
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发表时间：
1995-05-01
期刊：
影响因子：
3.7
通讯作者：
PAULS, J
中科院分区：
文献类型：
--
作者：
LOGOTHETIS, NK;PAULS, J
关于3D物体感知的一个关键问题是大脑用来表示它们的空间参考系。视觉系统能够快速转换存储的熟悉3D对象模型，或者能够指定视点不变特征或体积图元之间的关系，这些特征或图元可用于完成图像的结构描述，这可以解释识别过程的快速性。或者，视点不变的识别可以通过一个系统来实现，该系统具有在一组存储的2D模板之间执行插值的能力，这些模板是为每个有经验的视点创建的。训练猴子从给定的视角识别新的物体，随后测试它们对通过数学旋转物体围绕任意轴产生的视图的概括识别能力。新的物体被发现是在识别遭遇时物体视网膜投射的函数。当刺激物从熟悉的姿态旋转时，识别对猴子来说变得越来越困难。新的线状和球状物体的泛化场延伸到经验视点周围约+/-40度。当这些猴子接受训练时，只看到物体的三个视角，相隔120度，它们通常可以对围绕同一轴旋转产生的所有视角进行内插识别。在心理物理测试期间，颞下皮层的记录显示，一些神经元对猴子已经学会识别的物体的各个视角具有显著的选择性，绘制神经元的反应作为旋转角度的函数，揭示了系统的视图调谐曲线的旋转深度，一小部分的视图选择性细胞强烈响应特定的视图及其镜像对称的视图。对于一些测试对象，不同的神经元被发现对同一对象的不同视图进行调谐;视图调谐曲线的峰值相距40-50度，还发现神经元对不熟悉的对象或干扰物的视线做出反应。然而，当猴子执行简单的固定任务时，这些细胞对呈现的各种其他模式做出了非特异性反应。
A key question concerning the perception of 3D objects is the spatial reference frame used by the brain to represent them. The celerity of the recognition process could be explained by the visual system's ability to quickly transform stored models of familiar 3D objects, or by its ability to specify the relationship among viewpoint-invariant features or volumetric primitives that can be used to accomplish a structural description of an image. Alternatively, viewpoint-invariant recognition could be realized by a system endowed with the ability to perform an interpolation between a set of stored 2D templates, created for each experienced viewpoint.In the present study we set out to examine the nature of object representation in the primate in combined psychophysical-electro-physiological experiments, Monkeys were trained to recognize novel objects from a given viewpoint and subsequently were tested for their ability to generalize recognition for views generated by mathematically rotating the objects around any arbitrary axis.The perception of 3D novel objects was found to he a function of the object's retinal projection at the time of the recognition encounter, Recognition became increasingly difficult for the monkeys as the stimulus was rotated away from its familiar attitude. The generalization field for novel wire-like and spheroidal objects extended to about +/-40 degrees around an experienced viewpoint. When the animals were trained with as few as three views of the object, 120 degrees apart, they could often interpolate recognition for all views resulting from rotations around the same axis.Recordings from inferotemporal cortex during the psychophysical testing showed a number of neurons with remarkable selectivity for individual views of those objects that the monkey had learned to recognize, Plotting the response of neurons as a function of rotation angle revealed systematic view-tuning curves for rotations in depth, A small percentage of the view-selective cells responded strongly for a particular view and its mirror-symmetrical view. For some of the tested objects, different neurons were found to be tuned to different views of the same object; the peaks of the view-tuning curves were 40-50 degrees apart, Neurons were also found that responded to the sight of unfamiliar objects or distracters. Such cells, however, gave nonspecific responses to a variety of other patterns presented while the monkey performed a simple fixation task.