PREDICTIVE REPRESENTATION OF MOTION IN VISUAL CORTEX

大量的临床、行为和生理证据表明 支持了灵长类的后顶叶皮层 在环境中定位视觉刺激的重要作用， 分析视觉运动，并指导运动。 拟议 实验将检查后顶叶皮层中的一个区域， 外侧顶内区（LIP）编码预测性的 感兴趣的对象的运动的表示。 预测是 对视觉感知至关重要，支持物体的恒定性 当视觉信息不完整时，例如当 移动的对象被遮挡。 LIP神经元是否提供预测性表达的问题 视觉刺激的运动将在猕猴中进行研究 接受过行为训练的猴子 作为第一个测试， 将被识别，不依赖于视觉的存在， 刺激，例如，当移动刺激时持续存在的信号 从封堵器后面通过。神经元活动也将在 视觉刺激的预期运动不一致的情况 通过动物可能做出的动作来引导或获取 刺激。 神经元活动不能直接与感觉有关 输入或动物的移动计划可以编码预测的 表示刺激运动。 其次，如果LIP神经元预测运动，那么可以预期它们的 活动应该与动物的主观感知有关， 议案 在运动刺激被遮挡的情况下， 运动的主观感知可以通过以下方式来加强或减弱 改变封堵器相对于平面的表观深度， 运动，使用立体提示。 如果LIP活动信号 运动的预期，它应该是更强的时候，相对深度 与刺激运动一致。 在 此外，如果LIP细胞呈现明显的运动刺激， 其中感知到的运动方向是方向性的， 活动应该与动物对刺激的感知报告协变 方向 这类证据表明，LIP更 更关注刺激的预测运动而不是实际运动 运动刺激到视网膜。

A great deal of clinical, behavioral, and physiological evidence supports the notion that the posterior parietal cortex in primates plays an important role in localizing visual stimuli in the environment, in analyzing visual motion, and in guiding movements. The proposed experiments will examine whether one area in posterior parietal cortex, the lateral intraparietal area (LIP), encodes a predictive representation of the motion of objects of interest. Prediction is essential for visual perception, supporting constancy of object representation when visual information is incomplete, such as when a moving objects becomes occluded. The question of whether LIP neurons provide a predictive representation of the movement of visual stimuli will be investigated in macaque monkeys trained in behavioral tasks. As a first test, neuronal signals will be identified that do not depend on the presence of a visual stimulus, for example, signals that persist when a moving stimulus passes behind an occluder. Neuronal activity will also be compared under conditions in which the expected motion of a visual stimulus is at odds with movements that the animal might make to guide or acquire the stimulus. Neuronal activity that cannot be directly related to sensory input or the animal's plan to move may encode a predictive representation of stimulus motion. Second, if LIP neurons predict motion, it would be expected that their activity should be related to the animal's subjective perception of motion. In the case of a moving stimulus that becomes occluded, the subjective perception of motion can be strengthened or weakened by changing the apparent depth of the occluder relative to the plane of motion, using stereoscopic cues. If LIP activity signals the expectation of motion, it should be stronger when the relative depths of the occluder and stimulus are consistent with stimulus motion. In addition, if LIP cells are presented with an apparent motion stimulus in which the perceived direction of motion is bistable, the cells' activity should covary with the animal's perceptual report of stimulus direction. Evidence of this sort would suggest that LIP is more concerned with the predicted motion of the stimulus than with the actual motion stimulus to the retina.