NEURAL BASIS OF SHAPE REPRESENTATION AND RECOGNITION

这个子项目是许多研究子项目中利用 资源由NIH/NCRR资助的中心拨款提供。子项目和 调查员(PI)可能从NIH的另一个来源获得了主要资金， 并因此可以在其他清晰的条目中表示。列出的机构是 该中心不一定是调查人员的机构。 视觉系统快速准确地识别被部分遮挡的对象。我实验室研究的长期目标是确定灵长类视觉系统是如何实现这一点的。先前的研究已经证明，到达我们眼睛的视觉信息是沿着腹侧的多阶段“形状处理”途径进行处理的。我们的目标是破译V4区，这是这条通路的中间阶段，对部分遮挡的处理以及形状表征和物体识别的总体贡献。 在自然观看条件下，距离观看者较近的可视对象会部分或完全遮挡较远的对象。由于被遮挡对象和被遮挡对象的边界轮廓并置，这会产生“偶然”的轮廓特征。其次，被遮挡的物体的部分缺失，甚至可能在视网膜图像中出现碎片。为了在部分遮挡的情况下准确地识别被遮挡的物体，视觉系统需要剔除偶然的轮廓特征，然后通过动态地补齐丢失的轮廓来缝合碎片部分。心理学和理论证据表明，在视觉加工的早期阶段，对遮挡和遮挡轮廓线(类T形交叉点)的图像特征的分析是遮挡加工的基础，但其神经机制尚不清楚。我们实验室的初步结果表明，在清醒的灵长类动物中，V4神经元的反应不同地代表了真实和意外的轮廓。区域V4中的非模式完成信号也出现在部分遮挡对象的准确识别之前。这些结果有力地支持了部分遮挡条件下V4区对识别至关重要的假说。视觉失认症是枕颞部通路的一种功能障碍，物体识别能力受损。这些实验的结果将是我们对作为物体识别基础的大脑计算的理解的重大进步，并将使我们更接近于设计缓解和治疗这种大脑疾病的策略。

This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. The visual system rapidly and accurately recognizes objects that are partially occluded. The long-term goal of research in my laboratory is to determine how this is achieved by the primate visual system. Previous research has demonstrated that visual information that reaches our eyes is processed along the multi-stage ventral "shape processing" pathway. Our goal is to decipher the contributions of area V4, an intermediate stage in this pathway, to the processing of partial occlusion and to shape representation and object recognition in general. Under natural viewing conditions, visual objects that are closer to the viewer partially or completely occlude objects that are farther away. This produces "accidental" contour features due to the juxtaposition of the bounding contours of the occluded and occluding objects. Secondly, parts of the occluded object are missing and may even be fragmented in the retinal image. To accurately recognize the occluded object despite partial occlusion, the visual system needs to discount the accidental contour features and then sew together the fragmented parts by amodally completing the missing contours. Psychological and theoretical evidence suggests that analysis of image features at the intersecting junctions of the occluded and occluding contours (T-like junctions) in the early stages of visual processing underlies processing of occlusion but the neural mechanisms are unknown. Preliminary results from our laboratory suggest that responses of V4 neurons in awake primates differentially represent real and accidental contours. Amodal completion signals in area V4 also appear before accurate recognition of the partially occluded object. These results strongly support the hypothesis that area V4 is crucial for recognition under partial occlusion. Object recognition is impaired in visual agnosia, a dysfunction of the occipitotemporal pathway. Results from these experiments will constitute a major advance in our understanding of the brain computations that underlie object recognition and will bring us closer to devising strategies to alleviate and treat this brain disorder.