NEURAL BASIS OF SHAPE REPRESENTATION AND RECOGNITION

这个子项目是许多研究子项目中的一个 由NIH/NCRR资助的中心赠款提供的资源。子项目和 研究者（PI）可能从另一个NIH来源获得主要资金， 因此可以在其他CRISP条目中表示。所列机构为 研究中心，而研究中心不一定是研究者所在的机构。 视觉系统快速准确地识别部分被遮挡的物体。我实验室的长期研究目标是确定灵长类动物的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多阶段的腹侧“形状加工”通路进行加工的。我们的目标是破译V4区的贡献，在这一途径的中间阶段，部分遮挡的处理和形状表示和物体识别一般。 在自然观看条件下，更接近观看者的视觉对象部分或完全遮挡更远的对象。由于被遮挡和遮挡对象的边界轮廓的并置，这产生了“意外的”轮廓特征。其次，被遮挡的对象的部分丢失，甚至可能在视网膜图像中被分割。为了准确地识别被遮挡的物体，尽管部分遮挡，视觉系统需要折扣偶然的轮廓特征，然后通过非模态地完成缺失的轮廓将碎片部分缝合在一起。心理学和理论证据表明，在视觉处理的早期阶段，在被遮挡和遮挡轮廓的交叉路口（T形路口）的图像特征分析是遮挡处理的基础，但神经机制尚不清楚。我们实验室的初步结果表明，清醒的灵长类动物V4神经元的反应差异代表真实的和偶然的轮廓。区域V4中的非模态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V4区对部分遮挡下的识别至关重要的假设。视觉失认症是一种枕颞通路的功能障碍，其目标识别受损。这些实验的结果将构成我们对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制定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.