NEURAL BASIS OF SHAPE REPRESENTATION AND RECOGNITION

这个子项目是利用资源的许多研究子项目之一 由NIH/NCRR资助的中心拨款提供。子项目的主要支持 而子项目的主要调查员可能是由其他来源提供的， 包括其它NIH来源。 列出的子项目总成本可能 代表子项目使用的中心基础设施的估计数量， 而不是由NCRR赠款提供给子项目或子项目工作人员的直接资金。 我实验室的研究目标是了解视觉刺激的形式和颜色是如何在视觉皮层的神经活动模式中编码的，以及这种表征如何成为感知和物体识别的基础。我们刚刚发表了实验室第一组实验的结果，这些实验研究了部分被遮挡的物体是如何在灵长类动物的大脑中编码的。在日常情况下，物体通常被部分遮挡。但是，尽管部分遮挡导致视网膜图像失真，我们的视觉系统仍然能够稳健有效地识别物体。为了研究这是如何实现的，我们研究了V4区神经元的反应，V4区是形状加工途径的中间阶段。我们的研究结果表明，V4的反应更接近类似于感知的刺激比视网膜刺激，即V4神经元不编码的轮廓，可能会出现在视网膜图像中的结果，部分闭塞。我们的研究结果提供了深入了解轮廓编码的视觉场景和V4的反应如何可能有助于强大的感知。在第二个实验中，我们正在研究V4神经元的活动，因为动物正在进行形状匹配任务。我们的研究结果表明，大约50%的V4神经元的早期活动（刺激开始后200 ms）与行为密切相关。此外，动物的行为与三分之一的神经元的活动密切相关。这些结果表明，V4区的早期活动可能会影响物体识别性能。最后，我们对V4中颜色表征的研究揭示了一类新的V4神经元，它优先响应等亮度的彩色刺激，这可能在色彩定义的轮廓中发挥重要作用。

This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. Primary support for the subproject and the subproject's principal investigator may have been provided by other sources, including other NIH sources. The Total Cost listed for the subproject likely represents the estimated amount of Center infrastructure utilized by the subproject, not direct funding provided by the NCRR grant to the subproject or subproject staff. The goal of research in my laboratory is to understand how the form and color of visual stimuli are encoded in the neural activity patterns in the visual cortex and how this representation underlies perception and object recognition. We have just published the results from the first set of experiments in the laboratory which investigate how partially occluded objects are encoded in the primate brain. In everyday situations, objects are often partially occluded. But, despite retinal image distortions caused by partial occlusion, our visual system recognizes objects robustly and efficiently. To investigate how this is achieved, we studied the responses of neurons in area V4, an intermediate stage in the shape processing pathway. Our results indicate that V4 responses more closely resemble the perceived stimulus than the retinal stimulus, i.e. V4 neurons do not encode contours that are likely to arise in the retinal image as a result of partial occlusion. Our results provide insights into which contours are encoded in the visual scene and how V4 responses might contribute to robust perception. In a second experiment, we are studying the activity of V4 neurons as the animal is engaged in a shape matching task. Our results indicate that the early activity ( 200ms after stimulus onset) of roughly 50% of V4 neurons is strongly correlated with behavior. Further, animal behavior is significantly correlated with the activity of a third of the neurons. These results suggest that early activity in area V4 might inform object recognition performance. Finally, our investigations into color representation in V4 have revealed a novel class of V4 neuron that responds preferentially to colored stimuli at equiluminance which could play an important role in chromatically-defined contours.