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。对子项目的主要支持 子项目的首席调查员可能是由其他来源提供的， 包括美国国立卫生研究院的其他来源。为子项目列出的总成本可能 表示该子项目使用的中心基础设施的估计数量， 不是由NCRR赠款提供给次级项目或次级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质的神经活动模式中编码的，以及这种表现如何构成感知和物体识别的基础。我们刚刚公布了实验室中第一组实验的结果，这些实验研究了部分遮挡的物体在灵长类动物的大脑中是如何编码的。在日常情况下，物体经常被部分遮挡。但是，尽管部分遮挡会导致视网膜图像失真，但我们的视觉系统仍然能够稳健而高效地识别对象。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区是形状处理途径的中间阶段。我们的结果表明，V4反应比视网膜刺激更接近于感知刺激，即V4神经元不编码由于部分遮挡而可能在视网膜图像中出现的轮廓。我们的结果提供了关于视觉场景中哪些轮廓被编码以及V4响应如何有助于强健感知的见解。在第二个实验中，我们正在研究动物在进行形状匹配任务时V4神经元的活动。我们的结果表明，大约50%的V4神经元的早期活动(刺激开始后200ms)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显著相关。这些结果表明，V4区的早期活动可能会影响物体识别成绩。最后，我们对V4的颜色表征的研究揭示了一类新的V4神经元，它优先对等亮度的有色刺激做出反应，这可能在有色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.