COOPERATIVE INTERAREAL PROCESSING OF VISUAL CONTOURS

哺乳动物大脑皮层的特点是多皮质 区域，每个区域都有一个单独的感官世界的代表。然而，在这方面， 多重表征在感觉信息处理中作用是 未知作为了解多个皮层区域 合作处理视觉感知，这项建议旨在研究 V2（第二视觉皮层区域）内的轮廓表示，以及 它与V1（初级视觉）中轮廓表示的相互作用 皮质）。众所周知，V1中的方向选择性细胞是 响应于亮度对比度边缘。然而，许多视觉轮廓 不是由亮度对比度而是由更高阶的特征来定义的 (such如被遮挡的轮廓或纹理图案边界）。V2区 视觉皮层处理的第二个主要阶段，其特征在于： 细胞更喜欢这种高阶特征。该提案将探讨 不同的皮层区域处理不同的水平， 视觉轮廓的抽象，并研究这些如何分离 表征相互作用。具体来说，组织和互动 在对真实的轮廓敏感的细胞和对更高的轮廓敏感的细胞之间， 将检查订单轮廓。将检查这些电路， 颜色、形状和视差域中的每一个，它们一起包括 v2.所述目标将通过使用光学组合来实现。 成像、电生理和解剖学方法。V1-V2相互作用 将用互相关方法和光学成像方法进行研究 的V1-V2激活响应于"点"刺激（一个功能束 跟踪方法）;这些将与连接模式进行比较 从解剖学上揭示了这一点。此外，由于轮廓显著性的差异， 几何或特征特性将与刺激相关- 互动模式的相关变化。 通过阐明V1中轮廓知觉的神经回路， 和V2，这项研究将深入了解不同的皮质是否 区域相互强化相同的信息（即 类似定向的真实的和更高阶的轮廓单元）或更高阶的轮廓单元是否 存在一种层次关系，其中一个领域的产出是 用来在另一个区域构建一个完全不同的表示 （不同取向的真实的和高阶轮廓之间的相互作用 细胞）。或者，可以在不同的情况下使用不同的策略。 这种可能性将得到与刺激有关的 不同轮廓群的连通性或激活的变化 V2中的细胞。

The mammalian cerebral cortex is characterized by multiple cortical areas, each with a separate representation of the sensory world. However, the role of multiple representation in sensory information processing is unknown. As a prelude to understanding how multiple cortical areas cooperatively process visual percepts, this proposal aims to study contour representation within V2 (the second visual cortical area) and its interaction with contour representation in V1 (primary visual cortex). Orientation selective cells in V1 are well known to be responsive to luminance contrast edges. However, many visual contours are not defined by luminance contrast but rather by higher order features (such as occluded contours or texture pattern borders). Area V2, the second major stage of visual cortical processing, is characterized by cells which prefer such higher order features. This proposal will explore the idea that different cortical areas process different levels or abstractions of visual contours and examine how these separate representations interact. Specifically, the organization and interactions between cells responsive to real contours and those responsive to higher order contours will be examined. These circuitries will be examined for each of the color, form, and disparity domains which together comprise V2. The stated goals will be achieved by using a combination of optical imaging, electrophysiological, and anatomical methods. V1-V2 interactions will be studied with both cross correlation methods and optical imaging of V1-V2 activation in response to "spot" stimuli (a functional tract tracing method); these will be compared with connectivity patterns revealed anatomically. In addition, differences in contour saliency due to geometrical or featural characteristics will he related to stimulus- related changes in interaction patterns. By elucidating the neural circuitry underlying contour perception in V1 and V2, this research will offer insight into whether different cortical areas mutually reinforce the same information (i.e. interactions between similarly oriented real and higher order contour cells) or whether a more hierarchical relationship exists in which the outputs of one area are used to construct a quite different representation in another area (interactions between differently oriented real and higher order contour cells). Alternatively, different strategies could be used under different contexts, a possibility that would be supported by stimulus-related changes in connectivity or activation of different populations of contour cells in V2.