Abstract：
Area V4 is an intermediate-level area of the macaque visual cortical hierarchy that serves key functions in visual processing by integrating inputs from lower areas such as V1 and V2 and providing feedforward inputs to many higher cortical areas. Previous V4 imaging studies have focused on differential responses to color, orientation, disparity, and motion stimuli, but many details of the spatial organization of significant hue and orientation tuning have not been fully described. We used support vector machine (SVM) decoding of intrinsic cortical single-condition responses to generate high-resolution maps of hue and orientation tuning and to describe the organization of hue and orientation pinwheels in V4. Like V1 and V2, V4 contains maps of orientation that are organized as pinwheels. V4 also contains maps of hue that are organized as pinwheels, whose circular organization more closely represents the perception of hue than is observed in antecedent cortical areas. Unlike V1, where orientation is continuously mapped across the surface, V4 hue and orientation pinwheels are organized in limited numbers of pinwheel sequences. The organization of these sequences and the distance between pinwheels may provide insight into the functional organization of V4. Regions significantly tuned for hue occupy roughly four times that of the orientation, are largely separated from each other, and overlap by roughly 5%. This spatial organization is largely consistent with segregated inputs arising from V2 thin and interstripes. This modular organization of V4 suggests that further integration of color and shape might occur in higher areas in inferotemporal cortical.NEW & NOTEWORTHY The representation of hue and orientation in macaque monkey area V4 was determined by intrinsic cortical imaging of responses to isoluminant hues and achromatic grating stimuli. Vector summation of support vector machine (SVM) decoded single-condition responses was used to generate hue and orientation maps that, like V1 orientation maps, were both characterized by distinct pinwheel patterns. These data suggest that pinwheels are an important structure to represent different stimulus features across multiple visual cortical areas.
摘要：
区域V4是猕猴视觉皮层层次结构的中级区域，通过整合来自V1和V2等较低区域的多个功能隔室的前馈输入，并向下颞叶的许多区域提供前馈输入，在皮层视觉处理中发挥关键功能。顶叶,和前额叶皮层.虽然许多先前的V4成像研究已经分析了对颜色的差异响应，定位,视差,和运动刺激，许多细节的空间组织显著的色调和方向调整尚未得到充分描述。内在皮层单条件响应的支持向量机（SVM）解码用于生成V4中色调和方向调整的高分辨率图。与V1和V2一样，V4包含围绕风车中心组织的等向域图。V4包含由围绕风车中心的等色调域组成的色调图。与在先前的皮质区域中观察到的相比，这些风车的圆形组织更接近地代表了对色调的感知。色调显著调整的域占据取向域表面的大约四倍，很大程度上彼此隔离，重叠大约5%。色调和方向风车的空间组织及其域与V2的薄和条纹间隔室产生的大部分分离的输入基本一致。这种模块化的处理分离表明，颜色和形状的进一步整合必须发生在接受V4直接投射的下颞叶皮层区域。
