The perception of color is an internal label for the inferred spectral reflectance of visible surfaces. To study how spectral representation is transformed through modular subsystems of successive cortical areas, we undertook simultaneous optical imaging of intrinsic signals in macaque V1, V2, and V4, supplemented by higher-resolution electrophysiology and two-photon imaging in awake macaques. We find a progressive evolution in the scale and precision of chromotopic maps, expressed by a uniform blob-like architecture of hue responses within each area. Two-photon imaging reveals enhanced hue-specific cell clustering in V2 compared with V1. A phenomenon of endspectral (red and blue) responses that is clear in V1, recedes in V2, and is virtually absent in V4. The increase in mid- and extra-spectral hue representations through V2 and V4 reflects the nature of hierarchical processing as higher areas read out locations in chromatic space from progressive integration of signals relayed by V1.

对颜色的感知是推断可见表面光谱反射率的内部标记。为了研究光谱表示如何通过连续皮质区域的模块化子系统进行转换，我们对猕猴V1，V2和V4中的内在信号进行了同步光学成像，并辅以更高分辨率的电生理学和清醒的猕猴中的双光子成像。我们发现，在每个区域内，色调响应的统一斑点样体系结构表示了染色体图谱的规模和精度的逐步发展。与V1相比，双光子成像显示V2中增强的色相特定细胞簇。端光谱（红色和蓝色）响应的现象在V1中清晰可见，在V2中后退，而在V4中实际上不存在。