Long-Term Monochromatic Light Exposure Does Not Alter Modular Chromatic Representation in the Visual Cortex of Rhesus Monkeys.

Long-term exposure to monochromatic light during early life has been shown to significantly impact the development of myopia. However, its effect on color processing in the visual cortex remains unclear. In this study, we investigated the effects of different lighting conditions on the functional organization of color representation in the visual cortical areas V1, V2, and V4 of rhesus monkeys raised under long-wave and short-wave monochromatic illumination for four years. Using cytochrome oxidase staining and intrinsic signal optical imaging, we found that the sizes, densities, and response strengths of cortical color domains in V1, V2, and V4 were consistent across illumination conditions. In addition, the cortical distances between specific hue response patches did not significantly differ among the groups. These findings suggested that long-term monochromatic illumination does not alter the spatial organization or functional properties of color domains in the visual cortex of rhesus monkeys. This research provides new insights into the resilience of the visual system's chromatic representation despite altered lighting conditions in early life.