Valverde Salzmann Matthias F, Bartels Andreas, Logothetis Nikos K, Schüz Almut
Department of Physiology of Cognitive Processes, Max Planck Institute for Biological Cybernetics, D-72076 Tübingen, Germany.
J Neurosci. 2012 Jun 6;32(23):7881-94. doi: 10.1523/JNEUROSCI.4832-11.2012.
Color vision is reserved to only few mammals, such as Old World monkeys and humans. Most Old World monkeys are trichromats. Among them, macaques were shown to exhibit functional domains of color-selectivity, in areas V1 and V2 of the visual cortex. Such color domains have not yet been shown in New World monkeys. In marmosets a sex-linked dichotomy results in dichromatic and trichromatic genotypes, rendering most male marmosets color-blind. Here we used trichromatic female marmosets to examine the intrinsic signal response in V1 and V2 to chromatic and achromatic stimuli, using optical imaging. To activate the subsystems individually, we used spatially homogeneous isoluminant color opponent (red/green, blue/yellow) and hue versus achromatic flicker (red/gray, green/gray, blue/gray, yellow/gray), as well as achromatic luminance flicker. In contrast to previous optical imaging studies in marmosets, we find clearly segregated color domains, similar to those seen in macaques. Red/green and red/gray flicker were found to be the appropriate stimulus for revealing color domains in single-condition maps. Blue/gray and blue/yellow flicker stimuli resulted in faint patch-patterns. A recently described multimodal vessel mapping approach allowed for an accurate alignment of the functional and anatomical datasets. Color domains were tightly colocalized with cytochrome oxidase blobs in V1 and with thin stripes in V2. Thus, our findings are in accord with 2-Deoxy-D-glucose studies performed in V1 of macaques and studies on color representation in V2. Our results suggest a similar organization of early cortical color processing in trichromats of both Old World and New World monkeys.
只有少数哺乳动物具备色觉，如旧世界猴和人类。大多数旧世界猴是三色视者。其中，猕猴在视觉皮层的V1和V2区域表现出颜色选择性的功能域。新世界猴尚未发现此类颜色域。在狨猴中，一种性连锁二分法导致了二色性和三色性基因型，使得大多数雄性狨猴色盲。在此，我们使用三色性雌性狨猴，通过光学成像来检测V1和V2对彩色和非彩色刺激的内在信号反应。为了分别激活各个子系统，我们使用了空间均匀的等亮度颜色对立刺激（红/绿、蓝/黄）以及色调与非彩色闪烁刺激（红/灰、绿/灰、蓝/灰、黄/灰），还有非彩色亮度闪烁刺激。与之前对狨猴的光学成像研究不同，我们发现了明显分离的颜色域，类似于在猕猴中看到的那些。发现红/绿和红/灰闪烁是在单条件图谱中揭示颜色域的合适刺激。蓝/灰和蓝/黄闪烁刺激产生了微弱的斑块模式。最近描述的一种多模态血管图谱方法使得功能和解剖数据集能够精确对齐。颜色域在V1中与细胞色素氧化酶斑紧密共定位，在V2中与细条纹紧密共定位。因此，我们的发现与在猕猴V1中进行的2-脱氧-D-葡萄糖研究以及V2中颜色表征的研究结果一致。我们的结果表明，旧世界和新世界猴的三色视者在早期皮层颜色处理方面具有相似的组织方式。
