Study of the neural representation of different aspects of color perception in the inferior temporal cortex and the prefrontal cortex of the monkey

区分和分类是我们的颜色视觉的两个不同方面。一方面，我们可以区分颜色的细微差别;另一方面，我们把相似的颜色归为一组，如“红色”。为了研究颜色视觉的这些不同方面对下颞叶皮层颜色编码的影响，我们记录了两只日本猴子训练的颜色分类任务和颜色辨别任务的TE区神经元反应。在这两项任务中，当猴子凝视注视点时，测试刺激出现在中央凹上。在颜色分类任务中，注视点和眼跳点在测试刺激呈现后被显示。训练猴子在呈现红色时保持注视，并在呈现绿色时进行扫视作为测试。在颜色辨别任务中，在呈现测试颜色后同时显示两种颜色刺激（辨别刺激）。猴子们被训练向与测试相同的颜色扫视。在这两项任务中，我们使用了11种测试颜色，这些颜色从红色到绿色等间隔排列。猴子也被训练了一个简单的视觉固定任务。神经元被记录在TE区的一个子区域，其中神经元具有很强的颜色选择性，但形状选择性很小。从该区域记录的颜色选择神经元显示颜色调谐，这是非常相似的不同的任务，包括分类，歧视和简单的固定。这些结果表明，TE神经元编码精确的颜色信息独立的任务需求。

Discrimination and categorization are two different aspects of our color vision. On the one hand, we can discriminate subtle difference in color; on the other hand, we categorize similar colors into a single group such as 'red'. To study the effects of these different aspects of color vision on the color coding in the inferior temporal cortex, we recorded neuronal responses in area TE of two Japanese monkeys trained a color categorization task and a color discrimination task. In both tasks, while the monkey was gazing at the fixation spot, a test stimulus was presented on the fovea. In color categorization task, fixation point and saccade point were shown after presentation of a test stimulus. Monkeys were trained to keep fixation when reddish color was presented and to make saccade, when greenish color was presented as test. In color discrimination task, two color stimuli (discrimination stimuli) were shown simultaneously after presentation of a test color. Monkeys were trained to make saccade toward the same color as the test. In both tasks, we used eleven test colors that were arranged at equal intervals from red to green. Monkeys were also trained a simple visual fixation task. Neurons were recorded from a sub-region in area TE where neurons have strong color selectivity, but little shape selectivity. Color selective neurons recorded from this region showed color tuning which was very similar across different tasks including categorization, discrimination and simple fixation. These results suggest that TE neurons code exact color information independent of the task demand.