Jacobs G H, Neitz J
Vision Res. 1986;26(2):291-8. doi: 10.1016/0042-6989(86)90026-x.
The retina of the tree shrew (Tupaia belangeri) is heavily cone dominated, rods comprising less than 4% of the total photoreceptors. Spectral mechanisms and color vision were investigated in this species in both behavioral and electrophysiological experiments. In confirmation of an earlier investigation, the tree shrew was found to have a clear spectral neutral point (at ca 505 nm) and is thus a dichromat. Spectral sensitivity functions determined in an increment threshold discrimination task show two clear peaks (at ca 440 and 550-560 nm) with an intermediate region of lowered sensitivity centered at about 500 nm. Spectral sensitivity of the two cone types in this animal were determined using ERG flicker photometry. One of these cone classes has a peak at 556 nm; the other has a 444 nm peak.
树鼩（笔尾树鼩）的视网膜以视锥细胞为主，视杆细胞占总光感受器的比例不到4%。通过行为学和电生理学实验对该物种的光谱机制和色觉进行了研究。正如早期研究所证实的，树鼩有一个清晰的光谱中性点（约在505纳米处），因此是二色视者。在增量阈值辨别任务中测定的光谱敏感度函数显示出两个清晰的峰值（约在440和550 - 560纳米处），中间有一个以约500纳米为中心的敏感度降低的区域。使用视网膜电图闪烁光度法测定了这种动物两种视锥细胞类型的光谱敏感度。其中一类视锥细胞的峰值在556纳米处；另一类的峰值在444纳米处。
