FitzGibbon Thomas, Eriköz Bahar, Grünert Ulrike, Martin Paul R
School of Medical Sciences, University of Sydney, Sydney, NSW, 2006, Australia.
Department of Optometry and Vision Sciences, University of Melbourne, Vic., 3053, Australia.
J Comp Neurol. 2015 Sep 1;523(13):1948-66. doi: 10.1002/cne.23772. Epub 2015 Jul 14.
Marmosets are diurnal New World monkeys that show sex-linked cone photopigment polymorphism, whereby all males and some females are dichromats ("red-green colorblind"), but most females show trichromatic color vision. Here we asked whether trichromats express chromatic-specific circuitry in the lateral geniculate nucleus (LGN). The volume of parvocellular (P), magnocellular (M), and koniocellular (K) layers was calculated in Nissl-stained sections from the LGN of adult marmosets (Callithrix jacchus; 10 trichromatic females; 2 dichromatic females; and 13 dichromatic males). Retinal ganglion cell axon terminals within the P and K layers were reconstructed and measured following anterograde tracer (dextran) injections. We show that there is little difference in LGN layer volume with respect to age, weight, or sex of the animals, or between dichromatic and trichromatic phenotypes. The morphology of retinal ganglion cell terminals was largely indistinguishable on comparing dichromats and trichromats, and likewise on comparing terminals representing peripheral or foveal retina. We conclude that the LGN circuits we studied are largely independent of red-green color vision phenotype and visual field location.
狨猴是昼行性的新大陆猴，表现出与性别相关的视锥色素多态性，即所有雄性和部分雌性为二色视者（“红绿色盲”），但大多数雌性表现出三色视觉。在此，我们探究了三色视者在外侧膝状体核（LGN）中是否表达特定颜色的神经回路。在成年狨猴（普通狨猴；10只三色视雌性；2只二色视雌性；13只二色视雄性）LGN的尼氏染色切片中，计算了小细胞层（P）、大细胞层（M）和小细胞层（K）的体积。在进行顺行示踪剂（右旋糖酐）注射后，重建并测量了P层和K层内视网膜神经节细胞轴突终末。我们发现，LGN层体积在动物的年龄、体重或性别方面，以及在二色视和三色视表型之间几乎没有差异。比较二色视者和三色视者时，以及比较代表周边视网膜或中央凹视网膜的终末时，视网膜神经节细胞终末的形态在很大程度上难以区分。我们得出结论，我们所研究的LGN神经回路在很大程度上独立于红绿色觉表型和视野位置。
