title: Analysis of the lateral geniculate nucleus in dichromatic and trichromatic marmosets.
abstract: 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.
authors.affiliation: School of Medical Sciences, University of Sydney, Sydney, NSW, 2006, Australia.
authors.forename: Thomas
authors.initials: T
authors.lastname: FitzGibbon
authors.affiliation: Department of Optometry and Vision Sciences, University of Melbourne, Vic., 3053, Australia.
authors.forename: Bahar
authors.initials: B
authors.lastname: Eriköz
authors.affiliation: School of Medical Sciences, University of Sydney, Sydney, NSW, 2006, Australia.|Save Sight Institute, University of Sydney, NSW, 2000, Australia.|Australian Research Council Centre of Excellence for Integrative Brain Function, University of Sydney, 2000, Australia.
authors.forename: Ulrike
authors.initials: U
authors.lastname: Grünert
authors.affiliation: School of Medical Sciences, University of Sydney, Sydney, NSW, 2006, Australia.|Save Sight Institute, University of Sydney, NSW, 2000, Australia.|Australian Research Council Centre of Excellence for Integrative Brain Function, University of Sydney, 2000, Australia.
authors.forename: Paul R
authors.initials: PR
authors.lastname: Martin
mesh_terms: D000818:Animals; D001710:Biotin / Q000031:analogs & derivatives / Q000378:metabolism; D002144:Callithrix; D002452:Cell Count; D003118:Color Perception / Q000502:physiology*; D055253:Color Vision / Q000502:physiology*; D003911:Dextrans / Q000378:metabolism; D005260:Female; D005829:Geniculate Bodies / Q000033:anatomy & histology*; D008297:Male; D010641:Phenotype; D010775:Photic Stimulation; D012160:Retina / Q000502:physiology; D012165:Retinal Ganglion Cells / Q000502:physiology; D014795:Visual Pathways / Q000502:physiology*
chemical_list: D003911:Dextrans; C076397:biotinylated dextran amine; D001710:Biotin
keywords: color vision; koniocellular; magnocellular; parvocellular; retinal ganglion cells