The topography of rods, cones and intrinsically photosensitive retinal ganglion cells in the retinas of a nocturnal (Micaelamys namaquensis) and a diurnal (Rhabdomys pumilio) rodent

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dc.contributor.author Van der Merwe, Ingrid
dc.contributor.author Lukats, Akos
dc.contributor.author Blahova, Veronika
dc.contributor.author Oosthuizen, Maria Kathleen
dc.contributor.author Bennett, Nigel C., 1961-
dc.contributor.author Nemec, Pavel
dc.date.accessioned 2018-10-18T05:59:27Z
dc.date.available 2018-10-18T05:59:27Z
dc.date.issued 2018-08-09
dc.description.abstract We used immunocytochemistry to determine the presence and topographical density distributions of rods, cones, and intrinsically photosensitive retinal ganglion cells (ipRGCs) in the four-striped field mouse (Rhabdomys pumilio) and the Namaqua rock mouse (Micaelamys namaquensis). Both species possessed duplex retinas that were rod dominated. In R. pumilio, the density of both cones and rods were high (cone to rod ratio: 1:1.23) and reflected the species' fundamentally diurnal, but largely crepuscular lifestyle. Similarly, the ratio of cones to rods in M. namaquensis (1:12.4) reflected its nocturnal lifestyle. Similar rod density peaks were observed (R. pumilio: ~84467/mm2; M. namaquensis: ~81088/mm2), but a density gradient yielded higher values in the central (~56618/mm2) rather than in the peripheral retinal region (~32689/mm2) in R. pumilio. Two separate cone types (S-cones and M/L-cones) were identified implying dichromatic color vision in the study species. In M. namaquensis, both cone populations showed a centro-peripheral density gradient and a consistent S- to M/L-cone ratio (~1:7.8). In R. pumilio, S cones showed a centro-peripheral gradient (S- to M/L-cone ratio; central: 1:7.8; peripheral: 1:6.8) which appeared to form a visual streak, and a specialized area of M/L-cones (S- to M/L-cone ratio: 1:15) was observed inferior to the optic nerve. The number of photoreceptors per linear degree of visual angle, estimated from peak photoreceptor densities and eye size, were four cones and 15 rods per degree in M. namaquensis and 11 cones and 12 rods per degree in R. pumilio. Thus, in nocturnal M. namaquensis rods provide much finer image sampling than cones, whereas in diurnal/crepuscular R. pumilio both photoreceptor types provide fine image sampling. IpRGCs were comparably sparse in R. pumilio (total = 1012) and M. namaquensis (total = 862), but were homogeneously distributed in M. namaquensis and densest in the dorso-nasal quadrant in R. pumilio. The adaptive significance of the latter needs further investigation. en_ZA
dc.description.department Mammal Research Institute en_ZA
dc.description.department Zoology and Entomology en_ZA
dc.description.librarian am2018 en_ZA
dc.description.sponsorship The Grant Agency of Charles University (325515, to VB) and the DST-NRF SARChI chair of Mammal Behavioural Ecology and Physiology (64756, to NCB). Microscopy was performed in the Laboratory of Confocal and Fluorescence Microscopy co-financed by the European Regional Development Fund and the state budget of the Czech Republic (CZ.1.05/4.1.00/16.0347 and CZ.2.16/3.1.00/21515). en_ZA
dc.description.uri http://www.plosone.org en_ZA
dc.identifier.citation Van der Merwe I, Lukáts Á, Bláhová V, Oosthuizen MK, Bennett NC, Němec P (2018) The topography of rods, cones and intrinsically photosensitive retinal ganglion cells in the retinas of a nocturnal (Micaelamys namaquensis) and a diurnal (Rhabdomys pumilio) rodent. PLoS ONE 13(8): e0202106. https://doi.org/10.1371/journal.pone.0202106. en_ZA
dc.identifier.issn 1932-6203 (online)
dc.identifier.other 10.1371/journal.pone.0202106
dc.identifier.uri http://hdl.handle.net/2263/66937
dc.language.iso en en_ZA
dc.publisher Public Library of Science en_ZA
dc.rights © 2018 van der Merwe et al. This is an open access article distributed under the terms of the Creative Commons Attribution License. en_ZA
dc.subject Rodent en_ZA
dc.subject Immunocytochemistry en_ZA
dc.subject Density en_ZA
dc.subject Photoreceptors en_ZA
dc.subject Mouse retina en_ZA
dc.subject Architecture en_ZA
dc.subject Photoentrainment en_ZA
dc.subject Eye en_ZA
dc.subject Vision en_ZA
dc.subject Light en_ZA
dc.subject Rats en_ZA
dc.subject Mammalian retina en_ZA
dc.subject Locomotor activity en_ZA
dc.subject Ocular photoreceptors en_ZA
dc.subject Intrinsically photosensitive retinal ganglion cells (ipRGCs) en_ZA
dc.title The topography of rods, cones and intrinsically photosensitive retinal ganglion cells in the retinas of a nocturnal (Micaelamys namaquensis) and a diurnal (Rhabdomys pumilio) rodent en_ZA
dc.type Article en_ZA


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