Retinal Ganglion Cell Size and Distribution Predict Visual Capabilities of Dall's Porpoise

Murayama, Tomonori; Somiya, Hiroaki; Aoki, Ichiro; Ishii, Takeo

doi:10.1111/j.1748-7692.1995.tb00513.x

Cited by 32 publications

(47 citation statements)

References 23 publications

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“…We observed large cells in various regions of the retina irrespective of the cell density in these regions. With respect to large cell size, the manatee's retina was similar to those of other aquatic mammals that also contained large ganglion cells (Dawson et al, 1982;Waller, 1982;Dral, 1983;Mass and Supin, 1986, 1999Gao and Zhou, 1992;Murayama et al, 1992Murayama et al, , 1995. Thus, it appears that large ganglion cells are a common feature of aquatic mammals contrary to reports for many terrestrial mammals, which typically have ganglion cells no larger than 25-30 lm (Fukuda, 1977;Hughes, 1981;Oyster et al, 1981).…”

Section: Ganglion Cell Sizementioning

confidence: 68%

“…Many cetaceans, such as the common dolphin Delphinus delphis (Dral, 1983), bottlenose dolphin Tursiops truncatus (Dral, 1977;Mass and Supin, 1995), harbor porpoise Phocoena phocoena (Mass and Supin, 1986), Chinese river dolphin Lipotes vexillifer (Gao and Zhou, 1987), gray whale Eschrichtius gibbosus ), Dall's porpoise, and Minke whale Balaenoptera acutorostrata (Murayama et al, 1992(Murayama et al, , 1995, have two spots of high cell density, one in the nasal and the other in the temporal retinal quadrants. In pinnipeds, a high cell density area occurs as either a discrete spot (the northern fur seal, Mass and Supin, 1992; the Weddel seal, Welsch et al, 2001) or a streak (the walrus, Mass, 1992) or a combination of both (the sea otter Enhydra lutris, Mass and Supin, 2000; the harbor seal, Hanke et al, 2009; the Caspian Seal, Mass and Supin, 2010).…”

Section: Ganglion Cell Number and Distributionmentioning

confidence: 99%

“…Using this method, retinal resolution has been estimated in many terrestrial (rev. Pettigrew et al, 1988) and marine mammals (Landau and Dawson, 1970;Murayama et al, 1992Murayama et al, , 1995Supin et al, 2001;Welsch et al, 2001;Mass and Supin, 2003, 2010Hanke et al, 2009). To date, however, there is no investigation of this kind on manatee retinae.…”

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confidence: 99%

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Ganglion Cell Distribution and Retinal Resolution in the Florida Manatee, Trichechus Manatus Latirostris

Mass

Ketten

Odell

et al. 2011

The Anatomical Record

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The topographic organization of retinal ganglion cells was examined in the Florida manatee (Trichechus manatus latirostris) to assess ganglion cell size and distribution and to estimate retinal resolution. The ganglion cell layer of the manatee's retina was comprised primarily of large neurons with broad intercellular spaces. Cell sizes varied from 10 to 60 lm in diameter (mean 24.3 lm). The retinal wholemounts from adult animals measured 446-501 mm 2 in area with total ganglion cell counts of 62,000-81,800 (mean 70,200). The cell density changed across the retina, with the maximum in the area below the optic disc and decreasing toward the retinal edges and in the immediate vicinity of the optic disc. The maximum cell density ranged from 235 to 337 cells per millimeter square in the adult retinae. Two wholemounts obtained from juvenile animals were 271 and 282 mm 2 in area with total cell numbers of 70,900 and 68,700, respectively (mean 69,800), that is, nearly equivalent to those of adults, but juvenile retinae consequently had maximum cell densities that were higher than those of adults: 478 and 491 cells per millimeter square. Calculations indicate a retinal resolution of $19 0 (1.6 cycles per degree) in both adult and juvenile retinae. Anat Rec, 295:177-186, 2012. V V C 2011 Wiley Periodicals, Inc.Key words: manatee; Trichechus manatus; eye; retina; ganglion cells; cell topography; cell size; retinal resolution; visual acuityThe Sirenia order includes the manatee, dugong, and the extinct Steller cow. Sirenians are adapted to salt and fresh water habitats and, unlike other marine mammals, are exclusively herbivorous. Consequently, they have a range of unique anatomical, physiological, and behavioral adaptations. Further, all species of the order are endangered. The West Indian manatee is a slow grazer that inhabits the coastal areas and rivers of the Caribbean basin (Bertram and Bertram, 1962;Hartman, 1979; Nowak, 1991). The Florida manatee, Trichechus manatus latirostris, is a subspecies of the West Indian manatee, T. manatus. Knowing more about their sensory abilities, including their visual abilities, is of interest not only for basic evolutionary research but also for planning strategies for conserving this highly endangered species.

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Section: Ganglion Cell Sizementioning

confidence: 68%

Section: Ganglion Cell Number and Distributionmentioning

confidence: 99%

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Ganglion Cell Distribution and Retinal Resolution in the Florida Manatee, Trichechus Manatus Latirostris

Mass

Ketten

Odell

et al. 2011

The Anatomical Record

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“…The cetacean retina is much thicker than that of terrestrial mammals, reaching up to 425 mm (Dral, 1977;Dawson et al, 1982;Murayama et al, 1995). For comparison, the thickness of the retina in diurnal terrestrial mammals is 110-220 mm (Prince et al, 1960).…”

Section: Retinal Laminar Morphology Cetaceansmentioning

confidence: 99%

“…The laminar structure of the retina was investigated in a variety of cetacean species, including bottlenose dolphin (Tursiops truncatus) Dawson and Perez, 1973;Dral, 1975aDral, ,b, 1977Dawson, 1980;Dawson et al, 1982), common dolphin (Delphinus delphis) (Dral, 1983), Dall's porpoise (Phocenoides dalli) (Murayama et al, 1992a(Murayama et al, , 1995, beluga (Delphinapterus leucas) (Pü tter, 1903;Pilleri, 1964), pilot whale (Globicephala melaena) (Peichl et al, 2001), fin whale (Balaenoptera physalus) (Pilleri and Wandeler, 1964), and minke whale (B. acutorostrata) (Murayama et al, 1992a,b). The laminar structure of the retina in all cetaceans is qualitatively similar to that in terrestrial mammals (Fig.…”

Section: Retinal Laminar Morphology Cetaceansmentioning

confidence: 99%

Adaptive features of aquatic mammals' eye

Mass¹,

Supin²

2007

The Anatomical Record

116

129

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The eye of aquatic mammals demonstrates several adaptations to both underwater and aerial vision. This study offers a review of eye anatomy in four groups of aquatic animals: cetaceans (toothed and baleen whales), pinnipeds (seals, sea lions, and walruses), sirenians (manatees and dugongs), and sea otters. Eye anatomy and optics, retinal laminar morphology, and topography of ganglion cell distribution are discussed with particular reference to aquatic specializations for underwater versus aerial vision. Aquatic mammals display emmetropia (i.e., refraction of light to focus on the retina) while submerged, and most have mechanisms to achieve emmetropia above water to counter the resulting aerial myopia. As underwater vision necessitates adjusting to wide variations in luminosity, iris muscle contractions create species-specific pupil shapes that regulate the amount of light entering the pupil and, in pinnipeds, work in conjunction with a reflective optic tapetum. The retina of aquatic mammals is similar to that of nocturnal terrestrial mammals in containing mainly rod photoreceptors and a minor number of cones (however, residual color vision may take place). A characteristic feature of the cetacean and pinniped retina is the large size of ganglion cells separated by wide intercellular spaces. Studies of topographic distribution of ganglion cells in the retina of cetaceans revealed two areas of ganglion cell concentration (the best-vision areas) located in the temporal and nasal quadrants; pinnipeds, sirenians, and sea otters have only one such area. In general, the visual system of marine mammals demonstrates a high degree of development and several specific features associated with adaptation for vision in both the aquatic and aerial environments. Anat Rec 290: 701-715, 2007. 2007 Key words: vision; ocular optics; retina; ganglion cells; retinal topography; aquatic mammalsComparative studies of the visual system in animals adapted to various living conditions have revealed new specific features of neuronal structures, have aided our understanding of mechanisms of visual perception, and have described the many ways in which sensory systems show adaptations to various environments. In recent years, there has been a great interest in the visual system of aquatic mammals: cetaceans (dolphins, porpoises, and whales), pinnipeds (seals, sea lions, and walruses), sirenians (manatees and dugongs), and sea otters. These species demonstrate various extents of adaptation to the aquatic environment. Many aquatic mammals (cetaceans, sirenians) spend their entire life in the water; however, air-breathing confines them to a near-surface layer of water. Other marine mammals (pinnipeds, sea otters) spend a significant part of their life on land. As a result, the visual systems of these groups feature remarkable morphological and functional specializations for both

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Retinal ganglion cell topography and spatial resolving power in the white rhinoceros (Ceratotherium simum)

Coimbra

Manger

2017

J of Comparative Neurology

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This study sought to determine whether the retinal organization of the white rhinoceros (Ceratotherium simum), a large African herbivore with lips specialized for grazing in open savannahs, relates to its foraging ecology and habitat. Using stereology and retinal wholemounts, we estimated a total of 353,000 retinal ganglion cells. Their density distribution reveals an unusual topographic organization of a temporal (2,000 cells/mm ) and a nasal (1,800 cells/mm ) area embedded within a well-defined horizontal visual streak (800 cells/mm ), which is remarkably similar to the retinal organization in the black rhinoceros. Alpha ganglion cells comprise 3.5% (12,300) of the total population of ganglion cells and show a similar distribution pattern with maximum densities also occurring in the temporal (44 cells/mm ) and nasal (40 cells/mm ) areas. We found higher proportions of alpha cells in the dorsal and ventral retinas. Given their role in the detection of brisk transient stimuli, these higher proportions may facilitate the detection of approaching objects from the front and behind while grazing with the head at 45 °. Using ganglion cell peak density and eye size (29 mm, axial length), we estimated upper limits of spatial resolving power of 7 cycles/deg (temporal area), 6.6 cycles/deg (nasal area), and 4.4 cycles/deg (horizontal streak). The resolution of the temporal area potentially assists with grazing, while the resolution of the streak may be used for panoramic surveillance of the horizon. The nasal area may assist with detection of approaching objects from behind, potentially representing an adaptation compensating for limited neck and head mobility. J. Comp. Neurol., 525:2484-2498, 2017. © 2017 Wiley Periodicals, Inc.

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Retinal Ganglion Cell Size and Distribution Predict Visual Capabilities of Dall's Porpoise

Cited by 32 publications

References 23 publications

Ganglion Cell Distribution and Retinal Resolution in the Florida Manatee, Trichechus Manatus Latirostris

Ganglion Cell Distribution and Retinal Resolution in the Florida Manatee, Trichechus Manatus Latirostris

Adaptive features of aquatic mammals' eye

Retinal ganglion cell topography and spatial resolving power in the white rhinoceros (Ceratotherium simum)

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