Visual Capability of the Weakly Electric Fish Apteronotus albifrons as Revealed by a Modified Retinal Flat-Mount Method

2015 ◽  
Vol 86 (2) ◽  
pp. 122-130 ◽  
Author(s):  
Tomo Takiyama ◽  
Valdir Luna da Silva ◽  
Daniel Moura Silva ◽  
Sawako Hamasaki ◽  
Masayuki Yoshida
Keyword(s):  
Ganglion Cell ◽  
Ganglion Cells ◽  
Pigment Epithelium ◽  
The Body ◽  
Weakly Electric Fish ◽  
Resolving Power ◽  
Cell Distribution ◽  
High Acuity ◽  
Continuous Sheet ◽  
Cell Densities

Apteronotus albifrons (Gymnotiformes, Apteronotidae) is well known to have a sophisticated active electrosense system and is commonly described as having poor vision or being almost blind. However, some studies on this species suggest that the visual system may have a role in sensing objects in the environment. In this study, we investigated the visual capabilities of A. albifrons by focusing on eye morphology and retinal ganglion cell distribution. The eyes were almost embedded below the body surface and pigmented dermal tissue covered the peripheral regions of the pupil, limiting the direction of incoming light. The lens was remarkably flattened compared to the almost spherical lenses of other teleosts. The layered structure of the retina was not well delineated and ganglion cells did not form a continuous sheet of cell bodies. A newly modified retinal flat-mount method was applied to reveal the ganglion cell distribution. This method involved postembedding removal of the pigment epithelium of the retina for easier visualization of ganglion cells in small and/or fragile retinal tissues. We found that ganglion cell densities were relatively high in the periphery and highest in the nasal and temporal retina, although specialization was not so high (approx. 3:1) with regard to the medionasal or mediotemporal axis. The estimated highest possible spatial resolving power was around 0.57 and 0.54 cycles/degree in the nasal and temporal retina, respectively, confirming the lower importance of the visual sense in this species. However, considering the hunting nature of A. albifrons, the relatively high acuity of the caudal visual field in combination with electrolocation may well be used to locate prey situated close to the side of the body.

The retinal ganglion cell distribution and the representation of the visual field in area 17 of the owl monkey, Aotus trivirgatus

1993 ◽  
Vol 10 (5) ◽  
pp. 887-897 ◽  
Author(s):  
L. C. L. Silveira ◽  
V. H. Perry ◽  
E. S. Yamada
Keyword(s):  
Visual Cortex ◽  
Visual Field ◽  
Ganglion Cell ◽  
Cell Density ◽  
Ganglion Cells ◽  
Amacrine Cells ◽  
Temporal Region ◽  
Cell Distribution ◽  
Area 17 ◽  
Displaced Amacrine Cells

AbstractThe distribution of ganglion cells and displaced amacrine cells was determined in whole-mounted Aotus retinae. In contrast to diurnal simians, Aotus has only a rudimentary fovea. Ganglion cell density decreases towards the periphery at approximately the same rate along all meridians, but is 1.2–1.8 times higher in the nasal periphery when compared to temporal region at the same eccentricities. The total number of ganglion cells varied from 421,500 to 508,700. Ganglion cell density peaked at 15,000/mm2 at 0.25 mm dorsal to the fovea. The displaced amacrine cells have a shallow density gradient, their peak density in the central region is about 1500–2000/mm2 and their total number varied from 315,900 to 482,800. Comparison between ganglion cell density and areal cortical magnification factor for the primary visual cortex, area 17, shows that there is not a simple proportional representation of the ganglion cell distribution. There is an overrepresentation of the central 10 deg of the visual field in the visual cortex. The present results for Aotus and the results of a similar analysis of data from other primates indicate that the overrepresentation of the central visual field is a general feature of the visual system of primates.

Visual Specializations in Five Sympatric Species of Stingrays from the Family Dasyatidae

2015 ◽  
Vol 85 (4) ◽  
pp. 217-232 ◽  
Author(s):  
Eduardo Garza-Gisholt ◽  
Ryan M. Kempster ◽  
Nathan S. Hart ◽  
Shaun P. Collin
Keyword(s):  
Ganglion Cells ◽  
Sympatric Species ◽  
Geographic Region ◽  
Resolving Power ◽  
Retinal Cell ◽  
Ecological Niches ◽  
Scotopic Vision ◽  
Peak Density ◽  
The Family ◽  
Cell Densities

The eyes of five ray species (Taeniura lymma, Neotrygon kuhlii, Pastinachus atrus, Himantura uarnak and Urogymnus asperrimus) from the same taxonomic family (Dasyatidae) and the same geographic region (Ningaloo Reef, Western Australia) were studied to identify differences in retinal specializations that may reflect niche specialization. The topographic distributions of photoreceptors (rods and all cones) and ganglion cells were assessed and used to identify localized peaks in cell densities that indicate specializations for acute vision. These data were also used to calculate summation ratios of photoreceptors to ganglion cells in each species and estimate the anatomical spatial resolving power of the eye. Subtle differences in the distribution of retinal neurons appear to be related to the ecology of these closely related species of stingrays. The main specialization in the retinal cell density distribution is the dorsal streak that allows these animals to scan the substrate for potential prey. The blue-spotted fantail ray, T. lymma, showed the highest peak density of rods (86,700 rods mm-2) suggesting a specialization for scotopic vision. The highest peak density of cones (9,970 cones mm-2) was found in H. uarnak, and the highest peak density of ganglion cells (4,500 cells mm-2) was found in P. atrus. The proportion of rods to cones in the dorsal streak was higher in the two smaller species (12.5-14:1 in T. lymma and N. kuhlii) than the larger stingrays (6-8:1 in P. atrus, H. uarnak and U. asperrimus). Visual specializations in different sympatric species are subtle but may reflect specializations to specific ecological niches.

Eye growth in sharks: Ecological implications for changes in retinal topography and visual resolution

2009 ◽  
Vol 26 (4) ◽  
pp. 397-409 ◽  
Author(s):  
LENORE LITHERLAND ◽  
SHAUN P. COLLIN ◽  
KERSTIN A. FRITSCHES
Keyword(s):  
Ganglion Cell ◽  
Spatial Resolution ◽  
Ganglion Cells ◽  
Feeding Strategy ◽  
Resolving Power ◽  
Foraging Strategies ◽  
Sandbar Shark ◽  
Topographic Analysis ◽  
Eye Growth ◽  
Topographic Distribution

AbstractThe visual abilities of sharks show substantial interspecific variability. In addition, sharks may change their habitat and feeding strategy throughout life. As the eyes of sharks continue to grow throughout the animal’s lifetime, ontogenetic variability in visual ability may also occur. The topographic analysis of the photoreceptor and ganglion cell distributions can identify visual specializations and assess changes in visual abilities that may occur concurrently with eye growth. This study examines an ontogenetic series of whole-mounted retinas in two elasmobranch species, the sandbar shark, Carcharhinus plumbeus, and the shortspine spurdog, Squalus mitsukurii, to identify regional specializations mediating zones for improved spatial resolution. The study examines retinal morphology and presents data on summation ratios between photoreceptor and ganglion cell layers, anatomically determined peak spatial resolving power, and the angular extent of the visual field. Peak densities of photoreceptors and ganglion cells occur in similar retinal locations. The topographic distribution of neurons in the ganglion cell layer does not differ substantially with eye growth. However, predicted peak spatial resolution increases with eye growth from 4.3 to 8.9 cycles/deg in C. plumbeus and from 5.7 to 7.2 cycles/deg in S. mitsukurii. The topographic distribution of different-sized ganglion cells is also mapped in C. plumbeus, and a population of large ganglion cells (soma area 120–350 μm2) form a narrow horizontal streak across the retinal meridian, while the spatial distribution of ordinary-sized ganglion cells (soma area 30–120 μm2) forms an area in the central retina. Species-specific retinal specializations highlight differences in visually mediated behaviors and foraging strategies between C. plumbeus and S. mitsukurii.

The number, morphology, and distribution of retinal ganglion cells and optic axons in the Australian lungfishNeoceratodus forsteri(Krefft 1870)

2006 ◽  
Vol 23 (2) ◽  
pp. 257-273 ◽  
Author(s):  
HELENA J. BAILES ◽  
ANN E.O. TREZISE ◽  
SHAUN P. COLLIN
Keyword(s):  
Optic Nerve ◽  
Ganglion Cell ◽  
Retinal Ganglion Cells ◽  
Ganglion Cell Layer ◽  
Ganglion Cells ◽  
Cell Layer ◽  
Amacrine Cells ◽  
Resolving Power ◽  
Retinal Ganglion ◽  
Retrograde Labelling

Australian lungfishNeoceratodus forsterimay be the closest living relative to the first tetrapods and yet little is known about their retinal ganglion cells. This study reveals that lungfish possess a heterogeneous population of ganglion cells distributed in a horizontal streak across the retinal meridian, which is formed early in development and maintained through to adult stages. The number and complement of both ganglion cells and a population of putative amacrine cells within the ganglion cell layer are examined using retrograde labelling from the optic nerve and transmission electron-microscopic analysis of axons within the optic nerve. At least four types of retinal ganglion cells are present and lie predominantly within a thin ganglion cell layer, although two subpopulations are identified, one within the inner plexiform and the other within the inner nuclear layer. A subpopulation of retinal ganglion cells comprising up to 7% of the total population are significantly larger (>400 μm2) and are characterized as giant or alpha-like cells. Up to 44% of cells within the retinal ganglion cell layer represent a population of presumed amacrine cells. The optic nerve is heavily fasciculated and the proportion of myelinated axons increases with body length from 17% in subadults to 74% in adults. Spatial resolving power, based on ganglion cell spacing, is low (1.6–1.9 cycles deg−1,n= 2) and does not significantly increase with growth. This represents the first detailed study of retinal ganglion cells in sarcopterygian fish, and reveals that, despite variation amongst animal groups, trends in ganglion cell density distribution and characteristics of cell types were defined early in vertebrate evolution.

The Topographic Organization of Retinal Ganglion Cell Density and Spatial Resolving Power in an Unusual Arboreal and Slow-Moving Strepsirhine Primate, the Potto (Perodicticus potto)

2016 ◽  
Vol 87 (1) ◽  
pp. 4-18 ◽  
Author(s):  
João Paulo Coimbra ◽  
Consolate Kaswera-Kyamakya ◽  
Emmanuel Gilissen ◽  
Paul R. Manger ◽  
Shaun P. Collin
Keyword(s):  
Ganglion Cell ◽  
Cell Density ◽  
Retinal Ganglion Cells ◽  
Spatial Resolution ◽  
Ganglion Cells ◽  
Resolving Power ◽  
Retinal Ganglion ◽  
Upper Limits ◽  
Slow Moving ◽  
Topographic Distribution

The potto (Perodicticus potto) is an arboreal strepsirhine found in the rainforests of central Africa. In contrast to most primates, the potto shows slow-moving locomotion over the upper surface of branches, where it forages for exudates and crawling invertebrates with its head held very close to the substrate. Here, we asked whether the retina of the potto displays topographic specializations in neuronal density that correlate with its unusual lifestyle. Using stereology and retinal wholemounts, we measured the total number and topographic distribution of retinal ganglion cells (total and presumed parasol), as well as estimating the upper limits of the spatial resolution of the potto eye. We estimated ∼210,000 retinal ganglion cells, of which ∼7% (∼14,000) comprise presumed parasol ganglion cells. The topographic distribution of both total and parasol ganglion cells reveals a concentric centroperipheral organization with a nasoventral asymmetry. Combined with the upwardly shifted orbits of the potto, this nasoventral increase in parasol ganglion cell density enhances contrast sensitivity and motion detection skywards, which potentially assists with the detection of predators in the high canopy. The central area of the potto occurs ∼2.5 mm temporal to the optic disc and contains a maximum ganglion cell density of ∼4,300 cells/mm2. We found no anatomical evidence of a fovea within this region. Using maximum ganglion cell density and eye size (∼14 mm), we estimated upper limits of spatial resolving power between 4.1 and 4.4 cycles/degree. Despite their reported reliance on olfaction to detect exudates, this level of spatial resolution potentially assists pottos with foraging for small invertebrates and in the detection of predators.

Comparative visual function in elasmobranchs: Spatial arrangement and ecological correlates of photoreceptor and ganglion cell distributions

2008 ◽  
Vol 25 (4) ◽  
pp. 549-561 ◽  
Author(s):  
LENORE LITHERLAND ◽  
SHAUN P. COLLIN
Keyword(s):  
Ganglion Cell ◽  
Behavioral Ecology ◽  
Ganglion Cells ◽  
Spatial Arrangement ◽  
Resolving Power ◽  
Cresyl Violet ◽  
Topographic Analysis ◽  
Scotopic Vision ◽  
Preferential Sampling ◽  
Epaulette Shark

AbstractThe topographic analysis of retinal ganglion and photoreceptor cell distributions yields valuable information for assessing the visual capabilities and behavioral ecology of vertebrates. This study examines whole-mounted retinas of four elasmobranch species, the ornate wobbegong, Orectolobus ornatus; the whitetip reef shark, Triaenodon obesus; the epaulette shark, Hemiscyllium ocellatum; and the east Australia shovelnose ray, Aptychotrema rostrata, for regional specializations mediating zones of improved visual ability. These species represent a range of lifestyles: benthic, mid-water, diurnal, and nocturnal. Both photoreceptors (visualized using differential interference contrast optics) and ganglion cells (stained with cresyl violet) in the retina are extensively sampled, and their spatial distribution is found to be nonuniform, exhibiting areae or “visual streaks.” In general, the topographic distributions of both cell populations are in register and match well with respect to the location of regions of high density. However, the location of peaks in rod and cone densities can vary within a retina, indicating that preferential sampling of different regions of the visual field may occur in photopic and scotopic vision. Anatomical measures of the optical limits of resolving power, indicated by intercone spacing, range from 3.8 to 13.1 cycles/deg. Spatial limits of resolving power, calculated from ganglion cell spacing, range from 2.6 to 4.3 cycles/deg. Summation ratios, assessed by direct comparison of cell densities of photoreceptors (input cells) and ganglion cells (output cells), at more than 150 different loci across the retina, show topographic differences in signal convergence (ranging from 25:1 to over 70:1). Species-specific retinal specializations strongly correlate to the habitat and feeding behavior of each species.

scholarly journals Retinal specializations to a micro-predatory and crypto-benthic life-style in the Mediterranean triplefin blenny Tripterygion delaisi

2017 ◽  
Author(s):  
Roland Fritsch ◽  
Shaun P. Collin ◽  
Nico K. Michiels
Keyword(s):  
Visual Field ◽  
Ganglion Cell ◽  
Cross Sections ◽  
Ganglion Cells ◽  
Average Density ◽  
Resolving Power ◽  
Retinal Ganglion ◽  
Vast Number ◽  
The Mediterranean ◽  
Tripterygion Delaisi

AbstractThe environment and lifestyle of a species are known to exert selective pressure on the visual system, often demonstrating a tight link between visual morphology and ecology. Many studies have predicted the visual requirements of a species by examining the anatomical features of the eye. However, among the vast number of studies on visual specializations in aquatic animals, only a few have focused on small benthic fishes that occupy a heterogeneous and spatially complex visual environment. This study investigates the general retinal anatomy including the topography of both the photoreceptor and ganglion cell populations and estimates the spatial resolving power of the eye of the Mediterranean triplefin Tripterygion delaisi. Retinal wholemounts were prepared to systematically and quantitatively analyze photoreceptor and retinal ganglion cell densities using design-based stereology. To further examine the retinal structure, we also used magnetic resonance imaging and histological examination of retinal cross sections. Observations of the triplefin's eyes revealed them to be highly mobile, allowing them to view the surroundings without body movements. A rostral aphakic gap and the elliptical shape of the eye extend its visual field rostrally and allow for a rostro-caudal accommodatory axis, enabling this species to focus on prey at close range. Single and twin cones dominate the retina and are consistently arranged in one of two regular patterns, which may enhance motion detection and color vision. The retina features a prominent, dorso-temporal, convexiclivate fovea with an average density of 104,400 double and 30,800 single cones per mm2, and 81,000 retinal ganglion cells per mm2. Based on photoreceptor spacing, spatial resolving power was calculated to be between 6.7 and 9.0 cycles per degree. Location and resolving power of the fovea would benefit the detection and identification of small prey in the lower frontal region of the visual field.

scholarly journals Е. Holmgren. Note d. Spinal ganglion cells. (With. 11 images.). Anat. Vol. 16, № 7, p. 161-171. 1899. Idem. Further communications about d. Structure of the nerve cells. (With. 13 images.). Ibidem. Vol. 16. N 15/162 р. 388-397. 1899. F. Studnicka. About the occurrence of v. Canals u. Alveoli in the body d. Ganglion cells and in the axis cylinder of some nerve fibers, vol. 16. N 15/162 р. d. Vertebrates. Ibid. 397-401. 1899. Alb. Adamkiewicz. To the blood vessel system of the ganglion cell. Ibid. Vol. 17. N 2/3 p. 44. 1900. Е. Holmgren. Still other communications about the construction d. Nerve cells from various animals. (With. 17 image). Ibid. Vol. 17, N 6/7 p. 113 - 129. 1900. Idem. A few words on the occasion of the last communication published by Prof. Adamkiewicz. Ibidem, Vol. 17, N 15. 1900. A. Bethe. Some remarks on the “intracellular tubules” d spinal ganglion cells, etc. — Ibid. Vol. 17. N 16/17 p. 304-309 (with 3 images). 1900

2020 ◽  
Vol VIII (2) ◽  
pp. 171-178
Author(s):  
A. Geberg
Keyword(s):  
Blood Vessel ◽  
Ganglion Cell ◽  
Ganglion Cells ◽  
Nerve Fibers ◽  
Nerve Cells ◽  
Spinal Ganglion ◽  
The Body ◽  
Axis Cylinder ◽  
Spinal Ganglion Cells

The above articles, although they are b. including the nature of the preliminary reports, they do not doubtlessly prove with what lively interest in the last time various researchers have turned to the development of one question, with the resolution of which a lot should be clarified regarding the finer structure, as well as the biology of the nervous.

Retinal Ganglion Cell Distribution and Spatial Resolving Power in Deep-Sea Lanternfishes (Myctophidae)

2014 ◽  
Vol 84 (4) ◽  
pp. 262-276 ◽  
Author(s):  
Fanny de Busserolles ◽  
N. Justin Marshall ◽  
Shaun P. Collin
Keyword(s):  
Ganglion Cell ◽  
Retinal Ganglion Cell ◽  
Deep Sea ◽  
Resolving Power ◽  
Retinal Ganglion ◽  
Cell Distribution
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