Retinal Ganglion Cell Topography and Retinal Resolution in the Baikal Seal (Pusa sibirica)

2016 ◽  
Vol 88 (1) ◽  
pp. 59-67 ◽  
Author(s):  
Alla M. Mass ◽  
Alexander Y. Supin
Keyword(s):  
Ganglion Cell ◽  
Cell Density ◽  
Ganglion Cells ◽  
Cell Group ◽  
Nodal Distance ◽  
Distinct Cell ◽  
Area Centralis ◽  
Cell Densities ◽  
Retinal Resolution ◽  
Topographic Distribution

The total number, size, topographic distribution, and cell density of ganglion cells were studied in retinal wholemounts of Baikal seals (Pusa sibirica). The ganglion cell size varied from 10 to 38 μm. A distinct cell group consisted of large ganglion cells of more than 30 μm in diameter. The topographic distribution of ganglion cells showed a definite area of high cell density similar to the area centralis of terrestrial carnivores. This area was located approximately 6-7 mm dorsotemporally of the geometric center of the wholemount. In this area, the peak cell densities in two wholemounts were 3,800 and 3,400 cells/mm2 (mean 3,600 cells/mm2). With a posterior nodal distance of 24 mm (underwater), this density corresponds to 631 cells/square degree. These values predict a retinal resolution of 2.4′ in water and 3.0′ in air. The topographic distribution of large cells featured the highest density in the same location as the total ganglion cell population.

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.

scholarly journals Study of the density of ganglion cells in the terminal bowel of rats with anorectal malformations

2007 ◽  
Vol 22 (6) ◽  
pp. 441-445 ◽  
Author(s):  
Maurício Macedo ◽  
José Luiz Martins ◽  
Karine Furtado Meyer ◽  
Iberê Cauduro Soares
Keyword(s):  
Body Weight ◽  
Cesarean Section ◽  
Ganglion Cell ◽  
Cell Density ◽  
Ganglion Cells ◽  
Anorectal Malformations ◽  
Pregnant Rats ◽  
Group A ◽  
Cell Densities ◽  
Group B

PURPOSE: To study the ganglion cells (GC) in the terminal bowel of rats with ethylenethiourea (ETU) induced anorectal malformations (ARM). METHODS: The animals were divided into three groups: Group A - normal fetuses from pregnant rats that were not administered ETU; Group B - fetuses without ARM born from pregnant rats that were administered ETU and Group C - fetuses with ARM born from pregnant rats that received ETU. ETU was administered on the 11th day of pregnancy at the dose of 125 mg/kg body weight by gastric gavage. The rats had cesarean section on the 21st day of gestation. The fetuses’ terminal bowel tissue was analyzed by immunohistochemistry to demonstrate ganglion cells. RESULTS: Statistically significant differences were found between groups A, B and C regarding ganglion cell densities. Group A had the highest cell density, followed by Group B and the lowest density was found in Group C. CONCLUSION: Ganglion cell densities are decreased in the terminal bowel of rats with ARM.

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.

The morphology and topographic distribution of substance- P-like immunoreactive amacrine cells in the cat retina

1989 ◽  
Vol 237 (1289) ◽  
pp. 471-488 ◽  
Keyword(s):  
Substance P ◽  
Ganglion Cell ◽  
Plexiform Layer ◽  
Amacrine Cells ◽  
Maximum Density ◽  
Peripheral Retina ◽  
Inner Plexiform Layer ◽  
Cat Retina ◽  
Area Centralis ◽  
Topographic Distribution

In cat retinal wholemounts, substance-P-like immunoreactivity (SP-IR) was localized in a distinct population of amacrines whose cell bodies were normally placed in the ganglion cell layer. Although displaced amacrines accounted for 80-95% of the SP-IR amacrines in peripheral retina, this proportion decreased considerably within the area centralis, accounting for 50-80% of the labelled cells at maximum density. The SP-IR cells in both the inner nuclear and ganglion cell layers gave rise to well-defined varicose dendrites of uniform appearance that stratified around 60% depth (S3/S4) of the inner plexiform layer. In addition, sparse fine dendrites in stratum 1 (S1) could sometimes be traced to inner nuclear cells and occasionally to displaced amacrines. The combined SP-IR cell density ranged from less than 50 cells mm -2 in the far periphery to more than 500 cells mm -2 in the area centralis; the maximum density showed little individual variation despite wide differences in the proportion of displaced cells. The 39000 SP-IR amacrines in a mapped retina had a triangular topographic distribution, with intermediate isodensity lines extending vertically in superior retina and horizontally along both arms of the visual streak. Colocalization experiments established that all SP-IR cells in cat retina showed GABA-like immunoreactivity, and that the SP-IR amacrines were quite distinct from the cholinergic amacrines identified by choline acetyltransferase immunohistochemistry.

Anatomical correlations between soma size, axon diameter, and intraretinal length for the alpha ganglion cells of the cat retina

1991 ◽  
Vol 6 (2) ◽  
pp. 159-174 ◽  
Author(s):  
T. Fitzgibbon ◽  
K. Funke ◽  
U. Th. Eysel
Keyword(s):  
Optic Disc ◽  
Cell Density ◽  
Ganglion Cells ◽  
Present Report ◽  
Alpha Cell ◽  
Axon Diameter ◽  
Clear Trend ◽  
Area Centralis ◽  
Soma Size ◽  
Temporal Aspect

AbstractRetinal ganglion cells within the same region of the retina may have different lengths of axon before reaching the optic disc depending on the route they take with respect to the temporal raphe. We have investigated whether there is a correlation between soma and intraretinal axon diameter and how these parameters relate to intraretinal axon length on both sides of the cat temporal raphe. Retinas were wholemounted and alpha-cell somata and fibers stained with a modified neurofibrillar method. Moving peripherally from the area centralis along the raphe there was a progressively increasing difference between the intraretinal axon lengths for nearly adjacent cells across the raphe, which reached a maximum of 4–5 mm at the retinal periphery. Cells on the nasal aspect of the raphe had shorter axons than did adjacent cells on the temporal aspect of the raphe. Comparison of soma diameter s&les across the raphe showed there was no clear trend between soma diameter and intraretinal length. Replotting the raphe and s&le areas on a cell density map indicated that différences in soma diameter could be attributed to ganglion-cell density differences between the s&led areas.Examination of the stained cells revealed that within the initial length of the axon there was a region showing a reduction of axon diameter (diameter <1 μm), which varied in length from cell to cell. The axon was, therefore, divided into three segments: the portion of axon prior to thinning (A), the thin segment itself (B), and the part of the axon after the thin segment (C). The diameter of each segment (A, B, C) and the lengths of the first and second segments (A, B) were significantly correlated with soma diameter (P < 0.001). From measurements of the axon diameter of segment C, it was concluded that alpha-cell axons continue to increase in diameter along their path towards the optic disc.The present report indicates that alpha-cell soma size, when going from the area centralis to the periphery along the raphe, reaches a plateau and then declines within more peripheral retinal locations in spite of increasing intraretinal axon length. Thus, there is no positive correlation between soma or axon diameter and intraretinal axon length. The anatomical findings are discussed in relation to previous reports of retinal development and complementary conduction times within intraretinal and extraretinal visual pathways.

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.

Distribution and size of ganglion cells in the retinae of large Amazon rodents

1989 ◽  
Vol 2 (3) ◽  
pp. 221-235 ◽  
Author(s):  
L. C. L. Silveira ◽  
C. W. Picanço-Diniz ◽  
E. Oswaldo-Cruz
Keyword(s):  
Ganglion Cell ◽  
Cell Size ◽  
Cell Density ◽  
Ganglion Cells ◽  
Cell Number ◽  
Retinal Ganglion ◽  
Size Spectra ◽  
Topographical Distribution ◽  
Visual Streak ◽  
Soma Size

AbstractThe topographical distribution of density and soma size of the retinal ganglion cells were studied in three species of hystricomorph rodents. Flat-mounted retinae were stained by the Nissl method and the ganglion cells counted on a matrix covering the whole retinae. Soma size was determined for samples at different retinal regions. The agouti, a diurnal rodent, shows a well-developed visual streak, reaching a peak density of 6250 ganglion cells/mm2. The total number of ganglion cells ranged from 477, 427–548, 205 in eight retinae. The ganglion-cell-size histogram of the visual streak region exhibits a marked shift towards smaller values when compared to retinal periphery. Upper and lower regions differ in both cell density and cell size. The crepuscular capybara shows a less-developed visual streak with a peak ganglion cell density of 2250/mm2. The shift towards small-sized cells in the visual streak is less marked. Total ganglion cell population is 368,840. In the nocturnal paca, the upper half of the fundus oculi includes a tapetum lucidum. The retina of this species shows the least-developed visual streak of this group, with the lowest peak ganglion cell density reaching 925/mm2. The total ganglion cell number (230,804) is also smaller than in the two other species. Soma-size spectra of this species are characterized by the presence, in the lower hemi-retina, of very large perikarya comparable in size to the cat's alpha ganglion cells.

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.

Overrepresentation of the central visual field in the superior colliculus of the pigmented and albino ferret

1996 ◽  
Vol 13 (4) ◽  
pp. 627-638 ◽  
Author(s):  
C. Quevedo ◽  
K.-P. Hoffmann ◽  
R. Husemann ◽  
C. Distler
Keyword(s):  
Visual Field ◽  
Superior Colliculus ◽  
Ganglion Cell ◽  
Cell Density ◽  
Visual Space ◽  
Peripheral Retina ◽  
Magnification Factor ◽  
Central Visual Field ◽  
Visual Streak ◽  
Area Centralis

AbstractWe have examined the retinotopy in the superior colliculus of pigmented and albino ferrets using both anatomical and electrophysiological methods. While the distribution of contralaterally projecting retinotectal ganglion cells is characterized by the presence of an area centralis superimposed on a visual streak in both strains, the ipsilateral projection from temporal hemiretina is strongly reduced in albinos. In spite of the significantly altered retinotectal projection pattern, the collicular visual field map in the albino ferret reveals the same characteristics as in the pigmented animal with a strongly enlarged representation of the center of visual space. An areal comparison between retinotectal ganglion cell distribution and collicular areal magnification shows that the increase in areal magnification factor between the periphery and the representation of the central visual hemifield exceeds the corresponding increase in retinal ganglion cell density between peripheral retina and area centralis by a factor of three in pigmented and a factor of four in albino ferrets. The areal magnification factor of the representation of the retinal visual streak does not exceed the increase in retinotectal ganglion cell density. Thus, our results suggest that the representation of visual space in the superior colliculus of albino and pigmented ferrets does not simply follow the retinotectal ganglion cell density, but that there is an enhanced representation of the frontal central visual field. The possibility is discussed that the collicular visual field map may be determined either by both retinotectal and corticotectal projections or by the colliculus' intrinsic structure.

Changing patterns of vasculature in the developing amphibian retina.

1997 ◽  
Vol 200 (18) ◽  
pp. 2479-2492
Author(s):  
S A Dunlop ◽  
S R Moore ◽  
L D Beazley
Keyword(s):  
Ganglion Cell ◽  
Ganglion Cell Layer ◽  
Cell Layer ◽  
Retinal Vasculature ◽  
Tree Frog ◽  
Retinal Area ◽  
Branch Points ◽  
The Face ◽  
Area Centralis ◽  
Cell Densities

Patterns of vascularisation were examined in whole-mounted retinae from tadpole stages to adulthood in the tree frog Litoria moorei using perfusion with Indian ink. Changing cell densities in the underlying ganglion cell layer were studied in a parallel Cresyl-stained series. Throughout development, the vasculature was pan-retinal and the hyaloid vessel was prominent. In early tadpole stages, capillaries were arranged as a honeycomb, and their number increased at a rate sufficient to maintain high densities in the face of increasing retinal area; major arteries and veins condensed within the capillary network. By early post-metamorphic life, the retinal vasculature was remodelled by the loss of four-fifths of the capillaries; the reduction in their density was far greater than could be accounted for by continuing retinal growth. This loss resulted in a change from the honeycomb appearance to one with largely parallel vessels linked by fewer connecting ones, an arrangement that became increasingly pronounced. In post-metamorphic life, the number of branch points increased such that their density decreased only slightly in the face of considerable increases in retinal area. The density of branch points varied across the retina and changed with age. Initially, the vasculature was most dense centrally, but by mid-larval life densities were highest in two patches located in the mid-temporal and mid-nasal retina. Thereafter, the vasculature increasingly assumed gradients resembling an area centralis and visual streak, a profile that survived the vascular remodelling. The development of density gradients in the vasculature preceded that of cells in the ganglion cell layer, the latter appearing only following metamorphosis. However, in post-metamorphic life, the topographies of the retinal vasculature and cells in the ganglion cell layer were closely related.

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