Morphological classification and retinal distribution of large ganglion cells in the retina ofBufo marinus (original) (raw)
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Brazilian Journal of Medical and Biological Research, 2005
We performed a quantitative analysis of M and P cell mosaics of the common-marmoset retina. Ganglion cells were labeled retrogradely from optic nerve deposits of Biocytin. The labeling was visualized using horseradish peroxidase (HRP) histochemistry and 3-3'diaminobenzidine as chromogen. M and P cells were morphologically similar to those found in Old-and New-World primates. Measurements were performed on well-stained cells from 4 retinas of different animals. We analyzed separate mosaics for inner and outer M and P cells at increasing distances from the fovea (2.5-9 mm of eccentricity) to estimate cell density, proportion, and dendritic coverage. M cell density decreased towards the retinal periphery in all quadrants. M cell density was higher in the nasal quadrant than in other retinal regions at similar eccentricities, reaching about 740 cells/mm 2 at 2.5 mm of temporal eccentricity, and representing 8-14% of all ganglion cells. P cell density increased from peripheral to more central regions, reaching about 5540 cells/mm 2 at 2.5 mm of temporal eccentricity. P cells represented a smaller proportion of all ganglion cells in the nasal quadrant than in other quadrants, and their numbers increased towards central retinal regions. The M cell coverage factor ranged from 5 to 12 and the P cell coverage factor ranged from 1 to 3 in the nasal quadrant and from 5 to 12 in the other quadrants. These results show that central and peripheral retinal regions differ in terms of cell class proportions and dendritic coverage, and their properties do not result from simply scaling down cell density. Therefore, differences in functional properties between central and peripheral vision should take these distinct regional retinal characteristics into account.
Journal of Comparative Neurology, 1973
Giant ganglion cells (GGC) were demonstrated in retinas of adult dogfish by Golgi impregnation, reduced silver and vital methylene blue staining. All GGC have large, flattened perikarya, and dendrites which radiate in a single horizontal plane of the inner synaptic (plexiform) layer. They are identifiable as ganglion cells by their axons, which after a tortuous initial course enter the nerve fiber layer. We divide the GGC into three varieties: (1) ordinary, with perikarya in the layer of ganglion cells and nerve fibers, and with dendrites radiating in the inner (proximal) one-fourth of the inner synaptic layer; (2) displaced or Dogiel's cells, with perikarya in the amacrine cell layer and dendrites radiating in the outer (distal) one-fourth of the inner synaptic layer; and (3) intermediate, with both perikarya and dendritic trees at intermediate levels in the inner synaptic layer.Only the ordinary and displaced GGC in the ventral portion of retinas stained with methylene blue were studied in detail. Cells of both types are arranged in irregular patterns with perikarya about 0.8–1.0 mm apart. Dendrites of the ordinary GGC spread within an elliptical field having a major axis of about 1.7 mm (2.0 mm max) and a minor axis of about 1.5 mm (1.7 mm max). The major axis is vertical in the eye. Dendrites of the displaced GGC spread within a circular field having a diameter of about 1.9–2.0 mm (2.2 mm max). Quantitative comparison of the dendritic trees of ordinary and displaced GGC shows that they differ also in details of dendritic morphology, the dendrites of the ordinary GGC being on the average more numerous and highly branched but shorter than those of the displaced GGC. Ordinary and displaced GGC, therefore, comprise distinct populations which must be presumed to differ functionally.For both ordinary and displaced GGC, the dendritic density and, therefore, the total available postsynaptic surface per unit retinal area decline exponentially with distance from the center to the edge of the dendritic tree. In contrast, the sensitivity to light is constant throughout the receptive field centers of comparable diameter which have been analysed in parallel electrophysiological studies. While the diameters of the largest ganglion cell dendritic fields and receptive field centers are similar, therefore, more detailed correlations of structure and function cannot be made at present.
Neurons of the human retina: A Golgi study
The Journal of Comparative Neurology, 1992
Golgi techniques have been applied to post mortem specimens of human retina. Analysis was possible on 150 human retinas processed and viewed by light microscopy as wholemounts. Camera lucida drawings and photography were used to classify the impregnated neurons into 3 types of horizontal cell, 9 types of bipolar cell, 24 basic types of amacrine cell, a single type of interplexiform cell, and 18 types of ganglion cell.
Vision Research, 1982
The horizontal cells of the rabbit retina have been studied by light microscopy of Golgiimpregnated whole-mount retinas. The two types of horizontal cell of the rabbit retina are similar to the horizontal cells of the cat retina in most respects. However, the majority of the A-type horizontal cells of the rabbit have asymmetrical dendritic fields compared to the circular. symmetrical dendritic fields of this cell type in the cat. The A-type horizontal cells of the superior edge of the linear visual streak in the rabbit retina are the most strikingly asymmetric and most of them are elongated and oriented in a direction approximately parallel to the linear visual streak. Like HI axon terminals of the turtle retina the oriented. elongated A-type horizontal cells of the rabbit visual streak region may play a role in the neurocircuitry which underlies orientation sensitive ganglion cells.
Journal of Theoretical Biology, 2009
Type I retinal ganglion cells in the rat have been classified into several groups based on the cell body size and dendritic morphology. Considerable overlap and heterogeneity within groups have been reported, which is especially obvious for the morphology of the dendritic tree. For that purpose, we analysed quantitatively the dendritic morphology of the alpha and delta rat retinal ganglion cells, using parameters which provide information on the dendritic field size, shape of the dendritic tree and dendritic branching complexity. We show that the alpha and delta cells have significantly different dendritic field sizes. Taking into account the level of stratification of the dendritic tree, we found a difference in the properties of the dendritic morphology between alpha inner and alpha outer cells, while the opposite result was obtained for the delta inner and delta outer delta cells. In this study we also call attention to the relationship between morphological parameters and retinal eccentricity. The significance of our quantitative results in terms of present alpha and delta rat retinal ganglion cell classification is discussed.
Ganglion cells in the frog retina: Discriminant analysis of histological classes
Vision Research, 1989
Neurons in the ganglion cell layer were studied in Go&i-stained flat-mounted frog (Rana temporaria) retinas. Complementary data were obtained from methylene blue-and HRP-stained retinas. On the basis of qualitative criteria, 55 neurons were ordered into six groups, one class of amacrine cell (Al) and five classes of ganglion cells (GlG5). A discriminant function analysis based on seven morphological variables resulted in a separation of the cell classes in the space of three axes. The Al cells are small axonless neurons with knotty and dense dendritic trees. The Gl cells are also small, and apparently very numerous, while the G2 cells are medium-sired neurons with two loose dendritic layers, one vitreal and another (less conspicuous) scleral. The rest of the cells are medium-sized to large neurons with sturdy primary dendrites and more distinct dendritic layers, which in some cells (G3) spread both sclerally and vitreally, in other cells in a single either scleral (G4) or vitreal (G5) layer. The relation between our data and the classification of frog ganglion cells recently presented by Frank and Hollyheld is discussed at length, and in that context problems related to statistical classifications are dealt with. A hypothetical identification of the morphological types with the functional cell classes studied in the Helsinki laboratory is discussed.
Dendritic differentiation in the periphery of the growing zebrafish retina
Experimental Eye Research, 2010
In the retina of teleost fish, new ganglion cells are generated from a circumferential peripheral growth zone at the edge of the eye throughout life. Addressing the question how new cells are fitted into the existing retina, we investigated newly formed ganglion cells in the zebrafish retina morphologically, by tracing them from the cut optic nerve with rhodamine dextran. We identified proliferating cells by antibody detection against proliferating cell nuclear antigen. In addition, newly formed bipolar cell and amacrine cell dendrites were investigated by antibodies against protein kinase C (PKC) and choline-acetyl-transferase (ChaT), respectively, and analyzed in sections or wholemount preparations using confocal microscopy. In retinal sections we observed that ganglion cell dendritic branches in the inner plexiform layer were in close apposition to dividing cells. In the periphery of retinal wholemounts, we detected rhodamine traced ganglion cells adjacent to the growth zone, extending dendrites in proximity to the growth zone, typically branching off in opposite directions running parallel to the retinal rim over more then 100 microm. Ganglion cells with similar dendritic branching patterns were not found in more central retinal areas. Similarly, the dendrites of ChaT-positive amacrine cells showed a preference for running parallel to the circumference in the periphery. Dendritic branches of PKC-positive bipolar cells did not show similar preferred orientation. The change in shape of the dendritic tree with distance from the periphery was studied for the Ma type ganglion cell. The data are consistent with the idea that existing ganglion cells might control differentiation of new ganglion cells. Moreover, ganglion cells with specific branching patterns towards the retinal periphery undergo a restructuring of their dendritic trees.
Topography of pig retinal ganglion cells
The Journal of Comparative Neurology, 2005
In the present work we analyzed the distribution of retinal ganglion cells (RGCs) in the pig retina. RGCs were retrogradely labeled in vivo by injecting Fluoro-Gold into the optic nerve. RGC density and the distribution of RGCs in terms of soma size were analyzed. Different regions of the porcine retina were identified following analysis of the distribution of RGCs in terms of cell density and soma size: in the central retina, we found a high-density horizontal RGC band lying dorsal to the optic disc. Moreover, in this region, a high proportion of RCGs with small soma size was observed. From the central to the more peripheral retina, we observed a decrease in RGC density, together with a greater presence of RGCs with larger somas. The results of this study should prove to be useful as a foundation for future studies with the porcine retina as a model in ophthalmic research. The study also highlights the necessity to label the RGC population specifically with retrograde tracers in order to quantify precisely alterations in the cell population associated with experimental treatments. ML. 1974. The fine structure of the pig retina. Albrecht v Graefes Arch Klin Exp Ophthalmol 190:27-45. Berkelaar M, Clarke DB, Wang YC, Bray GM, Aguayo AJ. 1994. Axotomy results in delayed death and apoptosis of retinal ganglion cells in adult rats. J Neurosci 14:4368 -4374. Boycott BB, Wä ssle H. 1974. The morphological types of ganglion cells of the domestic cat's retina. J Physiol 240:397-419.
The Journal of Comparative Neurology, 1994
We have analyzed the effect of a small lesion to the retina of a two-day-old kitten and observed that after degeneration of ganglion cells whose axons were severed, a restricted region of the retina remained depleted of cells. Cells located near the borders of the depleted zone showed an abnormal elongation of dendrites towards the bare area. By means of a computeraided system, we analyzed the whole population of cells at the two borders, and in agreement with previous data found that the effect was most prominent at the border and progressively decreased to eventually disappear at a distance of approximately 500 pm. The distance from the border, however, is not the only factor to influence the degree of asymmetry; with comparable distances, the vicinity of an a-cell reduces the projection of the p-cell dendrites toward the empty area. We suggest that the organization of the adult retinal pattern is also influenced by interactions occurring between dendrites of different classes of ganglion cells.