Displaced amacrine and ganglion cells in the newt retina (original) (raw)
Related papers
Displaced ganglion cells in the retina of the monkey
Investigative ophthalmology & visual science, 1977
Horseradish peroxidase has been injected into the dorsal lateral geniculate nucleus of macaque monkeys to label ganglion cells of the retina by retrograde axoplasmic transport. Displaced ganglion cells, with somata in the inner nuclear layer and dendrites in the inner plexiform layer, were detected by virtue of their filling with peroxidase-positive granules. These cells were numerous in the peripapillary region, but relatively uncommon elsewhere in the retina.
The Journal of Comparative Neurology, 1975
This paper presents evidence on the retinal distribution and central projections of retinal ganglion cells of various cell body sizes in the adult macaque monkey. The ganglion cell sizes have been determined by computer assisted measurement of camera lucida drawings at various eccentricities of both flat mounted and sectioned retinae. The pattern of projections of individual ganglion cells to the dorsal lateral geniculate nucleus and superior colliculus has been studied using retrograde axonal transport of horseradish peroxidase. Following peroxidase injections into the parvocellular laminae of the geniculate, virtually every ganglion cell was labeled within a circumscribed zone of the retina known to project to the region of the geniculate immediately surrounding the injection needle tip. After magnocellular injections, only the largest cells of the peripheral retina and approximately 26% of the ganglion cells of the parafovea were labeled. Peroxidase idections into the superior colliculus produced labeling of scattered ganglion cells of all sizes in the retina, although no labeled cells were found within the centralmost 10" eccentricity. From these observations it is concluded that all ganglion cells of the macaque retina project to the parvocellular layers of the dorsal lateral geniculate, but that only the largest ganglion cells of the more peripheral retina and not all cells of the parafovea project to the magnocellular laminae. In contrast, only scattered ganglion cells, although these are of all sizes, appear to project to the superior colliculus.
Morphology of ganglion cells in the neotenous tiger salamander retina
The Journal of Comparative Neurology, 1995
The morphology of retinal ganglion cells in the neotenous tiger salamander (Ambystoma tigrinurn) was analyzed with the aid of morphometric techniques to determine the diversity of cell types and to evaluate the widely held notion that this form of Ambystoma has a simple retina, with little variance among its cell morphologies. Single-cell staining was achieved through retrograde labeling with horseradish peroxidase injected around the optic nerve sheath followed by a period of several days before tissue processing; 83 well-labelled cells with axons were studied in detail with light microscopy and a computer-aided reconstruction system. Five different morphological cell classes were devised based on broad morphometric criteria such as the dendritic area of influence; the number, length, and complexity of dendritic branches; and the amount of overlap between neighboring dendrites. These classes included small simple, small complex, medium simple, medium complex, and large cells. In addition, a class of cells with numerous varicosities among the dendrites was separately analyzed. These swellings did not stain for catecholamines. Based on optical determinations of the dendritic sublamination pattern within the inner plexiform layer, presumed On-Off cells are present in all subclasses, whereas On cells predominate in the smaller cell groups. Presumed Off cells are well represented in the large field units, although the small total number of cells in this latter class leads to uncertainty regarding the significance of this observation. The diversity of ganglion cell morphology revealed in the present study argues against the assumption that the neotenous tiger salamander has a simple retina, with a relatively invariant set of ganglion cells. On the contrary, it appears that this aquatic form shows morphological diversity in the retinal ganglion cell population rivaling that reported for other vertebrates, including mammals. A functional role for the different cell classes is briefly considered.
Article, 2009
The topography and morphology of retinal ganglion cells (RGCs) in the eastern newt were studied. Cells were retro-gradely labeled with tetramethylrhodamine-conjugated dextran amines or horseradish peroxidase and examined in retinal wholemounts. Their total number was 18,025 3,602 (mean SEM). The spatial density of RGCs varied from 2,100 cells/mm 2 in the retinal periphery to 4,500 cells/mm 2 in the dorsotemporal retina. No prominent retinal specializa-tions were found. The spatial resolution estimated from the spatial density of RGCs varied from 1.4 cycles per degree in the periphery to 1.95 cycles per degree in the region of the peak RGC density. A sample of 68 cells was camera lucida drawn and subjected to quantitative analysis. A total of 21 parameters related to RGC morphology and stratification in the retina were estimated. Partitionings obtained by using different clustering algorithms combined with automatic variable weighting and dimensionality reduction techniques were compared, and an effective solution was found by using silhouette analysis. A total of seven clusters were identified and associated with potential cell types. Kruskal-Wallis ANOVA-on-Ranks with post hoc Mann-Whitney U tests showed significant pairwise between-cluster differences in one or more of the clustering variables. The average silhouette values of the clusters were reasonably high, ranging from 0.52 to 0.79. Cells assigned to the same cluster displayed similar morphology and stratification in the retina. The advantages and limitations of the methodology adopted are discussed. The present classification is compared with known morphological and physiological RGC classifications in other salamanders. J. Comp. Neurol. 516:533–552, 2009. Understanding how the nervous system works is impossible without identification of its elementary blocks, neuron types. Knowing neuron types is also essential for establishing their evolutionary relationships in homologous lineages and elucidating the mechanisms of neuron ontogeny. The concept of neuron type is not as straightforward as it might seem at first glance (Cook, 1998, 2003). The key to the discovery of neuron types is to distinguish between within-and between-type variation of certain parameters related to neuron structure, function, or development (Rodieck and Brening, 1983). An obvious way to identify neuron types would be to use type-specific molecular markers. At present, however, it is not practicable because such markers are known for a limited number of neuron types and even these seem to be only partially specific (Masland and Raviola, 2000). Neuronal morphology therefore remains an adequate means for neuron classification. It has long been realized that neuron classification should be based on a set of nonsubjective parameters and should be made by using automated algorithms (Rodieck and Brening, 1983; Schweitzer and Renehan, 1997). Despite certain difficulties and limitations of this approach (Ertö z et al., 2003; Ivá ncsy et al., 2005), an increasing number of papers using it have been published in recent years. Retinal ganglion cells (RGCs) comprise the last relay in the retinal signal circuitry. They send axons to a variety of brain centers providing a link between the eye and the brain. The number of studies addressing the morphological diversity of
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.
The Topographic Organization of the Retinal Ganglion Cell Layer of the Lizard Ctenophorus nuchalis
Archives of Histology and Cytology, 1992
The numbers of neurons of the ganglion cell layer (GCL) and their distribution in the retina of an Australian lizard Ctenophorus nuchalis were investigated. Retinal wholemounts and sections were prepared for light microscopic and optic nerves for electron microscopic study. Counts of cell numbers in the GCL from wholemounts varied from 200,000 to 380,000. Neurons in the GCL were non-uniformly distributed, forming a high cell density streak along the naso-temporal axis of the retina. Neurons of the GCL formed 2 to 9 layers in the visual streak and a single layer in the rest of the retina. The number of neurons of the GCL in this area was estimated at about 2,100,000. Althouth the visual streak represented only 16% of the total retinal surface area, it contained about 90% of all neurons of the GCL. Optic axon counts yielded 147,000 myelinated and 2,643,000 unmyelinated fibres. The estimated optic fibre number of 2,790,000 was 18.2% less than the total number of neurons counted from sections in the GCL of the same eye. The unexpected high number of neurons in the area of the visual streak indicates that cell numbers obtained only from wholemount preparations may vastly underestimate the total neuron numbers in the GCL of the lizard retina.
Retrograde intraaxonal transport of horseradish peroxidase in retinal ganglion cells of the chick
Brain Research, 1975
Since the 1920's several investigators have noted the bidirectional movement of vesicles within neurites in tissue culture26,28, 80. Other investigators have demonstrated the retrograde movement of materials within axons more clearly by showing the accumulation of axoplasm as well as radioactive and endogenous chemical markers in both the proximal and distal portions of constricted or severed peripheral nerves 2, 10,11,~2,27,z8. Recently Kristensson and coworkers 1s-21 have demonstrated morphologically that when the exogenous proteins, Evans blue-labeled albumin or horseradish peroxidase (HRP) are injected into the vicinity of neuromuscular junctions, they are taken up and subsequently found within the cell bodies whose axons project to the injection sites. We have extended these observations to include neurons of the central nervous system 2a-25. We previously considered the transport to be intraaxonal because we found vesicles containing HRP within chick retinal ganglion cell axons soon after tectal injection of the protein marker 23,24. A similar intracellular localization in rat optic nerve has been noted by Hansson is. This report deals with the cellular organelles and mechanisms involved in the uptake and retrograde transport of HRP in chick retinal ganglion cells.
Characterization of a GABAergic population of interstitial amacrine cells in the teleost retina
Vision research, 1991
We used postembedding immunocytochemistry with an antiserum against BSA-conjugated GABA to study the inner plexiform layer of a cyprinid teleost, the roach. In this part of the retina, we observed a distinct banding pattern of GABA-positive material. There was a narrow unstained region separating the distal sublamina a from the proximal sublamina b; each sublamina was further subdivided into four (a) and two (b) sublayers of heavier staining, respectively. Using three-dimensional reconstruction of series of half-micron tangential sections, we were able to characterize a population of interstitial amacrine cells which contained GABA-like immunoreactive material. These cells had elliptical dendritic fields (area: about 0.04 mm2) and conspicuous, thick processes (dia. 4-5 microns). In tangential sections, the dendrites of individual cells appeared to be in close contact, occasionally resulting in difficulties in defining the boundaries of a single dendritic field. Two sub-populations o...
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.