The harp seal, Pagophilus groenlandicus (Erxleben, 1777). VI. Structure of retina

1970 ◽  
Vol 48 (2) ◽  
pp. 367-370 ◽  
Author(s):  
A. R. Nagy ◽  
K. Ronald
Keyword(s):  
Ganglion Cells ◽  
Outer Nuclear Layer ◽  
Horizontal Cell ◽  
Single Layer ◽  
Amacrine Cells ◽  
Visual Sensitivity ◽  
Harp Seal ◽  
Pagophilus Groenlandicus ◽  
Area Centralis ◽  
Cell Processes

The retina of the harp seal (Pagophilus groenlandicus) was studied by means of the light microscope. Ganglion cells occupy a single layer. Thinly dispersed throughout this layer are giant ganglion cells. There is no area centralis. The inner nuclear layer consists of large horizontal cell processes with bipolar and amacrine cells between the horizontal cell processes. The outer nuclear layer is the thickest of all retinal layers. Its density is constant in the central and peripheral areas of the retina, similar to that found in the inner nuclear and ganglion layers. Only rod photoreceptors were found; therefore it is presumed that seals have no color vision. The tapetum covers an extensive area and is 32–34 cellular layers thick centrally, diminishing in thickness peripherally. The combination of tapetum and rod receptors makes possible excellent visual sensitivity to dim light.

Population and density of the bipolar ganglion cells in the cochlea of the harp seal (Pagophilus groenlandicus Erxleben, 1777)

1976 ◽  
Vol 54 (11) ◽  
pp. 1918-1926 ◽  
Author(s):  
F. Ramprashad
Keyword(s):  
Hair Cells ◽  
Ganglion Cells ◽  
Spiral Ganglion ◽  
Harp Seal ◽  
Nerve Cell Body ◽  
Continuous Ring ◽  
Average Value ◽  
Pagophilus Groenlandicus ◽  
Sensory Hair Cells ◽  
Two Peaks

The population and density of the bipolar ganglion cells were determined from serial horizontal sections and graphic reconstructions of the cochleas of five captive harp seals. The [Formula: see text]-turn spiral ganglion forms a continuous ring throughout its course except at the extreme basal end where it is narrowest. The nerve cell body is 25 μm long (16.1–38.8 μm) and 16 μm wide (10–24 μm). The average number of ganglion cells present was 57 185 (46 389 – 70 952), with a corrected total number of 52 000 ganglion cells. Two peaks are present in the density curve of the ganglion cells. The first was at 1–1.5 mm and the second at 20 mm, where 2620 cells/mm2 and 2250 cells/mm2 respectively are present.The ratio of total ganglion cells to total sensory hair cells was about 3:1. This ratio was not uniform throughout the length of the cochlea; it was 6:1 at 2–3 mm from the basal end and declined gradually to 3:1 at the apical end. The average total of ganglion cells in the harp seal exceeded the average value in humans, but did not exceed the values found in dolphins.

Immuocytochemical analysis of spatial organization of photoreceptors and amacrine and ganglion cells in the tiger salamander retina

2004 ◽  
Vol 21 (2) ◽  
pp. 157-166 ◽  
Author(s):  
JIAN ZHANG ◽  
ZHUO YANG ◽  
SAMUEL M. WU
Keyword(s):  
Ganglion Cell ◽  
Spatial Organization ◽  
Ganglion Cells ◽  
Electrophysiological Study ◽  
Outer Nuclear Layer ◽  
Amacrine Cells ◽  
Spatial Arrangement ◽  
Cell Types ◽  
Proximal Region ◽  
Dorsal Retina

In the present study, using double- or triple-label immunocytochemistry in conjunction with confocal microscopy, we aimed to examine the population and distribution of photoreceptors, GABAergic and glycinergic amacrine cells, and ganglion cells, which are basic but important parameters for studying the structure–function relationship of the salamander retina. We found that the outer nuclear layer (ONL) contained 82,019 ± 3203 photoreceptors, of which 52% were rods and 48% were cones. The density of photoreceptors peaked at ∼8000 cells/mm2 in the ventral and dropped to ∼4000 cells/mm2 in the dorsal retina. In addition, the rod/cone ratio was less than 1 in the central retina but larger than 1 in the periphery. Moreover, in the proximal region of the inner nuclear layer (INL3), the total number of cells was 50,576 ± 8400. GABAergic and glycinergic amacrine cells made up approximately 78% of all cells in this layer, including 43% GABAergic, 32% glycinergic, and 3% GABA/glycine colocalized amacrine cells. The density of these amacrine cells was ∼6500 cells/mm2 in the ventral and ∼3200 cells/mm2 in the dorsal area. The ratio of GABAergic to glycinergic amacrine cells was larger than 1. Furthermore, in the ganglion cell layer (GCL), among a total of 36,007 ± 2010 cells, ganglion cells accounted for 65.7 ± 1.5% of the total cells, whereas displaced GABAergic and glycinergic amacrine cells comprised about 4% of the cells in this layer. The ganglion cell density was ∼1800 cells/mm2 in the ventral and ∼600 cells/mm2 in the dorsal retina. Our data demonstrate that all three major cell types are not uniformly distributed across the salamander retina. Instead, they exhibit a higher density in the ventral than in the dorsal retina and their spatial arrangement is associated with the retinal topography. These findings provide a basic anatomical reference for the electrophysiological study of this species.

Signal transmission in the catfish retina. V. Sensitivity and circuit

1987 ◽  
Vol 58 (6) ◽  
pp. 1329-1350 ◽  
Author(s):  
H. M. Sakai ◽  
K. Naka
Keyword(s):  
Ganglion Cells ◽  
Modulation Depth ◽  
Horizontal Cell ◽  
Amacrine Cells ◽  
Bipolar Cells ◽  
Modulation Response ◽  
First Order ◽  
Parametric Change ◽  
Type C ◽  
Mean Luminance

1. We analyzed the light-evoked responses of retinal neurons by means of a white-noise technique. Horizontal and bipolar cells produced a modulation response that was linearly related to a modulation of the mean luminance of a large field of light. The first-order kernels were capable of reproducing the cells' modulation response with a fair degree of accuracy. The amplitude as well as the waveform of the kernels changed with the change in the mean luminance. This is a parametric change and is a form of field adaptation. As the time constant of the parametric change was much longer than that of the modulation response (memory), neurons were assumed to be at a dynamic steady state at a given mean luminance. 2. With the presence of a steady annular illumination, the first-order kernel derived from stimulation with a small spot of light became faster in peak response time and larger in amplitude. For horizontal-cell somas and bipolar cells, the surround also linearized their modulation response. This surround enhancement has been seen in all the cone-driven retinal cells except the receptor and horizontal cell axon, in which a steady surround decreased the amplitude of the spot-evoked kernel but shortened the peak response time. 3. A change in the modulation depth did not affect either the amplitude or the wave-form of the first-order kernels from the horizontal and bipolar cells. In the amacrine and ganglion cells, on the other hand, the amplitude of kernels was related inversely to the depth of modulation. These cells were more sensitive to the modulation of a small modulation depth. 4. A static nonlinearity appeared when signals were transmitted to the amacrine cells. The nonlinearity was first produced in the type-C amacrine cells by a process, which could be modeled by squaring the bipolar cell response. A gamut of more complex second-order nonlinearities found in type-N amacrine cells could be modeled by a band-pass filtering of the type-C cell response. Linear components in the bipolar cells and nonlinear components in the amacrine cells are encoded into spike trains in the ganglion cells. Thus, under our simple stimulus regimen, the ganglion cells transformed the results of the preganglionic signal processing into a spike train without much modification. 5. We propose a tentative diagram of the signal flow in the cone-driven catfish retinal neurons based on this and previous studies.(ABSTRACT TRUNCATED AT 400 WORDS)

Morphological and functional identifications of catfish retinal neurons. I. Classical morphology

1975 ◽  
Vol 38 (1) ◽  
pp. 53-71 ◽  
Author(s):  
K. Naka ◽  
N. R. Garraway
Keyword(s):  
Ganglion Cells ◽  
Horizontal Cell ◽  
Dendritic Tree ◽  
Amacrine Cells ◽  
Cell Types ◽  
Bipolar Cells ◽  
Inner Nuclear Layer ◽  
Horizontal Cells ◽  
Specific Cell ◽  
Definition Of

The morphology of the catfish horizontal cells is comparable to that in other fish retinas. The external horizontal cells contact cone receptors and are stellate in shape; the intermediate horizontal cells are even more so and contact rod receptors. The internal horizontal cells constitute the most proximal layer of the inner nuclear layer and may possibly be, in reality, extended processes from the other two horizontal cell types. Bipolar cells resemble those in other teleost retinas: the size and shape of their dendritic tree encompass a continuous spectrum ranging from what is known as the small to the large bipolar cells. The accepted definition of amacrine cells is sufficiently vague to justify our originating a more descriptive and less inferential name for the (axonless) neurons in the inner nuclear layer which radiate processes throughout the inner synaptic layer. These starbust and spaghetti cells vary considerably in the character and extent of their dendritic spread, but correlates exist in other vertebrate retinas. Ganglion cells are found not only in the classical ganglion layer but displaced into the inner nuclear layer as well. Several types can be distinguished on the basis of cell geometry and by the properties of their dendritic tree. Not all of the categorization corresponds with previous descriptions; our findings suggest that some reorganization may be necessary in the accepted classification of cells in the proximal areas of the vertebrate retina. A subtle yet remarkable pattern underlies the entire structure of the catfish retina; there exists a definite gradient of size within a particular class of cells, and of configuration among the subclasses of a specific cell type. It remains to be seen if these morphological spectra bear any functional consequences. The fact that the structure of the catfish retina most closely resembles those of other phylogenetically ancient animals, such as the skate and the dogfish shark, testifies to its primitive organization; morphological and functional mechanisms discernible in this simple system may, therefore, be applicable to the retinas of higher ordered vertebrates.

Disruption of transient photoreceptor targeting within the inner plexiform layer following early ablation of cholinergic amacrine cells in the ferret

2001 ◽  
Vol 18 (5) ◽  
pp. 741-751 ◽  
Author(s):  
P.T. JOHNSON ◽  
M.A. RAVEN ◽  
B.E. REESE
Keyword(s):  
Retinal Ganglion Cells ◽  
Amacrine Cell ◽  
Ganglion Cells ◽  
Plexiform Layer ◽  
Amacrine Cells ◽  
Inner Plexiform Layer ◽  
Retinal Ganglion ◽  
Subcutaneous Injections ◽  
Cell Processes ◽  
Cholinergic Amacrine Cells

Photoreceptors in the ferret's retina have been shown to project transiently to the inner plexiform layer (IPL) prior to their differentiation of an outer segment. On postnatal day 15 (P-15), when this projection achieves maximal density, the photoreceptors projecting into the IPL extend primarily to one of two depths, coincident with the processes of cholinergic amacrine cells. The present study has used an excitotoxic approach employing subcutaneous injections of l-glutamate to ablate these cholinergic amacrine cells on P-7, in order to see whether their elimination alters this targeting of photoreceptor terminals within the IPL. The near-complete elimination of cholinergic amacrine cells at P-15 was confirmed, although the population of retinal ganglion cells was also affected, being depleted by roughly 50%. The rod opsin-immunopositive terminals in such treated ferrets no longer showed a stratified distribution, being found throughout the depth of the IPL, as well as extending into the ganglion cell layer. This effect should not be due to the partial loss of retinal ganglion cells, however, since optic nerve transection at P-2, which eliminates the ganglion cells entirely while leaving the cholinergic amacrine cell population intact, was shown not to affect the stratification pattern of the photoreceptors within the IPL. These results strongly suggest that the targeting of the photoreceptor terminals to discrete strata within the IPL is dependent upon the cholinergic amacrine cell processes.

The harp seal, Pagophilus groenlandicus (Erxleben 1777). XXIII. Spectral sensitivity

1972 ◽  
Vol 50 (9) ◽  
pp. 1197-1206 ◽  
Author(s):  
D. M. Lavigne ◽  
K. Ronald
Keyword(s):  
Spectral Sensitivity ◽  
Dark Adaptation ◽  
Relative Sensitivity ◽  
Visual Sensitivity ◽  
Harp Seal ◽  
Scotopic Sensitivity ◽  
Underwater Environment ◽  
Pagophilus Groenlandicus ◽  
Increased Sensitivity ◽  
Purkinje Shift

Behavioral determinations of harp seal spectral sensitivity, under light- and dark-adapted conditions, indicated the presence of a Purkinje shift. Maximum photopic sensitivity occurred near 550 nm. Scotopic sensitivity peaked in the region of 500–525 nm. A large increase in relative sensitivity, approaching 8 log units at 525 nm, accompanied dark adaptation. This confirms anatomical suggestions that the harp seal possesses excellent visual sensitivity. Increased sensitivity to green wavelengths may indicate adaptation to a particular underwater environment.

scholarly journals Synchronous inhibitory pathways create both efficiency and diversity in the retina

2017 ◽  
Author(s):  
Mihai Manu ◽  
Lane T. McIntosh ◽  
David B. Kastner ◽  
Benjamin N. Naecker ◽  
Stephen A. Baccus
Keyword(s):  
Information Transmission ◽  
Ganglion Cell ◽  
Ganglion Cells ◽  
Spatial Scales ◽  
Horizontal Cell ◽  
Receptive Fields ◽  
Amacrine Cells ◽  
Visual Features ◽  
Inhibitory Pathways ◽  
Wide Range

Visual information is conveyed from the retina to the brain by a diverse set of retinal ganglion cells. Although they have differing nonlinear properties, nearly all ganglion cell receptive fields on average compute a difference in intensity across space and time using a region known as the classical or linear surround1,2, a property that improves information transmission about natural visual scenes3,4. The spatiotemporal visual features that create this fundamental property have not been quantitatively assigned to specific interneurons. Here we describe a generalizable causal approach using simultaneous intracellular and multielectrode recording to directly measure and manipulate the sensory feature conveyed by a neural pathway to a downstream neuron. Analyzing two inhibitory cell classes, horizontal cells and linear amacrine cells, we find that rather than transmitting different temporal features, the two inhibitory pathways act synchronously to create the salamander ganglion cell surround at different spatial scales. Using these measured visual features and theories of efficient coding, we computed a fitness landscape representing the information transmitted using different weightings of the two inhibitory pathways. This theoretical landscape revealed a ridge that maintains near-optimal information transmission while allowing for receptive field diversity. The ganglion cell population showed a striking match to this prediction, concentrating along this ridge across a wide range of positions using different weightings of amacrine or horizontal cell visual features. These results show how parallel neural pathways synthesize a sensory computation, and why this architecture achieves the potentially competing objectives of high information transmission of individual ganglion cells, and diversity among receptive fields.

The photoresponses of structurally identified amacrine cells in the turtle retina

1982 ◽  
Vol 214 (1196) ◽  
pp. 403-415 ◽  
Keyword(s):  
Time Course ◽  
Amacrine Cell ◽  
Ganglion Cells ◽  
Plexiform Layer ◽  
Amacrine Cells ◽  
Homogeneous Distribution ◽  
Inner Plexiform Layer ◽  
Intracellular Recordings ◽  
Cell Processes ◽  
Layer I

Intracellular recordings were obtained from amacrine cells afterwards identified morphologically by horseradish peroxidase injection. There is a correlation between the time course of the photoresponses and the distribution of the cell processes across the inner plexiform layer (i. p. l.). Cells producing the shortest duration, transient ‘on‒off’ photoresponses branched in a single, narrow stratum of the i. p. l. (3‒7 μm across). Transient photoresponses with a longer time course were recorded from cells branching in a thicker stratum of i. p. l. (up to 20 μm), or from bistratified cells. Amacrine cells producing sustained centre-on or centre-off photoresponses were radially diffused across the whole i. p. l.; therefore this type of photoresponse need not be associated with a specific cellular stratification within the i. p. l. It is concluded that the two main functional types of amacrine cell, i. e. transient on‒off and sustained centre-on and centre-off, are subject to different structural organization of inputs than are the homologous physiological types of ganglion cells in this species, in the cat and in the carp. In a summary diagram the observed characteristics of the photoresponses are tentatively explained in term s of a non-homogeneous distribution of bipolar synaptic inputs along amacrine cell processes.

Functional organization of catfish retina

1977 ◽  
Vol 40 (1) ◽  
pp. 26-43 ◽  
Author(s):  
K. Naka
Keyword(s):  
Receptive Field ◽  
Ganglion Cell ◽  
Functional Organization ◽  
Ganglion Cells ◽  
Horizontal Cell ◽  
Receptive Fields ◽  
Amacrine Cells ◽  
Type A ◽  
Bipolar Cells ◽  
The Other

1. The basic organization of the biphasic (or concentric) receptive field is established in the bipolar cells as the result of an interaction between two signals, one local representing the activity of a small number of receptors, and the other integrating (19, 20) or global (28) coming from the S space or a lamina formed by the horizontal cells (8, 14, 22, 29). 2. Bipolar-ganglion cell pairs are segregated into two types; A (on center) and B (off center) pairs. A depolarization of a bipolar cell produces spike discharges from ganglion cells of the same type and a hyperpolarization depresses their discharges. I haven't detected any cross talk between the types A and B pairs. Bipolar and ganglion cells must be interfaced by the classical chemical synapses, the only such kind in the catfish retina. 3. Horizontal and type N neurons form two lateral transmission systems, one distal and the other proximal (19, 20). Signals in the lateral systems are shared by the two receptive-field types and are not excitatory or inhibitory in themselves; it is incumbent upon the postsynaptic neurons to decide the polarity of the synaptic transmission. The horizontal cell participates directly in the formation of biphasic receptive fields of bipolar cells by providing their surrounding, whereas type N neuron seems to modify the receptive-field organization established in the bipolar cells. 4. Type N neurons are amacrine cells because they do not produce spike discharges (2, 18, 21) and because they influence the activity of both A and B receptive fields. 5. The function of the type C neuron is as unique as its structure (21) and is not fully clear as yet. It is not a conventional amacrine cell as the type N appears to be, nor is it a classical ganglion cell which forms either a type A or B receptive field (2). 6. Type Y neurons are a class of ganglion cells which forms either a type A or B receptive field.

Relationships between Müller cells and neurons in a primitive tetrapod, the Australian lungfish

1997 ◽  
Vol 14 (4) ◽  
pp. 795-800 ◽  
Author(s):  
Stephen R. Robinson
Keyword(s):  
Ganglion Cells ◽  
Horizontal Cell ◽  
Müller Cells ◽  
Amacrine Cells ◽  
Müller Cell ◽  
Muller Cells ◽  
Cone Photoreceptors ◽  
Rod Photoreceptors ◽  
Muller Cell ◽  
Australian Lungfish

AbstractWe recently proposed a model of cytogenesis which assumes that primitive ancestral mammals and premammalian vertebrates had a retinal composition that consisted of about seven neurons per Müller cell, comprising 1–2 cone photoreceptors, 1–2 rod photoreceptors, 2–3 bipolar cells, 1–2 amacrine cells, less than 1 ganglion cell, and less than 1 horizontal cell (Reichenbach & Robinson, 1995). The Australian lungfish (Neoceratodus forsten) closely resembles the lobe-finned ancestors of land vertebrates, and has an extremely plesiomorphic nervous system. The present study, therefore, has examined the relative frequencies of retinal neurons and Müller cells (identified by immunolabelling for glutamine synthetase) in the lungfish retina. It was found that for each Müller cell there is an average of 1.9 cone photoreceptors, 1.7 rod photoreceptors, 3.1 amacrine/bipolar/horizontal cells, and 0.6 ganglion cells; amounting to a ratio of 7.3 neurons per Müller cell. These results support our conjecture that the sequence of cytogenesis in mammals is constrained by a developmental program that predates the evolution of mammals. The study also provides the first detailed morphological descriptions of lungfish Müller cells and their relationship with adjacent neurons. It was found that individual Müller cells in lungfish have a volume (more than 12,000 μm3) that is an order of magnitude higher than in mammals, yet the proportion of total retinal volume occupied by these cells (20%) is very similar.

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