X-cells in the cat retina: relationships between the morphology and physiology of a class of cat retinal ganglion cells

1987 ◽  
Vol 58 (5) ◽  
pp. 940-964 ◽  
Author(s):  
L. R. Stanford

1. The morphology of 21 physiologically characterized X-cells in the cat retina was studied using intracellular recording and injection with horseradish peroxidase. The data from these experiments were used to test directly the relationships between specific structural and functional characteristics of a sample of individual retinal ganglion cells of the same anatomical and physiological class. Where possible, the response properties of 53 other retinal X-cells that were not successfully injected and recovered are compared with those of the labeled sample. These comparisons, which included conduction velocities (both intraretinal and extraretinal) and receptive-field size, indicate that the labeled X-cells are a representative sample of the population of retinal X-cells at corresponding eccentricities. 2. The somata of this group of injected retinal X-cells increase in size with increasing distance from the area centralis up to 13 degrees eccentricity (the greatest distance from the area centralis at which an X-cell was injected and recovered). The soma sizes of this sample of retinal ganglion cells range from 143.5 to 529.9 micron 2 (diam = 13.5-26.0 micron). Comparison of the soma sizes of the injected and recovered retinal X-cells with those of 300 Nissl-stained neurons at comparable eccentricities in the same retinae indicate that the injected sample had soma sizes that are consistent with their classification as "medium-sized" retinal ganglion cells (5, 69, 74). 3. All of the physiologically characterized retinal X-cells of this study have the compact dendritic arbors described to the morphological class of retinal ganglion cell called beta-cells by Boycott and Wassle (5). The dendrites of some of these neurons have many spinelike appendages, whereas those of other cells are nearly appendage free. We found no obvious correlation between the presence of dendritic appendages and any specific response characteristic ("ON-" or "OFF-center", etc). Like the size of the soma, both the diameter of the dendritic arbors of these cells, and the number of primary dendrites (those dendrites that originate directly from the soma), increase with increasing distance from the area centralis. 4. Since both morphological and physiological data were obtained for these neurons, it is possible to describe the relationship between the size of the receptive-field center and the diameter of the dendritic arbor for individual retinal ganglion cells. These comparisons show that the relationship between the anatomical measure and this response parameter for the entire sample of labeled X-cells is not as strong as had previously been suggested.(ABSTRACT TRUNCATED AT 400 WORDS)

2006 ◽  
Vol 23 (1) ◽  
pp. 137-142 ◽  
Author(s):  
WAYNE MICHAEL KING ◽  
VIMAL SARUP ◽  
YVES SAUVÉ ◽  
COLLEEN M. MORELAND ◽  
DAVID O. CARPENTER ◽  
...  

Glaucoma is a major cause of blindness and is characterized by death of retinal ganglion cells. In a rat model of glaucoma in which intraocular pressure is raised by cautery of episcleral veins, the somata and dendritic arbors of surviving retinal ganglion cells expand. To assess physiological consequences of this change, we have measured visual receptive-field size in a primary retinal target, the superior colliculus. Using multiunit recording, receptive-field sizes were measured for glaucomatous eyes and compared to both those measured for contralateral control eyes and to homolateral eyes of unoperated animals. Episcleral vein occlusion increased intraocular pressure. This was accompanied by a significant increase in receptive-field size across the superior colliculus. The expansion of receptive fields was proportional to both degree and duration of the increase of intraocular pressure. We suggest that this increase in the size of receptive fields of glaucomatous eyes may be related to the increase in the size of dendritic arbors of the surviving ganglion cells in retina.


1987 ◽  
Vol 57 (1) ◽  
pp. 218-244 ◽  
Author(s):  
L. R. Stanford

Intracellular recording and iontophoresis of horseradish peroxidase were used to study the morphology of physiologically characterized W-cells in the cat retina. The recording experiments were performed in an in vivo preparation to allow the responses of these retinal ganglion cells to be compared with previous functional studies of these neurons. The physiological and morphological characteristics of 16 injected and recovered retinal W-cells were compared with similar data from 14 retinal X-cells injected in the same preparations. The soma sizes of retinal W-cells were found to fall into two distinct groups. The somata of the phasic W-cells, at every eccentricity, were smaller than the somata of tonic W-cells, with no overlap between the two distributions. Soma sizes of the tonic W-cells fell into the previously described “medium-sized” range of retinal ganglion cell soma sizes and were similar to, although slightly larger than, the soma sizes of physiologically identified beta- or X-cells. The dendritic arbors of all of the cells physiologically classified as tonic W-cells were similar. Every example of this type had four to five primary dendrites that branched a short distance from the soma to form a circular or cruciate dendritic arbor. The dendritic arrays of these cells were easily distinguishable from the compact dendritic arbors of the physiologically identified X-cells. The dendritic arbors of the phasic W-cells were much more heterogeneous, ranging from sparse, wide dendritic arbors to very compact dendritic arbors with many fine branches. No significant correlation was found between the extent of the dendritic arbor and the distance from the area centralis for either the tonic W-cells or the phasic W-cells. The axons of the tonic and phasic W-cells differed from one another and from X-cells on a number of different morphological and physiological measures. The intraretinal segments of the axons of the phasic W-cells had the smallest diameters of the three groups; the axons of X-cells in the retina were relatively large, and the axons of the tonic W-cells had diameters intermediate between the phasic W-cells and the X-cells. Although considerable overlap was seen between the X-cells, tonic W-cells, and phasic W-cells in their antidromic latencies to electrical stimulation of the optic chiasm, the intraretinal and extraretinal components of the conduction velocities of the three groups were significantly different.(ABSTRACT TRUNCATED AT 400 WORDS)


1991 ◽  
Vol 6 (3) ◽  
pp. 271-281 ◽  
Author(s):  
S.L. Pallas ◽  
B.L. Finlay

AbstractUnilateral partial ablation of the superior colliculus in the hamster results in a compression of the retinotopic map onto the remaining tectal fragment. In a previous electrophysiological study (Pallas & Finlay, 1989a), we demonstrated that receptive-field properties of single tectal units (including receptive-field size) remain unchanged, despite the increased afferent/target convergence ratios in the compressed tecta. The present study was done to investigate the mechanism that produces increased convergence from retina to tectum at the population level while maintaining apparent stability of convergence at the single neuron level. We injected comparable quantities of horseradish peroxidase into the tecta of normal adult hamsters and adult hamsters that had received neonatal partial tectal ablations of varying magnitude. We then compared the area of retina backfilled from the injection and the number and density of labeled retinal ganglion cells within it to the size of the remaining tectal fragment.As expected from earlier anatomical (Jhaveri & Schneider, 1974) and physiological (Finlay et al., 1979a; Pallas & Finlay, 1989a) studies demonstrating compression of the retinotectal projection, we found that the area of retina labeled from a single tectal injection site increases linearly with decreasing tectal fragment size. However, for fragment sizes down to 30% of normal, total number of retinal ganglion cells projecting to the injection site remains in or above the normal range. For large lesions (less than 30% of tectum remaining), total number of labeled retinal ganglion cells declines from normal, despite the fact that a larger absolute area of retina is represented on each unit of tectum under these conditions. Comparison of retinal ganglion cell density with tectal fragment size shows an initial decline with decreasing fragment size, which becomes sharper with very large lesions (small tectal fragments).The maintenance of the normal number of retinal ganglion cells innervating each patch of tectum could be accomplished by an elimination of the tectal collaterals of some retinal ganglion cells. Our results suggest that, in addition to collateral elimination, reduction in the size of ganglion cell arbors is occurring, since the peak density of backfilled ganglion cells declines less rapidly than backfilled retinal area increases, especially for small lesions. However, arbor reduction and collateral elimination must occur in such a way that individual tectal cells represent the same amount of visual space as normal.Thus, collateral elimination and arbor reduction are two mechanisms that operate to maintain afferent/target convergence ratios (and thus receptive-field properties) over large variations in afferent availability. This compensation may occur through an activity-dependent stabilization mechanism that does not change its selectivity even when excess afferents are available. For very large lesion sizes, receptive-field size and innervating ganglion cell number and density are not preserved, thus demonstrating a limit to the afferent/target matching mechanism. The same ontogenetic mechanisms might provide a buffer for normal variations in afferent populations, and could help to align topographic maps with differing numbers of afferents.


1979 ◽  
Vol 74 (2) ◽  
pp. 275-298 ◽  
Author(s):  
J D Victor ◽  
R M Shapley

We investigated receptive field properties of cat retinal ganglion cells with visual stimuli which were sinusoidal spatial gratings amplitude modulated in time by a sum of sinusoids. Neural responses were analyzed into the Fourier components at the input frequencies and the components at sum and difference frequencies. The first-order frequency response of X cells had a marked spatial phase and spatial frequency dependence which could be explained in terms of linear interactions between center and surround mechanisms in the receptive field. The second-order frequency response of X cells was much smaller than the first-order frequency response at all spatial frequencies. The spatial phase and spatial frequency dependence of the first-order frequency response in Y cells in some ways resembled that of X cells. However, the Y first-order response declined to zero at a much lower spatial frequency than in X cells. Furthermore, the second-order frequency response was larger in Y cells; the second-order frequency components became the dominant part of the response for patterns of high spatial frequency. This implies that the receptive field center and surround mechanisms are physiologically quite different in Y cells from those in X cells, and that the Y cells also receive excitatory drive from an additional nonlinear receptive field mechanism.


2021 ◽  
Vol 15 ◽  
Author(s):  
Hui Chen ◽  
Hong-Ping Xu ◽  
Ping Wang ◽  
Ning Tian

It was well documented that both the size of the dendritic field and receptive field of retinal ganglion cells (RGCs) are developmentally regulated in the mammalian retina, and visual stimulation is required for the maturation of the dendritic and receptive fields of mouse RGCs. However, it is not clear whether the developmental changes of the RGC receptive field correlate with the dendritic field and whether visual stimulation regulates the maturation of the dendritic field and receptive field of RGCs in a correlated manner. The present work demonstrated that both the dendritic and receptive fields of RGCs continuously develop after eye opening. However, the correlation between the developmental changes in the receptive field size and the dendritic field varies among different RGC types. These results suggest a continuous change of synaptic converging of RGC synaptic inputs in an RGC type-dependent manner. Besides, light deprivation impairs both the development of dendritic and receptive fields.


1983 ◽  
Vol 49 (2) ◽  
pp. 303-324 ◽  
Author(s):  
D. N. Mastronarde

1. The shared inputs to cat retinal ganglion cells have been investigated by studying correlations in the maintained firing of neighboring ganglion cells. The firing of one cell was recorded from its axon in the optic tract, while that of a neighboring cell was simultaneously recorded with a second electrode in the retina. The recorded cells were of the X- or Y-type and viewed a uniform screen having a luminance of 10 cd/m2. 2. Ganglion cells with overlapping receptive-field centers showed two basic forms of correlated firing: if they had the same center sign (both on-center or both off-center), then they tended to fire at the same time, as shown by a peak in their cross-correlogram; but if they had opposite center signs (an on- and and off-center cell), they tended not to fire at the same time, as shown by a well, or dip, in their cross-correlogram. 3. Both of these tendencies were strongest for cells that were close together and did not appear for cells with nonoverlapping receptive-field centers. The strongest correlations were between neighboring Y-cells, cells with large fields, and the weakest were between X-cells, cells with small fields. In general, the strength of the correlations depended primarily on the area of the overlap between fields. 4. These correlations in maintained firing appear to be principally or entirely caused by shared inputs to the ganglion cells from more distal retinal neurons. The signals from these distal neurons appear to have strong, brief (4-8 ms), well-defined effects on ganglion cells, which are observed even in the absence of a visual stimulus. The inputs responsible for the correlated firing are thus referred to as spontaneously active inputs or simply as active inputs. 5. An analysis of the features in the various types of cross-correlograms supports the following statements about these spontaneously active inputs. a) There are two types of active inputs: inputs excitatory to on-center cells and simultaneously inhibitory to off-center center cells and inputs excitatory to off-center cells and simultaneously inhibitory to on-center cells. b) The active inputs of each type provide excitation to both X- and Y-cells of one center sign and inhibition to both X- and Y-cells of the other center sign. There is no evidence for a special class of more selective inputs providing input only to X-cells or only to Y-cells. c) Active inputs account for the majority (about 80%) of the spikes in the maintained activity of Y-cells but only a small fraction (about 15%) of the spikes in the maintained activity of X-cells. 6. A likely source of the active input signals appears to be spiking amacrine cells with a low rate of spontaneous activity.


1995 ◽  
Vol 12 (2) ◽  
pp. 285-300 ◽  
Author(s):  
J.B. Troy ◽  
D.E. Schweitzer-Tong ◽  
Ch. Enroth-Cugell

AbstractThe goal of this work was to provide a detailed quantitative description of the recepii ve-field properties of one of the types of rarely encountered retinal ganglion cells of cat; the cell named the Q-cell by Enroth-Cugell et al. (1983). Quantitative comparisons are made between the discharge statistics and between the spatial receptive properties of Q-cells and the most common of cat retinal ganglion cells, the X-cells. The center-surround receptive field of the Q-cell is modeled here quantitatively and the typical Q-cell is described. The temporal properties of the Q-cell receptive field were also investigated and the dynamics of the center mechanism of the Q-cell modeled quantitatively. In addition, the response vs. contrast relationship for a Q-cell at optimal spatial and temporal frequencies is shown, and Q-cells are also demonstrated to have nonlinear spatial summation somewhat like that exhibited by Y-cells, although much higher contrasts are required to reveal this nonlinear behavior. Finally, the relationship between Q-cells and Barlow and Levick's (1969) luminance units was investigated and it was found that most Q-cells could not be luminance units.


1998 ◽  
Vol 80 (6) ◽  
pp. 2975-2990 ◽  
Author(s):  
Ethan D. Cohen

Cohen, Ethan D. Interactions of inhibition and excitation in the light-evoked currents of X type retinal ganglion cells. J. Neurophysiol. 80: 2975–2990, 1998. The excitatory and inhibitory conductances driving the light-evoked currents (LECs) of cat and ferret on- and off-center X ganglion cells were examined in sliced and isolated retina preparations using center spot stimulation in tetrodotoxin (TTX)-containing Ringer. on-center X ganglion cells showed an increase in an excitatory conductance reversed positive to +20 mV during the spot stimulus. At spot offset, a transient inhibitory conductance was activated on many cells that reversed near E Cl. off-center X ganglion cells showed increases in a sustained inhibitory conductance that reversed near E Cl during spot stimulation. At spot offset, an excitatory conductance was activated that reversed positive to +20 mV. The light-evoked current kinetics of on- and off-center X cells to spot stimulation did not significantly differ in form from their Y cell counterparts in TTX Ringer. When inhibition was blocked, current-voltage relations of the light-evoked excitatory postsynaptic currents (EPSCs) of both on- and off-X cells were L-shaped and reversed near 0 mV. The EPSCs averaged between 300 and 500 pA at −80 mV. The metabotropic glutamate receptor agonist 2-amino-4-phosphonobutyric acid (APB), was used to block on-center bipolar cell function. The LECs of on-X ganglion cells were totally blocked in APB at all holding potentials. APB caused prominent reductions in the dark holding current and synaptic noise of on-X cells. In contrast, the LECs of off-X ganglion cells remained in APB. An increase in the dark holding current was observed. The excitatory amino acid receptor antagonist combination of d-amino-5-phosphono-pentanoic acid (d-AP5) and 2,3-dihydroxy-6-nitro-7-sulfamoyl-benzo-(F)-quinoxalinedione (NBQX) was used to block ionotropic glutamate receptor retinal neurotransmission. The LECs of all on-X ganglion cells were totally blocked, and their holding currents were reduced similar to the actions of APB. For off-X ganglion cells, the antagonist combination always blocked the excitatory current at light-off; however, in many cells, the inhibitory current at light-on remained. on-center X ganglion cells receive active excitation during center illumination, and a transient inhibition at light-off. In contrast off-center X ganglion cells experience a sustained active inhibition during center illumination, and a shorter increase in excitation at light-offset. Cone bipolar cells provide a resting level of glutamate release on X ganglion cells on which their light-evoked currents are superimposed.


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