scholarly journals Control of Retinal Sensitivity

1974 ◽  
Vol 63 (1) ◽  
pp. 62-87 ◽  
Author(s):  
Frank S. Werblin
Keyword(s):  
Receptive Field ◽  
Bipolar Cell ◽  
Horizontal Cell ◽  
Full Range ◽  
Plexiform Layer ◽  
Cell System ◽  
Outer Plexiform Layer ◽  
Retinal Sensitivity ◽  
Second Stage ◽  
Graded Response

Test stimuli, presented at the center of the bipolar cell receptive field, spanning less than 2 log units of intensity, elicit the full range of graded response. The intensity range of test stimuli that elicits the graded response depends upon the background conditions. A higher range of log test intensities is required to elicit the graded bipolar response in the presence of surround backgrounds. But surround backgrounds can also serve to unsaturate the bipolar response and thereby increase sensitivity under certain conditions. The results suggest that a second stage of sensitivity-control is mediated by the horizontal cell system at the outer plexiform layer, concatenated with the effects of adaptation in the photoreceptors.

The interplexiform cell system - I. Synapses of the dopaminergic neurons of the goldfish retina

1978 ◽  
Vol 201 (1142) ◽  
pp. 7-26 ◽  
Keyword(s):  
Bipolar Cell ◽  
Dopaminergic Neurons ◽  
Structural Changes ◽  
Plexiform Layer ◽  
Amacrine Cells ◽  
Cell System ◽  
Outer Plexiform Layer ◽  
Horizontal Cells ◽  
Inner Plexiform Layer ◽  
Retinal Neuron

Interplexiform cells are a class of retinal neuron that extends processes widely in both plexiform layers. In goldfish they contain dopamine and readily take up certain biogenic amines. Two of these amines, 6-hydroxyopamine (6-HDA) and 5, 6-dihydroxytryptamine (5,6-DHT), induce fine structural changes in the neurons that accumulate them, allowing the processes of the cells to be recognized by electron microscopy. Typically, the synaptic vesicles within the processes show electron-dense cores. The terminal cytoplasm may also show increased density, as may the cellular and cytoplasmic membranes, presumably an indication of degenerative changes induced by the drugs. 5, 6-DHT gives more readily observable changes than 6-HDA but labels both dopaminergic and indoleamine-accumulating neurons. The terminals of the indoleamine-accumulating terminals were therefore removed by intraocular injections of 5, 7-dihydroxytryptamine (5, 7-DHT) prior to the labelling with 5, 6-DHT. This procedure allowed an analysis of the dopaminergic terminals without interference by the terminals of the indoleamine-accumulating cells. The dopaminergic neurons were found to make synapses of the conventional type. In the outer plexiform layer they contacted both external horizontal cells and bipolar cell dendrites, but not hotoreceptor terminals or intermediate (rod) horizontal cells. No synapses onto the dopaminergic processes were found in the outer plexiform layer despite an extensive search. In the inner plexiform layer the dopaminergic processes were observed to be both pre- and postsynaptic to amacrine cells and their processes. No synaptic contacts between dopaminergic processes and bipolar cell terminals or ganglion cell dendrites were seen. We conclude that the dopaminergic interplexiform cells provide a centri­fugal pathway for information flow in the retina from inner to outer plexiform layer.

Receptive field of the retinal bipolar cell: a pharmacological study in the tiger salamander

1996 ◽  
Vol 76 (3) ◽  
pp. 2005-2019 ◽  
Author(s):  
W. A. Hare ◽  
W. G. Owen
Keyword(s):  
Receptive Field ◽  
Gaba Receptors ◽  
Bipolar Cell ◽  
Horizontal Cell ◽  
Pharmacological Study ◽  
Bipolar Cells ◽  
Horizontal Cells ◽  
Gaba Uptake ◽  
Gamma Aminobutyric Acid ◽  
Gabaergic Synapse

1. It is widely believed that signals contributing to the receptive field surrounds of retinal bipolar cells pass from horizontal cells to bipolar cells via GABAergic synapses. To test this notion, we applied gamma-aminobutyric acid (GABA) agonists and antagonists to isolated, perfused retinas of the salamander Ambystoma tigrinum while recording intracellularly from bipolar cells, horizontal cells, and photoreceptors. 2. As we previously reported, administration of the GABA analogue D-aminovaleric acid in concert with picrotoxin did not block horizontal cell responses or the center responses of bipolar cells but blocked the surround responses of both on-center and off-center bipolar cells. 3. Surround responses were not blocked by the GABA, antagonists picrotoxin or bicuculline, the GABAB agonist baclofen or the GABAB antagonist phaclofen, and the GABAC antagonists picrotoxin or cis-4-aminocrotonic acid. Combinations of these drugs were similarly ineffective. 4. GABA itself activated a powerful GABA uptake mechanism in horizontal cells for which nipecotic acid is a competitive agonist. It also activated, both in horizontal cells and bipolar cells, large GABAA conductances that shunted light responses but that could be blocked by picrotoxin or bicuculline. 5. GABA, administered together with picrotoxin to block the shunting effect of GABAA activation, did not eliminate bipolar cell surround responses at concentrations sufficient to saturate the known types of GABA receptors. 6. Surround responses were not blocked by glycine or its antagonist strychnine, or by combinations of drugs designed to eliminate GABAergic and glycinergic pathways simultaneously. 7. Although we cannot fully discount the involvement of a novel GABAergic synapse, the simplest explanation of our findings is that the primary pathway mediating the bipolar cell's surround is neither GABAergic nor glycinergic.

Contribution of rod, on-bipolar, and horizontal cell light responses to the ERG of dogfish retina

1999 ◽  
Vol 16 (3) ◽  
pp. 503-511 ◽  
Author(s):  
R.A. SHIELLS ◽  
G. FALK
Keyword(s):  
Bipolar Cell ◽  
Time Course ◽  
Horizontal Cell ◽  
Full Range ◽  
Bipolar Cells ◽  
Horizontal Cells ◽  
Negative Wave ◽  
Low Light ◽  
Cell Responses ◽  
Light Intensities

Simultaneous extracellular ERG and intracellular recordings from horizontal and ON-bipolar cells were obtained from the dark-adapted retina of the dogfish. The light intensity–peak response relation (IR) and time course of on-bipolar cell responses closely resembled that of the ERG b-wave, but only at low light intensities [<10 rhodopsin molecules bleached per rod (Rh*)]. Block of on-bipolar cell responses with 50 μM 2-amino-4-phosphonobutyrate (APB) abolished the b-wave and unmasked a vitreal-negative wave. Subtraction from the control ERG resulted in the isolation of a vitreal-positive ERG with an IR which matched that of on-bipolar cells over the full range of light intensities. The D.C. component of the ERG arises as a result of sustained depolarization of on-bipolar cells in response to long (>0.5 s) dim light stimuli, or following bright light flashes. The IR of horizontal cells and the vitreal-negative wave unmasked by APB could be matched by scaling at low light intensities (<5 Rh*). However, horizontal cell responses saturated at about 30 Rh*, while the vitreal-negative wave continued to increase in amplitude. The time course of horizontal cell membrane current with dim flashes could be matched to the rising phase of the vitreal-negative wave, assuming that the delay in generating the voltage response in horizontal cells is due to their long (100 ms) membrane time constant. Blocking post-photoreceptor activity resulted in a much smaller vitreal-negative wave than that unmasked by APB alone. We conclude that the b-wave arises from on-bipolar cell depolarization, while the leading edge of the a-wave is a composite of the change in extracellular voltage drop across the rod layer and a component (proximal PIII) reflecting a decrease in extracellular K+ as horizontal cell synaptic channels close with light.

The interplexiform cell system II. Effects of dopamine on goldfish retinal neurones

1978 ◽  
Vol 201 (1142) ◽  
pp. 27-55 ◽  
Keyword(s):  
Horizontal Cell ◽  
Cell Activity ◽  
Plexiform Layer ◽  
Amacrine Cells ◽  
Cell System ◽  
Bipolar Cells ◽  
Horizontal Cells ◽  
Inner Plexiform Layer ◽  
Specific Effects ◽  
Β Blocker

The effects of atomized solutions of dopamine and certain related com­pounds have been tested on the intracellularly recorded activity of receptor, horizontal, bipolar and amacrine cells in the goldfish retina. Dopamine depolarizes the cone L-type horizontal cells and reduces the amplitude of light-evoked responses. These effects on L-type horizontal cells are completely abolished by the α-adrenergie blocker, phentolamine, but only partially depressed by the β-blocker, propanolol. L-Dopa, noradrenalin, and serotonin do not have effects on L-type horizontal cells when applied at concentrations similar to those that cause maximal dopamine effects. The results suggest that the effects of dopamine on L-type horizontal cells are specific, and we propose that they mimic the effects of interplexiform cell activity. Dopamine has no effects on rod horizontal cells in goldfish and variable effects on C-type horizontal cells. On bipolar cells, dopamine alters the dark membrane potential, enhances the central response to light, and depresses the surround response. Dopamine also decreases the horizontal cell feedback evident in cone responses. Finally, dopamine strongly depolarizes the transient type of amacrine cells, but it has no significant effect on the sustained type of amacrine cells. Assuming that dopamine is the transmitter of interplexiform cells, we suggest that these neurons regulate lateral inhibitory effects mediated by L-type horizontal cells in the outer plexiform layer and transient amacrine cells in the inner plexiform layer. In addition, it appears as if interplexiform cells have specific effects on bipolar cells and are capable of regulating centre-surround antagonism in these cells. The net effect of interplexiform cell activity is to isolate the bipolars from the influence of the surround.

scholarly journals Distinct synaptic mechanisms create parallel S-ON and S-OFF color opponent pathways in the primate retina

2013 ◽  
Vol 31 (2) ◽  
pp. 139-151 ◽  
Author(s):  
DENNIS M. DACEY ◽  
JOANNA D. CROOK ◽  
ORIN S. PACKER
Keyword(s):  
Receptive Field ◽  
Ganglion Cell ◽  
Bipolar Cell ◽  
Ganglion Cells ◽  
Horizontal Cell ◽  
Dendritic Tree ◽  
Field Center ◽  
Differential Weighting ◽  
Receptive Field Center ◽  
Synaptic Mechanisms

AbstractAnatomical and physiological approaches are beginning to reveal the synaptic origins of parallel ON- and OFF-pathway retinal circuits for the transmission of short (S-) wavelength sensitive cone signals in the primate retina. Anatomical data suggest that synaptic output from S-cones is largely segregated; central elements of synaptic triads arise almost exclusively from the “blue-cone” bipolar cell, a presumed ON bipolar, whereas triad-associated contacts derive primarily from the “flat” midget bipolar cell, a hyperpolarizing, OFF bipolar. Similarly, horizontal cell connectivity is also segregated, with only the H2 cell-type receiving numerous contacts from S-cones. Negative feedback from long (L-) and middle (M-) wavelength sensitive cones via the H2 horizontal cells elicits an antagonistic surround in S-cones demonstrating that S versus L + M or “blue-yellow” opponency is first established in the S-cone. However, the S-cone output utilizes distinct synaptic mechanisms to create color opponency at the ganglion cell level. The blue-cone bipolar cell is presynaptic to the small bistratified, “blue-ON” ganglion cell. S versus L + M cone opponency arises postsynaptically by converging S-ON and LM-OFF excitatory bipolar inputs to the ganglion cell’s bistratified dendritic tree. The common L + M cone surrounds of the parallel S-ON and LM-OFF cone bipolar inputs appear to cancel resulting in “blue-yellow” antagonism without center-surround spatial opponency. By contrast, in midget ganglion cells, opponency arises by the differential weighting of cone inputs to the receptive field center versus surround. In the macula, the “private-line” connection from a midget ganglion cell to a single cone predicts that S versus L + M opponency is transmitted from the S-cone to the S-OFF midget bipolar and ganglion cell. Beyond the macula, OFF-midget ganglion cell dendritic trees enlarge and collect additional input from multiple L and M cones. Thus S-OFF opponency via the midget pathway would be expected to become more complex in the near retinal periphery as L and/or M and S cone inputs sum to the receptive field center. An important goal for further investigation will be to explore the hypothesis that distinct bistratified S-ON versus midget S-OFF retinal circuits are the substrates for human psychophysical detection mechanisms attributed to S-ON versus S-OFF perceptual channels.

Organization of the outer plexiform layer of the primate retina: Electron microscopy of Golgi-impregnated Cells

1970 ◽  
Vol 258 (823) ◽  
pp. 261-283 ◽  
Keyword(s):  
Rhesus Monkeys ◽  
Horizontal Cell ◽  
Plexiform Layer ◽  
Outer Plexiform Layer ◽  
Serial Sections ◽  
Cell Contacts ◽  
Axon Terminals ◽  
Single Cone ◽  
Section Electron ◽  
Quantitative Manner

Golgi-impregnated retinae of rhesus monkeys have been examined by serial section electron microscopyto establish in a quantitative manner the neural connexions in the outer plexiform layer. The results have shown that there are two types of midget bipolar cell, here called the invaginating midget bipolar and the flat midget bipolar. Both types of midget bipolar are exclusive to a single cone. The invaginating midget bipolar has been found to fit a dendritic terminal process into every invagination in the cone pedicle base. The flat midget bipolar has dendritic terminals that make superficial contact on the cone pedicle base. There are twice as many dendritic terminals and points of contact with the cone pedicle on a flat midget bipolar top as com pared with an invaginating midget bipolar top. These observations, together with light microscope counts of the numbers of the two types of midget bipolars, suggest that there are two midget bipolars per cone. The diffuse cone bipolar (the flat bipolar) also makes superficial contacts on the cone pedicle base, and serial sections have shown that a flat bipolar contacts about six cones. Rod bipolars connect exclusively to rods and their dendritic term inals always end as one of the central processes that penetrate the invagination. Horizontal cell dendrites end exclusively in cone pedicles and their axon terminals end in rod spherules. The point of contact with both the types of receptor is as the lateral elements of the invaginations. A single small horizontal cell contacts about seven cones and a large horizontal cell contacts about twelve cones. The numbers of contacts per cone pedicle decrease from the centre to the periphery of the horizontal cell’s dendritic field, suggesting there is an overlap of four to six horizontal cells onto a single cone pedicle. The horizontal cell axon terminals are too numerous to assess in absolute numbers but there is only one terminal to a given rod spherule from any particular axon.

Early afferent signaling in the outer plexiform layer regulates development of horizontal cell morphology

2007 ◽  
Vol 506 (6) ◽  
pp. spc1-spc1
Author(s):  
Mary E. Raven ◽  
Noelle C. Orton ◽  
Hadi Nassar ◽  
Gary A. Williams ◽  
William K. Stell ◽  
...  
Keyword(s):  
Cell Morphology ◽  
Horizontal Cell ◽  
Plexiform Layer ◽  
Outer Plexiform Layer ◽  
Afferent Signaling

Early afferent signaling in the outer plexiform layer regulates development of horizontal cell morphology

2008 ◽  
Vol 506 (5) ◽  
pp. 745-758 ◽  
Author(s):  
Mary A. Raven ◽  
Noelle C. Orton ◽  
Hadi Nassar ◽  
Gary A. Williams ◽  
William K. Stell ◽  
...  
Keyword(s):  
Cell Morphology ◽  
Horizontal Cell ◽  
Plexiform Layer ◽  
Outer Plexiform Layer ◽  
Afferent Signaling

Effects of light stimuli on the release of dopamine from interplexiform cells in the white perch retina

1991 ◽  
Vol 7 (5) ◽  
pp. 451-458 ◽  
Author(s):  
Osamu Umino ◽  
Yunhee Lee ◽  
John E. Dowling
Keyword(s):  
Receptive Field ◽  
White Perch ◽  
Horizontal Cell ◽  
Receptive Fields ◽  
Plexiform Layer ◽  
Horizontal Cells ◽  
Field Size ◽  
Dopamine Antagonists ◽  
Flickering Light ◽  
Receptive Field Size

AbstractInterplexiform cells are centrifugal neurons in the retina carrying information from the inner to the outer plexiform layers. In teleost fish, interplexiform cells appear to release dopamine in the outer plexiform layer after prolonged darkness that modulates the receptive-field size and light responsiveness of horizontal cells (Mangel & Dowling, 1985; Yang et al., 1988a, b). It has been proposed that interplexiform cells may also release dopamine upon steady illumination because horizontal cells' receptive fields shrink in the light (Shigematsu & Yamada, 1988). Here, we report the shrinkage of the receptive fields of horizontal cells seen in the presence of background illumination is not blocked by dopamine antagonists, indicating that dopamine does not underlie the receptive-field size changes observed during steady illumination. Flickering light, however, does appear to stimulate the release of dopamine from the interplexiform cells, resulting in a marked reduction of horizontal cell receptive-field size. Taken together, experiments on horizontal cells indicate that dopamine is released from interplexiform cells in the teleost retina after prolonged darkness and during flickering light, but that dopamine release from interplexiform cells during steady retinal illumination is minimal.

Synaptic connexions made by horizontal cells within the outer plexiform layer of the retina of the cat and the rabbit

1974 ◽  
Vol 186 (1085) ◽  
pp. 317-331 ◽  
Keyword(s):  
Horizontal Cell ◽  
Plexiform Layer ◽  
Cell Types ◽  
Bipolar Cells ◽  
Outer Plexiform Layer ◽  
Horizontal Cells ◽  
Chemical Synapses

Two ultrastructurally distinctive types of horizontal cells are described in the retinae of the cat and the rabbit. Evidence is presented that they have different synaptic connexions in the outer plexiform layer. The majority of the presynaptic structures identified in the outer plexiform layer of the rabbit (as defined on page 320) belong to a neurofilamentous type of horizontal cell. It is suggested that the cat may be the same. No synapses have been identified on to, or from, the second, predominantly neurotubular, type of horizontal cell. No chemical synapses on to, or between, horizontal cells have been found. Thus input of this kind to both types of horizontal cells is as yet only known to be from the photoreceptors. All positively identified postsynaptic processes were the dendrites or perikarya of bipolar cells. Other cell types that are possibly pre- or postsynaptic in the outer plexiform layer are discussed.

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