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Tebbe L, Kakakhel M, Al-Ubaidi MR, Naash MI. The role of syntaxins in retinal function and health. Front Cell Neurosci 2024; 18:1380064. [PMID: 38799985 PMCID: PMC11119284 DOI: 10.3389/fncel.2024.1380064] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2024] [Accepted: 04/16/2024] [Indexed: 05/29/2024] Open
Abstract
The soluble N-ethylmaleimide-sensitive factor (NSF) attachment protein (SNAP) receptor (SNARE) superfamily plays a pivotal role in cellular trafficking by facilitating membrane fusion events. These SNARE proteins, including syntaxins, assemble into complexes that actively facilitate specific membrane fusion events. Syntaxins, as integral components of the SNARE complex, play a crucial role in initiating and regulating these fusion activities. While specific syntaxins have been extensively studied in various cellular processes, including neurotransmitter release, autophagy and endoplasmic reticulum (ER)-to-Golgi protein transport, their roles in the retina remain less explored. This review aims to enhance our understanding of syntaxins' functions in the retina by shedding light on how syntaxins mediate membrane fusion events unique to the retina. Additionally, we seek to establish a connection between syntaxin mutations and retinal diseases. By exploring the intricate interplay of syntaxins in retinal function and health, we aim to contribute to the broader comprehension of cellular trafficking in the context of retinal physiology and pathology.
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Affiliation(s)
| | | | | | - Muna I. Naash
- *Correspondence: Muna I. Naash, ; Muayyad R. Al-Ubaidi,
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2
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Godat T, Kohout K, Parkins K, Yang Q, McGregor JE, Merigan WH, Williams DR, Patterson SS. Cone-Opponent Ganglion Cells in the Primate Fovea Tuned to Noncardinal Color Directions. J Neurosci 2024; 44:e1738232024. [PMID: 38548340 PMCID: PMC11063829 DOI: 10.1523/jneurosci.1738-23.2024] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2023] [Revised: 02/20/2024] [Accepted: 03/15/2024] [Indexed: 04/09/2024] Open
Abstract
A long-standing question in vision science is how the three cone photoreceptor types-long (L), medium (M), and short (S) wavelength sensitive-combine to generate our perception of color. Hue perception can be described along two opponent axes: red-green and blue-yellow. Psychophysical measurements of color appearance indicate that the cone inputs to the red-green and blue-yellow opponent axes are M vs. L + S and L vs. M + S, respectively. However, the "cardinal directions of color space" revealed by psychophysical measurements of color detection thresholds following adaptation are L vs. M and S vs. L + M. These cardinal directions match the most common cone-opponent retinal ganglion cells (RGCs) in the primate retina. Accordingly, the cone opponency necessary for color appearance is thought to be established in the cortex. While neurons with the appropriate M vs. L + S and L vs. M + S opponency have been reported in the retina and lateral geniculate nucleus, their existence continues to be debated. Resolving this long-standing debate is necessary because a complete account of the cone opponency in the retinal output is critical for understanding how downstream neural circuits process color. Here, we performed adaptive optics calcium imaging to noninvasively measure foveal RGC light responses in the living Macaca fascicularis eye. We confirm the presence of L vs. M + S and M vs. L + S neurons with noncardinal cone opponency and demonstrate that cone-opponent signals in the retinal output are more diverse than classically thought.
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Affiliation(s)
- Tyler Godat
- Center for Visual Science, University of Rochester, Rochester, New York 14607
- Institute of Optics, University of Rochester, Rochester, New York 14611
| | - Kendall Kohout
- Center for Visual Science, University of Rochester, Rochester, New York 14607
| | - Keith Parkins
- Center for Visual Science, University of Rochester, Rochester, New York 14607
| | - Qiang Yang
- Center for Visual Science, University of Rochester, Rochester, New York 14607
| | - Juliette E McGregor
- Center for Visual Science, University of Rochester, Rochester, New York 14607
- Flaum Eye Institute, University of Rochester School of Medicine and Dentistry, Rochester, New York 14642
| | - William H Merigan
- Center for Visual Science, University of Rochester, Rochester, New York 14607
- Flaum Eye Institute, University of Rochester School of Medicine and Dentistry, Rochester, New York 14642
| | - David R Williams
- Center for Visual Science, University of Rochester, Rochester, New York 14607
- Institute of Optics, University of Rochester, Rochester, New York 14611
- Flaum Eye Institute, University of Rochester School of Medicine and Dentistry, Rochester, New York 14642
| | - Sara S Patterson
- Center for Visual Science, University of Rochester, Rochester, New York 14607
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3
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Sarossy M, Stepnicka K, Sarossy A, Wu Z. Using texture based features from the continuous wavelet transform of the electroretinogram to predict glaucoma . ANNUAL INTERNATIONAL CONFERENCE OF THE IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. ANNUAL INTERNATIONAL CONFERENCE 2023; 2023:1-4. [PMID: 38082633 DOI: 10.1109/embc40787.2023.10341019] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/18/2023]
Abstract
Glaucoma is an optic neuropathy resulting in the progressive loss of retinal ganglion cells (RCGs). The photopic negative response (PhNR) of the electroretinogram (ERG) has been used to objectively measure RCG function. This study sought to explore whether the usage of textural features extracted from the continuous wavelet transform of the ERG combined with ERG amplitude markers were more effective at predicting glaucoma severity than using the ERG markers alone. One-hundred and three eyes of 55 participants were included in this study, who underwent ERG testing with a protocol targeted at the PhNR. Predictive models for glaucoma severity based on the estimated RGC count were fitted using multiadaptive regression splines (MARS). The models informed by a combination of amplitude markers and texture analysis had a better predictive performance; R2 = 0.492, compared to models informed by markers alone having an R2 = 0.349 (p = 0.009).Clinical Relevance- As a direct measure of retinal function, the ERG has potential to determine the health of RGCs. This study demonstrates there is additional data within the ERG available to clinicians, which has the potential to improve the diagnosis and management of glaucoma.
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Kremers L, Sarieva K, Hoffmann F, Zhao Z, Ueffing M, Euler T, Nikić-Spiegel I, Schubert T. Super-resolution STED imaging in the inner and outer whole-mount mouse retina. FRONTIERS IN OPHTHALMOLOGY 2023; 3:1126338. [PMID: 38983015 PMCID: PMC11196978 DOI: 10.3389/fopht.2023.1126338] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/17/2022] [Accepted: 03/07/2023] [Indexed: 07/11/2024]
Abstract
Since its invention, super-resolution microscopy has become a popular tool for advanced imaging of biological structures, allowing visualisation of subcellular structures at a spatial scale below the diffraction limit. Thus, it is not surprising that recently, different super-resolution techniques are being applied in neuroscience, e.g. to resolve the clustering of neurotransmitter receptors and protein complex composition in presynaptic terminals. Still, the vast majority of these experiments were carried out either in cell cultures or very thin tissue sections, while there are only a few examples of super-resolution imaging in deeper layers (30 - 50 µm) of biological samples. In that context, the mammalian whole-mount retina has rarely been studied with super-resolution microscopy. Here, we aimed at establishing a stimulated-emission-depletion (STED) microscopy protocol for imaging whole-mount retina. To this end, we developed sample preparation including horizontal slicing of retinal tissue, an immunolabeling protocol with STED-compatible fluorophores and optimised the image acquisition settings. We labelled subcellular structures in somata, dendrites, and axons of retinal ganglion cells in the inner mouse retina. By measuring the full width at half maximum of the thinnest filamentous structures in our preparation, we achieved a resolution enhancement of two or higher compared to conventional confocal images. When combined with horizontal slicing of the retina, these settings allowed visualisation of putative GABAergic horizontal cell synapses in the outer retina. Taken together, we successfully established a STED protocol for reliable super-resolution imaging in the whole-mount mouse retina at depths between 30 and 50 µm, which enables investigating, for instance, protein complex composition and cytoskeletal ultrastructure at retinal synapses in health and disease.
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Affiliation(s)
- Leon Kremers
- Institute for Ophthalmic Research, University of Tübingen, Tübingen, Germany
- Werner Reichardt Centre for Integrative Neuroscience (CIN), University of Tübingen, Tübingen, Germany
- Institute for Experimental Epileptology and Cognition Research, University of Bonn, Bonn, Germany
- International Max Planck Research School for Brain and Behavior, Bonn, Germany
| | - Kseniia Sarieva
- Institute for Ophthalmic Research, University of Tübingen, Tübingen, Germany
- Werner Reichardt Centre for Integrative Neuroscience (CIN), University of Tübingen, Tübingen, Germany
- Hertie Institute for Clinical Brain Research, University of Tübingen, Tübingen, Germany
| | - Felix Hoffmann
- Institute for Ophthalmic Research, University of Tübingen, Tübingen, Germany
| | - Zhijian Zhao
- Institute for Ophthalmic Research, University of Tübingen, Tübingen, Germany
| | - Marius Ueffing
- Institute for Ophthalmic Research, University of Tübingen, Tübingen, Germany
| | - Thomas Euler
- Institute for Ophthalmic Research, University of Tübingen, Tübingen, Germany
- Werner Reichardt Centre for Integrative Neuroscience (CIN), University of Tübingen, Tübingen, Germany
| | - Ivana Nikić-Spiegel
- Werner Reichardt Centre for Integrative Neuroscience (CIN), University of Tübingen, Tübingen, Germany
| | - Timm Schubert
- Institute for Ophthalmic Research, University of Tübingen, Tübingen, Germany
- Werner Reichardt Centre for Integrative Neuroscience (CIN), University of Tübingen, Tübingen, Germany
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5
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Rezeanu D, Neitz M, Neitz J. From cones to color vision: a neurobiological model that explains the unique hues. JOURNAL OF THE OPTICAL SOCIETY OF AMERICA. A, OPTICS, IMAGE SCIENCE, AND VISION 2023; 40:A1-A8. [PMID: 37132996 PMCID: PMC11016238 DOI: 10.1364/josaa.477227] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/05/2022] [Accepted: 11/30/2022] [Indexed: 05/04/2023]
Abstract
The irreducible unique hues-red, green, blue, and yellow-remain one of the great mysteries of vision science. Attempts to create a physiologically parsimonious model that can predict the spectral locations of the unique hues all rely on at least one post hoc adjustment to produce appropriate loci for unique green and unique red, and struggle to explain the non-linearity of the Blue/Yellow system. We propose a neurobiological color vision model that overcomes these challenges by using physiological cone ratios, cone-opponent normalization to equal-energy white, and a simple adaptation mechanism to produce color-opponent mechanisms that accurately predict the spectral locations and variability of the unique hues.
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Affiliation(s)
- Dragos Rezeanu
- Graduate Program in Neuroscience, University of Washington, Seattle, WA 98109, USA
| | - Maureen Neitz
- Department of Ophthalmology, University of Washington, Seattle, WA 98109, USA
| | - Jay Neitz
- Department of Ophthalmology, University of Washington, Seattle, WA 98109, USA
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6
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Sarossy M, Crowston J, Kumar D, Weymouth A, Wu Z. Time-Frequency Analysis of ERG With Discrete Wavelet Transform and Matching Pursuits for Glaucoma. Transl Vis Sci Technol 2022; 11:19. [PMID: 36227605 PMCID: PMC9583752 DOI: 10.1167/tvst.11.10.19] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2022] [Accepted: 09/13/2022] [Indexed: 02/01/2023] Open
Abstract
Purpose To examine the performance of two time-frequency feature extraction techniques applied to electroretinograms (ERGs) for the prediction of glaucoma severity. Methods ERGs targeting the photopic negative response were obtained in 103 eyes of 55 patients with glaucoma. Features from the ERG recordings were extracted using two time-frequency extraction techniques based on the discrete wavelet transform (DWT) and the matching pursuit (MP) decomposition. Amplitude markers of the time-domain signal were also extracted. Linear and multivariate adaptive regression spline (MARS) models were fitted using combinations of these features to predict estimated retinal ganglion cell counts, a measure of glaucoma disease severity derived from standard automated perimetry and optical coherence tomography imaging. Results Predictive models using features from the time-frequency analyses-using both DWT and MP-combined with amplitude markers outperformed predictive models using the markers alone with linear (P = 0.001) and MARS (P ≤ 0.011) models. For example, the proportions of variance (R2) explained by the MARS model using the DWT and MP features with amplitude markers were 0.53 and 0.63, respectively, compared to 0.34 for the model using the markers alone (P = 0.011 and P = 0.001, respectively). Conclusions Novel time-frequency features extracted from the photopic ERG substantially added to the prediction of glaucoma severity compared to using the time-domain amplitude markers alone. Translational Relevance Substantial information about retinal ganglion cell dysfunction exists in the time-frequency domain of ERGs that could be useful in the management of glaucoma.
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Affiliation(s)
- Marc Sarossy
- Ophthalmology, Department of Surgery, University of Melbourne, Melbourne, Victoria, Australia
| | | | | | - Anne Weymouth
- Department of Optometry and Vision Sciences, University of Melbourne, Melbourne, Victoria, Australia
| | - Zhichao Wu
- Ophthalmology, Department of Surgery, University of Melbourne, Melbourne, Victoria, Australia
- Centre for Eye Research Australia, Royal Victorian Eye and Ear Hospital, East Melbourne, Victoria, Australia
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7
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Rezeanu D, Neitz M, Neitz J. How We See Black and White: The Role of Midget Ganglion Cells. Front Neuroanat 2022; 16:944762. [PMID: 35864822 PMCID: PMC9294633 DOI: 10.3389/fnana.2022.944762] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2022] [Accepted: 06/17/2022] [Indexed: 11/13/2022] Open
Abstract
According to classical opponent color theory, hue sensations are mediated by spectrally opponent neurons that are excited by some wavelengths of light and inhibited by others, while black-and-white sensations are mediated by spectrally non-opponent neurons that respond with the same sign to all wavelengths. However, careful consideration of the morphology and physiology of spectrally opponent L vs. M midget retinal ganglion cells (RGCs) in the primate retina indicates that they are ideally suited to mediate black-and-white sensations and poorly suited to mediate color. Here we present a computational model that demonstrates how the cortex could use unsupervised learning to efficiently separate the signals from L vs. M midget RGCs into distinct signals for black and white based only correlation of activity over time. The model also reveals why it is unlikely that these same ganglion cells could simultaneously mediate our perception of red and green, and shows how, in theory, a separate small population of midget RGCs with input from S, M, and L cones would be ideally suited to mediating hue perception.
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Affiliation(s)
| | | | - Jay Neitz
- Department of Ophthalmology, University of Washington, Seattle, WA, United States
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8
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Hirano AA, Vuong HE, Kornmann HL, Schietroma C, Stella SL, Barnes S, Brecha NC. Vesicular Release of GABA by Mammalian Horizontal Cells Mediates Inhibitory Output to Photoreceptors. Front Cell Neurosci 2020; 14:600777. [PMID: 33335476 PMCID: PMC7735995 DOI: 10.3389/fncel.2020.600777] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2020] [Accepted: 11/04/2020] [Indexed: 12/14/2022] Open
Abstract
Feedback inhibition by horizontal cells regulates rod and cone photoreceptor calcium channels that control their release of the neurotransmitter glutamate. This inhibition contributes to synaptic gain control and the formation of the center-surround antagonistic receptive fields passed on to all downstream neurons, which is important for contrast sensitivity and color opponency in vision. In contrast to the plasmalemmal GABA transporter found in non-mammalian horizontal cells, there is evidence that the mechanism by which mammalian horizontal cells inhibit photoreceptors involves the vesicular release of the inhibitory neurotransmitter GABA. Historically, inconsistent findings of GABA and its biosynthetic enzyme, L-glutamate decarboxylase (GAD) in horizontal cells, and the apparent lack of surround response block by GABAergic agents diminished support for GABA's role in feedback inhibition. However, the immunolocalization of the vesicular GABA transporter (VGAT) in the dendritic and axonal endings of horizontal cells that innervate photoreceptor terminals suggested GABA was released via vesicular exocytosis. To test the idea that GABA is released from vesicles, we localized GABA and GAD, multiple SNARE complex proteins, synaptic vesicle proteins, and Cav channels that mediate exocytosis to horizontal cell dendritic tips and axonal terminals. To address the perceived relative paucity of synaptic vesicles in horizontal cell endings, we used conical electron tomography on mouse and guinea pig retinas that revealed small, clear-core vesicles, along with a few clathrin-coated vesicles and endosomes in horizontal cell processes within photoreceptor terminals. Some small-diameter vesicles were adjacent to the plasma membrane and plasma membrane specializations. To assess vesicular release, a functional assay involving incubation of retinal slices in luminal VGAT-C antibodies demonstrated vesicles fused with the membrane in a depolarization- and calcium-dependent manner, and these labeled vesicles can fuse multiple times. Finally, targeted elimination of VGAT in horizontal cells resulted in a loss of tonic, autaptic GABA currents, and of inhibitory feedback modulation of the cone photoreceptor Cai, consistent with the elimination of GABA release from horizontal cell endings. These results in mammalian retina identify the central role of vesicular release of GABA from horizontal cells in the feedback inhibition of photoreceptors.
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Affiliation(s)
- Arlene A. Hirano
- Department of Neurobiology, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA, United States
- Veterans Administration Greater Los Angeles Healthcare System, Los Angeles, CA, United States
| | - Helen E. Vuong
- Department of Neurobiology, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA, United States
| | - Helen L. Kornmann
- Department of Neurobiology, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA, United States
| | - Cataldo Schietroma
- Department of Neurobiology, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA, United States
| | - Salvatore L. Stella
- Department of Neurobiology, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA, United States
| | - Steven Barnes
- Department of Neurobiology, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA, United States
- Department of Ophthalmology, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA, United States
- Doheny Eye Institute, University of California, Los Angeles, Los Angeles, CA, United States
| | - Nicholas C. Brecha
- Department of Neurobiology, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA, United States
- Veterans Administration Greater Los Angeles Healthcare System, Los Angeles, CA, United States
- Department of Ophthalmology, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA, United States
- Department of Medicine, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA, United States
- Stein Eye Institute, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA, United States
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Seifert M, Baden T, Osorio D. The retinal basis of vision in chicken. Semin Cell Dev Biol 2020; 106:106-115. [PMID: 32295724 DOI: 10.1016/j.semcdb.2020.03.011] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2020] [Revised: 03/31/2020] [Accepted: 03/31/2020] [Indexed: 12/20/2022]
Abstract
The Avian retina is far less known than that of mammals such as mouse and macaque, and detailed study is overdue. The chicken (Gallus gallus) has potential as a model, in part because research can build on developmental studies of the eye and nervous system. One can expect differences between bird and mammal retinas simply because whereas most mammals have three types of visual photoreceptor birds normally have six. Spectral pathways and colour vision are of particular interest, because filtering by oil droplets narrows cone spectral sensitivities and birds are probably tetrachromatic. The number of receptor inputs is reflected in the retinal circuitry. The chicken probably has four types of horizontal cell, there are at least 11 types of bipolar cell, often with bi- or tri-stratified axon terminals, and there is a high density of ganglion cells, which make complex connections in the inner plexiform layer. In addition, there is likely to be retinal specialisation, for example chicken photoreceptors and ganglion cells have separate peaks of cell density in the central and dorsal retina, which probably serve different types of behaviour.
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Affiliation(s)
- M Seifert
- Sussex Neuroscience, School of Life Sciences, University of Sussex, UK.
| | - T Baden
- Sussex Neuroscience, School of Life Sciences, University of Sussex, UK; Institute for Ophthalmic Research, University of Tuebingen, Germany
| | - D Osorio
- Sussex Neuroscience, School of Life Sciences, University of Sussex, UK
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10
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Walters D, Vogel KR, Brown M, Shi X, Roullet JB, Gibson KM. Transcriptome analysis in mice treated with vigabatrin identifies dysregulation of genes associated with retinal signaling circuitry. Epilepsy Res 2020; 166:106395. [PMID: 32679486 DOI: 10.1016/j.eplepsyres.2020.106395] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2020] [Revised: 06/02/2020] [Accepted: 06/09/2020] [Indexed: 10/24/2022]
Abstract
Vigabatrin (VGB; γ-vinyl-GABA) is an antiepileptic drug that elevates CNS GABA via irreversible inactivation of the GABA catabolic enzyme GABA-transaminase. VGB's clinical utility, however, can be curtailed by peripheral visual field constriction (pVFC) and thinning of the retinal nerve fiber layer (RNFL). Earlier studies from our laboratory revealed disruptions of autophagy by VGB. Here, we tested the hypothesis that VGB administration to animals would reveal alterations of gene expression in VGB-treated retina that associated with autophagy. VGB (140 mg/kg/d; subcutaneous minipump) was continuously administered to mice (n = 6 each VGB/vehicle) for 12 days, after which animals were euthanized. Retina was isolated for transcriptome (RNAseq) analysis and further validation using qRT-PCR and immunohistochemistry (IHC). For 112 differentially expressed retinal genes (RNAseq), two databases (Gene Ontology; Kyoto Encyclopedia of Genes and Genomes) were used to identify genes associated with visual function. Twenty four genes were subjected to qRT-PCR validation, and five (Gb5, Bdnf, Cplx9, Crh, Sox9) revealed significant dysregulation. IHC of fixed retinas verified significant down-regulation of Gb5 in photoreceptor cells. All of these genes have been previously shown to play a role in retinal function/circuitry signaling. Minimal impact of VGB on retinal autophagic gene expression was observed. This is the first transcriptome analysis of retinal gene expression associated with VGB intake, highlighting potential novel molecular targets potentially related to VGB's well known ocular toxicity.
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Affiliation(s)
- Dana Walters
- Department of Pharmacotherapy, Washington State University College of Pharmacy and Pharmaceutical Sciences, Spokane, WA, USA.
| | - Kara R Vogel
- Department of Ophthalmology and Visual Sciences, University of Wisconsin School of Medicine and Public Health, Madison, Wisconsin, USA.
| | - Madalyn Brown
- Department of Pharmacotherapy, Washington State University College of Pharmacy and Pharmaceutical Sciences, Spokane, WA, USA.
| | - Xutong Shi
- Department of Pharmacotherapy, Washington State University College of Pharmacy and Pharmaceutical Sciences, Spokane, WA, USA.
| | - Jean-Baptiste Roullet
- Department of Pharmacotherapy, Washington State University College of Pharmacy and Pharmaceutical Sciences, Spokane, WA, USA.
| | - K Michael Gibson
- Department of Pharmacotherapy, Washington State University College of Pharmacy and Pharmaceutical Sciences, Spokane, WA, USA.
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11
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Nemitz L, Dedek K, Janssen-Bienhold U. Rod Bipolar Cells Require Horizontal Cells for Invagination Into the Terminals of Rod Photoreceptors. Front Cell Neurosci 2019; 13:423. [PMID: 31619966 PMCID: PMC6760018 DOI: 10.3389/fncel.2019.00423] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2019] [Accepted: 09/03/2019] [Indexed: 01/22/2023] Open
Abstract
In the central nervous system, neuronal processing relies on the precisely orchestrated formation of synapses during development. The first synapse of the visual system is a triad synapse, comprising photoreceptors, horizontal cells and bipolar cells. During the second postnatal week, the axon terminal processes of horizontal cells invaginate rod spherules, followed by rod bipolar cell dendrites. Both elements finally oppose the synaptic ribbon (the release site of glutamate). However, it has not been fully elucidated whether horizontal cells are essential for rod bipolar cell dendrites to find their way into the rod terminal. In the present study, we investigated this question by specifically ablating horizontal cells from the early postnatal mouse retina. We monitored the formation of the rod-to-rod bipolar cell synapse during retinal maturation until postnatal day 21. Based on quantitative electron microscopy, we found that without horizontal cells, the dendrites of rod bipolar cells never entered rod terminals. Furthermore, rods displayed significantly fewer and shorter presynaptic ribbons, suggesting that glutamate release is decreased, which coincided with significantly reduced expression of postsynaptic proteins (mGluR6, GPR179) in rod bipolar cells. Collectively, our findings uncover that horizontal cells are indeed necessary guideposts for rod bipolar cells. Whether horizontal cells release diffusible guidance cues or provide structural guidance by expressing specific cell adhesion molecules remains to be seen.
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Affiliation(s)
- Lena Nemitz
- Visual Neuroscience, Department of Neuroscience, University of Oldenburg, Oldenburg, Germany
| | - Karin Dedek
- Animal Navigation/Neurosensorics, Institute for Biology and Environmental Sciences, University of Oldenburg, Oldenburg, Germany.,Research Center Neurosensory Science, University of Oldenburg, Oldenburg, Germany
| | - Ulrike Janssen-Bienhold
- Visual Neuroscience, Department of Neuroscience, University of Oldenburg, Oldenburg, Germany.,Research Center Neurosensory Science, University of Oldenburg, Oldenburg, Germany
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12
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Patterson SS, Neitz M, Neitz J. Reconciling Color Vision Models With Midget Ganglion Cell Receptive Fields. Front Neurosci 2019; 13:865. [PMID: 31474825 PMCID: PMC6707431 DOI: 10.3389/fnins.2019.00865] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/01/2019] [Accepted: 08/02/2019] [Indexed: 11/13/2022] Open
Abstract
Midget retinal ganglion cells (RGCs) make up the majority of foveal RGCs in the primate retina. The receptive fields of midget RGCs exhibit both spectral and spatial opponency and are implicated in both color and achromatic form vision, yet the exact mechanisms linking their responses to visual perception remain unclear. Efforts to develop color vision models that accurately predict all the features of human color and form vision based on midget RGCs provide a case study connecting experimental and theoretical neuroscience, drawing on diverse research areas such as anatomy, physiology, psychophysics, and computer vision. Recent technological advances have allowed researchers to test some predictions of color vision models in new and precise ways, producing results that challenge traditional views. Here, we review the progress in developing models of color-coding receptive fields that are consistent with human psychophysics, the biology of the primate visual system and the response properties of midget RGCs.
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Affiliation(s)
- Sara S Patterson
- Department of Ophthalmology, University of Washington, Seattle, WA, United States.,Neuroscience Graduate Program, University of Washington, Seattle, WA, United States
| | - Maureen Neitz
- Department of Ophthalmology, University of Washington, Seattle, WA, United States
| | - Jay Neitz
- Department of Ophthalmology, University of Washington, Seattle, WA, United States
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13
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Thoreson WB, Dacey DM. Diverse Cell Types, Circuits, and Mechanisms for Color Vision in the Vertebrate Retina. Physiol Rev 2019; 99:1527-1573. [PMID: 31140374 PMCID: PMC6689740 DOI: 10.1152/physrev.00027.2018] [Citation(s) in RCA: 72] [Impact Index Per Article: 14.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2018] [Revised: 03/27/2019] [Accepted: 04/02/2019] [Indexed: 01/13/2023] Open
Abstract
Synaptic interactions to extract information about wavelength, and thus color, begin in the vertebrate retina with three classes of light-sensitive cells: rod photoreceptors at low light levels, multiple types of cone photoreceptors that vary in spectral sensitivity, and intrinsically photosensitive ganglion cells that contain the photopigment melanopsin. When isolated from its neighbors, a photoreceptor confounds photon flux with wavelength and so by itself provides no information about color. The retina has evolved elaborate color opponent circuitry for extracting wavelength information by comparing the activities of different photoreceptor types broadly tuned to different parts of the visible spectrum. We review studies concerning the circuit mechanisms mediating opponent interactions in a range of species, from tetrachromatic fish with diverse color opponent cell types to common dichromatic mammals where cone opponency is restricted to a subset of specialized circuits. Distinct among mammals, primates have reinvented trichromatic color vision using novel strategies to incorporate evolution of an additional photopigment gene into the foveal structure and circuitry that supports high-resolution vision. Color vision is absent at scotopic light levels when only rods are active, but rods interact with cone signals to influence color perception at mesopic light levels. Recent evidence suggests melanopsin-mediated signals, which have been identified as a substrate for setting circadian rhythms, may also influence color perception. We consider circuits that may mediate these interactions. While cone opponency is a relatively simple neural computation, it has been implemented in vertebrates by diverse neural mechanisms that are not yet fully understood.
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Affiliation(s)
- Wallace B Thoreson
- Department of Ophthalmology and Visual Sciences, Truhlsen Eye Institute, University of Nebraska Medical Center , Omaha, Nebraska ; and Department of Biological Structure, Washington National Primate Research Center, University of Washington , Seattle, Washington
| | - Dennis M Dacey
- Department of Ophthalmology and Visual Sciences, Truhlsen Eye Institute, University of Nebraska Medical Center , Omaha, Nebraska ; and Department of Biological Structure, Washington National Primate Research Center, University of Washington , Seattle, Washington
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Chaffiol A, Ishii M, Cao Y, Mangel SC. Dopamine Regulation of GABA A Receptors Contributes to Light/Dark Modulation of the ON-Cone Bipolar Cell Receptive Field Surround in the Retina. Curr Biol 2017; 27:2600-2609.e4. [PMID: 28844643 DOI: 10.1016/j.cub.2017.07.063] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2017] [Revised: 05/22/2017] [Accepted: 07/27/2017] [Indexed: 10/19/2022]
Abstract
Cone bipolar cells are interneurons that receive synaptic input from cone photoreceptor cells and provide the output of the first synaptic layer of the retina. These cells exhibit center-surround receptive fields, a prototype of lateral inhibition between neighboring sensory cells in which stimulation of the receptive field center excites the cell whereas stimulation of the surrounding region laterally inhibits the cell. This fundamental sensory coding mechanism facilitates spatial discrimination and detection of stimulus edges. However, although it is well established that the receptive field surround is strongest when ambient or background illumination is most intense, e.g., at midday, and that the surround is minimal following maintained darkness, the synaptic mechanisms that produce and modulate the surround have not been resolved. Using electrical recording of bipolar cells under experimental conditions in which the cells exhibited surround light responses, and light and electron microscopic immunocytochemistry, we show in the rabbit retina that bright-light-induced activation of dopamine D1 receptors located on ON-center cone bipolar cell dendrites increases the expression and activity of GABAA receptors on the dendrites of the cells and that surround light responses depend on endogenous GABAA receptor activation. We also show that maintained darkness and D1 receptor blockade following maintained illumination and D1 receptor activation result in minimal GABAA receptor expression and activity and greatly diminished surrounds. Modulation of the D1/GABAA receptor signaling pathway of ON-cBC dendrites by the ambient light level facilitates detection of spatial details on bright days and large dim objects on moonless nights.
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Affiliation(s)
- Antoine Chaffiol
- Department of Neuroscience, The Ohio State University College Of Medicine, Columbus, OH 43210, USA
| | - Masaaki Ishii
- Department of Neuroscience, The Ohio State University College Of Medicine, Columbus, OH 43210, USA
| | - Yu Cao
- Department of Neuroscience, The Ohio State University College Of Medicine, Columbus, OH 43210, USA
| | - Stuart C Mangel
- Department of Neuroscience, The Ohio State University College Of Medicine, Columbus, OH 43210, USA.
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Schmidt BP, Touch P, Neitz M, Neitz J. Circuitry to explain how the relative number of L and M cones shapes color experience. J Vis 2017; 16:18. [PMID: 27366885 PMCID: PMC4927209 DOI: 10.1167/16.8.18] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
The wavelength of light that appears unique yellow is surprisingly consistent across people even though the ratio of middle (M) to long (L) wavelength sensitive cones is strikingly variable. This observation has been explained by normalization to the mean spectral distribution of our shared environment. Our purpose was to reconcile the nearly perfect alignment of everyone's unique yellow through a normalization process with the striking variability in unique green, which varies by as much as 60 nm between individuals. The spectral location of unique green was measured in a group of volunteers whose cone ratios were estimated with a technique that combined genetics and flicker photometric electroretinograms. In contrast to unique yellow, unique green was highly dependent upon relative cone numerosity. We hypothesized that the difference in neural architecture of the blue-yellow and red-green opponent systems in the presence of a normalization process creates the surprising dependence of unique green on cone ratio. We then compared the predictions of different theories of color vision processing that incorporate L and M cone ratio and a normalization process. The results of this analysis reveal that—contrary to prevailing notions--postretinal contributions may not be required to explain the phenomena of unique hues.
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Chapot CA, Euler T, Schubert T. How do horizontal cells 'talk' to cone photoreceptors? Different levels of complexity at the cone-horizontal cell synapse. J Physiol 2017; 595:5495-5506. [PMID: 28378516 DOI: 10.1113/jp274177] [Citation(s) in RCA: 39] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2017] [Accepted: 03/27/2017] [Indexed: 11/08/2022] Open
Abstract
The first synapse of the retina plays a fundamental role in the visual system. Due to its importance, it is critical that it encodes information from the outside world with the greatest accuracy and precision possible. Cone photoreceptor axon terminals contain many individual synaptic sites, each represented by a presynaptic structure called a 'ribbon'. These synapses are both highly sophisticated and conserved. Each ribbon relays the light signal to one ON cone bipolar cell and several OFF cone bipolar cells, while two dendritic processes from a GABAergic interneuron, the horizontal cell, modulate the cone output via parallel feedback mechanisms. The presence of these three partners within a single synapse has raised numerous questions, and its anatomical and functional complexity is still only partially understood. However, the understanding of this synapse has recently evolved, as a consequence of progress in understanding dendritic signal processing and its role in facilitating global versus local signalling. Indeed, for the downstream retinal network, dendritic processing in horizontal cells may be essential, as they must support important functional operations such as contrast enhancement, which requires spatial averaging of the photoreceptor array, while at the same time preserving accurate spatial information. Here, we review recent progress made towards a better understanding of the cone synapse, with an emphasis on horizontal cell function, and discuss why such complexity might be necessary for early visual processing.
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Affiliation(s)
- Camille A Chapot
- Institute for Ophthalmic Research, University of Tübingen, 72076, Tübingen, Germany.,Centre for Integrative Neuroscience, University of Tübingen, 72076, Tübingen, Germany.,Graduate Training Centre of Neuroscience, University of Tübingen, 72076, Tübingen, Germany
| | - Thomas Euler
- Institute for Ophthalmic Research, University of Tübingen, 72076, Tübingen, Germany.,Centre for Integrative Neuroscience, University of Tübingen, 72076, Tübingen, Germany.,Bernstein Centre for Computational Neuroscience, University of Tübingen, 72076, Tübingen, Germany
| | - Timm Schubert
- Institute for Ophthalmic Research, University of Tübingen, 72076, Tübingen, Germany.,Centre for Integrative Neuroscience, University of Tübingen, 72076, Tübingen, Germany
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Evolution of the circuitry for conscious color vision in primates. Eye (Lond) 2016; 31:286-300. [PMID: 27935605 DOI: 10.1038/eye.2016.257] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2016] [Accepted: 10/06/2016] [Indexed: 11/08/2022] Open
Abstract
There are many ganglion cell types and subtypes in our retina that carry color information. These have appeared at different times over the history of the evolution of the vertebrate visual system. They project to several different places in the brain and serve a variety of purposes allowing wavelength information to contribute to diverse visual functions. These include circadian photoentrainment, regulation of sleep and mood, guidance of orienting movements, detection and segmentation of objects. Predecessors to some of the circuits serving these purposes presumably arose before mammals evolved and different functions are represented by distinct ganglion cell types. However, while other animals use color information to elicit motor movements and regulate activity rhythms, as do humans, using phylogenetically ancient circuitry, the ability to appreciate color appearance may have been refined in ancestors to primates, mediated by a special set of ganglion cells that serve only that purpose. Understanding the circuitry for color vision has implications for the possibility of treating color blindness using gene therapy by recapitulating evolution. In addition, understanding how color is encoded, including how chromatic and achromatic percepts are separated is a step toward developing a complete picture of the diversity of ganglion cell types and their functions. Such knowledge could be useful in developing therapeutic strategies for blinding eye disorders that rely on stimulating elements in the retina, where more than 50 different neuron types are organized into circuits that transform signals from photoreceptors into specialized detectors many of which are not directly involved in conscious vision.
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Abstract
The mammalian retina is an important model system for studying neural circuitry: Its role in sensation is clear, its cell types are relatively well defined, and its responses to natural stimuli-light patterns-can be studied in vitro. To solve the retina, we need to understand how the circuits presynaptic to its output neurons, ganglion cells, divide the visual scene into parallel representations to be assembled and interpreted by the brain. This requires identifying the component interneurons and understanding how their intrinsic properties and synapses generate circuit behaviors. Because the cellular composition and fundamental properties of the retina are shared across species, basic mechanisms studied in the genetically modifiable mouse retina apply to primate vision. We propose that the apparent complexity of retinal computation derives from a straightforward mechanism-a dynamic balance of synaptic excitation and inhibition regulated by use-dependent synaptic depression-applied differentially to the parallel pathways that feed ganglion cells.
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Affiliation(s)
- Jonathan B Demb
- Department of Ophthalmology and Visual Science and Department of Cellular and Molecular Physiology, Yale University, New Haven, Connecticut 06511;
| | - Joshua H Singer
- Department of Biology, University of Maryland, College Park, Maryland 20742;
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Abstract
It has been possible to use viral-mediated gene therapy to transform dichromatic (red-green color-blind) primates to trichromatic. Even though the third cone type was added after the end of developmental critical periods, treated animals acquired red-green color vision. What happened in the treated animals may represent a recapitulation of the evolution of trichromacy, which seems to have evolved with the acquisition of a third cone type without the need for subsequent modification to the circuitry. Some transgenic mice in which a third cone type was added also acquired trichromacy. However, compared with treated primates, red-green color vision in mice is poor, indicating large differences between mice and monkeys in their ability to take advantage of the new input. These results have implications for understanding the limits and opportunities for using gene therapy to treat vision disorders caused by defects in cone function.
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Affiliation(s)
- Maureen Neitz
- Department of Ophthalmology, University of Washington, Seattle, Washington 98109
| | - Jay Neitz
- Department of Ophthalmology, University of Washington, Seattle, Washington 98109
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Puller C, Manookin MB, Neitz M, Neitz J. Specialized synaptic pathway for chromatic signals beneath S-cone photoreceptors is common to human, Old and New World primates. JOURNAL OF THE OPTICAL SOCIETY OF AMERICA. A, OPTICS, IMAGE SCIENCE, AND VISION 2014; 31:A189-94. [PMID: 24695169 PMCID: PMC4282935 DOI: 10.1364/josaa.31.00a189] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
The distribution of the soluble NSF-attachment protein receptor protein syntaxin-4 and the Na-K-Cl cotransporter (NKCC) were investigated in the outer plexiform layer of human retina using immunohistochemistry. Both proteins, which are proposed to be components of a gamma-aminobutyric acid mediated feed-forward circuit from horizontal cells directly to bipolar cells, were enriched beneath S-cones. The expression pattern of syntaxin-4 was further analyzed in baboon and marmoset to determine if the synaptic specialization is common to primates. Syntaxin-4 was enriched beneath S-cones in both species, which together with the human results indicates that this specialization may have evolved for the purpose of mediating unique color vision capacities that are exclusive to primates.
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Kuchenbecker JA, Greenwald SH, Neitz M, Neitz J. Cone-isolating ON-OFF electroretinogram for studying chromatic pathways in the retina. JOURNAL OF THE OPTICAL SOCIETY OF AMERICA. A, OPTICS, IMAGE SCIENCE, AND VISION 2014; 31:A208-A213. [PMID: 24695171 PMCID: PMC4143118 DOI: 10.1364/josaa.31.00a208] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
The electroretinogram (ERG) provides information about outer retina function in both clinical and research applications. ERG components elicited by light increments and decrements can be separated using a long-flash paradigm in which periods of light ON and OFF are alternated. Here, the ON-OFF ERG is combined with a silent substitution technique to elicit responses from individual cone photoreceptor classes by modulating the intensities of three color lights between the two periods. The results focus on the short wavelength (S) cone pathways since they are vulnerable to disease and because there are many unanswered questions about S-cone ON and OFF circuitry.
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Schmidt BP, Neitz M, Neitz J. Neurobiological hypothesis of color appearance and hue perception. JOURNAL OF THE OPTICAL SOCIETY OF AMERICA. A, OPTICS, IMAGE SCIENCE, AND VISION 2014; 31:A195-207. [PMID: 24695170 PMCID: PMC4167798 DOI: 10.1364/josaa.31.00a195] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/06/2023]
Abstract
De Valois and De Valois [Vis. Res.33, 1053 (1993)] showed that to explain hue appearance, S-cone signals have to be combined with M versus L opponent signals in two different ways to produce red-green and yellow-blue axes, respectively. Recently, it has been shown that color appearance is normal for individuals with genetic mutations that block S-cone input to blue-ON ganglion cells. This is inconsistent with the De Valois hypothesis in which S-opponent konio-geniculate signals are combined with L-M signals at a third processing stage in cortex. Instead, here we show that color appearance, including individual differences never explained before, are predicted by a model in which S-cone signals are combined with L versus M signals in the outer retina.
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Affiliation(s)
- Brian P. Schmidt
- Graduate Program in Neurobiology and Behavior, University of
Washington, Seattle WA, 98109
| | - Maureen Neitz
- Department of Ophthalmology, University of Washington, Seattle
WA, 98109
| | - Jay Neitz
- Department of Ophthalmology, University of Washington, Seattle
WA, 98109
- Corresponding author:
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