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Gonzalez LS, Fisher AA, Grover KE, Robinson JE. Examining the role of the photopigment melanopsin in the striatal dopamine response to light. Front Syst Neurosci 2025; 19:1568878. [PMID: 40242043 PMCID: PMC12000111 DOI: 10.3389/fnsys.2025.1568878] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2025] [Accepted: 03/17/2025] [Indexed: 04/18/2025] Open
Abstract
The mesolimbic dopamine system is a set of subcortical brain circuits that plays a key role in reward processing, reinforcement, associative learning, and behavioral responses to salient environmental events. In our previous studies of the dopaminergic response to salient visual stimuli, we observed that dopamine release in the lateral nucleus accumbens (LNAc) of mice encoded information about the rate and magnitude of rapid environmental luminance changes from darkness. Light-evoked dopamine responses were rate-dependent, robust to the time of testing or stimulus novelty, and required phototransduction by rod and cone opsins. However, it is unknown if these dopaminergic responses also involve non-visual opsins, such as melanopsin, the primary photopigment expressed by intrinsically photosensitive retinal ganglion cells (ipRGCs). In the current study, we evaluated the role of melanopsin in the dopaminergic response to light in the LNAc using the genetically encoded dopamine sensor dLight1 and fiber photometry. By measuring light-evoked dopamine responses across a broad irradiance and wavelength range in constitutive melanopsin (Opn4) knockout mice, we were able to provide new insights into the ability of non-visual opsins to regulate the mesolimbic dopamine response to visual stimuli.
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Affiliation(s)
- L. Sofia Gonzalez
- Division of Experimental Hematology and Cancer Biology, Department of Pediatrics, Cincinnati Children’s Hospital Medical Center, Cincinnati, OH, United States
- Department of Pediatrics, University of Cincinnati College of Medicine, Cincinnati, OH, United States
- Neuroscience Graduate Program, University of Cincinnati College of Medicine, Cincinnati, OH, United States
| | - Austen A. Fisher
- Division of Experimental Hematology and Cancer Biology, Department of Pediatrics, Cincinnati Children’s Hospital Medical Center, Cincinnati, OH, United States
- Department of Pediatrics, University of Cincinnati College of Medicine, Cincinnati, OH, United States
| | - Kassidy E. Grover
- Division of Experimental Hematology and Cancer Biology, Department of Pediatrics, Cincinnati Children’s Hospital Medical Center, Cincinnati, OH, United States
- Department of Pediatrics, University of Cincinnati College of Medicine, Cincinnati, OH, United States
- Neuroscience Graduate Program, University of Cincinnati College of Medicine, Cincinnati, OH, United States
| | - J. Elliott Robinson
- Division of Experimental Hematology and Cancer Biology, Department of Pediatrics, Cincinnati Children’s Hospital Medical Center, Cincinnati, OH, United States
- Department of Pediatrics, University of Cincinnati College of Medicine, Cincinnati, OH, United States
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Watanabe M, Yamada T, Koike C, Takahashi M, Tachibana M, Mandai M. Transplantation of genome-edited retinal organoids restores some fundamental physiological functions coordinated with severely degenerated host retinas. Stem Cell Reports 2025; 20:102393. [PMID: 39824188 PMCID: PMC11864131 DOI: 10.1016/j.stemcr.2024.102393] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2024] [Revised: 12/18/2024] [Accepted: 12/18/2024] [Indexed: 01/20/2025] Open
Abstract
We have previously shown that the transplantation of stem cell-derived retinal organoid (RO) sheets into animal models of end-stage retinal degeneration can lead to host-graft synaptic connectivity and restoration of vision, which was further improved using genome-edited Islet1-/- ROs (gROs) with a reduced number of ON-bipolar cells. However, the details of visual function restoration using this regenerative therapeutic approach have not yet been characterized. Here, we evaluated the electrophysiological properties of end-stage rd1 retinas after transplantation (TP-rd1) and compared them with those of wild-type (WT) retinas using multi-electrode arrays. Notably, retinal ganglion cells (RGCs) in TP-rd1 retinas acquired light sensitivity comparable to that of WT retinas. Furthermore, RGCs in TP-rd1 retinas showed light adaptation to a photopic background and responded to flickering stimuli. These results demonstrate that transplantation of gRO sheets may restore some fundamental physiological functions, possibly coordinating with the remaining functions in retinas with end-stage degeneration.
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Affiliation(s)
- Mikiya Watanabe
- VCCT Inc., Kobe, Hyogo 650-0047, Japan; Graduate School of Pharmacy, Ritsumeikan University, Kusatsu, Siga 525-8577, Japan; Cell and Gene Therapy in Ophthalmology Laboratory, BZP, RIKEN, Wako, Saitama 351-0198, Japan
| | - Takayuki Yamada
- Cell and Gene Therapy in Ophthalmology Laboratory, BZP, RIKEN, Wako, Saitama 351-0198, Japan; Vision Care Inc., Kobe, Hyogo 650-0047, Japan
| | - Chieko Koike
- Center for Systems Vision Science, Organization of Science and Technology, Ritsumeikan University, Kusatsu, Shiga 525-8577, Japan; Ritsumeikan Global Innovation Research Organization(R-GIRO), Ritsumeikan University, Kusatsu, Siga 525-8577, Japan; College of Pharmaceutical Science, Ritsumeikan University, Kusatsu, Siga 525-8577, Japan
| | - Masayo Takahashi
- Vision Care Inc., Kobe, Hyogo 650-0047, Japan; Ritsumeikan Advanced Research Academy, Ritsumeikan University, Kusatsu, Shiga 525-8577, Japan
| | - Masao Tachibana
- Center for Systems Vision Science, Organization of Science and Technology, Ritsumeikan University, Kusatsu, Shiga 525-8577, Japan
| | - Michiko Mandai
- Research Center, Kobe City Eye Hospital, Kobe, Hyogo 650-0047, Japan; Research Organization of Science and Technology, Ritsumeikan University, Kusatsu, Shiga 525-8577, Japan; Laboratory for Animal Resources and Genetic Engineering, RIKEN Center for Biosystems Dynamics Research, Kobe, Hyogo 650-0047, Japan.
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Barta CL, Thoreson WB. Retinal inputs that drive optomotor responses of mice under mesopic conditions. IBRO Neurosci Rep 2024; 17:138-144. [PMID: 39170059 PMCID: PMC11338136 DOI: 10.1016/j.ibneur.2024.07.003] [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: 03/05/2024] [Revised: 07/11/2024] [Accepted: 07/20/2024] [Indexed: 08/23/2024] Open
Abstract
Optomotor responses are a popular way to assess sub-cortical visual responses in mice. We studied photoreceptor inputs into optomotor circuits using genetically-modified mice lacking the exocytotic calcium sensors synaptotagmin 1 (Syt1) and 7 (Syt7) in rods or cones. We also tested mice that in which cone transducin, GNAT2, had been eliminated. We studied spatial frequency sensitivity under mesopic conditions by varying the spatial frequency of a grating rotating at 12 deg/s and contrast sensitivity by varying luminance contrast of 0.2c/deg gratings. We found that eliminating Syt1 from rods reduced responses to a low spatial frequency grating (0.05c/deg) consistent with low resolution in this pathway. Conversely, eliminating the ability of cones to respond to light (by eliminating GNAT2) or transmit light responses (by selectively eliminating Syt1) showed weaker responses to a high spatial frequency grating (3c/deg). Eliminating Syt7 from the entire optomotor pathway in a global knockout had no significant effect on optomotor responses. We isolated the secondary rod pathway involving transmission of rod responses to cones via gap junctions by simultaneously eliminating Syt1 from rods and GNAT2 from cones. We found that the secondary rod pathway is sufficient to drive robust optomotor responses under mesopic conditions. Finally, eliminating Syt1 from both rods and cones almost completely abolished optomotor responses, but we detected weak responses to large, bright rotating gratings that are likely driven by input from intrinsically photosensitive retinal ganglion cells.
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Affiliation(s)
- CL Barta
- Truhlsen Eye Institute and Department of Ophthalmology and Visual Sciences, USA
| | - WB Thoreson
- Truhlsen Eye Institute and Department of Ophthalmology and Visual Sciences, USA
- Pharmacology and Experimental Neuroscience, University of Nebraska Medical Center, Omaha, NE 68198, USA
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Franke K, Cai C, Ponder K, Fu J, Sokoloski S, Berens P, Tolias AS. Asymmetric distribution of color-opponent response types across mouse visual cortex supports superior color vision in the sky. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2023.06.01.543054. [PMID: 37333280 PMCID: PMC10274736 DOI: 10.1101/2023.06.01.543054] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/20/2023]
Abstract
Color is an important visual feature that informs behavior, and the retinal basis for color vision has been studied across various vertebrate species. While many studies have investigated how color information is processed in visual brain areas of primate species, we have limited understanding of how it is organized beyond the retina in other species, including most dichromatic mammals. In this study, we systematically characterized how color is represented in the primary visual cortex (V1) of mice. Using large-scale neuronal recordings and a luminance and color noise stimulus, we found that more than a third of neurons in mouse V1 are color-opponent in their receptive field center, while the receptive field surround predominantly captures luminance contrast. Furthermore, we found that color-opponency is especially pronounced in posterior V1 that encodes the sky, matching the statistics of natural scenes experienced by mice. Using unsupervised clustering, we demonstrate that the asymmetry in color representations across cortex can be explained by an uneven distribution of green-On/UV-Off color-opponent response types that are represented in the upper visual field. Finally, a simple model with natural scene-inspired parametric stimuli shows that green-On/UV-Off color-opponent response types may enhance the detection of "predatory"-like dark UV-objects in noisy daylight scenes. The results from this study highlight the relevance of color processing in the mouse visual system and contribute to our understanding of how color information is organized in the visual hierarchy across species.
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Affiliation(s)
- Katrin Franke
- Department of Ophthalmology, Byers Eye Institute, Stanford University School of Medicine, Stanford, CA, US
- Stanford Bio-X, Stanford University, Stanford, CA, US
- Wu Tsai Neurosciences Institute, Stanford University, Stanford, CA, US
- Department of Neuroscience & Center for Neuroscience and Artificial Intelligence, Baylor College of Medicine, Houston, TX, USA
| | - Chenchen Cai
- Institute for Ophthalmic Research, University of Tübingen, Tübingen, Germany
- Graduate Training Center of Neuroscience, International Max Planck Research School, University of Tübingen, Tübingen, Germany
| | - Kayla Ponder
- Department of Neuroscience & Center for Neuroscience and Artificial Intelligence, Baylor College of Medicine, Houston, TX, USA
| | - Jiakun Fu
- Department of Neuroscience & Center for Neuroscience and Artificial Intelligence, Baylor College of Medicine, Houston, TX, USA
| | - Sacha Sokoloski
- Institute for Ophthalmic Research, University of Tübingen, Tübingen, Germany
- Hertie Institute for AI in Brain Health, University of Tübingen, Tübingen, Germany
| | - Philipp Berens
- Institute for Ophthalmic Research, University of Tübingen, Tübingen, Germany
- Hertie Institute for AI in Brain Health, University of Tübingen, Tübingen, Germany
| | - Andreas S Tolias
- Department of Ophthalmology, Byers Eye Institute, Stanford University School of Medicine, Stanford, CA, US
- Stanford Bio-X, Stanford University, Stanford, CA, US
- Wu Tsai Neurosciences Institute, Stanford University, Stanford, CA, US
- Department of Neuroscience & Center for Neuroscience and Artificial Intelligence, Baylor College of Medicine, Houston, TX, USA
- Department of Electrical Engineering, Stanford University, Stanford, CA, US
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Sladek AL, Thoreson WB. Using optogenetics to dissect rod inputs to OFF ganglion cells in the mouse retina. FRONTIERS IN OPHTHALMOLOGY 2023; 3:1146785. [PMID: 37426783 PMCID: PMC10327572 DOI: 10.3389/fopht.2023.1146785] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Indexed: 07/11/2023]
Abstract
Introduction Light responses of rod photoreceptor cells traverse the retina through three pathways. The primary pathway involves synapses from rods to ON-type rod bipolar cells with OFF signals reaching retinal ganglion cells (RGCs) via sign-inverting glycinergic synapses. Secondly, rod signals can enter cones through gap junctions. Finally, rods can synapse directly onto cone OFF bipolar cells. Methods To analyze these pathways, we obtained whole cell recordings from OFF-type α RGCs in mouse retinas while expressing channelrhodopsin-2 in rods and/or cones. Results Optogenetic stimulation of rods or cones evoked large fast currents in OFF RGCs. Blocking the primary rod pathway with L-AP4 and/or strychnine reduced rod-driven optogenetic currents in OFF RGCs by ~1/3. Blocking kainate receptors of OFF cone bipolar cells suppressed both rod- and cone-driven optogenetic currents in OFF RGCs. Inhibiting gap junctions between rods and cones with mecloflenamic acid or quinpirole reduced rod-driven responses in OFF RGCs. Eliminating the exocytotic Ca2+ sensor, synaptotagmin 1 (Syt1), from cones abolished cone-driven optogenetic responses in RGCs. Rod-driven currents were not significantly reduced after isolating the secondary pathway by eliminating Syt1 and synaptotagmin 7 (Syt7) to block synaptic release from rods. Eliminating Syt1 from both rods and cones abolished responses to optogenetic stimulation. In Cx36 KO retinas lacking rod-cone gap junctions, optogenetic activation of rods evoked small and slow responses in most OFF RGCs suggesting rod signals reached them through an indirect pathway. Two OFF cells showed faster responses consistent with more direct input from cone OFF bipolar cells. Discussion These data show that the secondary rod pathway supports robust inputs into OFF α RGCs and suggests the tertiary pathway recruits both direct and indirect inputs.
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Affiliation(s)
- Asia L. Sladek
- Truhlsen Eye Institute and Department of Ophthalmology and Visual Sciences, University of Nebraska Medical Center, Omaha, NE, United States
| | - Wallace B. Thoreson
- Truhlsen Eye Institute and Department of Ophthalmology and Visual Sciences, University of Nebraska Medical Center, Omaha, NE, United States
- Pharmacology and Experimental Neuroscience, University of Nebraska Medical Center, Omaha, NE, United States
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Flood MD, Veloz HLB, Hattar S, Carvalho-de-Souza JL. Robust visual cortex evoked potentials (VEP) in Gnat1 and Gnat2 knockout mice. Front Cell Neurosci 2022; 16:1090037. [PMID: 36605613 PMCID: PMC9807669 DOI: 10.3389/fncel.2022.1090037] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2022] [Accepted: 12/05/2022] [Indexed: 12/24/2022] Open
Abstract
Intrinsically photosensitive retinal ganglion cells (ipRGCs) express the photopigment melanopsin, imparting to themselves the ability to respond to light in the absence of input from rod or cone photoreceptors. Since their discovery ipRGCs have been found to play a significant role in non-image-forming aspects of vision, including circadian photoentrainment, neuroendocrine regulation, and pupillary control. In the past decade it has become increasingly clear that some ipRGCs also contribute directly to pattern-forming vision, the ability to discriminate shapes and objects. However, the degree to which melanopsin-mediated phototransduction, versus that of rods and cones, contributes to this function is still largely unknown. Earlier attempts to quantify this contribution have relied on genetic knockout models that target key phototransductive proteins in rod and cone photoreceptors, ideally to isolate melanopsin-mediated responses. In this study we used the Gnat1-/-; Gnat2cpfl3/cpfl3 mouse model, which have global knockouts for the rod and cone α-transducin proteins. These genetic modifications completely abolish rod and cone photoresponses under light-adapted conditions, locking these cells into a "dark" state. We recorded visually evoked potentials in these animals and found that they still showed robust light responses, albeit with reduced light sensitivity, with similar magnitudes to control mice. These responses had characteristics that were in line with a melanopsin-mediated signal, including delayed kinetics and increased saturability. Additionally, we recorded electroretinograms in a sub-sample of these mice and were unable to find any characteristic waveform related the activation of photoreceptors or second-order retinal neurons, suggesting ipRGCs as the origin of light responses. Our results show a profound ability for melanopsin phototransduction to directly contribute to the primary pattern-forming visual pathway.
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Affiliation(s)
- Michael D. Flood
- Department of Anesthesiology, College of Medicine, The University of Arizona, Tucson, AZ, United States
| | - Hannah L. B. Veloz
- Department of Anesthesiology, College of Medicine, The University of Arizona, Tucson, AZ, United States
| | - Samer Hattar
- Section on Light and Circadian Rhythms (SLCR), National Institute of Mental Health, Bethesda, MD, United States
| | - Joao L. Carvalho-de-Souza
- Department of Anesthesiology, College of Medicine, The University of Arizona, Tucson, AZ, United States,Department of Physiology, College of Medicine, The University of Arizona, Tucson, AZ, United States,Department of Ophthalmology and Vision Science, College of Medicine, The University of Arizona, Tucson, AZ, United States,BIO5 Institute, The University of Arizona, Tucson, AZ, United States,*Correspondence: Joao L. Carvalho-de-Souza,
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7
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Mesnard CS, Hays CL, Barta CL, Sladek AL, Grassmeyer JJ, Hinz KK, Quadros RM, Gurumurthy CB, Thoreson WB. Synaptotagmins 1 and 7 in vesicle release from rods of mouse retina. Exp Eye Res 2022; 225:109279. [PMID: 36280223 PMCID: PMC9830644 DOI: 10.1016/j.exer.2022.109279] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2022] [Revised: 09/14/2022] [Accepted: 10/10/2022] [Indexed: 01/13/2023]
Abstract
Synaptotagmins are the primary Ca2+ sensors for synaptic exocytosis. Previous work suggested synaptotagmin-1 (Syt1) mediates evoked vesicle release from cone photoreceptor cells in the vertebrate retina whereas release from rods may involve another sensor in addition to Syt1. We found immunohistochemical evidence for syntaptotagmin-7 (Syt7) in mouse rod terminals and so performed electroretinograms (ERG) and single-cell recordings using mice in which Syt1 and/or Syt7 were conditionally removed from rods and/or cones. Synaptic release was measured in mouse rods by recording presynaptic anion currents activated during glutamate re-uptake and from exocytotic membrane capacitance changes. Deleting Syt1 from rods reduced glutamate release evoked by short depolarizing steps but not long steps whereas deleting Syt7 from rods reduced release evoked by long but not short steps. Deleting both sensors completely abolished depolarization-evoked release from rods. Effects of various intracellular Ca2+ buffers showed that Syt1-mediated release from rods involves vesicles close to ribbon-associated Ca2+ channels whereas Syt7-mediated release evoked by longer steps involves more distant release sites. Spontaneous release from rods was unaffected by eliminating Syt7. While whole animal knockout of Syt7 slightly reduced ERG b-waves and oscillatory potentials, selective elimination of Syt7 from rods had no effect on ERGs. Furthermore, eliminating Syt1 from rods and cones abolished ERG b-waves and additional elimination of Syt7 had no further effect. These results show that while Syt7 contributes to slow non-ribbon release from rods, Syt1 is the principal sensor shaping rod and cone inputs to bipolar cells in response to light flashes.
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Affiliation(s)
- C S Mesnard
- Truhlsen Eye Institute and Department of Ophthalmology and Visual Sciences, USA; Pharmacology and Experimental Neuroscience, USA
| | - C L Hays
- Truhlsen Eye Institute and Department of Ophthalmology and Visual Sciences, USA
| | - C L Barta
- Truhlsen Eye Institute and Department of Ophthalmology and Visual Sciences, USA
| | - A L Sladek
- Truhlsen Eye Institute and Department of Ophthalmology and Visual Sciences, USA
| | - J J Grassmeyer
- Truhlsen Eye Institute and Department of Ophthalmology and Visual Sciences, USA; Pharmacology and Experimental Neuroscience, USA
| | - K K Hinz
- Truhlsen Eye Institute and Department of Ophthalmology and Visual Sciences, USA
| | - R M Quadros
- Pharmacology and Experimental Neuroscience, USA; Mouse Genome Engineering Core Facility, Vice Chancellor for Research Office, College of Medicine, University of Nebraska Medical Center, Omaha, NE, 68106, USA
| | - C B Gurumurthy
- Pharmacology and Experimental Neuroscience, USA; Mouse Genome Engineering Core Facility, Vice Chancellor for Research Office, College of Medicine, University of Nebraska Medical Center, Omaha, NE, 68106, USA
| | - W B Thoreson
- Truhlsen Eye Institute and Department of Ophthalmology and Visual Sciences, USA; Pharmacology and Experimental Neuroscience, USA.
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Divergent outer retinal circuits drive image and non-image visual behaviors. Cell Rep 2022; 39:111003. [PMID: 35767957 PMCID: PMC9400924 DOI: 10.1016/j.celrep.2022.111003] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2022] [Revised: 04/25/2022] [Accepted: 06/03/2022] [Indexed: 11/22/2022] Open
Abstract
Image- and non-image-forming vision are essential for animal behavior. Here we use genetically modified mouse lines to examine retinal circuits driving image- and non-image-functions. We describe the outer retinal circuits underlying the pupillary light response (PLR) and circadian photoentrainment, two non-image-forming behaviors. Rods and cones signal light increments and decrements through the ON and OFF pathways, respectively. We find that the OFF pathway drives image-forming vision but cannot drive circadian photoentrainment or the PLR. Cone light responses drive image formation but fail to drive the PLR. At photopic levels, rods use the primary and secondary rod pathways to drive the PLR, whereas at the scotopic and mesopic levels, rods use the primary pathway to drive the PLR, and the secondary pathway is insufficient. Circuit dynamics allow rod ON pathways to drive two non-image-forming behaviors across a wide range of light intensities, whereas the OFF pathway is potentially restricted to image formation.
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Jin N, Tian LM, Fahrenfort I, Zhang Z, Postma F, Paul DL, Massey SC, Ribelayga CP. Genetic elimination of rod/cone coupling reveals the contribution of the secondary rod pathway to the retinal output. SCIENCE ADVANCES 2022; 8:eabm4491. [PMID: 35363529 PMCID: PMC10938630 DOI: 10.1126/sciadv.abm4491] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/21/2021] [Accepted: 02/10/2022] [Indexed: 06/14/2023]
Abstract
In the retina, signals originating from rod and cone photoreceptors can reach retinal ganglion cells (RGCs)-the output neurons-through different pathways. However, little is known about the exact sensitivities and operating ranges of these pathways. Previously, we created rod- or cone-specific Cx36 knockout (KO) mouse lines. Both lines are deficient in rod/cone electrical coupling and therefore provide a way to selectively remove the secondary rod pathway. We measured the threshold of the primary rod pathway in RGCs of wild-type mice. Under pharmacological blockade of the primary rod pathway, the threshold was elevated. This secondary component was removed in the Cx36 KOs to unmask the threshold of the third rod pathway, still below cone threshold. In turn, the cone threshold was estimated by several independent methods. Our work defines the functionality of the secondary rod pathway and describes an additive contribution of the different pathways to the retinal output.
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Affiliation(s)
- Nange Jin
- Ruiz Department of Ophthalmology and Visual Science, McGovern Medical School, The University of Texas Health Science Center at Houston (UTHealth Houston), Houston, TX, USA
| | - Lian-Ming Tian
- Ruiz Department of Ophthalmology and Visual Science, McGovern Medical School, The University of Texas Health Science Center at Houston (UTHealth Houston), Houston, TX, USA
| | - Iris Fahrenfort
- Ruiz Department of Ophthalmology and Visual Science, McGovern Medical School, The University of Texas Health Science Center at Houston (UTHealth Houston), Houston, TX, USA
| | - Zhijing Zhang
- Ruiz Department of Ophthalmology and Visual Science, McGovern Medical School, The University of Texas Health Science Center at Houston (UTHealth Houston), Houston, TX, USA
| | - Friso Postma
- Department of Neurobiology, Medical School, Harvard University, Boston, MA, USA
| | - David L. Paul
- Department of Neurobiology, Medical School, Harvard University, Boston, MA, USA
| | - Stephen C. Massey
- Ruiz Department of Ophthalmology and Visual Science, McGovern Medical School, The University of Texas Health Science Center at Houston (UTHealth Houston), Houston, TX, USA
- Elizabeth Morford Distinguished Chair in Ophthalmology and Research Director, Ruiz Department of Ophthalmology and Visual Science, McGovern Medical School, The University of Texas Health Science Center at Houston (UTHealth Houston), Houston, TX, USA
| | - Christophe P. Ribelayga
- Ruiz Department of Ophthalmology and Visual Science, McGovern Medical School, The University of Texas Health Science Center at Houston (UTHealth Houston), Houston, TX, USA
- Bernice Weingarten Chair in Ophthalmology, Ruiz Department of Ophthalmology and Visual Science, McGovern Medical School, The University of Texas Health Science Center at Houston (UTHealth Houston), Houston, TX, USA
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10
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Cangiano L, Asteriti S. Interphotoreceptor coupling: an evolutionary perspective. Pflugers Arch 2021; 473:1539-1554. [PMID: 33988778 PMCID: PMC8370920 DOI: 10.1007/s00424-021-02572-9] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2021] [Revised: 04/13/2021] [Accepted: 04/23/2021] [Indexed: 12/16/2022]
Abstract
In the vertebrate retina, signals generated by cones of different spectral preference and by highly sensitive rod photoreceptors interact at various levels to extract salient visual information. The first opportunity for such interaction is offered by electrical coupling of the photoreceptors themselves, which is mediated by gap junctions located at the contact points of specialised cellular processes: synaptic terminals, telodendria and radial fins. Here, we examine the evolutionary pressures for and against interphotoreceptor coupling, which are likely to have shaped how coupling is deployed in different species. The impact of coupling on signal to noise ratio, spatial acuity, contrast sensitivity, absolute and increment threshold, retinal signal flow and colour discrimination is discussed while emphasising available data from a variety of vertebrate models spanning from lampreys to primates. We highlight the many gaps in our knowledge, persisting discrepancies in the literature, as well as some major unanswered questions on the actual extent and physiological role of cone-cone, rod-cone and rod-rod communication. Lastly, we point toward limited but intriguing evidence suggestive of the ancestral form of coupling among ciliary photoreceptors.
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Affiliation(s)
- Lorenzo Cangiano
- Dept. of Translational Research, University of Pisa, Via San Zeno 31, 56123, Pisa, Italy.
| | - Sabrina Asteriti
- Dept. of Translational Research, University of Pisa, Via San Zeno 31, 56123, Pisa, Italy
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Temporal Contrast Sensitivity Increases despite Photoreceptor Degeneration in a Mouse Model of Retinitis Pigmentosa. eNeuro 2021; 8:ENEURO.0020-21.2021. [PMID: 33509952 PMCID: PMC8059883 DOI: 10.1523/eneuro.0020-21.2021] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2021] [Accepted: 01/18/2021] [Indexed: 11/21/2022] Open
Abstract
The detection of temporal variations in amplitude of light intensity, or temporal contrast sensitivity (TCS), depends on the kinetics of rod photoresponse recovery. Uncharacteristically fast rod recovery kinetics are facets of both human patients and transgenic animal models with a P23H rhodopsin mutation, a prevalent cause of retinitis pigmentosa (RP). Here, we show that mice with this mutation (RhoP23H/+) exhibit an age-dependent and illumination-dependent enhancement in TCS compared with controls. At retinal illumination levels producing ≥1000 R*/rod/s or more, postnatal day 30 (P30) RhoP23H/+ mice exhibit a 1.2-fold to 2-fold increase in retinal and optomotor TCS relative to controls in response to flicker frequencies of 3, 6, and 12 Hz despite significant photoreceptor degeneration and loss of flash electroretinogram (ERG) b-wave amplitude. Surprisingly, the TCS of RhoP23H/+ mice further increases as degeneration advances. Enhanced TCS is also observed in a second model (rhodopsin heterozygous mice, Rho+/-) with fast rod recovery kinetics and no apparent retinal degeneration. In both mouse models, enhanced TCS is explained quantitatively by a comprehensive model that includes photoresponse recovery kinetics, density and collecting area of degenerating rods. Measurement of TCS may be a non-invasive early diagnostic tool indicative of rod dysfunction in some forms of retinal degenerative disease.
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12
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Flood MD, Wellington AJ, Cruz LA, Eggers ED. Early diabetes impairs ON sustained ganglion cell light responses and adaptation without cell death or dopamine insensitivity. Exp Eye Res 2020; 200:108223. [PMID: 32910942 DOI: 10.1016/j.exer.2020.108223] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2020] [Revised: 08/17/2020] [Accepted: 09/03/2020] [Indexed: 10/23/2022]
Abstract
Retinal signaling under dark-adapted conditions is perturbed during early diabetes. Additionally, dopamine, the main neuromodulator of retinal light adaptation, is diminished in diabetic retinas. However, it is not known if this dopamine deficiency changes how the retina responds to increased light or dopamine. Here we determine whether light adaptation is impaired in the diabetic retina, and investigate potential mechanism(s) of impairment. Diabetes was induced in C57BL/6J male mice via 3 intraperitoneal injections of streptozotocin (75 mg/kg) and confirmed by blood glucose levels more than 200 mg/dL. After 6 weeks, whole-cell recordings of light-evoked and spontaneous inhibitory postsynaptic currents (IPSCs) or excitatory postsynaptic currents (EPSCs) were made from rod bipolar cells and ON sustained ganglion cells, respectively. Light responses were recorded before and after D1 receptor (D1R) activation (SKF-38393, 20 μM) or light adaptation (background of 950 photons·μm-2 ·s-1). Retinal whole mounts were stained for either tyrosine hydroxylase and activated caspase-3 or GAD65/67, GlyT1 and RBPMS and imaged. D1R activation and light adaptation both decreased inhibition, but the disinhibition was not different between control and diabetic rod bipolar cells. However, diabetic ganglion cell light-evoked EPSCs were increased in the dark and showed reduced light adaptation. No differences were found in light adaptation of spontaneous EPSC parameters, suggesting upstream changes. No changes in cell density were found for dopaminergic, glycinergic or GABAergic amacrine cells, or ganglion cells. Thus, in early diabetes, ON sustained ganglion cells receive excessive excitation under dark- and light-adapted conditions. Our results show that this is not attributable to loss in number or dopamine sensitivity of inhibitory amacrine cells or loss of dopaminergic amacrine cells.
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Affiliation(s)
- Michael D Flood
- Departments of Physiology and Biomedical Engineering, P.O. Box 245051, University of Arizona, Tucson, AZ, 85724, USA.
| | - Andrea J Wellington
- Departments of Physiology and Biomedical Engineering, P.O. Box 245051, University of Arizona, Tucson, AZ, 85724, USA.
| | - Luis A Cruz
- Departments of Physiology and Biomedical Engineering, P.O. Box 245051, University of Arizona, Tucson, AZ, 85724, USA.
| | - Erika D Eggers
- Departments of Physiology and Biomedical Engineering, P.O. Box 245051, University of Arizona, Tucson, AZ, 85724, USA.
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Szatko KP, Korympidou MM, Ran Y, Berens P, Dalkara D, Schubert T, Euler T, Franke K. Neural circuits in the mouse retina support color vision in the upper visual field. Nat Commun 2020; 11:3481. [PMID: 32661226 PMCID: PMC7359335 DOI: 10.1038/s41467-020-17113-8] [Citation(s) in RCA: 60] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2019] [Accepted: 04/21/2020] [Indexed: 02/06/2023] Open
Abstract
Color vision is essential for an animal’s survival. It starts in the retina, where signals from different photoreceptor types are locally compared by neural circuits. Mice, like most mammals, are dichromatic with two cone types. They can discriminate colors only in their upper visual field. In the corresponding ventral retina, however, most cones display the same spectral preference, thereby presumably impairing spectral comparisons. In this study, we systematically investigated the retinal circuits underlying mouse color vision by recording light responses from cones, bipolar and ganglion cells. Surprisingly, most color-opponent cells are located in the ventral retina, with rod photoreceptors likely being involved. Here, the complexity of chromatic processing increases from cones towards the retinal output, where non-linear center-surround interactions create specific color-opponent output channels to the brain. This suggests that neural circuits in the mouse retina are tuned to extract color from the upper visual field, aiding robust detection of predators and ensuring the animal’s survival. Mice are able to discriminate colors, at least in the upper visual field. Here, the authors provide a comprehensive characterization of retinal circuits underlying this behavior.
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Affiliation(s)
- Klaudia P Szatko
- Institute for Ophthalmic Research, University of Tübingen, Tübingen, Germany.,Bernstein Center for Computational Neuroscience, University of Tübingen, Tübingen, Germany.,Graduate Training Center of Neuroscience, International Max Planck Research School, University of Tübingen, Tübingen, Germany
| | - Maria M Korympidou
- Institute for Ophthalmic Research, University of Tübingen, Tübingen, Germany.,Graduate Training Center of Neuroscience, International Max Planck Research School, University of Tübingen, Tübingen, Germany.,Center for Integrative Neuroscience, University of Tübingen, Tübingen, Germany
| | - Yanli Ran
- Institute for Ophthalmic Research, University of Tübingen, Tübingen, Germany.,Center for Integrative Neuroscience, University of Tübingen, Tübingen, Germany
| | - Philipp Berens
- Institute for Ophthalmic Research, University of Tübingen, Tübingen, Germany.,Bernstein Center for Computational Neuroscience, University of Tübingen, Tübingen, Germany.,Institute for Bioinformatics and Medical Informatics, University of Tübingen, Tübingen, Germany
| | - Deniz Dalkara
- Sorbonne Université, INSERM, CNRS, Institut de la Vision, Paris, France
| | - Timm Schubert
- Institute for Ophthalmic Research, University of Tübingen, Tübingen, Germany.,Center for Integrative Neuroscience, University of Tübingen, Tübingen, Germany
| | - Thomas Euler
- Institute for Ophthalmic Research, University of Tübingen, Tübingen, Germany.,Bernstein Center for Computational Neuroscience, University of Tübingen, Tübingen, Germany.,Center for Integrative Neuroscience, University of Tübingen, Tübingen, Germany
| | - Katrin Franke
- Institute for Ophthalmic Research, University of Tübingen, Tübingen, Germany. .,Bernstein Center for Computational Neuroscience, University of Tübingen, Tübingen, Germany. .,Center for Integrative Neuroscience, University of Tübingen, Tübingen, Germany.
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