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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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2
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Hsiang JC, Shen N, Soto F, Kerschensteiner D. Distributed feature representations of natural stimuli across parallel retinal pathways. Nat Commun 2024; 15:1920. [PMID: 38429280 PMCID: PMC10907388 DOI: 10.1038/s41467-024-46348-y] [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: 08/10/2023] [Accepted: 02/22/2024] [Indexed: 03/03/2024] Open
Abstract
How sensory systems extract salient features from natural environments and organize them across neural pathways is unclear. Combining single-cell and population two-photon calcium imaging in mice, we discover that retinal ON bipolar cells (second-order neurons of the visual system) are divided into two blocks of four types. The two blocks distribute temporal and spatial information encoding, respectively. ON bipolar cell axons co-stratify within each block, but separate laminarly between them (upper block: diverse temporal, uniform spatial tuning; lower block: diverse spatial, uniform temporal tuning). ON bipolar cells extract temporal and spatial features similarly from artificial and naturalistic stimuli. In addition, they differ in sensitivity to coherent motion in naturalistic movies. Motion information is distributed across ON bipolar cells in the upper and the lower blocks, multiplexed with temporal and spatial contrast, independent features of natural scenes. Comparing the responses of different boutons within the same arbor, we find that axons of all ON bipolar cell types function as computational units. Thus, our results provide insights into the visual feature extraction from naturalistic stimuli and reveal how structural and functional organization cooperate to generate parallel ON pathways for temporal and spatial information in the mammalian retina.
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Affiliation(s)
- Jen-Chun Hsiang
- Department of Ophthalmology and Visual Sciences, Washington University School of Medicine, St. Louis, MO, 63110, USA
| | - Ning Shen
- Department of Ophthalmology and Visual Sciences, Washington University School of Medicine, St. Louis, MO, 63110, USA
| | - Florentina Soto
- Department of Ophthalmology and Visual Sciences, Washington University School of Medicine, St. Louis, MO, 63110, USA
| | - Daniel Kerschensteiner
- Department of Ophthalmology and Visual Sciences, Washington University School of Medicine, St. Louis, MO, 63110, USA.
- Department of Neuroscience, Washington University School of Medicine, St. Louis, MO, 63110, USA.
- Department of Biomedical Engineering, Washington University School of Medicine, St. Louis, MO, 63110, USA.
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3
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Gaynes JA, Budoff SA, Grybko MJ, Poleg-Polsky A. Heterogeneous presynaptic receptive fields contribute to directional tuning in starburst amacrine cells. eLife 2023; 12:RP90456. [PMID: 38149980 PMCID: PMC10752589 DOI: 10.7554/elife.90456] [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] [Indexed: 12/28/2023] Open
Abstract
The processing of visual information by retinal starburst amacrine cells (SACs) involves transforming excitatory input from bipolar cells (BCs) into directional calcium output. While previous studies have suggested that an asymmetry in the kinetic properties of BCs along the soma-dendritic axes of the postsynaptic cell could enhance directional tuning at the level of individual branches, it remains unclear whether biologically relevant presynaptic kinetics contribute to direction selectivity (DS) when visual stimulation engages the entire dendritic tree. To address this question, we built multicompartmental models of the bipolar-SAC circuit and trained them to boost directional tuning. We report that despite significant dendritic crosstalk and dissimilar directional preferences along the dendrites that occur during whole-cell stimulation, the rules that guide BC kinetics leading to optimal DS are similar to the single-dendrite condition. To correlate model predictions to empirical findings, we utilized two-photon glutamate imaging to study the dynamics of bipolar release onto ON- and OFF-starburst dendrites in the murine retina. We reveal diverse presynaptic dynamics in response to motion in both BC populations; algorithms trained on the experimental data suggested that the differences in the temporal release kinetics are likely to correspond to heterogeneous receptive field properties among the different BC types, including the spatial extent of the center and surround components. In addition, we demonstrate that circuit architecture composed of presynaptic units with experimentally recorded dynamics could enhance directional drive but not to levels that replicate empirical findings, suggesting other DS mechanisms are required to explain SAC function. Our study provides new insights into the complex mechanisms underlying DS in retinal processing and highlights the potential contribution of presynaptic kinetics to the computation of visual information by SACs.
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Affiliation(s)
- John A Gaynes
- Department of Physiology and Biophysics, University of Colorado School of MedicineAuroraUnited States
| | - Samuel A Budoff
- Department of Physiology and Biophysics, University of Colorado School of MedicineAuroraUnited States
| | - Michael J Grybko
- Department of Physiology and Biophysics, University of Colorado School of MedicineAuroraUnited States
| | - Alon Poleg-Polsky
- Department of Physiology and Biophysics, University of Colorado School of MedicineAuroraUnited States
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4
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Matsumoto A, Yonehara K. Emerging computational motifs: Lessons from the retina. Neurosci Res 2023; 196:11-22. [PMID: 37352934 DOI: 10.1016/j.neures.2023.06.003] [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: 02/22/2023] [Revised: 06/03/2023] [Accepted: 06/08/2023] [Indexed: 06/25/2023]
Abstract
The retinal neuronal circuit is the first stage of visual processing in the central nervous system. The efforts of scientists over the last few decades indicate that the retina is not merely an array of photosensitive cells, but also a processor that performs various computations. Within a thickness of only ∼200 µm, the retina consists of diverse forms of neuronal circuits, each of which encodes different visual features. Since the discovery of direction-selective cells by Horace Barlow and Richard Hill, the mechanisms that generate direction selectivity in the retina have remained a fascinating research topic. This review provides an overview of recent advances in our understanding of direction-selectivity circuits. Beyond the conventional wisdom of direction selectivity, emerging findings indicate that the retina utilizes complicated and sophisticated mechanisms in which excitatory and inhibitory pathways are involved in the efficient encoding of motion information. As will become evident, the discovery of computational motifs in the retina facilitates an understanding of how sensory systems establish feature selectivity.
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Affiliation(s)
- Akihiro Matsumoto
- Danish Research Institute of Translational Neuroscience - DANDRITE, Nordic-EMBL Partnership for Molecular Medicine, Department of Biomedicine, Aarhus University, Aarhus, Denmark; Department of Gene Function and Phenomics, National Institute of Genetics, Mishima, Japan; Department of Genetics, The Graduate University for Advanced Studies (SOKENDAI), Mishima, Japan.
| | - Keisuke Yonehara
- Danish Research Institute of Translational Neuroscience - DANDRITE, Nordic-EMBL Partnership for Molecular Medicine, Department of Biomedicine, Aarhus University, Aarhus, Denmark; Department of Gene Function and Phenomics, National Institute of Genetics, Mishima, Japan; Department of Genetics, The Graduate University for Advanced Studies (SOKENDAI), Mishima, Japan
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5
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Gaynes JA, Budoff SA, Grybko MJ, Poleg-Polsky A. Heterogeneous presynaptic receptive fields contribute to directional tuning in starburst amacrine cells. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.08.02.551732. [PMID: 37577661 PMCID: PMC10418172 DOI: 10.1101/2023.08.02.551732] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/15/2023]
Abstract
The processing of visual information by retinal starburst amacrine cells (SACs) involves transforming excitatory input from bipolar cells (BCs) into directional calcium output. While previous studies have suggested that an asymmetry in the kinetic properties of bipolar cells along the soma-dendritic axes of the postsynaptic cell could enhance directional tuning at the level of individual branches, it remains unclear whether biologically relevant presynaptic kinetics contribute to direction selectivity when visual stimulation engages the entire dendritic tree. To address this question, we built multicompartmental models of the bipolar-SAC circuit and trained them to boost directional tuning. We report that despite significant dendritic crosstalk and dissimilar directional preferences along the dendrites that occur during whole-cell stimulation, the rules that guide BC kinetics leading to optimal directional selectivity are similar to the single-dendrite condition. To correlate model predictions to empirical findings, we utilized two-photon glutamate imaging to study the dynamics of bipolar release onto ON- and OFF-starburst dendrites in the murine retina. We reveal diverse presynaptic dynamics in response to motion in both BC populations; algorithms trained on the experimental data suggested that the differences in the temporal release kinetics are likely to correspond to heterogeneous receptive field (RF) properties among the different BC types, including the spatial extent of the center and surround components. In addition, we demonstrate that circuit architecture composed of presynaptic units with experimentally recorded dynamics could enhance directional drive but not to levels that replicate empirical findings, suggesting other DS mechanisms are required to explain SAC function. Our study provides new insights into the complex mechanisms underlying direction selectivity in retinal processing and highlights the potential contribution of presynaptic kinetics to the computation of visual information by starburst amacrine cells.
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Affiliation(s)
- John A. Gaynes
- Department of Physiology and Biophysics, University of Colorado School of Medicine, Aurora, CO 80045, USA
| | - Samuel A. Budoff
- Department of Physiology and Biophysics, University of Colorado School of Medicine, Aurora, CO 80045, USA
| | - Michael J. Grybko
- Department of Physiology and Biophysics, University of Colorado School of Medicine, Aurora, CO 80045, USA
| | - Alon Poleg-Polsky
- Department of Physiology and Biophysics, University of Colorado School of Medicine, Aurora, CO 80045, USA
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6
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Wang B, Zhang Y. Asymmetric connections with starburst amacrine cells underlie the upward motion selectivity of J-type retinal ganglion cells. PLoS Biol 2023; 21:e3002301. [PMID: 37721959 PMCID: PMC10538761 DOI: 10.1371/journal.pbio.3002301] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2022] [Revised: 09/28/2023] [Accepted: 08/17/2023] [Indexed: 09/20/2023] Open
Abstract
Motion is an important aspect of visual information. The directions of visual motion are encoded in the retina by direction-selective ganglion cells (DSGCs). ON-OFF DSGCs and ON DSGCs co-stratify with starburst amacrine cells (SACs) in the inner plexiform layer and depend on SACs for their direction selectivity. J-type retinal ganglion cells (J-RGCs), a type of OFF DSGCs in the mouse retina, on the other hand, do not co-stratify with SACs, and how direction selectivity in J-RGCs emerges has not been understood. Here, we report that both the excitatory and inhibitory synaptic inputs to J-RGCs are direction-selective (DS), with the inhibitory inputs playing a more important role for direction selectivity. The DS inhibitory inputs come from SACs, and the functional connections between J-RGCs and SACs are spatially asymmetric. Thus, J-RGCs and SACs form functionally important synaptic contacts even though their dendritic arbors show little overlap. These findings underscore the need to look beyond the neurons' stratification patterns in retinal circuit studies. Our results also highlight the critical role of SACs for retinal direction selectivity.
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Affiliation(s)
- Bo Wang
- Institute of Neuroscience, Center for Excellence in Brain Science and Intelligence Technology, Chinese Academy of Sciences, Shanghai, China
| | - Yifeng Zhang
- Institute of Neuroscience, Center for Excellence in Brain Science and Intelligence Technology, Chinese Academy of Sciences, Shanghai, China
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7
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Gaynes JA, Budoff SA, Grybko MJ, Hunt JB, Poleg-Polsky A. Classical center-surround receptive fields facilitate novel object detection in retinal bipolar cells. Nat Commun 2022; 13:5575. [PMID: 36163249 PMCID: PMC9512824 DOI: 10.1038/s41467-022-32761-8] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2021] [Accepted: 08/16/2022] [Indexed: 11/11/2022] Open
Abstract
Antagonistic interactions between center and surround receptive field (RF) components lie at the heart of the computations performed in the visual system. Circularly symmetric center-surround RFs are thought to enhance responses to spatial contrasts (i.e., edges), but how visual edges affect motion processing is unclear. Here, we addressed this question in retinal bipolar cells, the first visual neuron with classic center-surround interactions. We found that bipolar glutamate release emphasizes objects that emerge in the RF; their responses to continuous motion are smaller, slower, and cannot be predicted by signals elicited by stationary stimuli. In our hands, the alteration in signal dynamics induced by novel objects was more pronounced than edge enhancement and could be explained by priming of RF surround during continuous motion. These findings echo the salience of human visual perception and demonstrate an unappreciated capacity of the center-surround architecture to facilitate novel object detection and dynamic signal representation.
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Affiliation(s)
- John A Gaynes
- Department of Physiology and Biophysics, University of Colorado School of Medicine, Aurora, CO, USA
| | - Samuel A Budoff
- Department of Physiology and Biophysics, University of Colorado School of Medicine, Aurora, CO, USA
| | - Michael J Grybko
- Department of Physiology and Biophysics, University of Colorado School of Medicine, Aurora, CO, USA
| | - Joshua B Hunt
- Department of Physiology and Biophysics, University of Colorado School of Medicine, Aurora, CO, USA
| | - Alon Poleg-Polsky
- Department of Physiology and Biophysics, University of Colorado School of Medicine, Aurora, CO, USA.
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8
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Strauss S, Korympidou MM, Ran Y, Franke K, Schubert T, Baden T, Berens P, Euler T, Vlasits AL. Center-surround interactions underlie bipolar cell motion sensitivity in the mouse retina. Nat Commun 2022; 13:5574. [PMID: 36163124 PMCID: PMC9513071 DOI: 10.1038/s41467-022-32762-7] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2021] [Accepted: 08/16/2022] [Indexed: 11/09/2022] Open
Abstract
Motion sensing is a critical aspect of vision. We studied the representation of motion in mouse retinal bipolar cells and found that some bipolar cells are radially direction selective, preferring the origin of small object motion trajectories. Using a glutamate sensor, we directly observed bipolar cells synaptic output and found that there are radial direction selective and non-selective bipolar cell types, the majority being selective, and that radial direction selectivity relies on properties of the center-surround receptive field. We used these bipolar cell receptive fields along with connectomics to design biophysical models of downstream cells. The models and additional experiments demonstrated that bipolar cells pass radial direction selective excitation to starburst amacrine cells, which contributes to their directional tuning. As bipolar cells provide excitation to most amacrine and ganglion cells, their radial direction selectivity may contribute to motion processing throughout the visual system.
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Affiliation(s)
- Sarah Strauss
- Institute for Ophthalmic Research, University of Tübingen, Tübingen, Germany
- Centre for Integrative Neuroscience, University of Tübingen, Tübingen, Germany
- Tübingen AI Center, University of Tübingen, Tübingen, Germany
| | - Maria M Korympidou
- Institute for Ophthalmic Research, University of Tübingen, Tübingen, Germany
- Centre for Integrative Neuroscience, University of Tübingen, Tübingen, Germany
| | - Yanli Ran
- Institute for Ophthalmic Research, University of Tübingen, Tübingen, Germany
- Centre for Integrative Neuroscience, University of Tübingen, Tübingen, Germany
| | - Katrin Franke
- Institute for Ophthalmic Research, University of Tübingen, Tübingen, Germany
- Centre for Integrative Neuroscience, University of Tübingen, Tübingen, Germany
| | - Timm Schubert
- Institute for Ophthalmic Research, University of Tübingen, Tübingen, Germany
- Centre for Integrative Neuroscience, University of Tübingen, Tübingen, Germany
| | - Tom Baden
- Institute for Ophthalmic Research, University of Tübingen, Tübingen, Germany
- School of Life Sciences, University of Sussex, Brighton, UK
| | - Philipp Berens
- Institute for Ophthalmic Research, University of Tübingen, Tübingen, Germany
- Centre for Integrative Neuroscience, University of Tübingen, Tübingen, Germany
- Tübingen AI Center, University of Tübingen, Tübingen, Germany
| | - Thomas Euler
- Institute for Ophthalmic Research, University of Tübingen, Tübingen, Germany.
- Centre for Integrative Neuroscience, University of Tübingen, Tübingen, Germany.
| | - Anna L Vlasits
- Institute for Ophthalmic Research, University of Tübingen, Tübingen, Germany.
- Centre for Integrative Neuroscience, University of Tübingen, Tübingen, Germany.
- Department of Neurobiology, Northwestern University, Evanston, IL, USA.
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9
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Abstract
Retinal circuits transform the pixel representation of photoreceptors into the feature representations of ganglion cells, whose axons transmit these representations to the brain. Functional, morphological, and transcriptomic surveys have identified more than 40 retinal ganglion cell (RGC) types in mice. RGCs extract features of varying complexity; some simply signal local differences in brightness (i.e., luminance contrast), whereas others detect specific motion trajectories. To understand the retina, we need to know how retinal circuits give rise to the diverse RGC feature representations. A catalog of the RGC feature set, in turn, is fundamental to understanding visual processing in the brain. Anterograde tracing indicates that RGCs innervate more than 50 areas in the mouse brain. Current maps connecting RGC types to brain areas are rudimentary, as is our understanding of how retinal signals are transformed downstream to guide behavior. In this article, I review the feature selectivities of mouse RGCs, how they arise, and how they are utilized downstream. Not only is knowledge of the behavioral purpose of RGC signals critical for understanding the retinal contributions to vision; it can also guide us to the most relevant areas of visual feature space. Expected final online publication date for the Annual Review of Vision Science, Volume 8 is September 2022. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.
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Affiliation(s)
- Daniel Kerschensteiner
- John F. Hardesty, MD, Department of Ophthalmology and Visual Sciences; Department of Neuroscience; Department of Biomedical Engineering; and Hope Center for Neurological Disorders, Washington University School of Medicine, Saint Louis, Missouri, USA;
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10
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Hellmer CB, Hall LM, Bohl JM, Sharpe ZJ, Smith RG, Ichinose T. Cholinergic feedback to bipolar cells contributes to motion detection in the mouse retina. Cell Rep 2021; 37:110106. [PMID: 34910920 PMCID: PMC8793255 DOI: 10.1016/j.celrep.2021.110106] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2021] [Revised: 08/11/2021] [Accepted: 11/16/2021] [Indexed: 11/25/2022] Open
Abstract
Retinal bipolar cells are second-order neurons that transmit basic features of the visual scene to postsynaptic partners. However, their contribution to motion detection has not been fully appreciated. Here, we demonstrate that cholinergic feedback from starburst amacrine cells (SACs) to certain presynaptic bipolar cells via alpha-7 nicotinic acetylcholine receptors (α7-nAChRs) promotes direction-selective signaling. Patch clamp recordings reveal that distinct bipolar cell types making synapses at proximal SAC dendrites also express α7-nAChRs, producing directionally skewed excitatory inputs. Asymmetric SAC excitation contributes to motion detection in On-Off direction-selective ganglion cells (On-Off DSGCs), predicted by computational modeling of SAC dendrites and supported by patch clamp recordings from On-Off DSGCs when bipolar cell α7-nAChRs is eliminated pharmacologically or by conditional knockout. Altogether, these results show that cholinergic feedback to bipolar cells enhances direction-selective signaling in postsynaptic SACs and DSGCs, illustrating how bipolar cells provide a scaffold for postsynaptic microcircuits to cooperatively enhance retinal motion detection.
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Affiliation(s)
- Chase B Hellmer
- Department of Ophthalmology, Visual and Anatomical Sciences, Wayne State University School of Medicine, Detroit, MI 48201, USA; Present address: Department of Ophthalmology and Visual Sciences, University of Louisville, Louisville, KY 40202, USA
| | - Leo M Hall
- Department of Ophthalmology, Visual and Anatomical Sciences, Wayne State University School of Medicine, Detroit, MI 48201, USA; Present address: Department of Internal Medicine, St. Mary Mercy Livonia Hospital, Livonia, MI 48154, USA
| | - Jeremy M Bohl
- Department of Ophthalmology, Visual and Anatomical Sciences, Wayne State University School of Medicine, Detroit, MI 48201, USA
| | - Zachary J Sharpe
- Department of Ophthalmology, Visual and Anatomical Sciences, Wayne State University School of Medicine, Detroit, MI 48201, USA
| | - Robert G Smith
- Department of Neuroscience, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Tomomi Ichinose
- Department of Ophthalmology, Visual and Anatomical Sciences, Wayne State University School of Medicine, Detroit, MI 48201, USA.
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11
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Matsumoto A, Agbariah W, Nolte SS, Andrawos R, Levi H, Sabbah S, Yonehara K. Direction selectivity in retinal bipolar cell axon terminals. Neuron 2021; 109:2928-2942.e8. [PMID: 34390651 PMCID: PMC8478419 DOI: 10.1016/j.neuron.2021.07.008] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2020] [Revised: 06/18/2021] [Accepted: 07/09/2021] [Indexed: 12/20/2022]
Abstract
The ability to encode the direction of image motion is fundamental to our sense of vision. Direction selectivity along the four cardinal directions is thought to originate in direction-selective ganglion cells (DSGCs) because of directionally tuned GABAergic suppression by starburst cells. Here, by utilizing two-photon glutamate imaging to measure synaptic release, we reveal that direction selectivity along all four directions arises earlier than expected at bipolar cell outputs. Individual bipolar cells contained four distinct populations of axon terminal boutons with different preferred directions. We further show that this bouton-specific tuning relies on cholinergic excitation from starburst cells and GABAergic inhibition from wide-field amacrine cells. DSGCs received both tuned directionally aligned inputs and untuned inputs from among heterogeneously tuned glutamatergic bouton populations. Thus, directional tuning in the excitatory visual pathway is incrementally refined at the bipolar cell axon terminals and their recipient DSGC dendrites by two different neurotransmitters co-released from starburst cells.
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Affiliation(s)
- Akihiro Matsumoto
- Danish Research Institute of Translational Neuroscience - DANDRITE, Nordic-EMBL Partnership for Molecular Medicine, Department of Biomedicine, Aarhus University, Ole Worms Allé 8, 8000 Aarhus C, Denmark
| | - Weaam Agbariah
- Department of Medical Neurobiology, Faculty of Medicine, Hebrew University of Jerusalem, Jerusalem 9112102, Israel
| | - Stella Solveig Nolte
- Danish Research Institute of Translational Neuroscience - DANDRITE, Nordic-EMBL Partnership for Molecular Medicine, Department of Biomedicine, Aarhus University, Ole Worms Allé 8, 8000 Aarhus C, Denmark
| | - Rawan Andrawos
- Department of Medical Neurobiology, Faculty of Medicine, Hebrew University of Jerusalem, Jerusalem 9112102, Israel
| | - Hadara Levi
- Department of Medical Neurobiology, Faculty of Medicine, Hebrew University of Jerusalem, Jerusalem 9112102, Israel
| | - Shai Sabbah
- Department of Medical Neurobiology, Faculty of Medicine, Hebrew University of Jerusalem, Jerusalem 9112102, Israel.
| | - Keisuke Yonehara
- Danish Research Institute of Translational Neuroscience - DANDRITE, Nordic-EMBL Partnership for Molecular Medicine, Department of Biomedicine, Aarhus University, Ole Worms Allé 8, 8000 Aarhus C, Denmark.
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12
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Pottackal J, Singer JH, Demb JB. Receptoral Mechanisms for Fast Cholinergic Transmission in Direction-Selective Retinal Circuitry. Front Cell Neurosci 2020; 14:604163. [PMID: 33324168 PMCID: PMC7726240 DOI: 10.3389/fncel.2020.604163] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2020] [Accepted: 10/22/2020] [Indexed: 01/09/2023] Open
Abstract
Direction selectivity represents an elementary sensory computation that can be related to underlying synaptic mechanisms. In mammalian retina, direction-selective ganglion cells (DSGCs) respond strongly to visual motion in a "preferred" direction and weakly to motion in the opposite, "null" direction. The DS mechanism depends on starburst amacrine cells (SACs), which provide null direction-tuned GABAergic inhibition and untuned cholinergic excitation to DSGCs. GABAergic inhibition depends on conventional synaptic transmission, whereas cholinergic excitation apparently depends on paracrine (i.e., non-synaptic) transmission. Despite its paracrine mode of transmission, cholinergic excitation is more transient than GABAergic inhibition, yielding a temporal difference that contributes essentially to the DS computation. To isolate synaptic mechanisms that generate the distinct temporal properties of cholinergic and GABAergic transmission from SACs to DSGCs, we optogenetically stimulated SACs while recording postsynaptic currents (PSCs) from DSGCs in mouse retina. Direct recordings from channelrhodopsin-2-expressing (ChR2+) SACs during quasi-white noise (WN) (0-30 Hz) photostimulation demonstrated precise, graded optogenetic control of SAC membrane current and potential. Linear systems analysis of ChR2-evoked PSCs recorded in DSGCs revealed cholinergic transmission to be faster than GABAergic transmission. A deconvolution-based analysis showed that distinct postsynaptic receptor kinetics fully account for the temporal difference between cholinergic and GABAergic transmission. Furthermore, GABAA receptor blockade prolonged cholinergic transmission, identifying a new functional role for GABAergic inhibition of SACs. Thus, fast cholinergic transmission from SACs to DSGCs arises from at least two distinct mechanisms, yielding temporal properties consistent with conventional synapses despite its paracrine nature.
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Affiliation(s)
- Joseph Pottackal
- Interdepartmental Neuroscience Program, Yale University, New Haven, CT, United States
| | - Joshua H. Singer
- Department of Biology, University of Maryland, College Park, MD, United States
| | - Jonathan B. Demb
- Interdepartmental Neuroscience Program, Yale University, New Haven, CT, United States
- Department of Ophthalmology and Visual Science, Yale University, New Haven, CT, United States
- Department of Cellular and Molecular Physiology, Yale University, New Haven, CT, United States
- Department of Neuroscience, Yale University, New Haven, CT, United States
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13
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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: 52] [Impact Index Per Article: 13.0] [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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14
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Spatiotemporally Asymmetric Excitation Supports Mammalian Retinal Motion Sensitivity. Curr Biol 2019; 29:3277-3288.e5. [PMID: 31564498 PMCID: PMC6865067 DOI: 10.1016/j.cub.2019.08.048] [Citation(s) in RCA: 30] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2019] [Revised: 08/15/2019] [Accepted: 08/20/2019] [Indexed: 11/20/2022]
Abstract
The detection of visual motion is a fundamental function of the visual system. How motion speed and direction are computed together at the cellular level, however, remains largely unknown. Here, we suggest a circuit mechanism by which excitatory inputs to direction-selective ganglion cells in the mouse retina become sensitive to the motion speed and direction of image motion. Electrophysiological, imaging, and connectomic analyses provide evidence that the dendrites of ON direction-selective cells receive spatially offset and asymmetrically filtered glutamatergic inputs along motion-preference axis from asymmetrically wired bipolar and amacrine cell types with distinct release dynamics. A computational model shows that, with this spatiotemporal structure, the input amplitude becomes sensitive to speed and direction by a preferred direction enhancement mechanism. Our results highlight the role of an excitatory mechanism in retinal motion computation by which feature selectivity emerges from non-selective inputs.
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15
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Hall LM, Hellmer CB, Koehler CC, Ichinose T. Bipolar Cell Type-Specific Expression and Conductance of Alpha-7 Nicotinic Acetylcholine Receptors in the Mouse Retina. Invest Ophthalmol Vis Sci 2019; 60:1353-1361. [PMID: 30934054 PMCID: PMC6738513 DOI: 10.1167/iovs.18-25753] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023] Open
Abstract
Purpose Motion detection is performed by a unique neural network in the mouse retina. Starburst amacrine cells (SACs), which release acetylcholine and gamma-aminobutyric acid (GABA) into the network, are key neurons in the motion detection pathway. Although GABA contributions to the network have been extensively studied, the role of acetylcholine is minimally understood. Acetylcholine receptors are present in a subset of bipolar, amacrine, and ganglion cells. We focused on α7-nicotinic acetylcholine receptor (α7-nAChR) expression in bipolar cells, and investigated which types of bipolar cells possess α7-nAChRs. Methods Retinal slice sections were prepared from C57BL/6J and Gus8.4-GFP mice. Specific expression of α7-nAChRs in bipolar cells was examined using α-bungarotoxin (αBgTx)-conjugated Alexa dyes co-labeled with specific bipolar cell markers. Whole-cell recordings were conducted from bipolar cells in retinal slice sections. A selective α7-nAChR agonist, PNU282987, was applied by a puff and responses were recorded. Results αBgTx fluorescence was observed primarily in bipolar cell somas. We found that α7-nAChRs were expressed by the majority of type 1, 2, 4, and 7 bipolar cells. Whole-cell recordings revealed that type 2 and 7 bipolar cells depolarized by PNU application. In contrast, α7-nAChRs were not detected in most of type 3, 5, 6, and rod bipolar cells. Conclusions We found that α7-nAChRs are present in bipolar cells in a type-specific manner. Because these bipolar cells provide synaptic inputs to SACs and direction selective ganglion cells, α7-nAChRs may play a role in direction selectivity by modulating these bipolar cells' outputs.
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Affiliation(s)
- Leo M Hall
- Department of Ophthalmology, Visual and Anatomical Sciences, Wayne State University School of Medicine, Detroit, Michigan, United States
| | - Chase B Hellmer
- Department of Ophthalmology, Visual and Anatomical Sciences, Wayne State University School of Medicine, Detroit, Michigan, United States
| | - Christina C Koehler
- Department of Ophthalmology, Visual and Anatomical Sciences, Wayne State University School of Medicine, Detroit, Michigan, United States
| | - Tomomi Ichinose
- Department of Ophthalmology, Visual and Anatomical Sciences, Wayne State University School of Medicine, Detroit, Michigan, United States
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16
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Abstract
Visual motion on the retina activates a cohort of retinal ganglion cells (RGCs). This population activity encodes multiple streams of information extracted by parallel retinal circuits. Motion processing in the retina is best studied in the direction-selective circuit. The main focus of this review is the neural basis of direction selectivity, which has been investigated in unprecedented detail using state-of-the-art functional, connectomic, and modeling methods. Mechanisms underlying the encoding of other motion features by broader RGC populations are also discussed. Recent discoveries at both single-cell and population levels highlight the dynamic and stimulus-dependent engagement of multiple mechanisms that collectively implement robust motion detection under diverse visual conditions.
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Affiliation(s)
- Wei Wei
- Department of Neurobiology, The University of Chicago, Chicago, Illinois 60637, USA
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17
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Sethuramanujam S, Awatramani GB, Slaughter MM. Cholinergic excitation complements glutamate in coding visual information in retinal ganglion cells. J Physiol 2018; 596:3709-3724. [PMID: 29758086 DOI: 10.1113/jp275073] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2017] [Accepted: 04/25/2018] [Indexed: 01/07/2023] Open
Abstract
KEY POINTS Starburst amacrine cells release GABA and ACh. This study explores the coordinated function of starburst-mediated cholinergic excitation and GABAergic inhibition to bistratified retinal ganglion cells, predominantly direction-selective ganglion cells (DSGCs). In rat retina, under our recording conditions, starbursts were found to provide the major excitatory drive to a sub-population of ganglion cells whose dendrites co-stratify with starburst dendrites (putative DSGCs). In mouse retina, recordings from genetically identified DSGCs at physiological temperatures reveal that ACh inputs dominate the response to small spot-high contrast light stimuli, with preferential addition of bipolar cell input shifting the balance towards glutamate for larger spot stimuli In addition, starbursts also appear to gate glutamatergic excitation to DSGCs by postsynaptic and possibly presynaptic inhibitory processes ABSTRACT: Starburst amacrine cells release both GABA and ACh, allowing them to simultaneously mediate inhibition and excitation. However, the precise pre- and postsynaptic targets for ACh and GABA remain under intense investigation. Most previous studies have focused on starburst-mediated postsynaptic GABAergic inhibition and its role in the formation of directional selectivity in ganglion cells. However, the significance of postsynaptic cholinergic excitation is only beginning to be appreciated. Here, we found that light-evoked responses measured in bi-stratified rat ganglion cells with dendrites that co-fasciculate with ON and OFF starburst dendrites (putative direction-selective ganglion cells, DSGCs) were abolished by the application of nicotinic receptor antagonists, suggesting ACh could act as the primary source of excitation. Recording from genetically labelled DSGCs in mouse retina at physiological temperatures revealed that cholinergic synaptic inputs dominated the excitation for high contrast stimuli only when the size of the stimulus was small. Canonical glutamatergic inputs mediated by bipolar cells were prominent when GABA/glycine receptors were blocked or when larger spot stimuli were utilized. In mouse DSGCs, bipolar cell excitation could also be unmasked through the activation of mGluR2,3 receptors, which we show suppresses starburst output, suggesting that GABA from starbursts serves to inhibit bipolar cell signals in DSGCs. Taken together, these results suggest that starbursts amplify excitatory signals traversing the retina, endowing DSGCs with the ability to encode fine spatial information without compromising their ability to encode direction.
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Affiliation(s)
- Santhosh Sethuramanujam
- Center for Neuroscience and Department of Physiology and Biophysics, University at Buffalo, Buffalo, NY, 14214, USA.,Department of Biology, University of Victoria, Victoria, BC, V8W2Y2, Canada
| | | | - Malcolm M Slaughter
- Center for Neuroscience and Department of Physiology and Biophysics, University at Buffalo, Buffalo, NY, 14214, USA
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18
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Chen Q, Wei W. Stimulus-dependent engagement of neural mechanisms for reliable motion detection in the mouse retina. J Neurophysiol 2018; 120:1153-1161. [PMID: 29897862 DOI: 10.1152/jn.00716.2017] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Direction selectivity is a fundamental computation in the visual system and is first computed by the direction-selective circuit in the mammalian retina. Although landmark discoveries on the neural basis of direction selectivity have been made in the rabbit, many technological advances designed for the mouse have emerged, making this organism a favored model for investigating the direction-selective circuit at the molecular, synaptic, and network levels. Studies using diverse motion stimuli in the mouse retina demonstrate that retinal direction selectivity is implemented by multilayered mechanisms. This review begins with a set of central mechanisms that are engaged under a wide range of visual conditions and then focuses on additional layers of mechanisms that are dynamically recruited under different visual stimulus conditions. Together, recent findings allude to an emerging theme: robust motion detection in the natural environment requires flexible neural mechanisms.
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Affiliation(s)
- Qiang Chen
- Department of Neurobiology, The University of Chicago , Chicago, Illinois.,Committee on Computational Neuroscience, The University of Chicago , Chicago, Illinois
| | - Wei Wei
- Department of Neurobiology, The University of Chicago , Chicago, Illinois.,Committee on Computational Neuroscience, The University of Chicago , Chicago, Illinois
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19
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Ray TA, Roy S, Kozlowski C, Wang J, Cafaro J, Hulbert SW, Wright CV, Field GD, Kay JN. Formation of retinal direction-selective circuitry initiated by starburst amacrine cell homotypic contact. eLife 2018; 7:e34241. [PMID: 29611808 PMCID: PMC5931800 DOI: 10.7554/elife.34241] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2017] [Accepted: 03/29/2018] [Indexed: 12/23/2022] Open
Abstract
A common strategy by which developing neurons locate their synaptic partners is through projections to circuit-specific neuropil sublayers. Once established, sublayers serve as a substrate for selective synapse formation, but how sublayers arise during neurodevelopment remains unknown. Here, we identify the earliest events that initiate formation of the direction-selective circuit in the inner plexiform layer of mouse retina. We demonstrate that radially migrating newborn starburst amacrine cells establish homotypic contacts on arrival at the inner retina. These contacts, mediated by the cell-surface protein MEGF10, trigger neuropil innervation resulting in generation of two sublayers comprising starburst-cell dendrites. This dendritic scaffold then recruits projections from circuit partners. Abolishing MEGF10-mediated contacts profoundly delays and ultimately disrupts sublayer formation, leading to broader direction tuning and weaker direction-selectivity in retinal ganglion cells. Our findings reveal a mechanism by which differentiating neurons transition from migratory to mature morphology, and highlight this mechanism's importance in forming circuit-specific sublayers.
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Affiliation(s)
- Thomas A Ray
- Department of NeurobiologyDuke University School of MedicineDurhamUnited States
- Department of OphthalmologyDuke University School of MedicineDurhamUnited States
| | - Suva Roy
- Department of NeurobiologyDuke University School of MedicineDurhamUnited States
| | - Christopher Kozlowski
- Department of NeurobiologyDuke University School of MedicineDurhamUnited States
- Department of OphthalmologyDuke University School of MedicineDurhamUnited States
| | - Jingjing Wang
- Department of NeurobiologyDuke University School of MedicineDurhamUnited States
- Department of OphthalmologyDuke University School of MedicineDurhamUnited States
| | - Jon Cafaro
- Department of NeurobiologyDuke University School of MedicineDurhamUnited States
| | - Samuel W Hulbert
- Department of NeurobiologyDuke University School of MedicineDurhamUnited States
| | - Christopher V Wright
- Department of Cell and Developmental BiologyVanderbilt University School of MedicineNashvilleUnited States
| | - Greg D Field
- Department of NeurobiologyDuke University School of MedicineDurhamUnited States
| | - Jeremy N Kay
- Department of NeurobiologyDuke University School of MedicineDurhamUnited States
- Department of OphthalmologyDuke University School of MedicineDurhamUnited States
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Clark DA, Demb JB. Parallel Computations in Insect and Mammalian Visual Motion Processing. Curr Biol 2017; 26:R1062-R1072. [PMID: 27780048 DOI: 10.1016/j.cub.2016.08.003] [Citation(s) in RCA: 36] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Sensory systems use receptors to extract information from the environment and neural circuits to perform subsequent computations. These computations may be described as algorithms composed of sequential mathematical operations. Comparing these operations across taxa reveals how different neural circuits have evolved to solve the same problem, even when using different mechanisms to implement the underlying math. In this review, we compare how insect and mammalian neural circuits have solved the problem of motion estimation, focusing on the fruit fly Drosophila and the mouse retina. Although the two systems implement computations with grossly different anatomy and molecular mechanisms, the underlying circuits transform light into motion signals with strikingly similar processing steps. These similarities run from photoreceptor gain control and spatiotemporal tuning to ON and OFF pathway structures, motion detection, and computed motion signals. The parallels between the two systems suggest that a limited set of algorithms for estimating motion satisfies both the needs of sighted creatures and the constraints imposed on them by metabolism, anatomy, and the structure and regularities of the visual world.
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Affiliation(s)
- Damon A Clark
- Department of Molecular, Cellular, and Developmental Biology and Department of Physics, Yale University, New Haven, CT 06511, USA.
| | - Jonathan B Demb
- Department of Ophthalmology and Visual Science and Department of Cellular and Molecular Physiology, Yale University, New Haven, CT 06511, USA.
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21
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Xu GZ, Cui LJ, Liu AL, Zhou W, Gong X, Zhong YM, Yang XL, Weng SJ. Transgene is specifically and functionally expressed in retinal inhibitory interneurons in the VGAT-ChR2-EYFP mouse. Neuroscience 2017; 363:107-119. [PMID: 28918256 DOI: 10.1016/j.neuroscience.2017.09.006] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2017] [Revised: 08/25/2017] [Accepted: 09/01/2017] [Indexed: 02/07/2023]
Abstract
Ectopic transgene expression in the retina has been reported in various transgenic mice, indicating the importance of characterizing retinal phenotypes. We examined transgene expression in the VGAT-ChR2-EYFP mouse retina by fluorescent immunohistochemistry and electrophysiology, with special emphasis on enhanced yellow fluorescent protein (EYFP) localization in retinal neuronal subtypes identified by specific markers. Strong EYFP signals were detected in both the inner and outer plexiform layers. In addition, the ChR2-EYFP fusion protein was also expressed in somata of the great majority of inhibitory interneurons, including horizontal cells and GABAergic and glycinergic amacrine cells. However, a small population of amacrine cells residing in the ganglion cell layer were not labeled by EYFP, and a part of them were cholinergic ones. In contrast, no EYFP signal was detected in the somata of retinal excitatory neurons: photoreceptors, bipolar and ganglion cells, as well as Müller glial cells. When glutamatergic transmission was blocked, bright blue light stimulation elicited inward photocurrents from amacrine cells, as well as post-synaptic inhibitory currents from ganglion cells, suggesting a functional ChR2 expression. The VGAT-ChR2-EYFP mouse therefore could be a useful animal model for dissecting retinal microcircuits when targeted labeling and/or optogenetic manipulation of retinal inhibitory neurons are required.
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Affiliation(s)
- Guo-Zhong Xu
- Institutes of Brain Science, State Key Laboratory of Medical Neurobiology and Collaborative Innovation Center for Brain Science, Fudan University, Shanghai, China; School of Life Science and Technology, Changchun University of Science and Technology, Changchun, China
| | - Ling-Jie Cui
- Institutes of Brain Science, State Key Laboratory of Medical Neurobiology and Collaborative Innovation Center for Brain Science, Fudan University, Shanghai, China
| | - Ai-Lin Liu
- Institutes of Brain Science, State Key Laboratory of Medical Neurobiology and Collaborative Innovation Center for Brain Science, Fudan University, Shanghai, China
| | - Wei Zhou
- Institutes of Brain Science, State Key Laboratory of Medical Neurobiology and Collaborative Innovation Center for Brain Science, Fudan University, Shanghai, China
| | - Xue Gong
- Institutes of Brain Science, State Key Laboratory of Medical Neurobiology and Collaborative Innovation Center for Brain Science, Fudan University, Shanghai, China
| | - Yong-Mei Zhong
- Institutes of Brain Science, State Key Laboratory of Medical Neurobiology and Collaborative Innovation Center for Brain Science, Fudan University, Shanghai, China
| | - Xiong-Li Yang
- Institutes of Brain Science, State Key Laboratory of Medical Neurobiology and Collaborative Innovation Center for Brain Science, Fudan University, Shanghai, China
| | - Shi-Jun Weng
- Institutes of Brain Science, State Key Laboratory of Medical Neurobiology and Collaborative Innovation Center for Brain Science, Fudan University, Shanghai, China.
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22
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Local synaptic integration enables ON-OFF asymmetric and layer-specific visual information processing in vGluT3 amacrine cell dendrites. Proc Natl Acad Sci U S A 2017; 114:11518-11523. [PMID: 28973895 DOI: 10.1073/pnas.1711622114] [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] [Indexed: 11/18/2022] Open
Abstract
A basic scheme of neuronal organization in the mammalian retina is the segregation of ON and OFF pathways in the inner plexiform layer (IPL), where glutamate is released from ON and OFF bipolar cell terminals in separate inner (ON) and outer (OFF) sublayers in response to light intensity increments and decrements, respectively. However, recent studies have found that vGluT3-expressing glutamatergic amacrine cells (GACs) generate ON-OFF somatic responses and release glutamate onto both ON and OFF ganglion cell types, raising the possibility of crossover excitation in violation of the canonical ON-OFF segregation scheme. To test this possibility, we recorded light-evoked Ca2+ responses from dendrites of individual GACs infected with GCaMP6s in mouse. Under two-photon imaging, a single GAC generated rectified local dendritic responses, showing ON-dominant responses in ON sublayers and OFF-dominant responses in OFF sublayers. This unexpected ON-OFF segregation within a small-field amacrine cell arose from local synaptic processing, mediated predominantly by synaptic inhibition. Multiple forms of synaptic inhibition compartmentalized the GAC dendritic tree and endowed all dendritic varicosities with a small-center, strong-surround receptive field, which varied in receptive field size and degree of ON-OFF asymmetry with IPL depth. The results reveal a form of short-range dendritic autonomy that enables a small-field, dual-transmitter amacrine cell to process diverse dendritic functions in a stratification level- and postsynaptic target-specific manner, while preserving the fundamental ON-OFF segregation scheme for parallel visual processing and high spatial resolution for small object motion and uniformity detection.
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23
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Retinal Circuitry Balances Contrast Tuning of Excitation and Inhibition to Enable Reliable Computation of Direction Selectivity. J Neurosci 2017; 36:5861-76. [PMID: 27225774 DOI: 10.1523/jneurosci.4013-15.2016] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2015] [Accepted: 04/23/2016] [Indexed: 11/21/2022] Open
Abstract
UNLABELLED Feedforward (FF) inhibition is a common motif in many neural networks. Typically, excitatory inputs drive both principal neurons and interneurons; the interneurons then inhibit the principal neurons, thereby regulating the strength and timing of the FF signal. The interneurons introduce a likely nonlinear processing step that could distort the excitation/inhibition (E/I) ratio in the principal neuron, potentially degrading the reliability of computation in the circuit. In the retina, FF inhibition is an essential feature of the circuitry underlying direction selectivity (DS): glutamatergic bipolar cells (BCs) provide excitatory input to direction-selective ganglion cells (DSGCs) and GABAergic starburst amacrine cells (SACs), and the SACs then provide FF inhibition onto DSGCs. Robust DS computation requires a consistent synaptic E/I ratio in the DSGC in various visual conditions. Here, we show in mouse retina that the E/I ratio is maintained in DSGCs over a wide stimulus contrast range due to compensatory mechanisms in the diverse population of presynaptic BCs. BC inputs to SACs exhibit higher contrast sensitivity, so that the subsequent nonlinear transformation in SACs reduces the contrast sensitivity of FF inhibition to match the sensitivity of direct excitatory inputs onto DSGCs. Measurements of light-evoked responses from individual BC synaptic terminals suggest that the distinct sensitivity of BC inputs reflects different contrast sensitivity between BC subtypes. Numerical simulations suggest that this network arrangement is crucial for reliable DS computation. SIGNIFICANCE STATEMENT Properly balanced excitation and inhibition are essential for many neuronal computations across brain regions. Feedforward inhibition circuitry, in which a common excitatory source drives both the principal cell and an interneuron, is a typical mechanism by which neural networks maintain this balance. Feedforward circuits may become imbalanced at low stimulation levels, however, if the excitatory drive is too weak to overcome the activation threshold in the interneuron. Here we reveal how excitation and inhibition remain balanced in direction selective ganglion cells in the mouse retina over a wide visual stimulus range.
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24
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Dendro-dendritic cholinergic excitation controls dendritic spike initiation in retinal ganglion cells. Nat Commun 2017; 8:15683. [PMID: 28589928 PMCID: PMC5477517 DOI: 10.1038/ncomms15683] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2016] [Accepted: 04/12/2017] [Indexed: 02/06/2023] Open
Abstract
The retina processes visual images to compute features such as the direction of image motion. Starburst amacrine cells (SACs), axonless feed-forward interneurons, are essential components of the retinal direction-selective circuitry. Recent work has highlighted that SAC-mediated dendro-dendritic inhibition controls the action potential output of direction-selective ganglion cells (DSGCs) by vetoing dendritic spike initiation. However, SACs co-release GABA and the excitatory neurotransmitter acetylcholine at dendritic sites. Here we use direct dendritic recordings to show that preferred direction light stimuli evoke SAC-mediated acetylcholine release, which powerfully controls the stimulus sensitivity, receptive field size and action potential output of ON-DSGCs by acting as an excitatory drive for the initiation of dendritic spikes. Consistent with this, paired recordings reveal that the activation of single ON-SACs drove dendritic spike generation, because of predominate cholinergic excitation received on the preferred side of ON-DSGCs. Thus, dendro-dendritic release of neurotransmitters from SACs bi-directionally gate dendritic spike initiation to control the directionally selective action potential output of retinal ganglion cells. Neural computations performed by the retinal microcircuit have been extensively studied. Here the authors report using dendritic recordings that the direction selective responses of retinal ganglion cells are controlled by dendro-dendritic cholinergic excitation from starburst amacrine cells.
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25
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Abstract
Images projected onto the retina of an animal eye are rarely still. Instead, they usually contain motion signals originating either from moving objects or from retinal slip caused by self-motion. Accordingly, motion signals tell the animal in which direction a predator, prey, or the animal itself is moving. At the neural level, visual motion detection has been proposed to extract directional information by a delay-and-compare mechanism, representing a classic example of neural computation. Neurons responding selectively to motion in one but not in the other direction have been identified in many systems, most prominently in the mammalian retina and the fly optic lobe. Technological advances have now allowed researchers to characterize these neurons' upstream circuits in exquisite detail. Focusing on these upstream circuits, we review and compare recent progress in understanding the mechanisms that generate direction selectivity in the early visual system of mammals and flies.
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Affiliation(s)
- Alex S Mauss
- Max Planck Institute of Neurobiology, 82152 Martinsried, Germany; ,
| | - Anna Vlasits
- Department of Molecular and Cell Biology & Helen Wills Neuroscience Institute, University of California, Berkeley, California 94720; ,
| | - Alexander Borst
- Max Planck Institute of Neurobiology, 82152 Martinsried, Germany; ,
| | - Marla Feller
- Department of Molecular and Cell Biology & Helen Wills Neuroscience Institute, University of California, Berkeley, California 94720; ,
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26
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Percival KA, Venkataramani S, Smith RG, Taylor WR. Directional excitatory input to direction-selective ganglion cells in the rabbit retina. J Comp Neurol 2017; 527:270-281. [PMID: 28295340 DOI: 10.1002/cne.24207] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2016] [Revised: 01/29/2017] [Accepted: 01/31/2017] [Indexed: 12/19/2022]
Abstract
Directional responses in retinal ganglion cells are generated in large part by direction-selective release of γ-aminobutyric acid from starburst amacrine cells onto direction-selective ganglion cells (DSGCs). The excitatory inputs to DSGCs are also widely reported to be direction-selective, however, recent evidence suggests that glutamate release from bipolar cells is not directional, and directional excitation seen in patch-clamp analyses may be an artifact resulting from incomplete voltage control. Here, we test this voltage-clamp-artifact hypothesis in recordings from 62 ON-OFF DSGCs in the rabbit retina. The strength of the directional excitatory signal varies considerably across the sample of cells, but is not correlated with the strength of directional inhibition, as required for a voltage-clamp artifact. These results implicate additional mechanisms in generating directional excitatory inputs to DSGCs.
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Affiliation(s)
- Kumiko A Percival
- Department of Ophthalmology, Casey Eye Institute, Oregon Health & Science University, Portland, Oregon
| | - Sowmya Venkataramani
- Department of Ophthalmology, Casey Eye Institute, Oregon Health & Science University, Portland, Oregon
| | - Robert G Smith
- Department of Neuroscience, University of Pennsylvania, Philadelphia, Pennsylvania
| | - W Rowland Taylor
- Department of Ophthalmology, Casey Eye Institute, Oregon Health & Science University, Portland, Oregon
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27
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Franke K, Berens P, Schubert T, Bethge M, Euler T, Baden T. Inhibition decorrelates visual feature representations in the inner retina. Nature 2017; 542:439-444. [PMID: 28178238 PMCID: PMC5325673 DOI: 10.1038/nature21394] [Citation(s) in RCA: 142] [Impact Index Per Article: 20.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2016] [Accepted: 01/18/2017] [Indexed: 01/25/2023]
Abstract
The retina extracts visual features for transmission to the brain. Different types of bipolar cell split the photoreceptor input into parallel channels and provide the excitatory drive for downstream visual circuits. Anatomically and genetically, mouse bipolar cell types have been described at great detail, but a similarly deep understanding of their functional diversity is lacking. By imaging light-driven glutamate release from more than 13,000 bipolar cell axon terminals in the intact retina, we here show that bipolar cell functional diversity is generated by the interplay of dendritic excitatory inputs and axonal inhibitory inputs. The resultant centre and surround components of bipolar cell receptive fields interact to decorrelate bipolar cell output in the spatial and temporal domain. Our findings highlight the importance of inhibitory circuits in generating functionally diverse excitatory pathways and suggest that decorrelation of parallel visual pathways begins already at the second synapse of the mouse visual system.
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Affiliation(s)
- Katrin Franke
- Centre for Integrative Neuroscience, University of Tübingen, Tübingen, Germany.,Bernstein Centre for Computational Neuroscience, University of Tübingen, Tübingen, Germany.,Institute for Ophthalmic Research, University of Tübingen, Tübingen, Germany.,Graduate School of Neural &Behavioural Sciences, International Max Planck Research School, University of Tübingen, Tübingen, Germany
| | - Philipp Berens
- Centre for Integrative Neuroscience, University of Tübingen, Tübingen, Germany.,Bernstein Centre for Computational Neuroscience, University of Tübingen, Tübingen, Germany.,Institute for Ophthalmic Research, University of Tübingen, Tübingen, Germany
| | - Timm Schubert
- Centre for Integrative Neuroscience, University of Tübingen, Tübingen, Germany.,Institute for Ophthalmic Research, University of Tübingen, Tübingen, Germany
| | - Matthias Bethge
- Centre for Integrative Neuroscience, University of Tübingen, Tübingen, Germany.,Bernstein Centre for Computational Neuroscience, University of Tübingen, Tübingen, Germany.,Institute for Theoretical Physics, University of Tübingen, Tübingen, Germany.,Max Planck Institute of Biological Cybernetics, Tübingen, Germany
| | - Thomas Euler
- Centre for Integrative Neuroscience, University of Tübingen, Tübingen, Germany.,Bernstein Centre for Computational Neuroscience, University of Tübingen, Tübingen, Germany.,Institute for Ophthalmic Research, University of Tübingen, Tübingen, Germany
| | - Tom Baden
- Centre for Integrative Neuroscience, University of Tübingen, Tübingen, Germany.,Bernstein Centre for Computational Neuroscience, University of Tübingen, Tübingen, Germany.,Institute for Ophthalmic Research, University of Tübingen, Tübingen, Germany.,School of Life Sciences, University of Sussex, Brighton, UK
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28
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Vlasits AL, Morrie RD, Tran-Van-Minh A, Bleckert A, Gainer CF, DiGregorio DA, Feller MB. A Role for Synaptic Input Distribution in a Dendritic Computation of Motion Direction in the Retina. Neuron 2016; 89:1317-1330. [PMID: 26985724 DOI: 10.1016/j.neuron.2016.02.020] [Citation(s) in RCA: 65] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2015] [Revised: 12/22/2015] [Accepted: 02/10/2016] [Indexed: 12/21/2022]
Abstract
The starburst amacrine cell in the mouse retina presents an opportunity to examine the precise role of sensory input location on neuronal computations. Using visual receptive field mapping, glutamate uncaging, two-photon Ca(2+) imaging, and genetic labeling of putative synapses, we identify a unique arrangement of excitatory inputs and neurotransmitter release sites on starburst amacrine cell dendrites: the excitatory input distribution is skewed away from the release sites. By comparing computational simulations with Ca(2+) transients recorded near release sites, we show that this anatomical arrangement of inputs and outputs supports a dendritic mechanism for computing motion direction. Direction-selective Ca(2+) transients persist in the presence of a GABA-A receptor antagonist, though the directional tuning is reduced. These results indicate a synergistic interaction between dendritic and circuit mechanisms for generating direction selectivity in the starburst amacrine cell.
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Affiliation(s)
- Anna L Vlasits
- Helen Wills Neuroscience Institute, University of California, Berkeley, Berkeley, CA 94720, USA
| | - Ryan D Morrie
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA 94720, USA
| | - Alexandra Tran-Van-Minh
- Unit of Dynamic Neuronal Imaging, Institut Pasteur, 75724 Paris Cedex 15, France; Centre National de la Recherche Scientifique, Unité Mixte de Recherche 3571, 75724 Paris Cedex 15, France
| | - Adam Bleckert
- Department of Biological Structure, University of Washington, Seattle, WA 98195, USA
| | - Christian F Gainer
- Department of Optometry, University of California, Berkeley, Berkeley, CA 94704, USA
| | - David A DiGregorio
- Unit of Dynamic Neuronal Imaging, Institut Pasteur, 75724 Paris Cedex 15, France; Centre National de la Recherche Scientifique, Unité Mixte de Recherche 3571, 75724 Paris Cedex 15, France.
| | - Marla B Feller
- Helen Wills Neuroscience Institute, University of California, Berkeley, Berkeley, CA 94720, USA; Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA 94720, USA.
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29
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Morrie RD, Feller MB. Development of synaptic connectivity in the retinal direction selective circuit. Curr Opin Neurobiol 2016; 40:45-52. [PMID: 27380013 DOI: 10.1016/j.conb.2016.06.009] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2016] [Revised: 05/07/2016] [Accepted: 06/21/2016] [Indexed: 12/26/2022]
Abstract
Direction selectivity is a classic neuronal computation that has been described in many different sensory systems. The circuit basis of this computation is perhaps best understood in the retina, where direction selectivity is the result of asymmetric connectivity patterns between excitatory and inhibitory circuit components. Retinal direction selective circuits emerge before eye-opening, though components of the circuit undergo refinement after vision begins. These features make the direction selective circuit a rich model in which to investigate neuronal circuit assembly. In this Opinion, we highlight recent experiments investigating the contribution of various molecular cues, as well as neuronal activity, to the development of the retinal direction selective circuit.
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Affiliation(s)
- Ryan D Morrie
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA 94720-3200, United States
| | - Marla B Feller
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA 94720-3200, United States; Helen Wills Neuroscience Institute, University of California, Berkeley, Berkeley, CA 94720-3200, United States.
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30
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Species-specific wiring for direction selectivity in the mammalian retina. Nature 2016; 535:105-10. [PMID: 27350241 PMCID: PMC4959608 DOI: 10.1038/nature18609] [Citation(s) in RCA: 130] [Impact Index Per Article: 16.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2015] [Accepted: 05/27/2016] [Indexed: 12/17/2022]
Abstract
Directionally tuned signaling in starburst amacrine cell (SAC) dendrites lies at the heart of the direction selective (DS) circuit in the mammalian retina. The relative contributions of intrinsic cellular properties and network connectivity to SAC DS remain unclear. We present a detailed connectomic reconstruction of SAC circuitry in mouse retina and describe previously unknown features of synapse distributions along SAC dendrites: 1) input and output synapses are segregated, with inputs restricted to proximal dendrites; 2) the distribution of inhibitory inputs is fundamentally different from that observed in rabbit retina. An anatomically constrained SAC network model suggests that SAC-SAC wiring differences between mouse and rabbit retina underlie distinct contributions of synaptic inhibition to velocity and contrast tuning and receptive field structure. In particular, the model indicates that mouse connectivity enables SACs to encode lower linear velocities that account for smaller eye diameter, thereby conserving angular velocity tuning. These predictions are confirmed with calcium imaging of mouse SAC dendrites in response to directional stimuli.
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31
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NMDA Receptors Multiplicatively Scale Visual Signals and Enhance Directional Motion Discrimination in Retinal Ganglion Cells. Neuron 2016; 89:1277-1290. [PMID: 26948896 DOI: 10.1016/j.neuron.2016.02.013] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2015] [Revised: 11/25/2015] [Accepted: 01/15/2016] [Indexed: 11/24/2022]
Abstract
Postsynaptic responses in many CNS neurons are typically small and variable, often making it difficult to distinguish physiologically relevant signals from background noise. To extract salient information, neurons are thought to integrate multiple synaptic inputs and/or selectively amplify specific synaptic activation patterns. Here, we present evidence for a third strategy: directionally selective ganglion cells (DSGCs) in the mouse retina multiplicatively scale visual signals via a mechanism that requires both nonlinear NMDA receptor (NMDAR) conductances in DSGC dendrites and directionally tuned inhibition provided by the upstream retinal circuitry. Postsynaptic multiplication enables DSGCs to discriminate visual motion more accurately in noisy visual conditions without compromising directional tuning. These findings demonstrate a novel role for NMDARs in synaptic processing and provide new insights into how synaptic and network features interact to accomplish physiologically relevant neural computations.
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32
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Analogous Convergence of Sustained and Transient Inputs in Parallel On and Off Pathways for Retinal Motion Computation. Cell Rep 2016; 14:1892-900. [PMID: 26904938 PMCID: PMC6404534 DOI: 10.1016/j.celrep.2016.02.001] [Citation(s) in RCA: 71] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2015] [Revised: 11/20/2015] [Accepted: 01/23/2016] [Indexed: 02/03/2023] Open
Abstract
Visual motion information is computed by parallel On and Off pathways in the retina, which lead to On and Off types of starburst amacrine cells (SACs). The approximate mirror symmetry between this pair of cell types suggests that On and Off pathways might compute motion using analogous mechanisms. To test this idea, we reconstructed On SACs and On bipolar cells (BCs) from serial electron microscopic images of a mouse retina. We defined a new On BC type in the course of classifying On BCs. Through quantitative contact analysis, we found evidence that sustained and transient On BC types are wired to On SAC dendrites at different distances from the SAC soma, mirroring our previous wiring diagram for the Off BC-SAC circuit. Our finding is consistent with the hypothesis that On and Off pathways contain parallel correlation-type motion detectors. Greene et al. find that in the mouse retina, sustained and transient On bipolar cell (BC) types are wired to dendrites of On starburst amacrine cells (SACs) at different distances from the SAC soma. This wiring specificity may support retinal computation of the direction of a moving stimulus.
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Conditional Knock-Out of Vesicular GABA Transporter Gene from Starburst Amacrine Cells Reveals the Contributions of Multiple Synaptic Mechanisms Underlying Direction Selectivity in the Retina. J Neurosci 2015; 35:13219-32. [PMID: 26400950 DOI: 10.1523/jneurosci.0933-15.2015] [Citation(s) in RCA: 55] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Direction selectivity of direction-selective ganglion cells (DSGCs) in the retina results from patterned excitatory and inhibitory inputs onto DSGCs during motion stimuli. The inhibitory inputs onto DSGCs are directionally tuned to the antipreferred (null) direction and therefore potently suppress spiking during motion in the null direction. However, whether direction-selective inhibition is indispensable for direction selectivity is unclear. Here, we selectively eliminated the directional tuning of inhibitory inputs onto DSGCs by disrupting GABA release from the presynaptic interneuron starburst amacrine cell in the mouse retina. We found that, even without directionally tuned inhibition, direction selectivity can still be implemented in a subset of On-Off DSGCs by direction-selective excitation and a temporal offset between excitation and isotropic inhibition. Our results therefore demonstrate the concerted action of multiple synaptic mechanisms for robust direction selectivity in the retina. Significance statement: The direction-selective circuit in the retina has been a classic model to study neural computations by the brain. An important but unresolved question is how direction selectivity is implemented by directionally tuned excitatory and inhibitory mechanisms. Here we specifically removed the direction tuning of inhibition from the circuit. We found that direction tuning of inhibition is important but not indispensable for direction selectivity of DSGCs' spiking activity, and that the residual direction selectivity is implemented by direction-selective excitation and temporal offset between excitation and inhibition. Our results highlight the concerted actions of synaptic excitation and inhibition required for robust direction selectivity in the retina and provide critical insights into how patterned excitation and inhibition collectively implement sensory processing.
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34
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Hellmer CB, Zhou Y, Fyk-Kolodziej B, Hu Z, Ichinose T. Morphological and physiological analysis of type-5 and other bipolar cells in the Mouse Retina. Neuroscience 2015; 315:246-58. [PMID: 26704635 DOI: 10.1016/j.neuroscience.2015.12.016] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2015] [Revised: 12/06/2015] [Accepted: 12/09/2015] [Indexed: 11/17/2022]
Abstract
Retinal bipolar cells are second-order neurons in the visual system, which initiate multiple image feature-based neural streams. Among more than ten types of bipolar cells, type-5 cells are thought to play a role in motion detection pathways. Multiple subsets of type-5 cells have been reported; however, detailed characteristics of each subset have not yet been elucidated. Here, we found that they exhibit distinct morphological features as well as unique voltage-gated channel expression. We have conducted electrophysiological and immunohistochemical analysis of retinal bipolar cells. We defined type-5 cells by their axon terminal ramification in the inner plexiform layer between the border of ON/OFF sublaminae and the ON choline acetyltransferase (ChAT) band. We found three subsets of type-5 cells: XBCs had the widest axon terminals that stratified at a close approximation of the ON ChAT band as well as exhibiting large voltage-gated Na(+) channel activity, type-5-1 cells had compact terminals and no Na(+) channel activity, and type-5-2 cells contained umbrella-shaped terminals as well as large voltage-gated Na(+) channel activity. Hyperpolarization-activated cyclic nucleotide-gated (HCN) currents were also evoked in all type-5 bipolar cells. We found that XBCs and type-5-2 cells exhibited larger HCN currents than type-5-1 cells. Furthermore, the former two types showed stronger HCN1 expression than the latter. Our previous observations (Ichinose et al., 2014) match the current study: low temporal tuning cells that we named 5S corresponded to 5-1 in this study, while high temporal tuning 5f cells from the previous study corresponded to 5-2 cells. Taken together, we found three subsets of type-5 bipolar cells based on their morphologies and physiological features.
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Affiliation(s)
- C B Hellmer
- Department of Anatomy and Cell Biology, Wayne State University School of Medicine, Detroit, MI 48201, United States
| | - Y Zhou
- Department of Otolaryngology, Wayne State University School of Medicine, Detroit, MI 48201, United States
| | - B Fyk-Kolodziej
- Department of Anatomy and Cell Biology, Wayne State University School of Medicine, Detroit, MI 48201, United States
| | - Z Hu
- Department of Otolaryngology, Wayne State University School of Medicine, Detroit, MI 48201, United States
| | - T Ichinose
- Department of Anatomy and Cell Biology, Wayne State University School of Medicine, Detroit, MI 48201, United States; Department of Ophthalmology, Wayne State University School of Medicine, Detroit, MI 48201, United States.
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35
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Purgert RJ, Lukasiewicz PD. Differential encoding of spatial information among retinal on cone bipolar cells. J Neurophysiol 2015. [PMID: 26203104 DOI: 10.1152/jn.00287.2015] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
The retina is the first stage of visual processing. It encodes elemental features of visual scenes. Distinct cone bipolar cells provide the substrate for this to occur. They encode visual information, such as color and luminance, a principle known as parallel processing. Few studies have directly examined whether different forms of spatial information are processed in parallel among cone bipolar cells. To address this issue, we examined the spatial information encoded by mouse ON cone bipolar cells, the subpopulation excited by increments in illumination. Two types of spatial processing were identified. We found that ON cone bipolar cells with axons ramifying in the central inner plexiform layer were tuned to preferentially encode small stimuli. By contrast, ON cone bipolar cells with axons ramifying in the proximal inner plexiform layer, nearest the ganglion cell layer, were tuned to encode both small and large stimuli. This dichotomy in spatial tuning is attributable to amacrine cells providing stronger inhibition to central ON cone bipolar cells compared with proximal ON cone bipolar cells. Furthermore, background illumination altered this difference in spatial tuning. It became less pronounced in bright light, as amacrine cell-driven inhibition became pervasive among all ON cone bipolar cells. These results suggest that differential amacrine cell input determined the distinct spatial encoding properties among ON cone bipolar cells. These findings enhance the known parallel processing capacity of the retina.
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Affiliation(s)
- Robert J Purgert
- Department of Ophthalmology and Visual Sciences, Washington University School of Medicine, St. Louis, Missouri; and
| | - Peter D Lukasiewicz
- Department of Ophthalmology and Visual Sciences, Washington University School of Medicine, St. Louis, Missouri; and Department of Anatomy and Neurobiology, Washington University School of Medicine, St. Louis, Missouri
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36
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Hoggarth A, McLaughlin AJ, Ronellenfitch K, Trenholm S, Vasandani R, Sethuramanujam S, Schwab D, Briggman KL, Awatramani GB. Specific wiring of distinct amacrine cells in the directionally selective retinal circuit permits independent coding of direction and size. Neuron 2015; 86:276-91. [PMID: 25801705 DOI: 10.1016/j.neuron.2015.02.035] [Citation(s) in RCA: 56] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2014] [Revised: 11/13/2014] [Accepted: 02/11/2015] [Indexed: 01/24/2023]
Abstract
Local and global forms of inhibition controlling directionally selective ganglion cells (DSGCs) in the mammalian retina are well documented. It is established that local inhibition arising from GABAergic starburst amacrine cells (SACs) strongly contributes to direction selectivity. Here, we demonstrate that increasing ambient illumination leads to the recruitment of GABAergic wide-field amacrine cells (WACs) endowing the DS circuit with an additional feature: size selectivity. Using a combination of electrophysiology, pharmacology, and light/electron microscopy, we show that WACs predominantly contact presynaptic bipolar cells, which drive direct excitation and feedforward inhibition (through SACs) to DSGCs, thus maintaining the appropriate balance of inhibition/excitation required for generating DS. This circuit arrangement permits high-fidelity direction coding over a range of ambient light levels, over which size selectivity is adjusted. Together, these results provide novel insights into the anatomical and functional arrangement of multiple inhibitory interneurons within a single computational module in the retina.
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Affiliation(s)
- Alex Hoggarth
- Department of Biology, University of Victoria, Victoria, BC V8W 3N5, Canada
| | | | - Kara Ronellenfitch
- Department of Biology, University of Victoria, Victoria, BC V8W 3N5, Canada
| | - Stuart Trenholm
- Department of Biology, University of Victoria, Victoria, BC V8W 3N5, Canada
| | - Rishi Vasandani
- Department of Biology, University of Victoria, Victoria, BC V8W 3N5, Canada
| | | | - David Schwab
- Department of Physics & Astronomy, Northwestern University, 2145 Sheridan Road F165, Evanston, IL 60208, USA
| | - Kevin L Briggman
- Circuit Dynamics and Connectivity Unit, National Institutes of Health, Bethesda, MD 20892, USA
| | - Gautam B Awatramani
- Department of Biology, University of Victoria, Victoria, BC V8W 3N5, Canada.
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