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Famiglietti EV. Mammalian Retinal Bipolar Cells: Morphological Identification and Systematic Classification in Rabbit Retina. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.09.19.613998. [PMID: 39345639 PMCID: PMC11429971 DOI: 10.1101/2024.09.19.613998] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/01/2024]
Abstract
Retinal bipolar cells (BCs) convey visual signals from photoreceptors to more than 50 types of rabbit retinal ganglion cells (Famiglietti, 2020). More than 40 years ago, 10-11 types of bipolar cell were recognized in rabbit and cat retinas (Famiglietti, 1981). Twenty years later 10 were identified in mouse, rat, and monkey (Gosh et al., 2004), while recent molecular genetic studies indicate that there are 15 types of bipolar cell in mouse retina (Shekhar et al., 2016). The present detailed study of more than 800 bipolar cells in ten Golgi-impregnated rabbit retinas indicates that there are 14-16 types of cone bipolar cell and one type of rod bipolar cell in rabbit retina. These have been carefully analyzed in terms of dendritic and axonal morphology, and axon terminal stratification with respect to fiducial starburst amacrine cells. In fortuitous proximity, several types of bipolar cell can be related to identified ganglion cells by stratification and by contacts suggestive of synaptic connection. These results are compared with other studies of rabbit bipolar cells. Homologies with bipolar cells of mouse and monkey are considered in functional terms.
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Sigulinsky CL, Pfeiffer RL, Jones BW. Retinal Connectomics: A Review. Annu Rev Vis Sci 2024; 10:263-291. [PMID: 39292552 DOI: 10.1146/annurev-vision-102122-110414] [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] [Indexed: 09/20/2024]
Abstract
The retina is an ideal model for understanding the fundamental rules for how neural networks are constructed. The compact neural networks of the retina perform all of the initial processing of visual information before transmission to higher visual centers in the brain. The field of retinal connectomics uses high-resolution electron microscopy datasets to map the intricate organization of these networks and further our understanding of how these computations are performed by revealing the fundamental topologies and allowable networks behind retinal computations. In this article, we review some of the notable advances that retinal connectomics has provided in our understanding of the specific cells and the organization of their connectivities within the retina, as well as how these are shaped in development and break down in disease. Using these anatomical maps to inform modeling has been, and will continue to be, instrumental in understanding how the retina processes visual signals.
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Affiliation(s)
- Crystal L Sigulinsky
- Department of Ophthalmology and Visual Sciences, John Moran Eye Center, University of Utah, Salt Lake City, Utah, USA;
| | - Rebecca L Pfeiffer
- Department of Ophthalmology and Visual Sciences, John Moran Eye Center, University of Utah, Salt Lake City, Utah, USA;
| | - Bryan William Jones
- Department of Ophthalmology and Visual Sciences, John Moran Eye Center, University of Utah, Salt Lake City, Utah, USA;
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Chander PR, Hanson L, Chundekkad P, Awatramani GB. Neural Circuits Underlying Multifeature Extraction in the Retina. J Neurosci 2024; 44:e0910232023. [PMID: 37957014 PMCID: PMC10919202 DOI: 10.1523/jneurosci.0910-23.2023] [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: 05/17/2023] [Revised: 08/31/2023] [Accepted: 09/13/2023] [Indexed: 11/21/2023] Open
Abstract
Classic ON-OFF direction-selective ganglion cells (DSGCs) that encode the four cardinal directions were recently shown to also be orientation-selective. To clarify the mechanisms underlying orientation selectivity, we employed a variety of electrophysiological, optogenetic, and gene knock-out strategies to test the relative contributions of glutamate, GABA, and acetylcholine (ACh) input that are known to drive DSGCs, in male and female mouse retinas. Extracellular spike recordings revealed that DSGCs respond preferentially to either vertical or horizontal bars, those that are perpendicular to their preferred-null motion axes. By contrast, the glutamate input to all four DSGC types measured using whole-cell patch-clamp techniques was found to be tuned along the vertical axis. Tuned glutamatergic excitation was heavily reliant on type 5A bipolar cells, which appear to be electrically coupled via connexin 36 containing gap junctions to the vertically oriented processes of wide-field amacrine cells. Vertically tuned inputs are transformed by the GABAergic/cholinergic "starburst" amacrine cells (SACs), which are critical components of the direction-selective circuit, into distinct patterns of inhibition and excitation. Feed-forward SAC inhibition appears to "veto" preferred orientation glutamate excitation in dorsal/ventral (but not nasal/temporal) coding DSGCs "flipping" their orientation tuning by 90° and accounts for the apparent mismatch between glutamate input tuning and the DSGC's spiking response. Together, these results reveal how two distinct synaptic motifs interact to generate complex feature selectivity, shedding light on the intricate circuitry that underlies visual processing in the retina.
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Affiliation(s)
| | - Laura Hanson
- Department of Biology, University of Victoria, Victoria, British Columbia V8W 4A4, Canada
| | - Pavitra Chundekkad
- Department of Biology, University of Victoria, Victoria, British Columbia V8W 4A4, Canada
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Acarón Ledesma H, Ding J, Oosterboer S, Huang X, Chen Q, Wang S, Lin MZ, Wei W. Dendritic mGluR2 and perisomatic Kv3 signaling regulate dendritic computation of mouse starburst amacrine cells. Nat Commun 2024; 15:1819. [PMID: 38418467 PMCID: PMC10901804 DOI: 10.1038/s41467-024-46234-7] [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: 12/13/2021] [Accepted: 02/20/2024] [Indexed: 03/01/2024] Open
Abstract
Dendritic mechanisms driving input-output transformation in starburst amacrine cells (SACs) are not fully understood. Here, we combine two-photon subcellular voltage and calcium imaging and electrophysiological recording to determine the computational architecture of mouse SAC dendrites. We found that the perisomatic region integrates motion signals over the entire dendritic field, providing a low-pass-filtered global depolarization to dendrites. Dendrites integrate local synaptic inputs with this global signal in a direction-selective manner. Coincidental local synaptic inputs and the global motion signal in the outward motion direction generate local suprathreshold calcium transients. Moreover, metabotropic glutamate receptor 2 (mGluR2) signaling in SACs modulates the initiation of calcium transients in dendrites but not at the soma. In contrast, voltage-gated potassium channel 3 (Kv3) dampens fast voltage transients at the soma. Together, complementary mGluR2 and Kv3 signaling in different subcellular regions leads to dendritic compartmentalization and direction selectivity, highlighting the importance of these mechanisms in dendritic computation.
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Affiliation(s)
- Héctor Acarón Ledesma
- Graduate Program in Biophysical Sciences, The University of Chicago, Chicago, IL, 60637, USA
- F.M. Kirby Neurobiology Center, Boston Children's Hospital, Harvard Medical School, Boston, MA, 02115, USA
| | - Jennifer Ding
- The Committee on Neurobiology Graduate Program, The University of Chicago, Chicago, IL, 60637, USA
- Department of Neurobiology, Harvard Medical School, Boston, MA, 02115, USA
| | - Swen Oosterboer
- The Committee on Neurobiology Graduate Program, The University of Chicago, Chicago, IL, 60637, USA
| | - Xiaolin Huang
- The Committee on Neurobiology Graduate Program, The University of Chicago, Chicago, IL, 60637, USA
- Division of Neurobiology, Department of Molecular and Cell Biology, Helen Wills Neuroscience Institute, University of California, Berkeley, CA, 94720, USA
| | - Qiang Chen
- The Committee on Computational Neuroscience Graduate Program, The University of Chicago, Chicago, IL, 60637, USA
- Department of Physiology & Biophysics, University of Washington, Seattle, WA, 98195, USA
| | - Sui Wang
- Department of Ophthalmology, Stanford University, Stanford, CA, 94305, USA
| | - Michael Z Lin
- Department of Neurobiology, Department of Bioengineering, Stanford University, Stanford, CA, 94305, USA
| | - Wei Wei
- Department of Neurobiology and the Neuroscience Institute, The University of Chicago, Chicago, IL, 60637, USA.
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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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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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Wu J, Kim YJ, Dacey DM, Troy JB, Smith RG. Two mechanisms for direction selectivity in a model of the primate starburst amacrine cell. Vis Neurosci 2023; 40:E003. [PMID: 37218623 PMCID: PMC10207453 DOI: 10.1017/s0952523823000019] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2022] [Revised: 04/25/2023] [Accepted: 04/25/2023] [Indexed: 05/24/2023]
Abstract
In a recent study, visual signals were recorded for the first time in starburst amacrine cells of the macaque retina, and, as for mouse and rabbit, a directional bias observed in calcium signals was recorded from near the dendritic tips. Stimulus motion from the soma toward the tip generated a larger calcium signal than motion from the tip toward the soma. Two mechanisms affecting the spatiotemporal summation of excitatory postsynaptic currents have been proposed to contribute to directional signaling at the dendritic tips of starbursts: (1) a "morphological" mechanism in which electrotonic propagation of excitatory synaptic currents along a dendrite sums bipolar cell inputs at the dendritic tip preferentially for stimulus motion in the centrifugal direction; (2) a "space-time" mechanism that relies on differences in the time-courses of proximal and distal bipolar cell inputs to favor centrifugal stimulus motion. To explore the contributions of these two mechanisms in the primate, we developed a realistic computational model based on connectomic reconstruction of a macaque starburst cell and the distribution of its synaptic inputs from sustained and transient bipolar cell types. Our model suggests that both mechanisms can initiate direction selectivity in starburst dendrites, but their contributions differ depending on the spatiotemporal properties of the stimulus. Specifically, the morphological mechanism dominates when small visual objects are moving at high velocities, and the space-time mechanism contributes most for large visual objects moving at low velocities.
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Affiliation(s)
- Jiajia Wu
- Department of Biomedical Engineering, Northwestern University, Evanston, IL, USA
| | - Yeon Jin Kim
- Department of Biological Structure, Washington National Primate Research Center, University of Washington, Seattle, WA, USA
| | - Dennis M. Dacey
- Department of Biological Structure, Washington National Primate Research Center, University of Washington, Seattle, WA, USA
| | - John B. Troy
- Department of Biomedical Engineering, Northwestern University, Evanston, IL, USA
| | - Robert G. Smith
- Department of Neuroscience, University of Pennsylvania, Philadelphia, PA, USA
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Hanson L, Ravi-Chander P, Berson D, Awatramani GB. Hierarchical retinal computations rely on hybrid chemical-electrical signaling. Cell Rep 2023; 42:112030. [PMID: 36696265 DOI: 10.1016/j.celrep.2023.112030] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2022] [Revised: 11/08/2022] [Accepted: 01/10/2023] [Indexed: 01/26/2023] Open
Abstract
Bipolar cells (BCs) are integral to the retinal circuits that extract diverse features from the visual environment. They bridge photoreceptors to ganglion cells, the source of retinal output. Understanding how such circuits encode visual features requires an accounting of the mechanisms that control glutamate release from bipolar cell axons. Here, we demonstrate orientation selectivity in a specific genetically identifiable type of mouse bipolar cell-type 5A (BC5A). Their synaptic terminals respond best when stimulated with vertical bars that are far larger than their dendritic fields. We provide evidence that this selectivity involves enhanced excitation for vertical stimuli that requires gap junctional coupling through connexin36. We also show that this orientation selectivity is detectable postsynaptically in direction-selective ganglion cells, which were not previously thought to be selective for orientation. Together, these results demonstrate how multiple features are extracted by a single hierarchical network, engaging distinct electrical and chemical synaptic pathways.
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Affiliation(s)
- Laura Hanson
- Department of Biology, University of Victoria, Victoria, BC V8W 3N5, Canada
| | | | - David Berson
- Department of Neuroscience, Brown University, Providence, RI 02912, USA
| | - Gautam B Awatramani
- Department of Biology, University of Victoria, Victoria, BC V8W 3N5, Canada.
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Srivastava P, de Rosenroll G, Matsumoto A, Michaels T, Turple Z, Jain V, Sethuramanujam S, Murphy-Baum BL, Yonehara K, Awatramani GB. Spatiotemporal properties of glutamate input support direction selectivity in the dendrites of retinal starburst amacrine cells. eLife 2022; 11:81533. [PMID: 36346388 PMCID: PMC9674338 DOI: 10.7554/elife.81533] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2022] [Accepted: 11/02/2022] [Indexed: 11/09/2022] Open
Abstract
The asymmetric summation of kinetically distinct glutamate inputs across the dendrites of retinal 'starburst' amacrine cells is one of the several mechanisms that have been proposed to underlie their direction-selective properties, but experimentally verifying input kinetics has been a challenge. Here, we used two-photon glutamate sensor (iGluSnFR) imaging to directly measure the input kinetics across individual starburst dendrites. We found that signals measured from proximal dendrites were relatively sustained compared to those measured from distal dendrites. These differences were observed across a range of stimulus sizes and appeared to be shaped mainly by excitatory rather than inhibitory network interactions. Temporal deconvolution analysis suggests that the steady-state vesicle release rate was ~3 times larger at proximal sites compared to distal sites. Using a connectomics-inspired computational model, we demonstrate that input kinetics play an important role in shaping direction selectivity at low stimulus velocities. Taken together, these results provide direct support for the 'space-time wiring' model for direction selectivity.
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Affiliation(s)
| | | | - Akihiro Matsumoto
- Danish Research Institute of Translational Neuroscience, Nordic-EMBL Partnership for Molecular Medicine, Department of Biomedicine, Aarhus UniversityAarhusDenmark
| | - Tracy Michaels
- Department of Biology, University of VictoriaVictoriaCanada
| | - Zachary Turple
- Department of Biology, University of VictoriaVictoriaCanada
| | - Varsha Jain
- Department of Biology, University of VictoriaVictoriaCanada
| | | | | | - Keisuke Yonehara
- Danish Research Institute of Translational Neuroscience, Nordic-EMBL Partnership for Molecular Medicine, Department of Biomedicine, Aarhus UniversityAarhusDenmark
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