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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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2
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Souihel S, Cessac B. On the potential role of lateral connectivity in retinal anticipation. JOURNAL OF MATHEMATICAL NEUROSCIENCE 2021; 11:3. [PMID: 33420903 PMCID: PMC7796858 DOI: 10.1186/s13408-020-00101-z] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 08/24/2020] [Accepted: 12/15/2020] [Indexed: 06/12/2023]
Abstract
We analyse the potential effects of lateral connectivity (amacrine cells and gap junctions) on motion anticipation in the retina. Our main result is that lateral connectivity can-under conditions analysed in the paper-trigger a wave of activity enhancing the anticipation mechanism provided by local gain control (Berry et al. in Nature 398(6725):334-338, 1999; Chen et al. in J. Neurosci. 33(1):120-132, 2013). We illustrate these predictions by two examples studied in the experimental literature: differential motion sensitive cells (Baccus and Meister in Neuron 36(5):909-919, 2002) and direction sensitive cells where direction sensitivity is inherited from asymmetry in gap junctions connectivity (Trenholm et al. in Nat. Neurosci. 16:154-156, 2013). We finally present reconstructions of retinal responses to 2D visual inputs to assess the ability of our model to anticipate motion in the case of three different 2D stimuli.
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Affiliation(s)
- Selma Souihel
- Biovision Team and Neuromod Institute, Inria, Université Côte d'Azur, Nice, France.
| | - Bruno Cessac
- Biovision Team and Neuromod Institute, Inria, Université Côte d'Azur, Nice, France
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3
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Franke K, Baden T. General features of inhibition in the inner retina. J Physiol 2017; 595:5507-5515. [PMID: 28332227 PMCID: PMC5556161 DOI: 10.1113/jp273648] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2016] [Accepted: 02/08/2017] [Indexed: 11/08/2022] Open
Abstract
Visual processing starts in the retina. Within only two synaptic layers, a large number of parallel information channels emerge, each encoding a highly processed feature like edges or the direction of motion. Much of this functional diversity arises in the inner plexiform layer, where inhibitory amacrine cells modulate the excitatory signal of bipolar and ganglion cells. Studies investigating individual amacrine cell circuits like the starburst or A17 circuit have demonstrated that single types can possess specific morphological and functional adaptations to convey a particular function in one or a small number of inner retinal circuits. However, the interconnected and often stereotypical network formed by different types of amacrine cells across the inner plexiform layer prompts that they should be also involved in more general computations. In line with this notion, different recent studies systematically analysing inner retinal signalling at a population level provide evidence that general functions of the ensemble of amacrine cells across types are critical for establishing universal principles of retinal computation like parallel processing or motion anticipation. Combining recent advances in the development of indicators for imaging inhibition with large-scale morphological and genetic classifications will help to further our understanding of how single amacrine cell circuits act together to help decompose the visual scene into parallel information channels. In this review, we aim to summarise the current state-of-the-art in our understanding of how general features of amacrine cell inhibition lead to general features of computation.
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Affiliation(s)
- Katrin Franke
- Centre for Integrative NeuroscienceUniversity of TübingenGermany
- Institute for Ophthalmic ResearchTübingenGermany
- Bernstein Centre for Computational NeuroscienceTübingenGermany
| | - Tom Baden
- Institute for Ophthalmic ResearchTübingenGermany
- School of Life SciencesUniversity of SussexBrightonUK
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4
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Lee JS, Kim HJ, Ahn CH, Jeon CJ. Expression of Nicotinic Acetylcholine Receptor α4 and β2 Subunits on Direction-Selective Retinal Ganglion Cells in the Rabbit. Acta Histochem Cytochem 2017; 50:29-37. [PMID: 28386148 PMCID: PMC5374101 DOI: 10.1267/ahc.16024] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2016] [Accepted: 12/26/2016] [Indexed: 11/22/2022] Open
Abstract
The direction selectivity of the retina is a distinct mechanism that is critical function of eyes for survival. The direction-selective retinal ganglion cells (DS RGCs) strongly respond to a preferred direction, but rarely respond to opposite direction or null directional visual stimuli. The DS RGCs are sensitive to acetylcholine, which is secreted from starburst amacrine cells (SACs) to the DS RGCs. Here, we investigated the existence and distribution of the nicotinic acetylcholine receptor (nAChR) α4 and β2 subunits on the dendritic arbors of the DS RGCs in adult rabbit retina using immunocytochemistry. The DS RGCs were injected with Lucifer yellow to identify their dendritic morphology. The double-labeled images of dendrites and nAChR subunits were visualized for reconstruction using high-resolution confocal microscopy. Although our results revealed that the distributional pattern of the nAChR subunits on the dendritic arbors of the DS RGCs was not asymmetric in the adult rabbit retina, the distribution of nAChR α4 and β2 subunits and molecular profiles of cholinergic inputs to DS RGCs in adult rabbit retina provide anatomical evidence for direction selectivity.
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Affiliation(s)
- Jun-Seok Lee
- Department of Biology, School of Life Sciences, BK21 Plus KNU Creative BioResearch Group, College of Natural Sciences, and Brain Science and Engineering Institute, Kyungpook National University
| | - Hyun-Jin Kim
- Department of Life Sciences, Pohang University of Science and Technology
| | - Chang-Hyun Ahn
- Department of Biology, School of Life Sciences, BK21 Plus KNU Creative BioResearch Group, College of Natural Sciences, and Brain Science and Engineering Institute, Kyungpook National University
| | - Chang-Jin Jeon
- Department of Biology, School of Life Sciences, BK21 Plus KNU Creative BioResearch Group, College of Natural Sciences, and Brain Science and Engineering Institute, Kyungpook National University
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5
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Abstract
Abstract
How direction of image motion is detected as early as at the level of the vertebrate eye has been intensively studied in retina research. Although the first direction-selective (DS) retinal ganglion cells were already described in the 1960s and have since then been in the focus of many studies, scientists are still puzzled by the intricacy of the neuronal circuits and computational mechanisms underlying retinal direction selectivity. The fact that the retina can be easily isolated and studied in a Petri dish-by presenting light stimuli while recording from the various cell types in the retinal circuits-in combination with the extensive anatomical, molecular and physiological knowledge about this part of the brain presents a unique opportunity for studying this intriguing visual circuit in detail. This article provides a brief overview of the history of research on retinal direction selectivity, but then focuses on the past decade and the progress achieved, in particular driven by methodological advances in optical recording techniques, molecular genetics approaches and large-scale ultrastructural reconstructions. As it turns out, retinal direction selectivity is a complex, multi-tiered computation, involving dendrite-intrinsic mechanisms as well as several types of network interactions on the basis of highly selective, likely genetically predetermined synaptic connectivity. Moreover, DS ganglion cell types appear to be more diverse than previously thought, differing not only in their preferred direction and response polarity, but also in physiology, DS mechanism, dendritic morphology and, importantly, the target area of their projections in the brain.
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6
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Stincic T, Smith RG, Taylor WR. Time course of EPSCs in ON-type starburst amacrine cells is independent of dendritic location. J Physiol 2016; 594:5685-94. [PMID: 27219620 DOI: 10.1113/jp272384] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2016] [Accepted: 05/19/2016] [Indexed: 12/17/2022] Open
Abstract
KEY POINTS Direction selectivity has been widely studied as an example of a complex neural computation. Directional GABA release from starburst amacrine cells (SBACs) is critical for generating directional signals in direction-selective ganglion cells. The mechanisms producing the directional release remain unclear. For SBACs, ordered distribution of sustained and transient bipolar cell inputs along the dendrites is proposed to generate directional GABA release. This study tests whether this hypothesis applies to ON-type SBACs. EPSCs activated at proximal and distal dendritic locations have the same time course. Therefore, the ordered arrangement of inputs from bipolar cells with different kinetic properties cannot be responsible for generating directional GABA release from ON-type SBACs. ABSTRACT Direction selectivity in the retina relies critically on directionally asymmetric GABA release from the dendritic tips of starburst amacrine cells (SBACs). GABA release from each radially directed dendrite is larger for motion outward from the soma toward the dendritic tips than for motion inwards toward the soma. The biophysical mechanisms generating these directional signals remain controversial. A model based on electron-microscopic reconstructions of the mouse retina proposed that an ordered arrangement of kinetically distinct bipolar cell inputs to ON- and OFF-type SBACs could produce directional GABA release. We tested this prediction by measuring the time course of EPSCs in ON-type SBACs in the mouse retina, activated by proximal and distal light stimulation. Contrary to the prediction, the kinetics of the excitatory inputs were independent of dendritic location. Computer simulations based on 3D reconstructions of SBAC dendrites demonstrated that the response kinetics of distal inputs were not significantly altered by dendritic filtering. These direct physiological measurements, do not support the hypothesis that directional signals in SBACs arise from the ordered arrangement of kinetically distinct bipolar cell inputs.
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Affiliation(s)
- Todd Stincic
- Department of Ophthalmology, Casey Eye Institute, Oregon Health & Science University, Portland, OR, 97239, USA
| | - Robert G Smith
- Department of Neuroscience, University of Pennsylvania, Philadelphia, PA, 19104, USA
| | - W Rowland Taylor
- Department of Ophthalmology, Casey Eye Institute, Oregon Health & Science University, Portland, OR, 97239, USA.
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7
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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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8
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Koizumi A, Poznanski RR. Does heterogeneity of intracellular Ca[Formula: see text] dynamics underlie speed tuning of direction-selective responses in starburst amacrine cells? J Integr Neurosci 2016; 14:1-17. [PMID: 26762484 DOI: 10.1142/s0219635215500259] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The starburst amacrine cell (SAC) plays a fundamental role in retinal motion perception. In the vertebrate retina, SAC dendrites have been shown to be directionally selective in terms of their Ca[Formula: see text] responses for stimuli that move centrifugally from the soma. The mechanism by which SACs show Ca[Formula: see text] bias for centrifugal motion is yet to be determined with precision. Recent morphological studies support a presynaptic delay in glutamate receptor activation induced Ca[Formula: see text] release from bipolar cells preferentially contacting SACs. However, bipolar cells are known to be electrotonically coupled so time delays between the bipolar cells that provide input to SACs seem unlikely. Using fluorescent microscopy and imunnostaining, we found that the endoplasmic reticulum (ER) is omnipresent in the soma extending to the distal processes of SACs. Consequently, a working hypothesis on heterogeneity of intracellular Ca[Formula: see text] dynamics from ER is proposed as a possible explanation for the cause of speed tuning of direction-selective Ca[Formula: see text] responses in dendrites of SACs.
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Affiliation(s)
- Amane Koizumi
- * National Institutes of Natural Sciences 105-0001, Tokyo, Japan
- † National Institute for Physiological Sciences Okazaki, Aichi 444-8585, Japan
| | - Roman R Poznanski
- ‡ Department of Clinical Sciences Faculty of Biosciences and Medical Engineering Universiti Teknologi Malaysia 81310 Johor Bahru, Malaysia
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9
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Mata D, Linn DM, Linn CL. Retinal ganglion cell neuroprotection induced by activation of alpha7 nicotinic acetylcholine receptors. Neuropharmacology 2015; 99:337-46. [PMID: 26239818 DOI: 10.1016/j.neuropharm.2015.07.036] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2015] [Revised: 07/28/2015] [Accepted: 07/29/2015] [Indexed: 10/23/2022]
Abstract
The α7nAChR agonist, PNU-282987, has previously been shown to have a neuroprotective effect against loss of retinal ganglion cells (RGCs) in an in vivo glaucoma model when the agent was injected into the vitreous chamber of adult Long Evans rat eyes. Here, we characterized the neuroprotective effect of PNU-282987 at the nerve fiber and retinal ganglion cell layer, determined that neuroprotection occurred when the agonist was applied as eye drops and verified detection of the agonist in the retina, using LC/MS/MS. To induce glaucoma-like conditions in adult Long Evans rats, hypertonic saline was injected into the episcleral veins to induce scar tissue and increase intraocular pressure. Within one month, this procedure produced significant loss of RGCs compared to untreated conditions. RGCs were quantified after immunostaining with an antibody against Thy 1.1 and imaged using a confocal microscope. In dose-response studies, concentrations of PNU-282987 were applied to the animal's right eye two times each day, while the left eye acted as an internal control. Eye drops of PNU-282987 resulted in neuroprotection against RGC loss in a dose-dependent manner using concentrations between 100 μM and 2 mM PNU-282987. LC/MS/MS results demonstrated that PNU-282987 was detected in the retina when applied as eye drops, relatively small amounts of PNU-282987 were measured in blood plasma and no PNU-282987 was detected in cardiac tissue. These results support the hypothesis that eye drop application of PNU-282987 can prevent loss of RGCs associated with glaucoma, which can lead to neuroprotective treatments for diseases that involve α7nAChRs.
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Affiliation(s)
- David Mata
- Western Michigan University, Department of Biological Sciences, Kalamazoo, MI 49008, USA.
| | - David M Linn
- Grand Valley State University, Department of Biomedical Sciences, Allendale, MI 49401, USA.
| | - Cindy L Linn
- Western Michigan University, Department of Biological Sciences, Kalamazoo, MI 49008, USA.
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10
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Kostadinov D, Sanes JR. Protocadherin-dependent dendritic self-avoidance regulates neural connectivity and circuit function. eLife 2015; 4. [PMID: 26140686 PMCID: PMC4548410 DOI: 10.7554/elife.08964] [Citation(s) in RCA: 107] [Impact Index Per Article: 11.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2015] [Accepted: 07/02/2015] [Indexed: 12/30/2022] Open
Abstract
Dendritic and axonal arbors of many neuronal types exhibit self-avoidance, in which branches repel each other. In some cases, these neurites interact with those of neighboring neurons, a phenomenon called self/non-self discrimination. The functional roles of these processes remain unknown. In this study, we used retinal starburst amacrine cells (SACs), critical components of a direction-selective circuit, to address this issue. In SACs, both processes are mediated by the gamma-protocadherins (Pcdhgs), a family of 22 recognition molecules. We manipulated Pcdhg expression in SACs and recorded from them and their targets, direction-selective ganglion cells (DSGCs). SACs form autapses when self-avoidance is disrupted and fail to form connections with other SACs when self/non-self discrimination is perturbed. Pcdhgs are also required to prune connections between closely spaced SACs. These alterations degrade the direction selectivity of DSGCs. Thus, self-avoidance, self/non-self discrimination, and synapse elimination are essential for proper function of a circuit that computes directional motion. DOI:http://dx.doi.org/10.7554/eLife.08964.001 Nerve cells (or neurons) connect to one another to form circuits that control the animal's behavior. Typically, each neuron receives signals from other cells via branch-like structures called dendrites. Each specific type of neuron has a characteristic pattern of branched dendrites, which is different from the pattern of other types of neuron. Therefore, it is reasonable to imagine that the shape of these branches can influence how the neuron works; however, this idea has rarely been tested experimentally. Different processes are known to act together to control the pattern of the branched dendrites. For example, dendrites in some neurons avoid other dendrites from the same neuron. This phenomenon is referred to as ‘self-avoidance’. In some of these cases, the same dendrites freely interact with the dendrites of neighboring neurons of the same type; this is called ‘self/non-self discrimination’. It is not clear, however, how these two processes influence the activity of neural circuits. Both self-avoidance and self/non-self discrimination rely on the expression of genes that encode so-called recognition molecules. Kostadinov and Sanes have now altered the expression of these genes in mice to see the effect that disrupting these two phenomena has on a set of neurons called ‘starburst amacrine cells’ that are found at the back the eye. The dendrites of starburst amacrine cells generate signals when objects move across the animal's field of vision. These dendrites then signal to other starburst amacrine cells and to so-called ‘direction-selective ganglion cells’, which in turn send this information to the brain for further processing. The experiments revealed that these disruptions affected the connections between the dendrites. Starburst amacrine cells that lacked self-avoidance mistakenly formed connections with themselves—as if they mistook their own dendrites for those of other starburst cells. In contrast, neurons that lacked self/non-self discrimination made the opposite mistake, and rarely formed connections with each other—as if they mistook the dendrites of other starbursts for their own. Disruptions to either phenomenon interfered with the activity of the direction-selective ganglion cells. Following on from the work of Kostadinov and Sanes, the next challenges include uncovering how the recognition molecules help with self-avoidance and self/non-self discrimination. It will also be important to examine whether the conclusions based on one type of neurons can be generalized to others that also exhibit these two phenomena. DOI:http://dx.doi.org/10.7554/eLife.08964.002
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Affiliation(s)
- Dimitar Kostadinov
- Center for Brain Science, Department of Molecular and Cellular Biology, Harvard University, Cambridge, United States
| | - Joshua R Sanes
- Center for Brain Science, Department of Molecular and Cellular Biology, Harvard University, Cambridge, United States
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11
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Lipin MY, Taylor WR, Smith RG. Inhibitory input to the direction-selective ganglion cell is saturated at low contrast. J Neurophysiol 2015; 114:927-41. [PMID: 26063782 DOI: 10.1152/jn.00413.2015] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2015] [Accepted: 06/09/2015] [Indexed: 01/10/2023] Open
Abstract
Direction-selective ganglion cells (DSGCs) respond selectively to motion toward a "preferred" direction, but much less to motion toward the opposite "null" direction. Directional signals in the DSGC depend on GABAergic inhibition and are observed over a wide range of speeds, which precludes motion detection based on a fixed temporal correlation. A voltage-clamp analysis, using narrow bar stimuli similar in width to the receptive field center, demonstrated that inhibition to DSGCs saturates rapidly above a threshold contrast. However, for wide bar stimuli that activate both the center and surround, inhibition depends more linearly on contrast. Excitation for both wide and narrow bars was also more linear. We propose that positive feedback, likely within the starburst amacrine cell or its network, produces steep saturation of inhibition at relatively low contrast. This mechanism renders GABA release essentially contrast and speed invariant, which enhances directional signals for small objects and thereby increases the signal-to-noise ratio for direction-selective signals in the spike train over a wide range of stimulus conditions. The steep saturation of inhibition confers to a neuron immunity to noise in its spike train, because when inhibition is strong no spikes are initiated.
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Affiliation(s)
- Mikhail Y Lipin
- Department of Neuroscience, University of Pennsylvania, Philadelphia, Pennsylvania; and
| | - W Rowland Taylor
- Casey Eye Institute, Oregon Health and Science University, Portland, Oregon
| | - Robert G Smith
- Department of Neuroscience, University of Pennsylvania, Philadelphia, Pennsylvania; and
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12
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Escobar MJ, Pezo D, Orio P. Mathematical analysis and modeling of motion direction selectivity in the retina. ACTA ACUST UNITED AC 2013; 107:349-59. [PMID: 24008129 DOI: 10.1016/j.jphysparis.2013.08.003] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2013] [Revised: 07/31/2013] [Accepted: 08/20/2013] [Indexed: 10/26/2022]
Abstract
Motion detection is one of the most important and primitive computations performed by our visual system. Specifically in the retina, ganglion cells producing motion direction-selective responses have been addressed by different disciplines, such as mathematics, neurophysiology and computational modeling, since the beginnings of vision science. Although a number of studies have analyzed theoretical and mathematical considerations for such responses, a clear picture of the underlying cellular mechanisms is only recently emerging. In general, motion direction selectivity is based on a non-linear asymmetric computation inside a receptive field differentiating cell responses between preferred and null direction stimuli. To what extent can biological findings match these considerations? In this review, we outline theoretical and mathematical studies of motion direction selectivity, aiming to map the properties of the models onto the neural circuitry and synaptic connectivity found in the retina. Additionally, we review several compartmental models that have tried to fill this gap. Finally, we discuss the remaining challenges that computational models will have to tackle in order to fully understand the retinal motion direction-selective circuitry.
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Affiliation(s)
- María-José Escobar
- Universidad Técnica Federico Santa María, Department of Electronics Engineering, Avda España 1680, Valparaíso, Chile
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13
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Al Abed A, Yin S, Suaning GJ, Lovell NH, Dokos S. Convolution based method for calculating inputs from dendritic fields in a continuum model of the retina. ANNUAL INTERNATIONAL CONFERENCE OF THE IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. ANNUAL INTERNATIONAL CONFERENCE 2013; 2012:215-8. [PMID: 23365869 DOI: 10.1109/embc.2012.6345908] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Computational models are valuable tools that can be used to aid the design and test the efficacy of electrical stimulation strategies in prosthetic vision devices. In continuum models of retinal electrophysiology, the effective extracellular potential can be considered as an approximate measure of the electrotonic loading a neuron's dendritic tree exerts on the soma. A convolution based method is presented to calculate the local spatial average of the effective extracellular loading in retinal ganglion cells (RGCs) in a continuum model of the retina which includes an active RGC tissue layer. The method can be used to study the effect of the dendritic tree size on the activation of RGCs by electrical stimulation using a hexagonal arrangement of electrodes (hexpolar) placed in the suprachoroidal space.
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Affiliation(s)
- Amr Al Abed
- Graduate School of Biomedical Engineering, University of New South Wales, Sydney, NSW 2052, Australia
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14
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Abstract
Starburst amacrine cells (SBACs) within the adult mammalian retina provide the critical inhibition that underlies the receptive field properties of direction-selective ganglion cells (DSGCs). The SBACs generate direction-selective output of GABA that differentially inhibits the DSGCs. We review the biophysical mechanisms that produce directional GABA release from SBACs and test a network model that predicts the effects of reciprocal inhibition between adjacent SBACs. The results of the model simulations suggest that reciprocal inhibitory connections between closely spaced SBACs should be spatially selective, while connections between more widely spaced cells could be indiscriminate. SBACs were initially identified as cholinergic neurons and were subsequently shown to contain release both acetylcholine and GABA. While the role of the GABAergic transmission is well established, the role of the cholinergic transmission remains unclear.
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15
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Vaney DI, Sivyer B, Taylor WR. Direction selectivity in the retina: symmetry and asymmetry in structure and function. Nat Rev Neurosci 2012; 13:194-208. [PMID: 22314444 DOI: 10.1038/nrn3165] [Citation(s) in RCA: 208] [Impact Index Per Article: 17.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Visual information is processed in the retina to a remarkable degree before it is transmitted to higher visual centres. Several types of retinal ganglion cells (the output neurons of the retina) respond preferentially to image motion in a particular direction, and each type of direction-selective ganglion cell (DSGC) is comprised of multiple subtypes with different preferred directions. The direction selectivity of the cells is generated by diverse mechanisms operating within microcircuits that rely on independent neuronal processing in individual dendrites of both the DSGCs and the presynaptic neurons that innervate them.
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Affiliation(s)
- David I Vaney
- Queensland Brain Institute, University of Queensland, Brisbane, Queensland 4072, Australia.
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16
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Dmitriev AV, Gavrikov KE, Mangel SC. GABA-mediated spatial and temporal asymmetries that contribute to the directionally selective light responses of starburst amacrine cells in retina. J Physiol 2012; 590:1699-720. [PMID: 22289910 DOI: 10.1113/jphysiol.2011.225482] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Starburst amacrine cells (SACs) are an essential component of the mechanism that generates direction selectivity in the retina. SACs exhibit opposite polarity, directionally selective (DS) light responses, depolarizing to stimuli that move centrifugally away from the cell through the receptive field surround, but hyperpolarizing to stimuli that move centripetally towards the cell through the surround.Recent findings suggest that (1) the intracellular chloride concentration ([Cl(−)](i)) is high in SAC proximal, but low in SAC distal dendritic compartments, so that GABA depolarizes and hyperpolarizes the proximal and distal compartments, respectively, and (2) this [Cl(−)](i) gradient plays an essential role in generating SAC DS light responses. Employing a biophysically realistic, computational model of SACs, which incorporated experimental measurements of SAC electrical properties and GABA and glutamate responses, we further investigated whether and how a [Cl(−)](i) gradient along SAC dendrites produces their DS responses. Our computational analysis suggests that robust DS light responses would be generated in both the SAC soma and distal dendrites if (1) the Cl(−) equilibrium potential is more positive in the proximal dendrite and more negative in the distal dendrite than the resting membrane potential, so that GABA depolarizes and hyperpolarizes the proximal and distal compartments, respectively, and (2) the GABA-evoked increase in the Cl(−) conductance lasts longer than the glutamate-evoked increase in cation conductance. The combination of these two specific GABA-associated spatial and temporal asymmetries, in conjunction with symmetric glutamate excitation, may underlie the opposite polarity, DS light responses of SACs.
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Affiliation(s)
- Andrey V Dmitriev
- Department of Neuroscience, Ohio State University College of Medicine, Columbus, OH 43210, USA.
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Borst A, Euler T. Seeing Things in Motion: Models, Circuits, and Mechanisms. Neuron 2011; 71:974-94. [PMID: 21943597 DOI: 10.1016/j.neuron.2011.08.031] [Citation(s) in RCA: 154] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/31/2011] [Indexed: 12/31/2022]
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Wei W, Feller MB. Organization and development of direction-selective circuits in the retina. Trends Neurosci 2011; 34:638-45. [PMID: 21872944 DOI: 10.1016/j.tins.2011.08.002] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2011] [Revised: 07/13/2011] [Accepted: 08/02/2011] [Indexed: 10/17/2022]
Abstract
The direction-selective circuit in the retina extracts the directional information of image motion in the visual scene. It is a classic model for neural circuit analysis because its input and output are well-defined and accessible to physiological measurements. However, the neural basis of direction selectivity is still not fully understood. Indeed, this ostensibly simple computation arises from a collection of complex neural mechanisms at all levels of circuit organization. In this review, we describe recent advances in genetic, imaging and optogenetic techniques that have improved our understanding of the synaptic organization and development underlying retinal direction selectivity.
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Affiliation(s)
- Wei Wei
- Department of Molecular and Cell Biology and the Helen Wills Neuroscience Institute, University of California at Berkeley, Berkeley, CA 94720, USA
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Eichner H, Joesch M, Schnell B, Reiff D, Borst A. Internal Structure of the Fly Elementary Motion Detector. Neuron 2011; 70:1155-64. [DOI: 10.1016/j.neuron.2011.03.028] [Citation(s) in RCA: 129] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/22/2011] [Indexed: 11/28/2022]
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POZNANSKI RR. CELLULAR INHIBITORY BEHAVIOR UNDERLYING THE FORMATION OF RETINAL DIRECTION SELECTIVITY IN THE STARBURST NETWORK. J Integr Neurosci 2010; 9:299-335. [DOI: 10.1142/s0219635210002457] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2010] [Accepted: 08/26/2010] [Indexed: 11/18/2022] Open
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