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Vita DJ, Orsi FS, Stanko NG, Clark NA, Tiriac A. Development and organization of the retinal orientation selectivity map. Nat Commun 2024; 15:4829. [PMID: 38844438 PMCID: PMC11156980 DOI: 10.1038/s41467-024-49206-z] [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: 06/29/2023] [Accepted: 05/24/2024] [Indexed: 06/09/2024] Open
Abstract
Orientation or axial selectivity, the property of neurons in the visual system to respond preferentially to certain angles of visual stimuli, plays a pivotal role in our understanding of visual perception and information processing. This computation is performed as early as the retina, and although much work has established the cellular mechanisms of retinal orientation selectivity, how this computation is organized across the retina is unknown. Using a large dataset collected across the mouse retina, we demonstrate functional organization rules of retinal orientation selectivity. First, we identify three major functional classes of retinal cells that are orientation selective and match previous descriptions. Second, we show that one orientation is predominantly represented in the retina and that this predominant orientation changes as a function of retinal location. Third, we demonstrate that neural activity plays little role on the organization of retinal orientation selectivity. Lastly, we use in silico modeling followed by validation experiments to demonstrate that the overrepresented orientation aligns along concentric axes. These results demonstrate that, similar to direction selectivity, orientation selectivity is organized in a functional map as early as the retina.
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Affiliation(s)
- Dominic J Vita
- Department of Biological Sciences, Vanderbilt University, Nashville, TN, 37232, USA
| | - Fernanda S Orsi
- Department of Biological Sciences, Vanderbilt University, Nashville, TN, 37232, USA
| | - Nathan G Stanko
- Department of Biological Sciences, Vanderbilt University, Nashville, TN, 37232, USA
| | - Natalie A Clark
- Department of Biological Sciences, Vanderbilt University, Nashville, TN, 37232, USA
| | - Alexandre Tiriac
- Department of Biological Sciences, Vanderbilt University, Nashville, TN, 37232, USA.
- Vanderbilt Brain Institute, Vanderbilt University, Nashville, TN, 37232, USA.
- Department of Ophthalmology and Visual Sciences, Vanderbilt University, Nashville, TN, 37232, USA.
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2
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Vita DJ, Orsi FS, Stanko NG, Clark NA, Tiriac A. Development and Organization of the Retinal Orientation Selectivity Map. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.03.27.585774. [PMID: 38585937 PMCID: PMC10996665 DOI: 10.1101/2024.03.27.585774] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/09/2024]
Abstract
Orientation or axial selectivity, the property of neurons in the visual system to respond preferentially to certain angles of a visual stimuli, plays a pivotal role in our understanding of visual perception and information processing. This computation is performed as early as the retina, and although much work has established the cellular mechanisms of retinal orientation selectivity, how this computation is organized across the retina is unknown. Using a large dataset collected across the mouse retina, we demonstrate functional organization rules of retinal orientation selectivity. First, we identify three major functional classes of retinal cells that are orientation selective and match previous descriptions. Second, we show that one orientation is predominantly represented in the retina and that this predominant orientation changes as a function of retinal location. Third, we demonstrate that neural activity plays little role on the organization of retinal orientation selectivity. Lastly, we use in silico modeling followed by validation experiments to demonstrate that the overrepresented orientation aligns along concentric axes. These results demonstrate that, similar to direction selectivity, orientation selectivity is organized in a functional map as early as the retina. One Sentence Summary Development and organization of retinal orientation selectivity.
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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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Blumberg MS, Adolph KE. Protracted development of motor cortex constrains rich interpretations of infant cognition. Trends Cogn Sci 2023; 27:233-245. [PMID: 36681607 PMCID: PMC9957955 DOI: 10.1016/j.tics.2022.12.014] [Citation(s) in RCA: 9] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2022] [Revised: 12/18/2022] [Accepted: 12/29/2022] [Indexed: 01/21/2023]
Abstract
Cognition in preverbal human infants must be inferred from overt motor behaviors such as gaze shifts, head turns, or reaching for objects. However, infant mammals - including human infants - show protracted postnatal development of cortical motor outflow. Cortical control of eye, face, head, and limb movements is absent at birth and slowly emerges over the first postnatal year and beyond. Accordingly, the neonatal cortex in humans cannot generate the motor behaviors routinely used to support inferences about infants' cognitive abilities, and thus claims of developmental continuity between infant and adult cognition are suspect. Recognition of the protracted development of motor cortex should temper rich interpretations of infant cognition and motivate more serious consideration of the role of subcortical mechanisms in early cognitive development.
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Affiliation(s)
- Mark S Blumberg
- Department of Psychological & Brain Sciences, University of Iowa, Iowa City, IA 52242, USA; Iowa Neuroscience Institute, University of Iowa, Iowa City, IA 52242, USA; DeLTA Center, University of Iowa, Iowa City, IA 52242, USA.
| | - Karen E Adolph
- Department of Psychology, New York University, New York, NY 10003, 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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6
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Liang D, Leung TW, Kee CS. Measuring Retinal Thickness and Visual Acuity in Eyes with Different Types of Astigmatism in a Cohort of Hong Kong Chinese Adults. Invest Ophthalmol Vis Sci 2023; 64:2. [PMID: 36595274 PMCID: PMC9819738 DOI: 10.1167/iovs.64.1.2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
Abstract
Purpose The purpose of this study was to investigate optical coherence tomography (OCT)-measured retinal thickness (RT) and best-corrected distance visual acuity (BCDVA) in eyes with different types of astigmatism. Methods This is a case-control study of 101 participants stratified into With-The-Rule (WTR; n = 41), Against-The-Rule (ATR; n = 25), and control (n = 35) groups by noncycloplegic subjective refraction. Inclusion criteria were ages between 18 and 45 years, spherical-equivalent (SE) refraction ≥-10.00 diopters (D), negative cylindrical power (CYL) ≤-0.75 D with axes of 0 to 30 degrees/150 to 180 degrees for WTR and 60 to 120 degrees for ATR, or CYL ≥-0.25 D for controls. Participants suffering from ocular diseases related to retinal defects, having a history of ocular surgery, with BCDVA >0.10 LogMAR, or poor OCT imaging quality were excluded. Fovea-centered scans were performed using spectral-domain OCT (SD-OCT), and RT automatically measured by the inbuilt software. Only right eyes were analyzed. Groups were matched for age, gender, SE, axial length, and corneal curvature. Results One-way ANOVA showed a significant difference in both BCDVA (P = 0.039) and macular RT (P = 0.028) among the three groups. Bonferroni's post hoc test revealed statistically significant between-group differences in BCDVA (WTR vs. controls, P = 0.041), as well as in RT at inner-nasal (WTR vs. ATR, P = 0.034) and outer-temporal subfields (WTR vs. controls, P = 0.042). BCDVA was positively associated with macular RT (r = 0.206, P = 0.041) after adjusting for age, gender, and axial length. Conclusions Greater RT and poorer BCDVA were found in eyes with WTR astigmatism. Our findings suggest that the effect of astigmatism on retinal thickness and BCDVA may vary depending on not only magnitude, but also axis of astigmatism.
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Affiliation(s)
- Dong Liang
- School of Optometry, The Hong Kong Polytechnic University, Hong Kong
| | - Tsz-Wing Leung
- School of Optometry, The Hong Kong Polytechnic University, Hong Kong,Research Centre for SHARP Vision (RCSV), The Hong Kong Polytechnic University, Hong Kong,Centre for Eye and Vision Research (CEVR), 17W Hong Kong Science Park, Hong Kong
| | - Chea-Su Kee
- School of Optometry, The Hong Kong Polytechnic University, Hong Kong,Research Centre for SHARP Vision (RCSV), The Hong Kong Polytechnic University, Hong Kong,Centre for Eye and Vision Research (CEVR), 17W Hong Kong Science Park, Hong Kong
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Davey CE, Grayden DB, Burkitt AN. Emergence of radial orientation selectivity: Effect of cell density changes and eccentricity in a layered network. Front Comput Neurosci 2022; 16:881046. [PMID: 36582812 PMCID: PMC9793711 DOI: 10.3389/fncom.2022.881046] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2022] [Accepted: 11/04/2022] [Indexed: 12/15/2022] Open
Abstract
We establish a simple mechanism by which radially oriented simple cells can emerge in the primary visual cortex. In 1986, R. Linsker. proposed a means by which radially symmetric, spatial opponent cells can evolve, driven entirely by noise, from structure in the initial synaptic connectivity distribution. We provide an analytical derivation of Linsker's results, and further show that radial eigenfunctions can be expressed as a weighted sum of degenerate Cartesian eigenfunctions, and vice-versa. These results are extended to allow for radially dependent cell density, from which we show that, despite a circularly symmetric synaptic connectivity distribution, radially biased orientation selectivity emerges in the third layer when cell density in the first layer, or equivalently, synaptic radius, changes with eccentricity; i.e., distance to the center of the lamina. This provides a potential mechanism for the emergence of radial orientation in the primary visual cortex before eye opening and the onset of structured visual input after birth.
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Affiliation(s)
- Catherine E. Davey
- Melbourne Brain Centre Imaging Unit, University of Melbourne, Parkville, VIC, Australia,Department of Biomedical Engineering, University of Melbourne, Parkville, VIC, Australia,*Correspondence: Catherine E. Davey
| | - David B. Grayden
- Department of Biomedical Engineering, University of Melbourne, Parkville, VIC, Australia
| | - Anthony N. Burkitt
- Department of Biomedical Engineering, University of Melbourne, Parkville, VIC, Australia
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8
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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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Flitcroft DI, Harb EN, Wildsoet CF. The Spatial Frequency Content of Urban and Indoor Environments as a Potential Risk Factor for Myopia Development. Invest Ophthalmol Vis Sci 2021; 61:42. [PMID: 32986814 PMCID: PMC7533745 DOI: 10.1167/iovs.61.11.42] [Citation(s) in RCA: 44] [Impact Index Per Article: 14.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Purpose To examine the hypothesis that the spatial frequency spectra of urban and indoor environments differ from the natural environment in ways that may promote the development of myopia. Methods A total of 814 images were analyzed from three datasets; University of California Berkeley (UCB), University of Texas (UT), and Botswana (UPenn). Images were processed in Matlab (Mathworks Inc) to map the camera color characteristics to human cone sensitivities. From the photopic luminance images generated, two-dimensional spatial frequency (SF) spectra were calculated and converted to one-dimensional spectra by rotational averaging. The spatial filtering profile of a 0.4 Bangerter foil, which has been shown to induce myopia experimentally, was also determined. Results The SF slope for natural scenes followed the recognized 1/fα relationship with mean slopes of −1.08, −0.90, and −1.04 for the UCB, UT and UPenn image sets, respectively. Indoor scenes had a significantly steeper slope (−1.48, UCB; −1.52, UT; P < 0.0001). Urban environments showed an intermediate slope (−1.29, UCB; −1.22, UT) that was significantly different from the slopes derived from the natural scenes (P < 0.0001). The change in SF content between natural outdoor scenes and indoors was comparable to that induced by a 0.4 Bangerter foil, which reduced the SF slope of a natural scene from −0.88 to −1.47. Conclusions Compared to natural outdoor images, man-made outdoor and indoor environments have spatial frequency characteristics similar to those known to induce form-deprivation myopia in animal models. The spatial properties of the man-made environment may be one of the missing drivers of the human myopia epidemic.
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Affiliation(s)
- Daniel Ian Flitcroft
- Ophthalmology, Children's University Hospital, Dublin, Ireland.,Technological University of Dublin, Dublin, Ireland
| | - Elise N Harb
- School of Optometry, University of California, Berkeley, California, United States
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10
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Sawant A, Ebbinghaus BN, Bleckert A, Gamlin C, Yu WQ, Berson D, Rudolph U, Sinha R, Hoon M. Organization and emergence of a mixed GABA-glycine retinal circuit that provides inhibition to mouse ON-sustained alpha retinal ganglion cells. Cell Rep 2021; 34:108858. [PMID: 33730586 PMCID: PMC8030271 DOI: 10.1016/j.celrep.2021.108858] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2020] [Revised: 12/07/2020] [Accepted: 02/19/2021] [Indexed: 12/04/2022] Open
Abstract
In the retina, amacrine interneurons inhibit retinal ganglion cell (RGC) dendrites to shape retinal output. Amacrine cells typically use either GABA or glycine to exert synaptic inhibition. Here, we combined transgenic tools with immunohistochemistry, electrophysiology, and 3D electron microscopy to determine the composition and organization of inhibitory synapses across the dendritic arbor of a well-characterized RGC type in the mouse retina: the ON-sustained alpha RGC. We find mixed GABA-glycine receptor synapses across this RGC type, unveiling the existence of "mixed" inhibitory synapses in the retinal circuit. Presynaptic amacrine boutons with dual release sites are apposed to ON-sustained alpha RGC postsynapses. We further reveal the sequence of postsynaptic assembly for these mixed synapses: GABA receptors precede glycine receptors, and a lack of early GABA receptor expression impedes the recruitment of glycine receptors. Together our findings uncover the organization and developmental profile of an additional motif of inhibition in the mammalian retina.
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Affiliation(s)
- Abhilash Sawant
- Department of Ophthalmology and Visual Sciences, University of Wisconsin-Madison, Madison, WI, USA; Department of Neuroscience, University of Wisconsin-Madison, Madison, WI, USA
| | - Briana N Ebbinghaus
- Department of Ophthalmology and Visual Sciences, University of Wisconsin-Madison, Madison, WI, USA; McPherson Eye Research Institute, University of Wisconsin-Madison, Madison, WI, USA
| | - Adam Bleckert
- Department of Biological Structure, University of Washington, Seattle, WA, USA
| | - Clare Gamlin
- Department of Biological Structure, University of Washington, Seattle, WA, USA
| | - Wan-Qing Yu
- Department of Biological Structure, University of Washington, Seattle, WA, USA
| | - David Berson
- Department of Neuroscience, Brown University, Providence, RI, USA
| | - Uwe Rudolph
- Department of Comparative Biosciences, College of Veterinary Medicine, University of Illinois at Urbana-Champaign, Champaign, IL, USA; Carl R. Woese Institute for Genomic Biology, University of Illinois at Urbana-Champaign, Champaign, IL, USA
| | - Raunak Sinha
- Department of Ophthalmology and Visual Sciences, University of Wisconsin-Madison, Madison, WI, USA; Department of Neuroscience, University of Wisconsin-Madison, Madison, WI, USA; McPherson Eye Research Institute, University of Wisconsin-Madison, Madison, WI, USA
| | - Mrinalini Hoon
- Department of Ophthalmology and Visual Sciences, University of Wisconsin-Madison, Madison, WI, USA; Department of Neuroscience, University of Wisconsin-Madison, Madison, WI, USA; McPherson Eye Research Institute, University of Wisconsin-Madison, Madison, WI, USA.
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11
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Hoseini-Yazdi H, Vincent SJ, Read SA, Collins MJ. Astigmatic Defocus Leads to Short-Term Changes in Human Choroidal Thickness. Invest Ophthalmol Vis Sci 2021; 61:48. [PMID: 32729913 PMCID: PMC7425733 DOI: 10.1167/iovs.61.8.48] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Purpose To examine the choroidal thickness (ChT) response to short-term with-the-rule (WTR) and against-the-rule (ATR) simple myopic astigmatic defocus, with the response to spherical myopic defocus and clear vision used as control conditions. Methods The left eye of 18 healthy adults aged 28 ± 6 years was exposed to clear vision, +3 D spherical myopic defocus, +3 D × 180 WTR, or +3 D × 90 ATR astigmatic defocus for 60 minutes, over four randomly ordered visits, while their right eye was optimally corrected. The macular ChT was measured with optical coherence tomography along the vertical and horizontal meridians before and after 20, 40, and 60 minutes of defocus. Results After 60 minutes of defocus, ChT increased by +8 ± 5 µm (P < 0.001) with spherical myopic defocus, but varied with simple myopic astigmatic defocus, depending on the axis of astigmatism (P < 0.001), increasing by +5 ± 6 µm (P = 0.037) with WTR and decreasing by −4 ± 5 µm (P = 0.011) with ATR astigmatic defocus. These changes were similar across the vertical and horizontal meridians (P = 0.22). The ChT changes were greater than the change during the clear vision control condition (−1 ± 4 µm) for WTR (+5 ± 5 µm, P = 0.002) but not ATR (−4 ± 6 µm, P = 0.09) astigmatic defocus. Conclusions These results provide insights into the human ChT response to short-term astigmatic defocus and highlight a potential difference in the myopiagenic signal associated with the orientation of astigmatic blur.
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12
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Mohan YS, Jayakumar J, Lloyd EKJ, Levichkina E, Vidyasagar TR. Diversity of Feature Selectivity in Macaque Visual Cortex Arising from a Limited Number of Broadly Tuned Input Channels. Cereb Cortex 2019; 29:5255-5268. [PMID: 31220214 DOI: 10.1093/cercor/bhz063] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023] Open
Abstract
Spike (action potential) responses of most primary visual cortical cells in the macaque are sharply tuned for the orientation of a line or an edge, and neurons preferring similar orientations are clustered together in cortical columns. The preferred stimulus orientation of these columns span the full range of orientations, as observed in recordings of spikes and in classical optical imaging of intrinsic signals. However, when we imaged the putative thalamic input to striate cortical cells that can be seen in imaging of intrinsic signals when they are analyzed on a larger spatial scale, we found that the orientation domain map of the primary visual cortex did not show the same diversity of orientations. This map was dominated by just the one orientation that is most commonly preferred by neurons in the retina and the lateral geniculate nucleus. This supports cortical feature selectivity and columnar architecture being built upon feed-forward signals transmitted from the thalamus in a very limited number of broadly tuned input channels.
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Affiliation(s)
- Yamni S Mohan
- Department of Optometry & Vision Science, University of Melbourne, Parkville, Victoria, Australia
| | - Jaikishan Jayakumar
- Department of Optometry & Vision Science, University of Melbourne, Parkville, Victoria, Australia.,Centre for Computational Brain Research, Indian Institute of Technology-Madras, Chennai, India
| | - Errol K J Lloyd
- Department of Optometry & Vision Science, University of Melbourne, Parkville, Victoria, Australia
| | - Ekaterina Levichkina
- Department of Optometry & Vision Science, University of Melbourne, Parkville, Victoria, Australia.,Institute for Information Transmission Problems, Russian Academy of Sciences, Moscow, Russia
| | - Trichur R Vidyasagar
- Department of Optometry & Vision Science, University of Melbourne, Parkville, Victoria, Australia.,Melbourne Neuroscience Institute, University of Melbourne, Parkville, Victoria, Australia
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13
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2-D Peripheral image quality metrics with different types of multifocal contact lenses. Sci Rep 2019; 9:18487. [PMID: 31811185 PMCID: PMC6898319 DOI: 10.1038/s41598-019-54783-x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2019] [Accepted: 11/18/2019] [Indexed: 12/19/2022] Open
Abstract
To evaluate the impact of multifocal contact lens wear on the image quality metrics across the visual field in the context of eye growth and myopia control. Two-dimensional cross-correlation coefficients were estimated by comparing a reference image against the computed retinal images for every location. Retinal images were simulated based on the measured optical aberrations of the naked eye and a set of multifocal contact lenses (centre-near and centre-distance designs), and images were spatially filtered to match the resolution limit at each eccentricity. Value maps showing the reduction in the quality of the image through each optical condition were obtained by subtracting the optical image quality from the theoretical physiological limits. Results indicate that multifocal contact lenses degrade the image quality independently from their optical design, though this result depends on the type of analysis conducted. Analysis of the image quality across the visual field should not be oversimplified to a single number but split into regional and groups because it provides more insightful information and can avoid misinterpretation of the results. The decay of the image quality caused by the multifocal contacts alone, cannot explain the translation of peripheral defocus towards protection on myopia progression, and a different explanation needs to be found.
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14
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Cheung A, Trevers KE, Reyes-Corral M, Antinucci P, Hindges R. Expression and Roles of Teneurins in Zebrafish. Front Neurosci 2019; 13:158. [PMID: 30914911 PMCID: PMC6423166 DOI: 10.3389/fnins.2019.00158] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2018] [Accepted: 02/12/2019] [Indexed: 12/21/2022] Open
Abstract
The teneurins, also known as Ten-m/Odz, are highly conserved type II transmembrane glycoproteins widely expressed throughout the nervous system. Functioning as dimers, these large cell-surface adhesion proteins play a key role in regulating neurodevelopmental processes such as axon targeting, synaptogenesis and neuronal wiring. Synaptic specificity is driven by molecular interactions, which can occur either in a trans-homophilic manner between teneurins or through a trans-heterophilic interaction across the synaptic cleft between teneurins and other cell-adhesion molecules, such as latrophilins. The significance of teneurins interactions during development is reflected in the widespread expression pattern of the four existing paralogs across interconnected regions of the nervous system, which we demonstrate here via in situ hybridization and the generation of transgenic BAC reporter lines in zebrafish. Focusing on the visual system, we will also highlight the recent developments that have been made in furthering our understanding of teneurin interactions and their functionality, including the instructive role of teneurin-3 in specifying the functional wiring of distinct amacrine and retinal ganglion cells in the vertebrate visual system underlying a particular functionality. Based on the distinct expression pattern of all teneurins in different retinal cells, it is conceivable that the combination of different teneurins is crucial for the generation of discrete visual circuits. Finally, mutations in all four human teneurin genes have been linked to several types of neurodevelopmental disorders. The opportunity therefore arises that findings about the roles of zebrafish teneurins or their orthologs in other species shed light on the molecular mechanisms in the etiology of such human disorders.
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Affiliation(s)
- Angela Cheung
- Centre for Developmental Neurobiology, King's College London, London, United Kingdom.,MRC Centre for Neurodevelopmental Disorders, King's College London, London, United Kingdom
| | - Katherine E Trevers
- Centre for Developmental Neurobiology, King's College London, London, United Kingdom.,MRC Centre for Neurodevelopmental Disorders, King's College London, London, United Kingdom
| | - Marta Reyes-Corral
- Centre for Developmental Neurobiology, King's College London, London, United Kingdom
| | - Paride Antinucci
- Centre for Developmental Neurobiology, King's College London, London, United Kingdom
| | - Robert Hindges
- Centre for Developmental Neurobiology, King's College London, London, United Kingdom.,MRC Centre for Neurodevelopmental Disorders, King's College London, London, United Kingdom
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