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Ding QA, Gu C, Li J, Li X, Hou B, Peng Y, Chen B, Yao Y. Mimicking the retinal neuron functions by a photoresponsive single transistor with a double gate. Biophys J 2024; 123:1804-1814. [PMID: 38783604 DOI: 10.1016/j.bpj.2024.05.023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2024] [Revised: 05/07/2024] [Accepted: 05/21/2024] [Indexed: 05/25/2024] Open
Abstract
To realize a low-cost neuromorphic visual system, employing an artificial neuron capable of mimicking the retinal neuron functions is essential. A photoresponsive single transistor neuron composed of a vertical silicon nanowire is proposed. Similar to retinal neurons, various photoresponsive characteristics of the single transistor neuron can be modulated by light intensity as well as wavelength and have a high responsivity to green light like the human eye. The device is designed with a cylindrical surrounding double-gate structure, enclosed by an independently controlled outer gate and inner gate. The outer gate has the function of selectively inhibiting neuron activity, which can mimic lateral inhibition of amacrine cells to ganglion cells, and the inner gate can be utilized for the adjustment of the firing threshold voltage, which can be used to mimic the regulation of photoresponsivity by horizontal cells for adaptive visual perception. Furthermore, a myelination function that controls the speed of information transmission is obtained according to the inherent asymmetric source/drain structure of a vertical silicon nanowire. This work can enable photoresponsive neuronal function using only a single transistor, providing a promising hardware implementation for building miniaturized neuromorphic vision systems at low cost.
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Affiliation(s)
- Qing-An Ding
- School of Electronic and Information Engineering, Shandong University of Science and Technology, Qingdao, China
| | - Chaoran Gu
- School of Electronic and Information Engineering, Shandong University of Science and Technology, Qingdao, China
| | - Jianyu Li
- School of Electronic and Information Engineering, Shandong University of Science and Technology, Qingdao, China
| | - Xiaoyuan Li
- School of Electronic and Information Engineering, Shandong University of Science and Technology, Qingdao, China; Affiliated Hospital of Qingdao University, Qingdao, China.
| | - BingHui Hou
- Affiliated Hospital of Qingdao University, Qingdao, China.
| | - Yandong Peng
- School of Electronic and Information Engineering, Shandong University of Science and Technology, Qingdao, China.
| | - Bing Chen
- School of Electronic and Information Engineering, Shandong University of Science and Technology, Qingdao, China
| | - Youli Yao
- School of Electronic and Information Engineering, Shandong University of Science and Technology, Qingdao, China
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2
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Bhagwandin A, Molnár Z, Bertelsen MF, Karlsson KÆ, Alagaili AN, Bennett NC, Hof PR, Kaswera-Kyamakya C, Gilissen E, Jayakumar J, Manger PR. Where Do Core Thalamocortical Axons Terminate in Mammalian Neocortex When There Is No Cytoarchitecturally Distinct Layer 4? J Comp Neurol 2024; 532:e25652. [PMID: 38962882 DOI: 10.1002/cne.25652] [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: 03/15/2024] [Revised: 05/20/2024] [Accepted: 06/07/2024] [Indexed: 07/05/2024]
Abstract
Although the mammalian cerebral cortex is most often described as a hexalaminar structure, there are cortical areas (primary motor cortex) and species (elephants, cetaceans, and hippopotami), where a cytoarchitecturally indistinct, or absent, layer 4 is noted. Thalamocortical projections from the core, or first order, thalamic system terminate primarily in layers 4/inner 3. We explored the termination sites of core thalamocortical projections in cortical areas and in species where there is no cytoarchitecturally distinct layer 4 using the immunolocalization of vesicular glutamate transporter 2, a known marker of core thalamocortical axon terminals, in 31 mammal species spanning the eutherian radiation. Several variations from the canonical cortical column outline of layer 4 and core thalamocortical inputs were noted. In shrews/microchiropterans, layer 4 was present, but many core thalamocortical projections terminated in layer 1 in addition to layers 4 and inner 3. In primate primary visual cortex, the sublaminated layer 4 was associated with a specialized core thalamocortical projection pattern. In primate primary motor cortex, no cytoarchitecturally distinct layer 4 was evident and the core thalamocortical projections terminated throughout layer 3. In the African elephant, cetaceans, and river hippopotamus, no cytoarchitecturally distinct layer 4 was observed and core thalamocortical projections terminated primarily in inner layer 3 and less densely in outer layer 3. These findings are contextualized in terms of cortical processing, perception, and the evolutionary trajectory leading to an indistinct or absent cortical layer 4.
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Affiliation(s)
- Adhil Bhagwandin
- School of Anatomical Sciences, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, Republic of South Africa
| | - Zoltán Molnár
- Department of Physiology, Anatomy and Genetics, Sherrington Building, University of Oxford, Oxford, UK
| | - Mads F Bertelsen
- Centre for Zoo and Wild Animal Health, Copenhagen Zoo, Frederiksberg, Denmark
| | - Karl Æ Karlsson
- Biomedical Engineering, Reykjavik University, Reykjavik, Iceland
| | | | - Nigel C Bennett
- South African Research Chair of Mammal Behavioural Ecology and Physiology, University of Pretoria, Pretoria, South Africa
| | - Patrick R Hof
- Nash Family Department of Neuroscience, Center for Discovery and Innovation, and Friedman Brain Institute, Icahn School of Medicine at Mount Sinai, New York, New York, USA
| | | | - Emmanuel Gilissen
- Department of African Zoology, Royal Museum for Central Africa, Tervuren, Belgium
- Laboratory of Histology and Neuropathology, Université Libre de Bruxelles, Brussels, Belgium
| | - Jaikishan Jayakumar
- Sudha Gopalakrishnan Brain Centre, Indian Institute of Technology Madras, Chennai, India
- Center for Computational Brain Research, Indian Institute of Technology Madras, Chennai, India
| | - Paul R Manger
- School of Anatomical Sciences, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, Republic of South Africa
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3
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Williams JC, Tubiolo PN, Zheng ZJ, Silver-Frankel EB, Pham DT, Haubold NK, Abeykoon SK, Abi-Dargham A, Horga G, Van Snellenberg JX. Functional Localization of the Human Auditory and Visual Thalamus Using a Thalamic Localizer Functional Magnetic Resonance Imaging Task. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.04.28.591516. [PMID: 38746171 PMCID: PMC11092475 DOI: 10.1101/2024.04.28.591516] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/16/2024]
Abstract
Functional magnetic resonance imaging (fMRI) of the auditory and visual sensory systems of the human brain is an active area of investigation in the study of human health and disease. The medial geniculate nucleus (MGN) and lateral geniculate nucleus (LGN) are key thalamic nuclei involved in the processing and relay of auditory and visual information, respectively, and are the subject of blood-oxygen-level-dependent (BOLD) fMRI studies of neural activation and functional connectivity in human participants. However, localization of BOLD fMRI signal originating from neural activity in MGN and LGN remains a technical challenge, due in part to the poor definition of boundaries of these thalamic nuclei in standard T1-weighted and T2-weighted magnetic resonance imaging sequences. Here, we report the development and evaluation of an auditory and visual sensory thalamic localizer (TL) fMRI task that produces participant-specific functionally-defined regions of interest (fROIs) of both MGN and LGN, using 3 Tesla multiband fMRI and a clustered-sparse temporal acquisition sequence, in less than 16 minutes of scan time. We demonstrate the use of MGN and LGN fROIs obtained from the TL fMRI task in standard resting-state functional connectivity (RSFC) fMRI analyses in the same participants. In RSFC analyses, we validated the specificity of MGN and LGN fROIs for signals obtained from primary auditory and visual cortex, respectively, and benchmark their performance against alternative atlas- and segmentation-based localization methods. The TL fMRI task and analysis code (written in Presentation and MATLAB, respectively) have been made freely available to the wider research community.
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Krug A, Eberhardt LV, Huckauf A. Transient attention does not alter the eccentricity effect in estimation of duration. Atten Percept Psychophys 2024; 86:392-403. [PMID: 37550478 PMCID: PMC10806013 DOI: 10.3758/s13414-023-02766-6] [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] [Accepted: 07/16/2023] [Indexed: 08/09/2023]
Abstract
Previous research investigating the influence of stimulus eccentricity on perceived duration showed an increasing duration underestimation with increasing eccentricity. Based on studies showing that precueing the stimulus location prolongs perceived duration, one might assume that this eccentricity effect is influenced by spatial attention. In the present study, we assessed the influence of transient covert attention on the eccentricity effect in duration estimation in two experiments, one online and one in a laboratory setting. In a duration estimation task, participants judged whether a comparison stimulus presented near or far from fixation with a varying duration was shorter or longer than a standard stimulus presented foveally with a constant duration. To manipulate transient covert attention, either a transient luminance cue was used (valid cue) to direct attention to the position of the subsequent peripheral comparison stimulus or all positions were marked by luminance (neutral cue). Results of both experiments yielded a greater underestimation of duration for the far than for the near stimulus, replicating the eccentricity effect. Although cueing was effective (i.e., shorter response latencies for validly cued stimuli), cueing did not alter the eccentricity effect on estimation of duration. This indicates that cueing leads to covert attentional shifts but does not account for the eccentricity effect in perceived duration.
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Affiliation(s)
- Alina Krug
- Department of General Psychology, Institute of Psychology and Education, Ulm University, 89069, Ulm, Germany.
| | - Lisa Valentina Eberhardt
- Department of General Psychology, Institute of Psychology and Education, Ulm University, 89069, Ulm, Germany
| | - Anke Huckauf
- Department of General Psychology, Institute of Psychology and Education, Ulm University, 89069, Ulm, Germany
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5
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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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6
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Chauhan T, Jakovljev I, Thompson LN, Wuerger SM, Martinovic J. Decoding of EEG signals reveals non-uniformities in the neural geometry of colour. Neuroimage 2023; 268:119884. [PMID: 36657691 DOI: 10.1016/j.neuroimage.2023.119884] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2022] [Revised: 11/04/2022] [Accepted: 01/15/2023] [Indexed: 01/19/2023] Open
Abstract
The idea of colour opponency maintains that colour vision arises through the comparison of two chromatic mechanisms, red versus green and yellow versus blue. The four unique hues, red, green, blue, and yellow, are assumed to appear at the null points of these the two chromatic systems. Here we hypothesise that, if unique hues represent a tractable cortical state, they should elicit more robust activity compared to other, non-unique hues. We use a spatiotemporal decoding approach to report that electroencephalographic (EEG) responses carry robust information about the tested isoluminant unique hues within a 100-350 ms window from stimulus onset. Decoding is possible in both passive and active viewing tasks, but is compromised when concurrent high luminance contrast is added to the colour signals. For large hue-differences, the efficiency of hue decoding can be predicted by mutual distance in a nominally uniform perceptual colour space. However, for small perceptual neighbourhoods around unique hues, the encoding space shows pivotal non-uniformities which suggest that anisotropies in neurometric hue-spaces may reflect perceptual unique hues.
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Affiliation(s)
- Tushar Chauhan
- The Picower Institute for Learning and Memory, Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology, 02139 Cambridge MA, USA.
| | - Ivana Jakovljev
- Department of Psychology. Faculty of Philosophy, University of Novi Sad, Serbia
| | | | - Sophie M Wuerger
- Department of Psychology, University of Liverpool, Liverpool, L697ZA, UK
| | - Jasna Martinovic
- School of Psychology, University of Aberdeen, Aberdeen, AB24 3FX, UK; Department of Psychology, School of Philosophy, Psychology and Language Sciences, University of Edinburgh, Edinburgh, EH8 9JZ, UK.
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7
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Martin PR. The Verriest Lecture: Pathways to color in the eye and brain. JOURNAL OF THE OPTICAL SOCIETY OF AMERICA. A, OPTICS, IMAGE SCIENCE, AND VISION 2023; 40:V1-V10. [PMID: 37133001 DOI: 10.1364/josaa.480106] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
In common with the majority of New World monkeys, marmosets show polymorphic color vision by allelic variation of X-chromosome genes encoding opsin pigments in the medium/long wavelength range. Male marmosets are thus obligate dichromats ("red-green color blind"), whereas females carrying distinct alleles on X chromosomes show one of three trichromatic phenotypes. Marmosets thus represent a "natural knock-out" system enabling comparison of red-green color vision in dichromatic and trichromatic visual systems. Further, study of short-wave (blue) cone pathways in marmosets has provided insights into primitive visual pathways for depth perception and attention. These investigations represent a parallel line to clinical research on color vision defects that was pioneered in studies by Guy Verreist, whom we honor in this eponymous lecture.
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Santana NNM, Silva EHA, dos Santos SF, Costa MSMO, Nascimento Junior ES, Engelberth RCJG, Cavalcante JS. Retinorecipient areas in the common marmoset ( Callithrix jacchus): An image-forming and non-image forming circuitry. Front Neural Circuits 2023; 17:1088686. [PMID: 36817647 PMCID: PMC9932520 DOI: 10.3389/fncir.2023.1088686] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2022] [Accepted: 01/10/2023] [Indexed: 02/05/2023] Open
Abstract
The mammalian retina captures a multitude of diverse features from the external environment and conveys them via the optic nerve to a myriad of retinorecipient nuclei. Understanding how retinal signals act in distinct brain functions is one of the most central and established goals of neuroscience. Using the common marmoset (Callithrix jacchus), a monkey from Northeastern Brazil, as an animal model for parsing how retinal innervation works in the brain, started decades ago due to their marmoset's small bodies, rapid reproduction rate, and brain features. In the course of that research, a large amount of new and sophisticated neuroanatomical techniques was developed and employed to explain retinal connectivity. As a consequence, image and non-image-forming regions, functions, and pathways, as well as retinal cell types were described. Image-forming circuits give rise directly to vision, while the non-image-forming territories support circadian physiological processes, although part of their functional significance is uncertain. Here, we reviewed the current state of knowledge concerning retinal circuitry in marmosets from neuroanatomical investigations. We have also highlighted the aspects of marmoset retinal circuitry that remain obscure, in addition, to identify what further research is needed to better understand the connections and functions of retinorecipient structures.
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Affiliation(s)
- Nelyane Nayara M. Santana
- Laboratory of Neurochemical Studies, Department of Physiology and Behavior, Bioscience Center, Federal University of Rio Grande do Norte, Natal, Brazil
| | - Eryck H. A. Silva
- Laboratory of Neurochemical Studies, Department of Physiology and Behavior, Bioscience Center, Federal University of Rio Grande do Norte, Natal, Brazil
| | - Sâmarah F. dos Santos
- Laboratory of Neurochemical Studies, Department of Physiology and Behavior, Bioscience Center, Federal University of Rio Grande do Norte, Natal, Brazil
| | - Miriam S. M. O. Costa
- Laboratory of Neuroanatomy, Department of Morphology, Bioscience Center, Federal University of Rio Grande do Norte, Natal, Brazil
| | - Expedito S. Nascimento Junior
- Laboratory of Neuroanatomy, Department of Morphology, Bioscience Center, Federal University of Rio Grande do Norte, Natal, Brazil
| | - Rovena Clara J. G. Engelberth
- Laboratory of Neurochemical Studies, Department of Physiology and Behavior, Bioscience Center, Federal University of Rio Grande do Norte, Natal, Brazil
| | - Jeferson S. Cavalcante
- Laboratory of Neurochemical Studies, Department of Physiology and Behavior, Bioscience Center, Federal University of Rio Grande do Norte, Natal, Brazil,*Correspondence: Jeferson S. Cavalcante,
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9
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Contribution of parasol-magnocellular pathway ganglion cells to foveal retina in macaque monkey. Vision Res 2023; 202:108154. [PMID: 36436365 DOI: 10.1016/j.visres.2022.108154] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2022] [Revised: 10/18/2022] [Accepted: 10/28/2022] [Indexed: 11/25/2022]
Abstract
Parasol-magnocellular pathway ganglion cells form an important output stream of the primate retina and make a major contribution to visual motion detection. They are known to comprise ON and OFF type response polarities but the relative numbers of ON and OFF parasol cells, and the overall contribution of parasol cells to high-acuity foveal vision are not well understood. Here we use antibodies against carbonic anhydrase 8 (CA8) and intracellular injections of the liphilic dye DiI to show that CA8 selectively labels OFF parasol cells in macaque retina. By combined labeling with CA8 antibodies and a previously-described marker for parasol cells (GABAA receptor antibodies), we show that ON and OFF parasol cells each comprise ∼ 6% of all ganglion cells in central retina (each peak density ∼ 3000 cells/mm2 at 5 deg.), and each population comprises ∼ 10% of all ganglion cells in peripheral temporal retina. Thus, the spatial density of parasol cells in central retina is greater than reported by previous anatomical studies, and the central-peripheral gradient in parasol cell density is shallower than previously reported. The data nevertheless predict decline in spatial acuity with visual field eccentricity for both midget-parvocellular pathway and parasol-magnocellular pathway mediated visual functions. The spatial resolving power of the OFF parasol array (peak ∼ 7 cpd) falls short of macaque behavioral grating acuity by at least a factor of three throughout the retina.
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10
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Uprety S, Adhikari P, Feigl B, Zele AJ. Melanopsin photoreception differentially modulates rod-mediated and cone-mediated human temporal vision. iScience 2022; 25:104529. [PMID: 35754721 PMCID: PMC9218364 DOI: 10.1016/j.isci.2022.104529] [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] [Received: 03/11/2022] [Revised: 05/04/2022] [Accepted: 05/30/2022] [Indexed: 11/17/2022] Open
Abstract
To evaluate the nature of interactions between visual pathways transmitting the slower melanopsin and faster rod and cone signals, we implement a temporal phase summation paradigm in human observers using photoreceptor-directed stimuli. We show that melanopsin stimulation interacts with and alters both rod-mediated and cone-mediated vision regardless of whether it is perceptually visible or not. Melanopsin-rod interactions result in either inhibitory or facilitatory summation depending on the temporal frequency and photoreceptor pathway contrast sensitivity. Moreover, by isolating rod vision, we reveal a bipartite intensity response property of the rod pathway in photopic lighting that extends its operational range at lower frequencies to beyond its classic saturation limits but at the expense of attenuating sensitivity at higher frequencies. In comparison, melanopsin-cone interactions always lead to facilitation. These interactions can be described by linear or probability summations and potentially involve multiple intraretinal and visual cortical pathways to set human visual contrast sensitivity. Melanopsin ipRGCs support vision independent of the rod and cone signals Rod pathways mediate robust visual responses in daylight Temporal contrast sensitivity is contingent on the melanopsin excitation level Visual performance is collectively regulated by melanopsin, rod and cone pathways
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Affiliation(s)
- Samir Uprety
- Centre for Vision and Eye Research, Queensland University of Technology (QUT), Brisbane, QLD 4059, Australia.,School of Optometry and Vision Science, Queensland University of Technology (QUT), Brisbane, QLD 4059, Australia
| | - Prakash Adhikari
- Centre for Vision and Eye Research, Queensland University of Technology (QUT), Brisbane, QLD 4059, Australia.,School of Optometry and Vision Science, Queensland University of Technology (QUT), Brisbane, QLD 4059, Australia
| | - Beatrix Feigl
- Centre for Vision and Eye Research, Queensland University of Technology (QUT), Brisbane, QLD 4059, Australia.,School of Biomedical Sciences, Queensland University of Technology (QUT), Brisbane, QLD 4059, Australia.,Queensland Eye Institute, Brisbane, QLD 4101, Australia
| | - Andrew J Zele
- Centre for Vision and Eye Research, Queensland University of Technology (QUT), Brisbane, QLD 4059, Australia.,School of Optometry and Vision Science, Queensland University of Technology (QUT), Brisbane, QLD 4059, Australia
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11
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Effects of spatial attention on spatial and temporal acuity: A computational account. Atten Percept Psychophys 2022; 84:1886-1900. [PMID: 35729455 DOI: 10.3758/s13414-022-02527-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/01/2022] [Indexed: 11/08/2022]
Abstract
In our daily lives, the visual system receives a plethora of visual information that competes for the brain's limited processing capacity. Nevertheless, not all visual information is useful for our cognitive, emotional, social, and ultimately survival purposes. Therefore, the brain employs mechanisms to select critical information and thereby optimizes its limited resources. Attention is the selective process that serves such a function. In particular, covert spatial attention - attending to a particular location in the visual field without eye movements - improves spatial resolution and paradoxically deteriorates temporal resolution. The neural correlates underlying these attentional effects still remainelusive. In this work, we tested a neural model's predictions that explain these phenomena based on interactions between channels with different spatiotemporal sensitivities - namely, the magnocellular (transient) and parvocellular (sustained) channels. More specifically, our model postulates that spatial attention enhances activities in the parvocellular pathway, thereby producing improved performance in spatial resolution tasks. However, the enhancement of parvocellular activities leads to decreased magnocellular activities due to parvo-magno inhibitory interactions. As a result, spatial attention hampers temporal resolution. We compared the predictions of the model to psychophysical data, and show that our model can account qualitatively and quantitatively for the effects of spatial attention on spatial and temporal acuity.
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12
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Baldicano AK, Nasir-Ahmad S, Novelli M, Lee SCS, Do MTH, Martin PR, Grünert U. Retinal ganglion cells expressing CaM kinase II in human and nonhuman primates. J Comp Neurol 2022; 530:1470-1493. [PMID: 35029299 PMCID: PMC9010361 DOI: 10.1002/cne.25292] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2021] [Revised: 12/19/2021] [Accepted: 12/20/2021] [Indexed: 11/07/2022]
Abstract
Immunoreactivity for calcium-/calmodulin-dependent protein kinase II (CaMKII) in the primate dorsal lateral geniculate nucleus (dLGN) has been attributed to geniculocortical relay neurons and has also been suggested to arise from terminals of retinal ganglion cells. Here, we combined immunostaining with single-cell injections to investigate the expression of CaMKII in retinal ganglion cells of three primate species: macaque (Macaca fascicularis, M. nemestrina), human, and marmoset (Callithrix jacchus). We found that in all species, about 2%-10% of the total ganglion cell population expressed CaMKII. In all species, CaMKII was expressed by multiple types of wide-field ganglion cell including large sparse, giant sparse (melanopsin-expressing), broad thorny, and narrow thorny cells. Three other ganglion cells types, namely, inner and outer stratifying maze cells in macaque and tufted cells in marmoset were also found. Double labeling experiments showed that CaMKII-expressing cells included inner and outer stratifying melanopsin cells. Nearly all CaMKII-expressing ganglion cell types identified here are known to project to the koniocellular layers of the dLGN as well as to the superior colliculus. The best characterized koniocellular projecting cell type-the small bistratified (blue ON/yellow OFF) cell-was, however, not CaMKII-positive in any species. Our results indicate that the pattern of CaMKII expression in retinal ganglion cells is largely conserved across different species of primate suggesting a common functional role. But the results also show that CaMKII is not a marker for all koniocellular projecting retinal ganglion cells.
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Affiliation(s)
- Alyssa K Baldicano
- Save Sight Institute and Discipline of Ophthalmology, Faculty of Medicine and Health, The University of Sydney, Sydney, NSW, Australia
| | - Subha Nasir-Ahmad
- Save Sight Institute and Discipline of Ophthalmology, Faculty of Medicine and Health, The University of Sydney, Sydney, NSW, Australia.,Australian Research Council Centre of Excellence for Integrative Brain Function, The University of Sydney, Sydney, NSW, 2000, Australia
| | - Mario Novelli
- Save Sight Institute and Discipline of Ophthalmology, Faculty of Medicine and Health, The University of Sydney, Sydney, NSW, Australia
| | - Sammy C S Lee
- Save Sight Institute and Discipline of Ophthalmology, Faculty of Medicine and Health, The University of Sydney, Sydney, NSW, Australia.,Australian Research Council Centre of Excellence for Integrative Brain Function, The University of Sydney, Sydney, NSW, 2000, Australia
| | - Michael Tri H Do
- F.M. Kirby Neurobiology Center and Department of Neurology, Boston Children's Hospital and Harvard Medical School, Boston, Massachusetts, USA
| | - Paul R Martin
- Save Sight Institute and Discipline of Ophthalmology, Faculty of Medicine and Health, The University of Sydney, Sydney, NSW, Australia.,Australian Research Council Centre of Excellence for Integrative Brain Function, The University of Sydney, Sydney, NSW, 2000, Australia
| | - Ulrike Grünert
- Save Sight Institute and Discipline of Ophthalmology, Faculty of Medicine and Health, The University of Sydney, Sydney, NSW, Australia.,Australian Research Council Centre of Excellence for Integrative Brain Function, The University of Sydney, Sydney, NSW, 2000, Australia
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13
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Nasir-Ahmad S, Vanstone KA, Novelli M, Lee SCS, Do MTH, Martin PR, Grünert U. Satb1 expression in retinal ganglion cells of marmosets, macaques, and humans. J Comp Neurol 2022; 530:923-940. [PMID: 34622958 PMCID: PMC8831458 DOI: 10.1002/cne.25258] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2021] [Revised: 09/28/2021] [Accepted: 10/01/2021] [Indexed: 12/18/2022]
Abstract
Recent advances in single-cell RNA sequencing have enabled the molecular distinction of ganglion cell populations in mammalian retinas. Here we used antibodies against the transcription factor special AT-rich binding protein 1 (Satb1, a protein which is expressed by on-off direction-selective ganglion cells in mouse retina) to study Satb1 expression in the retina of marmosets (Callithrix jacchus), macaques (Macaca fascicularis), and humans. In all species, Satb1 was exclusively expressed in retinal ganglion cells. The Satb1 cells made up ∼2% of the ganglion cell population in the central retina of all species, rising to a maximum ∼7% in peripheral marmoset retina. Intracellular injections in marmoset and macaque retinas revealed that most Satb1 expressing ganglion cells are widefield ganglion cells. In marmoset, Satb1 cells have a densely branching dendritic tree and include broad and narrow thorny, recursive bistratified, and parasol cells, all of which show some costratification with the outer or inner cholinergic amacrine cells. The recursive bistratified cells showed the strongest costratification but did not show extensive cofasciculation as reported for on-off direction-selective ganglion cells in rabbit and rodent retinas. In macaque, Satb1 was not expressed in recursive bistratified cells, but in large sparsely branching cells. Our findings further support the idea that the expression of transcription factors in retinal ganglion cells is not conserved across Old World (human and macaque) and New World (marmoset) primates and provides a further step to link a molecular marker with specific cell types.
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Affiliation(s)
- Subha Nasir-Ahmad
- Faculty of Medicine and Health, Save Sight Institute, and Discipline of Ophthalmology, The University of Sydney, Sydney, Australia.,Australian Research Council Centre of Excellence for Integrative Brain Function, Sydney Node, The University of Sydney, Sydney, Australia
| | - Kurt A Vanstone
- Faculty of Medicine and Health, Save Sight Institute, and Discipline of Ophthalmology, The University of Sydney, Sydney, Australia
| | - Mario Novelli
- Faculty of Medicine and Health, Save Sight Institute, and Discipline of Ophthalmology, The University of Sydney, Sydney, Australia
| | - Sammy C S Lee
- Faculty of Medicine and Health, Save Sight Institute, and Discipline of Ophthalmology, The University of Sydney, Sydney, Australia.,Australian Research Council Centre of Excellence for Integrative Brain Function, Sydney Node, The University of Sydney, Sydney, Australia
| | - Michael Tri H Do
- F.M. Kirby Neurobiology Center and Department of Neurology, Boston Children's Hospital and Harvard Medical School, Boston, Massachusetts, USA
| | - Paul R Martin
- Faculty of Medicine and Health, Save Sight Institute, and Discipline of Ophthalmology, The University of Sydney, Sydney, Australia.,Australian Research Council Centre of Excellence for Integrative Brain Function, Sydney Node, The University of Sydney, Sydney, Australia
| | - Ulrike Grünert
- Faculty of Medicine and Health, Save Sight Institute, and Discipline of Ophthalmology, The University of Sydney, Sydney, Australia.,Australian Research Council Centre of Excellence for Integrative Brain Function, Sydney Node, The University of Sydney, Sydney, Australia
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14
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Paknahad J, Humayun M, Lazzi G. Selective Activation of Retinal Ganglion Cell Subtypes Through Targeted Electrical Stimulation Parameters. IEEE Trans Neural Syst Rehabil Eng 2022; 30:350-359. [PMID: 35130164 PMCID: PMC8904155 DOI: 10.1109/tnsre.2022.3149967] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
To restore vision to the low vision, epiretinal implants have been developed to electrically stimulate the healthy retinal ganglion cells (RGCs) in the degenerate retina. Given the diversity of retinal ganglion cells as well as the difference in their visual function, selective activation of RGCs subtypes can significantly improve the quality of the restored vision. Our recent results demonstrated that with the proper modulation of the current amplitude, small D1-bistratified cells with the contribution to blue/yellow color opponent pathway can be selectively activated at high frequency (200 Hz). The computational results correlated with the clinical findings revealing the blue sensation of 5/7 subjects with epiretinal implants at high frequency. Here we further explored the impacts of alterations in pulse duration and interphase gap on the response of RGCs at high frequency. We used the developed RGCs, A2-monostratified and D1-bistratified, and examined their response to a range of pulse durations (0.1−1.2 ms) and interphase gaps (0−1 ms). We found that the use of short pulse durations with no interphase gap at high frequency increases the differential response of RGCs, offering better opportunities for selective activation of D1 cells. The presence of the interphase gap has shown to reduce the overall differential response of RGCs. We also explored how the low density of calcium channels enhances the responsiveness of RGCs at high frequency.
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15
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Roberts JW, Bennett SJ. Online control of rapid target-directed aiming using blurred visual feedback. Hum Mov Sci 2021; 81:102917. [PMID: 34954624 DOI: 10.1016/j.humov.2021.102917] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2021] [Revised: 12/11/2021] [Accepted: 12/15/2021] [Indexed: 11/04/2022]
Abstract
The accuracy and precision of target-directed aiming is contingent upon the availability of online visual feedback. The present study aimed to examine the visual regulation of aiming with blurred vision. The aiming task was executed using a stylus on a graphics digitizing board, which was translated onto a screen in the form of a cursor (representing the moving limb) and target. The vision conditions involved the complete disappearance or blur of the cursor alone, target alone, and cursor+target. These conditions involved leaving the screen uncovered or covering with a diffusing sheet to induce blur. The distance between the screen and sheet was increased to make the blur progressively more severe (0 cm, 3 cm). Results showed significantly less radial and variable error under blurred compared to no vision of the cursor and cursor+target. These findings were corroborated by the movement kinematics including a shorter proportion of time to peak velocity, more negative within-participant correlation between the distances travelled to and after peak velocity, and lower spatial variability from peak velocity to the end of the movement under blurred vision. The superior accuracy and precision under the blurred compared to no vision conditions is consistent with functioning visual regulation of aiming, which is primarily contingent upon the online visual feedback of the moving limb. This outcome may be attributed to the processing of low spatial-high temporal frequencies. Potential implications for low vision diagnostics are discussed.
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Affiliation(s)
- James W Roberts
- Liverpool Hope University, Psychology, Action and Learning of Movement (PALM) Laboratory, School of Health Sciences, Liverpool L16 9JD, UK.
| | - Simon J Bennett
- Liverpool John Moores University, Research Institute of Sport & Exercise Sciences, Brain & Behaviour Research Group, Liverpool L3 5AF, UK
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16
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Kislinger L. Photographs of Actions: What Makes Them Special Cues to Social Perception. Brain Sci 2021; 11:brainsci11111382. [PMID: 34827381 PMCID: PMC8615998 DOI: 10.3390/brainsci11111382] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2021] [Revised: 10/18/2021] [Accepted: 10/18/2021] [Indexed: 11/16/2022] Open
Abstract
I have reviewed studies on neural responses to pictured actions in the action observation network (AON) and the cognitive functions of these responses. Based on this review, I have analyzed the specific representational characteristics of action photographs. There has been consensus that AON responses provide viewers with knowledge of observed or pictured actions, but there has been controversy about the properties of this knowledge. Is this knowledge causally provided by AON activities or is it dependent on conceptual processing? What elements of actions does it refer to, and how generalized or specific is it? The answers to these questions have come from studies that used transcranial magnetic stimulation (TMS) to stimulate motor or somatosensory cortices. In conjunction with electromyography (EMG), TMS allows researchers to examine changes of the excitability in the corticospinal tract and muscles of people viewing pictured actions. The timing of these changes and muscle specificity enable inferences to be drawn about the cognitive products of processing pictured actions in the AON. Based on a review of studies using TMS and other neuroscience methods, I have proposed a novel hypothetical account that describes the characteristics of action photographs that make them effective cues to social perception. This account includes predictions that can be tested experimentally.
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17
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Werth R. Is Developmental Dyslexia Due to a Visual and Not a Phonological Impairment? Brain Sci 2021; 11:1313. [PMID: 34679378 PMCID: PMC8534212 DOI: 10.3390/brainsci11101313] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2021] [Revised: 09/21/2021] [Accepted: 09/27/2021] [Indexed: 11/16/2022] Open
Abstract
It is a widely held belief that developmental dyslexia (DD) is a phonological disorder in which readers have difficulty associating graphemes with their corresponding phonemes. In contrast, the magnocellular theory of dyslexia assumes that DD is a visual disorder caused by dysfunctional magnocellular neural pathways. The review explores arguments for and against these theories. Recent results have shown that DD is caused by (1) a reduced ability to simultaneously recognize sequences of letters that make up words, (2) longer fixation times required to simultaneously recognize strings of letters, and (3) amplitudes of saccades that do not match the number of simultaneously recognized letters. It was shown that pseudowords that could not be recognized simultaneously were recognized almost without errors when the fixation time was extended. However, there is an individual maximum number of letters that each reader with DD can recognize simultaneously. Findings on the neurobiological basis of temporal summation have shown that a necessary prolongation of fixation times is due to impaired processing mechanisms of the visual system, presumably involving magnocells and parvocells. An area in the mid-fusiform gyrus also appears to play a significant role in the ability to simultaneously recognize words and pseudowords. The results also contradict the assumption that DD is due to a lack of eye movement control. The present research does not support the assumption that DD is caused by a phonological disorder but shows that DD is due to a visual processing dysfunction.
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Affiliation(s)
- Reinhard Werth
- Institute for Social Pediatrics and Adolescent Medicine, University of Munich, Haydnstrasse 5, D-80336 Munich, Germany
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18
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Abstract
Our sense of sight relies on photoreceptors, which transduce photons into the nervous system's electrochemical interpretation of the visual world. These precious photoreceptors can be disrupted by disease, injury, and aging. Once photoreceptors start to die, but before blindness occurs, the remaining retinal circuitry can withstand, mask, or exacerbate the photoreceptor deficit and potentially be receptive to newfound therapies for vision restoration. To maximize the retina's receptivity to therapy, one must understand the conditions that influence the state of the remaining retina. In this review, we provide an overview of the retina's structure and function in health and disease. We analyze a collection of observations on photoreceptor disruption and generate a predictive model to identify parameters that influence the retina's response. Finally, we speculate on whether the retina, with its remarkable capacity to function over light levels spanning nine orders of magnitude, uses these same adaptational mechanisms to withstand and perhaps mask photoreceptor loss.
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Affiliation(s)
- Joo Yeun Lee
- Department of Ophthalmology, University of California, San Francisco, California 94143, USA; , , ,
| | - Rachel A Care
- Department of Ophthalmology, University of California, San Francisco, California 94143, USA; , , ,
| | - Luca Della Santina
- Department of Ophthalmology, University of California, San Francisco, California 94143, USA; , , ,
- Bakar Computational Health Sciences Institute, University of California, San Francisco, California 94143, USA
| | - Felice A Dunn
- Department of Ophthalmology, University of California, San Francisco, California 94143, USA; , , ,
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19
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Grünert U, Martin PR. Morphology, Molecular Characterization, and Connections of Ganglion Cells in Primate Retina. Annu Rev Vis Sci 2021; 7:73-103. [PMID: 34524877 DOI: 10.1146/annurev-vision-100419-115801] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
The eye sends information about the visual world to the brain on over 20 parallel signal pathways, each specialized to signal features such as spectral reflection (color), edges, and motion of objects in the environment. Each pathway is formed by the axons of a separate type of retinal output neuron (retinal ganglion cell). In this review, we summarize what is known about the excitatory retinal inputs, brain targets, and gene expression patterns of ganglion cells in humans and nonhuman primates. We describe how most ganglion cell types receive their input from only one or two of the 11 types of cone bipolar cell and project selectively to only one or two target regions in the brain. We also highlight how genetic methods are providing tools to characterize ganglion cells and establish cross-species homologies.
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Affiliation(s)
- Ulrike Grünert
- Save Sight Institute, Faculty of Medicine and Health, The University of Sydney, Sydney NSW 2000, Australia; , .,Sydney Node, Australian Research Council Centre of Excellence for Integrative Brain Function, The University of Sydney, Sydney NSW 2000, Australia
| | - Paul R Martin
- Save Sight Institute, Faculty of Medicine and Health, The University of Sydney, Sydney NSW 2000, Australia; , .,Sydney Node, Australian Research Council Centre of Excellence for Integrative Brain Function, The University of Sydney, Sydney NSW 2000, Australia
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20
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Hepschke JL, Martin PR, Fraser CL. Short-Wave Sensitive ("Blue") Cone Activation Is an Aggravating Factor for Visual Snow Symptoms. Front Neurol 2021; 12:697923. [PMID: 34489849 PMCID: PMC8418220 DOI: 10.3389/fneur.2021.697923] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2021] [Accepted: 06/29/2021] [Indexed: 11/13/2022] Open
Abstract
Background and Purpose: Visual Snow (VS) is a disorder characterised by the subjective perception of black-and-white visual static. The aetiology of this condition is not known. In our previous work we suggested that there is a link between short-wave (S or “blue” cone) signals and severity of visual snow symptoms. Therefore we aimed to further characterise this potential link. Methods: Patients (n = 22) with classic VS based on the diagnostic criteria and healthy controls (n = 12), underwent Intuitive Colorimetry (IC) testing (Cerium Visual Technologies). Twelve hue directions (expressed as angle in CIE 1976 LUV space relative to D65) were rated on a five-point scale from preferred (relieving, positive score) to non-preferred (exacerbating, negative score), and overall preferred and non-preferred angles were chosen. Results: A non-preferred violet region near the tritanopic confusion line / S-cone axis (267 deg.) was strongly associated with exacerbation of VS symptoms (range 250–310 deg, mean 276 ± 16, n = 20, Rayleigh p < 0.001). Two subjects with non-preferred region > 90 deg from mean were considered as outliers. Median rank at hue angle 270 deg was significantly lower than at angle 90 (−1.5 vs. 0.0, p < 0.001, Wilcoxon non-parametric rank-sum test). Patients showed preference for one of two spectral regions which relieved VS symptoms: orange-yellow (range 50–110 deg., mean 79 ± 24, n = 14) and turquoise-blue (range (210–250 deg., mean 234 ± 27, n = 8). Conclusion: Our results show that visual snow symptoms are exacerbated by colour modulation that selectively increased levels of S-cone excitation. Because S-cone signals travel on primordial brain pathways that regulate cortical rhythms (koniocellular pathways) we hypothesis that these pathways contribute to the pathogenesis of this disorder.
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Affiliation(s)
- Jenny L Hepschke
- Faculty of Health and Medicine, Save Sight Institute, The University of Sydney, Sydney, NSW, Australia
| | - Paul R Martin
- Faculty of Health and Medicine, Save Sight Institute, The University of Sydney, Sydney, NSW, Australia
| | - Clare L Fraser
- Faculty of Health and Medicine, Save Sight Institute, The University of Sydney, Sydney, NSW, Australia
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21
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Nunez V, Gordon J, Shapley RM. A multiplicity of color-responsive cortical mechanisms revealed by the dynamics of cVEPs. Vision Res 2021; 188:234-245. [PMID: 34388605 DOI: 10.1016/j.visres.2021.07.017] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2021] [Revised: 07/26/2021] [Accepted: 07/28/2021] [Indexed: 10/20/2022]
Abstract
Our results connect higher-order color mechanisms deduced from psychophysics with the known diversity of populations of double-opponent, color-responsive cells in V1. We used the chromatic visual evoked potential, the cVEP, to study responses in human visual cortex to equiluminant color patterns. Stimuli were modulated along three directions in color space: the cardinal directions, L-M and S, and along the line in color space from the white point to the color of the Red LED in the display screen (the Red direction). The Red direction is roughly intermediate between L-M and S in DKL space in cone-contrast coordinates. While cVEP response amplitude, latency, and width--and their dependences on cone contrast-- were similar in the L-M and Red directions, the Transientness of the Red response was significantly greater than for responses to stimuli in the L-M direction and in the S direction. This difference in response dynamics supports the concept that there are multiple, distinct neuronal populations, so-called higher- order color mechanisms, for color perception within human V1 cortex.
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Affiliation(s)
- Valerie Nunez
- Center for Neural Science, New York University, 4 Washington Place, New York, NY 10003, USA.
| | - James Gordon
- Center for Neural Science, New York University, 4 Washington Place, New York, NY 10003, USA; Psychology Department, CUNY Hunter College, 695 Park Ave, New York, NY 10065, USA
| | - Robert M Shapley
- Center for Neural Science, New York University, 4 Washington Place, New York, NY 10003, USA
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22
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Chen J, Gegenfurtner KR. Electrophysiological evidence for higher-level chromatic mechanisms in humans. J Vis 2021; 21:12. [PMID: 34357373 PMCID: PMC8354086 DOI: 10.1167/jov.21.8.12] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2020] [Accepted: 07/13/2021] [Indexed: 11/24/2022] Open
Abstract
Color vision in humans starts with three types of cones (short [S], medium [M], and long [L] wavelengths) in the retina and three retinal and subcortical cardinal mechanisms, which linearly combine cone signals into the luminance channel (L + M), the red-green channel (L - M), and the yellow-blue channel (S-(L + M)). Chromatic mechanisms at the cortical level, however, are less well characterized. The present study investigated such higher-order chromatic mechanisms by recording electroencephalograms (EEGs) on human observers in a noise masking paradigm. Observers viewed colored stimuli that consisted of a target embedded in noise. Color directions of the target and noise varied independently and systematically in an isoluminant plane of color space. The target was flickering on-off at 3 Hz, eliciting steady-state visual evoked potential (SSVEP) responses. As a result, the masking strength could be estimated from the SSVEP amplitude in the presence of 6 Hz noise. Masking was strongest (i.e. target eliciting smallest SSVEPs) when the target and noise were along the same color direction, and was weakest (i.e. target eliciting highest SSVEPs) when the target and noise were along orthogonal directions. This pattern of results was observed both when the target color varied along the cardinal and intermediate directions, which is evidence for higher-order chromatic mechanisms tuned to intermediate axes. The SSVEP result can be well predicted by a model with multiple broadly tuned chromatic mechanisms. In contrast, a model with only cardinal mechanisms failed to account for the data. These results provide strong electrophysiological evidence for multiple chromatic mechanisms in the early visual cortex of humans.
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Affiliation(s)
- Jing Chen
- School of Psychology, Shanghai University of Sport, Shanghai, China
- https://orcid.org/0000-0002-3038-1786
| | - Karl R Gegenfurtner
- Abteilung Allgemeine Psychologie and Center for Mind, Brain & Behavior, Justus-Liebig-Universität Gießen, Gießen, Germany
- https://www.allpsych.uni-giessen.de/karl/
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23
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Grünert U, Lee SCS, Kwan WC, Mundinano IC, Bourne JA, Martin PR. Retinal ganglion cells projecting to superior colliculus and pulvinar in marmoset. Brain Struct Funct 2021; 226:2745-2762. [PMID: 34021395 DOI: 10.1007/s00429-021-02295-8] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2021] [Accepted: 05/08/2021] [Indexed: 12/29/2022]
Abstract
We determined the retinal ganglion cell types projecting to the medial subdivision of inferior pulvinar (PIm) and the superior colliculus (SC) in the common marmoset monkey, Callithrix jacchus. Adult marmosets received a bidirectional tracer cocktail into the PIm (conjugated to Alexa fluor 488), and the SC (conjugated to Alexa fluor 594) using an MRI-guided approach. One SC injection included the pretectum. The large majority of retrogradely labelled cells were obtained from SC injections, with only a small proportion obtained after PIm injections. Retrogradely labelled cells were injected intracellularly in vitro using lipophilic dyes (DiI, DiO). The SC and PIm both received input from a variety of ganglion cell types. Input to the PIm was dominated by broad thorny (41%), narrow thorny (24%) and large bistratified (25%) ganglion cells. Input to the SC was dominated by parasol (37%), broad thorny (24%) and narrow thorny (17%) cells. Midget ganglion cells (which make up the large majority of primate retinal ganglion cells) and small bistratified (blue-ON/yellow OFF) cells were never observed to project to SC or PIm. Small numbers of other wide-field ganglion cell types were also encountered. Giant sparse (presumed melanopsin-expressing) cells were only seen following the tracer injection which included the pretectum. We note that despite the location of pulvinar complex in dorsal thalamus, and its increased size and functional importance in primate evolution, the retinal projections to pulvinar have more in common with SC projections than they do with projections to the dorsal lateral geniculate nucleus.
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Affiliation(s)
- Ulrike Grünert
- Save Sight Institute, Discipline of Clinical Ophthalmology, Sydney Medical School, The University of Sydney, 8 Macquarie Street, Sydney, NSW, 2000, Australia.
- Australian Research Council Centre of Excellence for Integrative Brain Function, Sydney Node, The University of Sydney, Sydney, NSW, 2000, Australia.
| | - Sammy C S Lee
- Save Sight Institute, Discipline of Clinical Ophthalmology, Sydney Medical School, The University of Sydney, 8 Macquarie Street, Sydney, NSW, 2000, Australia
- Australian Research Council Centre of Excellence for Integrative Brain Function, Sydney Node, The University of Sydney, Sydney, NSW, 2000, Australia
| | - William C Kwan
- Australian Regenerative Medicine Institute, Monash University, Clayton, VIC, Australia
| | | | - James A Bourne
- Australian Regenerative Medicine Institute, Monash University, Clayton, VIC, Australia
| | - Paul R Martin
- Save Sight Institute, Discipline of Clinical Ophthalmology, Sydney Medical School, The University of Sydney, 8 Macquarie Street, Sydney, NSW, 2000, Australia
- Australian Research Council Centre of Excellence for Integrative Brain Function, Sydney Node, The University of Sydney, Sydney, NSW, 2000, Australia
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24
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Li Y, Zhang F, Sun M, Lai L, Lv X, Liu C, Wang M, Wang N. Safety and Long-term Scleral Biomechanical Stability of Rhesus Eyes after Scleral Cross-linking by Blue Light. Curr Eye Res 2021; 46:1061-1070. [PMID: 33213212 DOI: 10.1080/02713683.2020.1853781] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Abstract
Purpose: To assess the safety and long-term scleral biomechanical stability of rhesus eyes after blue light scleral CXL by investigating the biomechanical and microstructural changes.Methods: Seven rhesus monkeys (14 eyes) were observed in this study. All right eyes received blue light scleral CXL at the superior temporal equatorial sclera, and the left eyes served as controls. Biological ocular parameters were followed up to 1 year after scleral CXL. Stress-strain measurements of three rhesus sclera were measured, three rhesus retinas were examined histologically by H&E and TUNEL staining. And the microstructure of both the sclera and retina were observed by transmission electron microscopy at 1 year.Results: As for the retinal thickness, choroidal thickness, flow density of retinal superficial vascular networks and flash electroretinography (f-ERG) results, no significant differences were observed between the paired eyes at 1 year (P >.05). At the same time, the scleral collagen fibril distribution was much tighter, and the scleral biomechanical properties were significantly increased in the experimental eyes. However, apoptotic cells and retinal ultrastructural changes could still be found in the retina of the experimental eyes.Conclusion: This study demonstrates that blue light scleral CXL could effectively increase the scleral stiffness of the rhesus eye for at least 1 year, but ultrastructural change was still observed in the retina of scleral CXL eye. Therefore, the long-term intraocular safety of the blue light scleral CXL technique for preventing myopia progression should be investigated further.
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Affiliation(s)
- Yu Li
- Beijing Tongren Eye Center, Beijing Tongren Hospital, Capital Medical University, Beijing Ophthalmology & Visual Sciences Key Lab, Beijing, China
| | - Fengju Zhang
- Beijing Tongren Eye Center, Beijing Tongren Hospital, Capital Medical University, Beijing Ophthalmology & Visual Sciences Key Lab, Beijing, China
| | - Mingshen Sun
- Beijing Tongren Eye Center, Beijing Tongren Hospital, Capital Medical University, Beijing Ophthalmology & Visual Sciences Key Lab, Beijing, China
| | - Lingbo Lai
- Beijing Tongren Eye Center, Beijing Tongren Hospital, Capital Medical University, Beijing Ophthalmology & Visual Sciences Key Lab, Beijing, China
| | - Xiaotong Lv
- Beijing Tongren Eye Center, Beijing Tongren Hospital, Capital Medical University, Beijing Ophthalmology & Visual Sciences Key Lab, Beijing, China
| | - Chong Liu
- Beijing Tongren Eye Center, Beijing Tongren Hospital, Capital Medical University, Beijing Ophthalmology & Visual Sciences Key Lab, Beijing, China
| | - Mengmeng Wang
- Hebei Ophthalmology Key Lab, Hebei Eye Hospital, Xingtai, Hebei Province, China
| | - Ningli Wang
- Beijing Tongren Eye Center, Beijing Tongren Hospital, Capital Medical University, Beijing Ophthalmology & Visual Sciences Key Lab, Beijing, China
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25
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Paknahad J, Loizos K, Yue L, Humayun MS, Lazzi G. Color and cellular selectivity of retinal ganglion cell subtypes through frequency modulation of electrical stimulation. Sci Rep 2021; 11:5177. [PMID: 33664347 PMCID: PMC7933163 DOI: 10.1038/s41598-021-84437-w] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2020] [Accepted: 02/15/2021] [Indexed: 01/31/2023] Open
Abstract
Epiretinal prostheses aim at electrically stimulating the inner most surviving retinal cells-retinal ganglion cells (RGCs)-to restore partial sight to the blind. Recent tests in patients with epiretinal implants have revealed that electrical stimulation of the retina results in the percept of color of the elicited phosphenes, which depends on the frequency of stimulation. This paper presents computational results that are predictive of this finding and further support our understanding of the mechanisms of color encoding in electrical stimulation of retina, which could prove pivotal for the design of advanced retinal prosthetics that elicit both percept and color. This provides, for the first time, a directly applicable "amplitude-frequency" stimulation strategy to "encode color" in future retinal prosthetics through a predictive computational tool to selectively target small bistratified cells, which have been shown to contribute to "blue-yellow" color opponency in the retinal circuitry. The presented results are validated with experimental data reported in the literature and correlated with findings in blind patients with a retinal prosthetic implant collected by our group.
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Affiliation(s)
- Javad Paknahad
- grid.42505.360000 0001 2156 6853Department of Electrical Engineering, University of Southern California, Los Angeles, CA USA ,grid.42505.360000 0001 2156 6853The Institute for Technology and Medical Systems (ITEMS), Keck School of Medicine, University of Southern California, Los Angeles, CA USA
| | - Kyle Loizos
- grid.42505.360000 0001 2156 6853The Institute for Technology and Medical Systems (ITEMS), Keck School of Medicine, University of Southern California, Los Angeles, CA USA
| | - Lan Yue
- grid.42505.360000 0001 2156 6853Roski Eye Institute, University of Southern California, Los Angeles, CA USA
| | - Mark S. Humayun
- grid.42505.360000 0001 2156 6853Roski Eye Institute, University of Southern California, Los Angeles, CA USA ,grid.42505.360000 0001 2156 6853Departments of Ophthalmology and Biomedical Engineering, University of Southern California, Los Angeles, CA USA
| | - Gianluca Lazzi
- grid.42505.360000 0001 2156 6853Department of Electrical Engineering, University of Southern California, Los Angeles, CA USA ,grid.42505.360000 0001 2156 6853The Institute for Technology and Medical Systems (ITEMS), Keck School of Medicine, University of Southern California, Los Angeles, CA USA ,grid.42505.360000 0001 2156 6853Departments of Ophthalmology and Biomedical Engineering, University of Southern California, Los Angeles, CA USA
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Shah NP, Chichilnisky EJ. Computational challenges and opportunities for a bi-directional artificial retina. J Neural Eng 2020; 17:055002. [PMID: 33089827 DOI: 10.1088/1741-2552/aba8b1] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
A future artificial retina that can restore high acuity vision in blind people will rely on the capability to both read (observe) and write (control) the spiking activity of neurons using an adaptive, bi-directional and high-resolution device. Although current research is focused on overcoming the technical challenges of building and implanting such a device, exploiting its capabilities to achieve more acute visual perception will also require substantial computational advances. Using high-density large-scale recording and stimulation in the primate retina with an ex vivo multi-electrode array lab prototype, we frame several of the major computational problems, and describe current progress and future opportunities in solving them. First, we identify cell types and locations from spontaneous activity in the blind retina, and then efficiently estimate their visual response properties by using a low-dimensional manifold of inter-retina variability learned from a large experimental dataset. Second, we estimate retinal responses to a large collection of relevant electrical stimuli by passing current patterns through an electrode array, spike sorting the resulting recordings and using the results to develop a model of evoked responses. Third, we reproduce the desired responses for a given visual target by temporally dithering a diverse collection of electrical stimuli within the integration time of the visual system. Together, these novel approaches may substantially enhance artificial vision in a next-generation device.
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Affiliation(s)
- Nishal P Shah
- Department of Electrical Engineering, Stanford University, Stanford, CA, United States of America. Hansen Experimental Physics Laboratory, Stanford University, Stanford, CA, United States of America. Department of Neurosurgery, Stanford University, Stanford, CA, United States of America. Author to whom any correspondence should be addressed
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Masri RA, Grünert U, Martin PR. Analysis of Parvocellular and Magnocellular Visual Pathways in Human Retina. J Neurosci 2020; 40:8132-8148. [PMID: 33009001 PMCID: PMC7574660 DOI: 10.1523/jneurosci.1671-20.2020] [Citation(s) in RCA: 34] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2020] [Revised: 08/26/2020] [Accepted: 09/22/2020] [Indexed: 12/18/2022] Open
Abstract
Two main subcortical pathways serving conscious visual perception are the midget-parvocellular (P), and the parasol-magnocellular (M) pathways. It is generally accepted that the P pathway serves red-green color vision, but the relative contribution of P and M pathways to spatial vision is a long-standing and unresolved issue. Here, we mapped the spatial sampling properties of P and M pathways across the human retina. Data were obtained from immunolabeled vertical sections of six postmortem male and female human donor retinas and imaged using high-resolution microscopy. Cone photoreceptors, OFF-midget bipolar cells (P pathway), OFF-diffuse bipolar (DB) types DB3a and DB3b (M pathway), and ganglion cells were counted along the temporal horizontal meridian, taking foveal spatial distortions (postreceptoral displacements) into account. We found that the density of OFF-midget bipolar and OFF-midget ganglion cells can support one-to-one connections to 1.05-mm (3.6°) eccentricity. One-to-one connections of cones to OFF-midget bipolar cells are present to at least 10-mm (35°) eccentricity. The OFF-midget ganglion cell array acuity is well-matched to photopic spatial acuity measures throughout the central 35°, but the OFF-parasol array acuity is well below photopic spatial acuity, supporting the view that the P pathway underlies high-acuity spatial vision. Outside the fovea, array acuity of both OFF-midget and OFF-DB cells exceeds psychophysical measures of photopic spatial acuity. We conclude that parasol and midget pathway bipolar cells deliver high-acuity spatial signals to the inner plexiform layer, but outside the fovea, this spatial resolution is lost at the level of ganglion cells.SIGNIFICANCE STATEMENT We make accurate maps of the spatial density and distribution of neurons in the human retina to aid in understanding human spatial vision, interpretation of diagnostic tests, and the implementation of therapies for retinal diseases. Here, we map neurons involved with the midget-parvocellular (P pathway) and parasol-magnocellular (M pathway) through human retina. We find that P-type bipolar cells outnumber M-type bipolar cells at all eccentricities. We show that cone photoreceptors and P-type pathway bipolar cells are tightly connected throughout the retina, but that spatial resolution is lost at the level of the ganglion cells. Overall, the results support the view that the P pathway is specialized to serve both high acuity vision and red-green color vision.
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Affiliation(s)
- Rania A Masri
- Faculty of Medicine and Health, Save Sight Institute and Discipline of Clinical Ophthalmology, The University of Sydney, Sydney, New South Wales 2000, Australia
- Australian Research Council Center of Excellence for Integrative Brain Function, The University of Sydney, Sydney, New South Wales 2000, Australia
| | - Ulrike Grünert
- Faculty of Medicine and Health, Save Sight Institute and Discipline of Clinical Ophthalmology, The University of Sydney, Sydney, New South Wales 2000, Australia
- Australian Research Council Center of Excellence for Integrative Brain Function, The University of Sydney, Sydney, New South Wales 2000, Australia
| | - Paul R Martin
- Faculty of Medicine and Health, Save Sight Institute and Discipline of Clinical Ophthalmology, The University of Sydney, Sydney, New South Wales 2000, Australia
- Australian Research Council Center of Excellence for Integrative Brain Function, The University of Sydney, Sydney, New South Wales 2000, Australia
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Fairless R, Williams SK, Katiyar R, Maxeiner S, Schmitz F, Diem R. ERG Responses in Mice with Deletion of the Synaptic Ribbon Component RIBEYE. Invest Ophthalmol Vis Sci 2020; 61:37. [PMID: 32437548 PMCID: PMC7405791 DOI: 10.1167/iovs.61.5.37] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Purpose To determine the influence of RIBEYE deletion and the resulting absence of synaptic ribbons on retinal light signaling by electroretinography. Methods Full-field flash electroretinograms (ERGs) were recorded in RIBEYE knock-out (KO) and wild-type (WT) littermate mice under photopic and scotopic conditions, with oscillatory potentials (OPs) extracted by digital filtering. Flicker ERGs and ERGs following intravitreal injection of pharmacological agents were also obtained under scotopic conditions. Results The a-wave amplitudes were unchanged between RIBEYE KO and WT mice; however, the b-wave amplitudes were reduced in KOs under scotopic, but not photopic, conditions. Increasing stimulation frequency led to a greater reduction in RIBEYE KO b-wave amplitudes compared with WTs. Furthermore, we observed prominent, supernormal OPs in RIBEYE KO mice in comparison with WT mice. Following intravitreal injections with l-2 amino-4-phosphonobutyric acid and cis-2,3 piperidine dicarboxylic acid to block ON and OFF responses at photoreceptor synapses, OPs were completely abolished in both mice types, indicating a synaptic origin of the prominent OPs in the KOs. Conversely, tetrodotoxin treatment to block voltage-gated Na+ channels/spiking neurons did not differentially affect OPs in WT and KO mice. Conclusions The decreased scotopic b-wave and decreased responses to increased stimulation frequencies are consistent with signaling malfunctions at photoreceptor and inner retinal ribbon synapses. Because phototransduction in the photoreceptor outer segments is unaffected in the KOs, their supernormal OPs presumably result from a dysfunction in retinal synapses. The relatively mild ERG phenotype in KO mice, particularly in the photopic range, is probably caused by compensatory mechanisms in retinal signaling pathways.
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Abstract
We have compared two explanations for poor peripheral binding. Binding is the ability to assign the correct features (e.g., color, direction of motion, orientation) to objects. Wu, Kanai, and Shimojo (Nature, 429(6989), 262, 2004) showed that subjects performed poorly on binding dot color with direction of motion in the periphery. Suzuki, Wolfe, Horowitz, and Noguchi (Vision Research, 82, 58-65, 2013) similarly showed that subjects had trouble binding color with line orientation in the periphery. These authors concluded that performance in the periphery was poor because binding is poor in the periphery. However, both studies used red and green stimuli. We tested an alternative hypothesis, that poor peripheral binding is in part due to poor peripheral red/green color vision. Eccentricity-dependent changes in visual processing cause peripheral red/green vision to be worse than foveal vision. In contrast, blue/yellow vision remains centrifugally more stable. We tested 9 subjects in a replication and extension of Suzuki and colleagues' line orientation judgment, in red and green, and in blue and yellow. There were three central conditions: (1) red (or blue) all horizontal, green (or yellow) all vertical; (2) red (or blue) all vertical, green (or yellow) all horizontal; or (3) random pairing of color and orientation. In both the red/green and the blue/yellow color schemes, peripheral performance was influenced by central line orientation, replicating Suzuki and colleagues. However, the effect with blue/yellow lines was smaller, indicating that poor peripheral "binding," as hypothesized by both Wu and colleagues and Suzuki and colleagues, is due in part to their use of red and green stimuli.
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Parry NRA, Rodrigo-Diaz E, Murray IJ. Anomalous pupillary responses to M-cone onsets are linked to ${\rm L}{:}{\rm M}$L:M ratio. JOURNAL OF THE OPTICAL SOCIETY OF AMERICA. A, OPTICS, IMAGE SCIENCE, AND VISION 2020; 37:A163-A169. [PMID: 32400539 DOI: 10.1364/josaa.382262] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/06/2019] [Accepted: 02/23/2020] [Indexed: 06/11/2023]
Abstract
M-cone stimulation induces a pupil constriction to stimulus offset, whereas, with L cones, the pupil responds conventionally with a constriction to onset. To test the possibility that this paradox is linked to the ${\rm L}{:}{\rm M}$L:M ratio, we measured the strength of the effect by injecting a variable amount of positive or negative luminance contamination on either side of M-cone isolation and identifying a balance point at which the pupil responded equally to onset and offset. Nineteen individuals were recruited. In observers with low ${\rm L}{:}{\rm M}$L:M ratio, the paradoxical effect was weak. There was a significant relationship (${{r}^2} = {0.561}$r2=0.561) between the balance point and ${\rm L}{:}{\rm M}$L:M ratio. The effect is likely to be linked to strong inhibitory signals associated with cone-opponent pathways.
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Danilova MV, Mollon JD. Discrimination of hue angle and discrimination of colorimetric purity assessed with a common metric. JOURNAL OF THE OPTICAL SOCIETY OF AMERICA. A, OPTICS, IMAGE SCIENCE, AND VISION 2020; 37:A226-A236. [PMID: 32400547 DOI: 10.1364/josaa.382382] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/06/2019] [Accepted: 02/17/2020] [Indexed: 06/11/2023]
Abstract
It has been suggested that thresholds for discriminating colorimetric purity are systematically higher than those for discriminating hue angle, a difference captured in Judd's phrase "the super-importance of hue." However, to compare the two types of discrimination, the measured thresholds must be expressed in the same units. An attractive test is offered by measurements along the horizontal lines in the chromaticity diagram of MacLeod and Boynton [ J. Opt. Soc. Am.69, 1183 (1979)JOSAAH0030-394110.1364/JOSA.69.001183], i.e., a chromaticity diagram. A horizontal line that extends radially from the white point represents a variation in colorimetric purity alone (and subjectively a variation that is primarily in saturation). In contrast, a horizontal line that runs along the $x$x axis of the diagram, close to the long-wave spectrum locus, corresponds predominantly to variation in hue angle. Yet, in both cases, only the ratio of the excitations of the long- and middle-wave cones is being modulated, and so the thresholds can be expressed in a common metric. Measuring forced-choice thresholds for 180 ms foveal targets presented on a steady field metameric to Illuminant D65, we do not find general support for Judd's working rule that thresholds for purity are systematically twice those for saturation. Thresholds for colorimetric purity were only a little higher than those for hue angle, and the advantage for hue was seen in only part of the ranges that were tested. However, in the upper-left quadrant of the MacLeod-Boynton diagram, where the excitation of short-wave cones is high and where both hue angle and colorimetric purity vary along any given horizontal line, thresholds were indeed sometimes half those observed for discrimination of purity alone.
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Zele AJ, Dey A, Adhikari P, Feigl B. Rhodopsin and melanopsin contributions to human brightness estimation. JOURNAL OF THE OPTICAL SOCIETY OF AMERICA. A, OPTICS, IMAGE SCIENCE, AND VISION 2020; 37:A145-A153. [PMID: 32400534 DOI: 10.1364/josaa.379182] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/04/2019] [Accepted: 02/09/2020] [Indexed: 06/11/2023]
Abstract
We examined the contributions of rhodopsin and melanopsin to human brightness estimation under dim lighting. Absolute brightness magnitudes were estimated for full-field, rhodopsin-, or melanopsin-equated narrowband lights (${\lambda _{\rm max}}:\;{462}$λmax:462, 499, 525 nm). Our data show that in scotopic illumination ($ - {5.1}$-5.1 to $ - {3.9}\;{\log}\;\unicode{x00B5} {\rm Watts}\cdot{\rm cm}^{ - 2}$-3.9logµWatts⋅cm-2), the perceptual brightness estimates of rhodopic irradiance-equated conditions are independent of their corresponding melanopic irradiance, whereas brightness estimates with melanopic irradiance-equated conditions increase with increasing rhodopic irradiance. In mesopic illumination ($ - {3.4}$-3.4 to $ - {1.9}\;{\log}\;\unicode{x00B5} {\rm Watts}\cdot{\rm cm}^{ - 2}$-1.9logµWatts⋅cm-2), the brightness estimates with both lighting conditions increase with increasing rhodopic or melanopic irradiances. Rhodopsin activation therefore entirely signals scotopic brightness perception and plateaus in mesopic illumination where intrinsic melanopsin contributions become first evident. We infer that all photoreceptor signals are transmitted to higher visual centers for representing scene brightness in scotopic and mesopic illumination through both conventional and melanopsin ganglion cell pathways.
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Munn B, Zeater N, Pietersen AN, Solomon SG, Cheong SK, Martin PR, Gong P. Fractal spike dynamics and neuronal coupling in the primate visual system. J Physiol 2020; 598:1551-1571. [DOI: 10.1113/jp278935] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2019] [Accepted: 12/18/2019] [Indexed: 12/23/2022] Open
Affiliation(s)
- Brandon Munn
- School of Physics University of Sydney Sydney New South Wales 2006 Australia
- Australian Research Council Centre of Excellence for Integrative Brain Function University of Sydney Sydney New South Wales 2006 Australia
| | - Natalie Zeater
- Australian Research Council Centre of Excellence for Integrative Brain Function University of Sydney Sydney New South Wales 2006 Australia
- Save Sight Institute Eye Hospital Campus University of Sydney Sydney New South Wales 2001 Australia
| | - Alexander N. Pietersen
- Australian Research Council Centre of Excellence for Integrative Brain Function University of Sydney Sydney New South Wales 2006 Australia
- Save Sight Institute Eye Hospital Campus University of Sydney Sydney New South Wales 2001 Australia
| | - Samuel G. Solomon
- Discipline of Physiology University of Sydney Sydney New South Wales 2006 Australia
- Department of Experimental Psychology University College London London WC1P 0AH UK
| | - Soon Keen Cheong
- Australian Research Council Centre of Excellence for Integrative Brain Function University of Sydney Sydney New South Wales 2006 Australia
- Save Sight Institute Eye Hospital Campus University of Sydney Sydney New South Wales 2001 Australia
| | - Paul R. Martin
- Australian Research Council Centre of Excellence for Integrative Brain Function University of Sydney Sydney New South Wales 2006 Australia
- Save Sight Institute Eye Hospital Campus University of Sydney Sydney New South Wales 2001 Australia
- Discipline of Physiology University of Sydney Sydney New South Wales 2006 Australia
| | - Pulin Gong
- School of Physics University of Sydney Sydney New South Wales 2006 Australia
- Australian Research Council Centre of Excellence for Integrative Brain Function University of Sydney Sydney New South Wales 2006 Australia
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Grünert U, Martin PR. Cell types and cell circuits in human and non-human primate retina. Prog Retin Eye Res 2020; 78:100844. [PMID: 32032773 DOI: 10.1016/j.preteyeres.2020.100844] [Citation(s) in RCA: 76] [Impact Index Per Article: 19.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2019] [Revised: 01/28/2020] [Accepted: 01/31/2020] [Indexed: 12/12/2022]
Abstract
This review summarizes our current knowledge of primate including human retina focusing on bipolar, amacrine and ganglion cells and their connectivity. We have two main motivations in writing. Firstly, recent progress in non-invasive imaging methods to study retinal diseases mean that better understanding of the primate retina is becoming an important goal both for basic and for clinical sciences. Secondly, genetically modified mice are increasingly used as animal models for human retinal diseases. Thus, it is important to understand to which extent the retinas of primates and rodents are comparable. We first compare cell populations in primate and rodent retinas, with emphasis on how the fovea (despite its small size) dominates the neural landscape of primate retina. We next summarise what is known, and what is not known, about the postreceptoral neurone populations in primate retina. The inventories of bipolar and ganglion cells in primates are now nearing completion, comprising ~12 types of bipolar cell and at least 17 types of ganglion cell. Primate ganglion cells show clear differences in dendritic field size across the retina, and their morphology differs clearly from that of mouse retinal ganglion cells. Compared to bipolar and ganglion cells, amacrine cells show even higher morphological diversity: they could comprise over 40 types. Many amacrine types appear conserved between primates and mice, but functions of only a few types are understood in any primate or non-primate retina. Amacrine cells appear as the final frontier for retinal research in monkeys and mice alike.
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Affiliation(s)
- Ulrike Grünert
- The University of Sydney, Save Sight Institute, Faculty of Medicine and Health, Sydney, NSW, 2000, Australia; Australian Research Council Centre of Excellence for Integrative Brain Function, Sydney Node, The University of Sydney, Sydney, NSW, 2000, Australia.
| | - Paul R Martin
- The University of Sydney, Save Sight Institute, Faculty of Medicine and Health, Sydney, NSW, 2000, Australia; Australian Research Council Centre of Excellence for Integrative Brain Function, Sydney Node, The University of Sydney, Sydney, NSW, 2000, Australia
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Retinogenesis of the Human Fetal Retina: An Apical Polarity Perspective. Genes (Basel) 2019; 10:genes10120987. [PMID: 31795518 PMCID: PMC6947654 DOI: 10.3390/genes10120987] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2019] [Revised: 11/25/2019] [Accepted: 11/26/2019] [Indexed: 12/20/2022] Open
Abstract
The Crumbs complex has prominent roles in the control of apical cell polarity, in the coupling of cell density sensing to downstream cell signaling pathways, and in regulating junctional structures and cell adhesion. The Crumbs complex acts as a conductor orchestrating multiple downstream signaling pathways in epithelial and neuronal tissue development. These pathways lead to the regulation of cell size, cell fate, cell self-renewal, proliferation, differentiation, migration, mitosis, and apoptosis. In retinogenesis, these are all pivotal processes with important roles for the Crumbs complex to maintain proper spatiotemporal cell processes. Loss of Crumbs function in the retina results in loss of the stratified appearance resulting in retinal degeneration and loss of visual function. In this review, we begin by discussing the physiology of vision. We continue by outlining the processes of retinogenesis and how well this is recapitulated between the human fetal retina and human embryonic stem cell (ESC) or induced pluripotent stem cell (iPSC)-derived retinal organoids. Additionally, we discuss the functionality of in utero and preterm human fetal retina and the current level of functionality as detected in human stem cell-derived organoids. We discuss the roles of apical-basal cell polarity in retinogenesis with a focus on Leber congenital amaurosis which leads to blindness shortly after birth. Finally, we discuss Crumbs homolog (CRB)-based gene augmentation.
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Thoreson WB, Dacey DM. Diverse Cell Types, Circuits, and Mechanisms for Color Vision in the Vertebrate Retina. Physiol Rev 2019; 99:1527-1573. [PMID: 31140374 DOI: 10.1152/physrev.00027.2018] [Citation(s) in RCA: 63] [Impact Index Per Article: 12.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023] Open
Abstract
Synaptic interactions to extract information about wavelength, and thus color, begin in the vertebrate retina with three classes of light-sensitive cells: rod photoreceptors at low light levels, multiple types of cone photoreceptors that vary in spectral sensitivity, and intrinsically photosensitive ganglion cells that contain the photopigment melanopsin. When isolated from its neighbors, a photoreceptor confounds photon flux with wavelength and so by itself provides no information about color. The retina has evolved elaborate color opponent circuitry for extracting wavelength information by comparing the activities of different photoreceptor types broadly tuned to different parts of the visible spectrum. We review studies concerning the circuit mechanisms mediating opponent interactions in a range of species, from tetrachromatic fish with diverse color opponent cell types to common dichromatic mammals where cone opponency is restricted to a subset of specialized circuits. Distinct among mammals, primates have reinvented trichromatic color vision using novel strategies to incorporate evolution of an additional photopigment gene into the foveal structure and circuitry that supports high-resolution vision. Color vision is absent at scotopic light levels when only rods are active, but rods interact with cone signals to influence color perception at mesopic light levels. Recent evidence suggests melanopsin-mediated signals, which have been identified as a substrate for setting circadian rhythms, may also influence color perception. We consider circuits that may mediate these interactions. While cone opponency is a relatively simple neural computation, it has been implemented in vertebrates by diverse neural mechanisms that are not yet fully understood.
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Affiliation(s)
- Wallace B Thoreson
- Department of Ophthalmology and Visual Sciences, Truhlsen Eye Institute, University of Nebraska Medical Center , Omaha, Nebraska ; and Department of Biological Structure, Washington National Primate Research Center, University of Washington , Seattle, Washington
| | - Dennis M Dacey
- Department of Ophthalmology and Visual Sciences, Truhlsen Eye Institute, University of Nebraska Medical Center , Omaha, Nebraska ; and Department of Biological Structure, Washington National Primate Research Center, University of Washington , Seattle, Washington
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Abstract
The jawless fish that were ancestral to all living vertebrates had four spectral cone types that were probably served by chromatic-opponent retinal circuits. Subsequent evolution of photoreceptor spectral sensitivities is documented for many vertebrate lineages, giving insight into the ecological adaptation of color vision. Beyond the photoreceptors, retinal color processing is best understood in mammals, especially the blueON system, which opposes short- against long-wavelength receptor responses. For other vertebrates that often have three or four types of cone pigment, new findings from zebrafish are extending older work on teleost fish and reptiles to reveal rich color circuitry. Here, horizontal cells establish diverse and complex spectral responses even in photoreceptor outputs. Cone-selective connections to bipolar cells then set up color-opponent synaptic layers in the inner retina, which lead to a large variety of color-opponent channels for transmission to the brain via retinal ganglion cells.
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Affiliation(s)
- T Baden
- School of Life Sciences, University of Sussex, BN1 9QG Brighton, United Kingdom; ,
- Institute for Ophthalmic Research, University of Tübingen, 72076 Tübingen, Germany
| | - D Osorio
- School of Life Sciences, University of Sussex, BN1 9QG Brighton, United Kingdom; ,
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Connectomic Identification and Three-Dimensional Color Tuning of S-OFF Midget Ganglion Cells in the Primate Retina. J Neurosci 2019; 39:7893-7909. [PMID: 31405926 DOI: 10.1523/jneurosci.0778-19.2019] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2019] [Revised: 06/27/2019] [Accepted: 08/06/2019] [Indexed: 11/21/2022] Open
Abstract
In the trichromatic primate retina, the "midget" retinal ganglion cell is the classical substrate for red-green color signaling, with a circuitry that enables antagonistic responses between long (L)- and medium (M)-wavelength-sensitive cone inputs. Previous physiological studies showed that some OFF midget ganglion cells may receive sparse input from short (S)-wavelength-sensitive cones, but the effect of S-cone inputs on the chromatic tuning properties of such cells has not been explored. Moreover, anatomical evidence for a synaptic pathway from S cones to OFF midget ganglion cells through OFF midget bipolar cells remains ambiguous. In this study, we address both questions for the macaque monkey retina. First, we used serial block-face electron microscopy to show that every S cone in the parafoveal retina synapses principally with a single OFF midget bipolar cell, which in turn forms a private-line connection with an OFF midget ganglion cell. Second, we used patch electrophysiology to characterize the chromatic tuning of OFF midget ganglion cells in the near peripheral retina that receive combined input from L, M, and S cones. These "S-OFF" midget cells have a characteristic S-cone spatial signature, but demonstrate heterogeneous color properties due to the variable strength of L, M, and S cone input across the receptive field. Together, these findings strongly support the hypothesis that the OFF midget pathway is the major conduit for S-OFF signals in primate retina and redefines the pathway as a chromatically complex substrate that encodes color signals beyond the classically recognized L versus M and S versus L+M cardinal mechanisms.SIGNIFICANCE STATEMENT The first step of color processing in the visual pathway of primates occurs when signals from short (S)-, middle (M)-, and long (L)-wavelength-sensitive cone types interact antagonistically within the retinal circuitry to create color-opponent pathways. The midget (L versus M or "red-green") and small bistratified (S vs L+M, or "blue-yellow") ganglion cell pathways appear to provide the physiological origin of the cardinal axes of human color vision. Here we confirm the presence of an additional S-OFF midget circuit in the macaque monkey fovea with scanning block-face electron microscopy and show physiologically that a subpopulation of S-OFF midget cells combine S, L, and M cone inputs along noncardinal directions of color space, expanding the retinal role in color coding.
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Receptive Field Properties of Koniocellular On/Off Neurons in the Lateral Geniculate Nucleus of Marmoset Monkeys. J Neurosci 2018; 38:10384-10398. [PMID: 30327419 DOI: 10.1523/jneurosci.1679-18.2018] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2018] [Revised: 09/12/2018] [Accepted: 10/04/2018] [Indexed: 11/21/2022] Open
Abstract
The koniocellular (K) layers of the primate dorsal lateral geniculate nucleus house a variety of visual receptive field types, not all of which have been fully characterized. Here we made single-cell recordings targeted to the K layers of diurnal New World monkeys (marmosets). A subset of recorded cells was excited by both increments and decrements of light intensity (on/off-cells). Histological reconstruction of the location of these cells confirmed that they are segregated to K layers; we therefore refer to these cells as K-on/off cells. The K-on/off cells show high contrast sensitivity, strong bandpass spatial frequency tuning, and their response magnitude is strongly reduced by stimuli larger than the excitatory receptive field (silent suppressive surrounds). Stationary counterphase gratings evoke unmodulated spike rate increases or frequency-doubled responses in K-on/off cells; such responses are largely independent of grating spatial phase. The K-on/off cells are not orientation or direction selective. Some (but not all) properties of K-on/off cells are consistent with those of local-edge-detector/impressed-by-contrast cells reported in studies of cat retina and geniculate, and broad-thorny ganglion cells recorded in macaque monkey retina. The receptive field properties of K-on/off cells and their preferential location in the ventral K layers (K1 and K2) make them good candidates for the direct projection from geniculate to extrastriate cortical area MT/V5. If so, they could contribute to visual information processing in the dorsal ("where" or "action") visual stream.SIGNIFICANCE STATEMENT We characterize cells in an evolutionary ancient part of the visual pathway in primates. The cells are located in the lateral geniculate nucleus (the main visual afferent relay nucleus), in regions called koniocellular layers that are known to project to extrastriate visual areas as well as primary visual cortex. The cells show high contrast sensitivity and rapid, transient responses to light onset and offset. Their properties suggest they could contribute to visual processing in the dorsal ("where" or "action") visual stream.
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Conway BR, Eskew RT, Martin PR, Stockman A. A tour of contemporary color vision research. Vision Res 2018; 151:2-6. [PMID: 29959956 PMCID: PMC6345392 DOI: 10.1016/j.visres.2018.06.009] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2018] [Revised: 06/12/2018] [Accepted: 06/23/2018] [Indexed: 11/17/2022]
Abstract
The study of color vision encompasses many disciplines, including art, biochemistry, biophysics, brain imaging, cognitive neuroscience, color preferences, colorimetry, computer modelling, design, electrophysiology, language and cognition, molecular genetics, neuroscience, physiological optics, psychophysics and physiological optics. Coupled with the elusive nature of the subjective experience of color, this wide range of disciplines makes the study of color as challenging as it is fascinating. This overview of the special issue Color: Cone Opponency and Beyond outlines the state of the science of color, and points to some of the many questions that remain to be answered in this exciting field.
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Affiliation(s)
- Bevil R Conway
- National Eye Institute and National Institute of Mental Health, National Institutes of Health, Bethesda, MD 20892, USA
| | - Rhea T Eskew
- Department of Psychology, 125 Nightingale Hall, Northeastern University, Boston, MA 02115, USA
| | - Paul R Martin
- Save Sight Institute and School of Medical Sciences, The University of Sydney, Sydney, New South Wales, Australia
| | - Andrew Stockman
- UCL Institute of Ophthalmology, University College London, 11-43 Bath Street, London EC1V 9EL, England, United Kingdom
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Veruki ML, Schubert T. Neural Circuits: When Neurons 'Remember' Their Connectivity. Curr Biol 2018; 28:R662-R664. [PMID: 29870705 DOI: 10.1016/j.cub.2018.04.059] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Loss of neurons due to injury or neurodegeneration can lead to dramatically altered neural circuits, resulting in reduced or lost function. One mechanism to preserve function could be to re-establish the stereotypic connectivity among the remnant neurons. In the mammalian retina, such a selective re-wiring has now been described.
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Affiliation(s)
- Margaret L Veruki
- Department of Biomedicine, University of Bergen, 5009 Bergen, Norway
| | - Timm Schubert
- Centre for Integrative Neuroscience (CIN) and Institute for Ophthalmic Research, University of Tübingen, 72076 Tübingen, Germany.
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42
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Harmonics added to a flickering light can upset the balance between ON and OFF pathways to produce illusory colors. Proc Natl Acad Sci U S A 2018; 115:E4081-E4090. [PMID: 29632212 PMCID: PMC5924891 DOI: 10.1073/pnas.1717356115] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
Abstract
By varying the temporal waveforms of complex flickering stimuli, we can produce alterations in their mean color that can be predicted by a physiologically based model of visual processing. The model highlights the perceptual effects of a well-known feature of most visual pathways, namely the early separation of visual signals into increments and decrements. The role of this separation in improving the efficiency and sensitivity of the visual system has been discussed before, but its effect on perception has been neglected. The application of a model incorporating half-wave rectification offers an exciting psychophysical method for investigating the inner workings of the human visual system. The neural signals generated by the light-sensitive photoreceptors in the human eye are substantially processed and recoded in the retina before being transmitted to the brain via the optic nerve. A key aspect of this recoding is the splitting of the signals within the two major cone-driven visual pathways into distinct ON and OFF branches that transmit information about increases and decreases in the neural signal around its mean level. While this separation is clearly important physiologically, its effect on perception is unclear. We have developed a model of the ON and OFF pathways in early color processing. Using this model as a guide, we can produce imbalances in the ON and OFF pathways by changing the shapes of time-varying stimulus waveforms and thus make reliable and predictable alterations to the perceived average color of the stimulus—although the physical mean of the waveforms does not change. The key components in the model are the early half-wave rectifying synapses that split retinal photoreceptor outputs into the ON and OFF pathways and later sigmoidal nonlinearities in each pathway. The ability to systematically vary the waveforms to change a perceptual quality by changing the balance of signals between the ON and OFF visual pathways provides a powerful psychophysical tool for disentangling and investigating the neural workings of human vision.
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Hathibelagal AR, Feigl B, Zele AJ. Correlated cone noise decreases rod signal contributions to the post-receptoral pathways. JOURNAL OF THE OPTICAL SOCIETY OF AMERICA. A, OPTICS, IMAGE SCIENCE, AND VISION 2018; 35:B78-B84. [PMID: 29603926 DOI: 10.1364/josaa.35.000b78] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/02/2017] [Accepted: 01/21/2018] [Indexed: 06/08/2023]
Abstract
This study investigated how invisible extrinsic temporal white noise that correlates with the activity of one of the three [magnocellular (MC), parvocellular (PC), or koniocellular (KC)] post-receptoral pathways alters mesopic rod signaling. A four-primary photostimulator provided independent control of the rod and three cone photoreceptor excitations. The rod contributions to the three post-receptoral pathways were estimated by perceptually matching a 20% contrast rod pulse by independently varying the LMS (MC pathway), +L-M (PC pathway), and S-cone (KC pathway) excitations. We show that extrinsic cone noise caused a predominant decrease in the overall magnitude and ratio of the rod contributions to each pathway. Thus, the relative cone activity in the post-receptoral pathways determines the relative mesopic rod inputs to each pathway.
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Hathibelagal AR, Feigl B, Cao D, Zele AJ. Extrinsic cone-mediated post-receptoral noise inhibits the rod temporal impulse response function. JOURNAL OF THE OPTICAL SOCIETY OF AMERICA. A, OPTICS, IMAGE SCIENCE, AND VISION 2018; 35:B72-B77. [PMID: 29603925 DOI: 10.1364/josaa.35.000b72] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/02/2017] [Accepted: 01/21/2018] [Indexed: 06/08/2023]
Abstract
We determined how extrinsic white noise correlating with cone inputs to the three primary visual pathways affects both rod-pathway temporal contrast sensitivity and the impulse response function. A four-primary photostimulator provided independent control of rod and cone photoreceptor excitations under mesopic illumination (20 photopic Td). We show that rod-pathway temporal contrast sensitivity uniformly decreases across all temporal frequencies in the presence of cone noise correlating with the inferred magnocellular, parvocellular, or koniocellular pathways. The rod-pathway temporal impulse response functions derived using the Stork-Falk procedure (with a minimum phase assumption) had lower amplitudes in the pathway-specific cone noise. Therefore, cone noise impairs rod-pathway temporal contrast sensitivity without delaying rod-pathway signal transmission.
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45
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Murray IJ, Kremers J, McKeefry D, Parry NRA. Paradoxical pupil responses to isolated M-cone increments. JOURNAL OF THE OPTICAL SOCIETY OF AMERICA. A, OPTICS, IMAGE SCIENCE, AND VISION 2018; 35:B66-B71. [PMID: 29603924 DOI: 10.1364/josaa.35.000b66] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/03/2017] [Accepted: 12/27/2017] [Indexed: 06/08/2023]
Abstract
M-cone onsets appear dimmer than the background and elicit electroretinograms (ERGs) resembling the light offset response. We sought a corresponding anomalous pupillary light reflex (PLR) using a 4-primary ganzfeld as stimulator and pupillometer. Increments and decrements of white light were compared with M- and L-cone onsets and offsets using silent substitution. Luminance bias (LB) could be added to or subtracted from the cone-isolating stimuli. There was a normal PLR to L-cone increments, but the pupil constricted mainly to M-cone decrements. Changing LB produced a neutral point where on and off responses were balanced. The results reflect ERG and psychophysical studies. This observation may be linked to the antagonistic nature of the M-cone input to cone opponent mechanisms.
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46
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Schmidt BP, Touch P, Neitz M, Neitz J. Circuitry to explain how the relative number of L and M cones shapes color experience. J Vis 2017; 16:18. [PMID: 27366885 PMCID: PMC4927209 DOI: 10.1167/16.8.18] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
The wavelength of light that appears unique yellow is surprisingly consistent across people even though the ratio of middle (M) to long (L) wavelength sensitive cones is strikingly variable. This observation has been explained by normalization to the mean spectral distribution of our shared environment. Our purpose was to reconcile the nearly perfect alignment of everyone's unique yellow through a normalization process with the striking variability in unique green, which varies by as much as 60 nm between individuals. The spectral location of unique green was measured in a group of volunteers whose cone ratios were estimated with a technique that combined genetics and flicker photometric electroretinograms. In contrast to unique yellow, unique green was highly dependent upon relative cone numerosity. We hypothesized that the difference in neural architecture of the blue-yellow and red-green opponent systems in the presence of a normalization process creates the surprising dependence of unique green on cone ratio. We then compared the predictions of different theories of color vision processing that incorporate L and M cone ratio and a normalization process. The results of this analysis reveal that—contrary to prevailing notions--postretinal contributions may not be required to explain the phenomena of unique hues.
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47
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Majander A, Robson AG, João C, Holder GE, Chinnery PF, Moore AT, Votruba M, Stockman A, Yu-Wai-Man P. The pattern of retinal ganglion cell dysfunction in Leber hereditary optic neuropathy. Mitochondrion 2017; 36:138-149. [PMID: 28729193 PMCID: PMC5644721 DOI: 10.1016/j.mito.2017.07.006] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2016] [Revised: 07/02/2017] [Accepted: 07/14/2017] [Indexed: 02/07/2023]
Abstract
Leber inherited optic neuropathy (LHON) is characterized by subacute bilateral loss of central vision due to dysfunction and loss of retinal ganglion cells (RGCs). Comprehensive visual electrophysiological investigations (including pattern reversal visual evoked potentials, pattern electroretinography and the photopic negative response) performed on 13 patients with acute and chronic LHON indicate early impairment of RGC cell body function and severe axonal dysfunction. Temporal, spatial and chromatic psychophysical tests performed on 7 patients with acute LHON and 4 patients with chronic LHON suggest severe involvement or loss of the midget, parasol and bistratified RGCs associated with all three principal visual pathways.
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Affiliation(s)
- A Majander
- UCL Institute of Ophthalmology, London, UK; Moorfields Eye Hospital, London, UK; Department of Ophthalmology, University of Helsinki, Helsinki University Hospital, Helsinki, Finland.
| | - A G Robson
- UCL Institute of Ophthalmology, London, UK; Moorfields Eye Hospital, London, UK
| | - C João
- UCL Institute of Ophthalmology, London, UK
| | - G E Holder
- UCL Institute of Ophthalmology, London, UK; Moorfields Eye Hospital, London, UK
| | - P F Chinnery
- MRC-Mitochondrial Biology Unit, Cambridge Biomedical Campus, Cambridge, UK; Department of Clinical Neurosciences, Cambridge Biomedical Campus, University of Cambridge, Cambridge, UK
| | - A T Moore
- UCL Institute of Ophthalmology, London, UK; Moorfields Eye Hospital, London, UK; Ophthalmology Department, UCSF School of Medicine, San Francisco, CA, United States
| | - M Votruba
- School of Optometry and Vision Sciences, Cardiff University, and Cardiff Eye Unit, University Hospital Wales, Cardiff, UK
| | - A Stockman
- UCL Institute of Ophthalmology, London, UK
| | - P Yu-Wai-Man
- UCL Institute of Ophthalmology, London, UK; Moorfields Eye Hospital, London, UK; Department of Clinical Neurosciences, Cambridge Biomedical Campus, University of Cambridge, Cambridge, UK; Wellcome Trust Centre for Mitochondrial Research, Newcastle University, and Newcastle Eye Centre, Royal Victoria Infirmary, Newcastle upon Tyne, UK.
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48
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Wang Z, Fang Y. A hybrid approach for face alignment. PATTERN RECOGNITION AND IMAGE ANALYSIS 2017. [DOI: 10.1134/s1054661817030312] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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49
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Peichl L, Kaiser A, Rakotondraparany F, Dubielzig RR, Goodman SM, Kappeler PM. Diversity of photoreceptor arrangements in nocturnal, cathemeral and diurnal Malagasy lemurs. J Comp Neurol 2017; 527:13-37. [DOI: 10.1002/cne.24167] [Citation(s) in RCA: 51] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2016] [Revised: 12/29/2016] [Accepted: 12/30/2016] [Indexed: 12/23/2022]
Affiliation(s)
- Leo Peichl
- Max Planck Institute for Brain Research; Max-von-Laue-Straße 4, 60438 Frankfurt am Main Germany
- Ernst Strüngmann Institute for Neuroscience; Deutschordenstraße 46, 60528 Frankfurt am Main Germany
- Institute of Cellular and Molecular Anatomy, Dr. Senckenbergische Anatomie, Goethe University Frankfurt; Theodor-Stern-Kai 7, 60590 Frankfurt am Main Germany
| | - Alexander Kaiser
- Department Biology II; Ludwig-Maximilians University Munich; Großhaderner Straße 2-4, 82152 Martinsried-Planegg Germany
- Institute of Zoology; University of Veterinary Medicine Hannover; Bünteweg 17, 30559 Hannover Germany
| | - Felix Rakotondraparany
- Département de Zoologie et Biodiversité Animale; Université d’Antananarivo; BP 906, Antananarivo 101 Madagascar
| | - Richard R. Dubielzig
- School of Veterinary Medicine; University of Wisconsin; 2015 Linden Drive Madison Wisconsin 53706
| | - Steven M. Goodman
- The Field Museum of Natural History; 1400 South Lake Shore Drive, Chicago Illinois 60605
- Association Vahatra; BP 3972, Antananarivo 101 Madagascar
| | - Peter M. Kappeler
- Behavioral Ecology and Sociobiology Unit, German Primate Center; Kellnerweg 4, 37077 Göttingen Germany
- Johann-Friedrich-Blumenbach-Institute of Zoology and Anthropology; University Göttingen; Kellnerweg 6, 37077 Göttingen Germany
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50
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Retinal Lateral Inhibition Provides the Biological Basis of Long-Range Spatial Induction. PLoS One 2016; 11:e0168963. [PMID: 28030651 PMCID: PMC5193432 DOI: 10.1371/journal.pone.0168963] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2016] [Accepted: 12/05/2016] [Indexed: 11/19/2022] Open
Abstract
Retinal lateral inhibition is one of the conventional efficient coding mechanisms in the visual system that is produced by interneurons that pool signals over a neighborhood of presynaptic feedforward cells and send inhibitory signals back to them. Thus, the receptive-field (RF) of a retinal ganglion cell has a center-surround receptive-field (RF) profile that is classically represented as a difference-of-Gaussian (DOG) adequate for efficient spatial contrast coding. The DOG RF profile has been attributed to produce the psychophysical phenomena of brightness induction, in which the perceived brightness of an object is affected by that of its vicinity, either shifting away from it (brightness contrast) or becoming more similar to it (brightness assimilation) depending on the size of the surfaces surrounding the object. While brightness contrast can be modeled using a DOG with a narrow surround, brightness assimilation requires a wide suppressive surround. Early retinal studies determined that the suppressive surround of a retinal ganglion cell is narrow (< 100–300 μm; ‘classic RF’), which led researchers to postulate that brightness assimilation must originate at some post-retinal, possibly cortical, stage where long-range interactions are feasible. However, more recent studies have reported that the retinal interneurons also exhibit a spatially wide component (> 500–1000 μm). In the current study, we examine the effect of this wide interneuron RF component in two biophysical retinal models and show that for both of the retinal models it explains the long-range effect evidenced in simultaneous brightness induction phenomena and that the spatial extent of this long-range effect of the retinal model responses matches that of perceptual data. These results suggest that the retinal lateral inhibition mechanism alone can regulate local as well as long-range spatial induction through the narrow and wide RF components of retinal interneurons, arguing against the existing view that spatial induction is operated by two separate local vs. long-range mechanisms.
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