scholarly journals Beyond colour gamuts: Novel metrics for the reproduction of photoreceptor signals

2021 ◽  
Author(s):  
Allie C. Hexley ◽  
Takuma Morimoto ◽  
Hannah E. Smithson ◽  
Manuel Spitschan
Keyword(s):  
Retinal Ganglion Cells ◽  
Ganglion Cells ◽  
Three Dimensional ◽  
Retinal Ganglion ◽  
Chromaticity Diagram ◽  
Colour Space ◽  
Light Responses ◽  
Light Levels ◽  
Primary Display ◽  
Visual Light

AbstractColour gamuts describe the chromaticity reproduction capabilities of a display, i.e. its ability to reproduce the relative cone excitations from real-world radiance spectra. While the cones dominate “canonical” visual function (i.e. perception of colour, space, and motion) under photopic light levels, they are not the only photoreceptors in the human retina. Rods and melanopsin-containing intrinsically photosensitive retinal ganglion cells (ipRGCs) also respond to light and contribute to both visual and non-visual light responses, including circadian rhythms, sleep-wake control, mood, pupil size, and alertness. Three-primary display technologies, with their focus on reproducing colour, are not designed to reproduce the rod and melanopsin excitations. Moreover, conventional display metrics used to characterize three-primary displays fail to describe the display’s ability (or inability) to reproduce rod and melanopsin excitations, and thus do not capture the display’s ability to reproduce the full human physiological response to light. In this paper, three novel physiologically relevant metrics are proposed for quantifying the reproduction and distortion of the photoreceptor signals by visual displays. A novel equal-luminance photoreceptor excitation diagram is proposed, extending the well-known MacLeod-Boynton chromaticity diagram, to allow visualizations of the five-dimensional photoreceptor signal space in a three-dimensional projection.

scholarly journals Hereditary Optic Neuropathies: Induced Pluripotent Stem Cell-Based 2D/3D Approaches

Genes ◽  
2021 ◽  
Vol 12 (1) ◽  
pp. 112
Author(s):  
Marta García-López ◽  
Joaquín Arenas ◽  
M. Esther Gallardo
Keyword(s):  
Stem Cell ◽  
Retinal Ganglion Cells ◽  
Pluripotent Stem Cell ◽  
Ganglion Cells ◽  
Genetic Disorders ◽  
Three Dimensional ◽  
Induced Pluripotent Stem Cell ◽  
Underlying Mechanism ◽  
Retinal Ganglion ◽  
Induced Pluripotent

Inherited optic neuropathies share visual impairment due to the degeneration of retinal ganglion cells (RGCs) as the hallmark of the disease. This group of genetic disorders are caused by mutations in nuclear genes or in the mitochondrial DNA (mtDNA). An impaired mitochondrial function is the underlying mechanism of these diseases. Currently, optic neuropathies lack an effective treatment, and the implementation of induced pluripotent stem cell (iPSC) technology would entail a huge step forward. The generation of iPSC-derived RGCs would allow faithfully modeling these disorders, and these RGCs would represent an appealing platform for drug screening as well, paving the way for a proper therapy. Here, we review the ongoing two-dimensional (2D) and three-dimensional (3D) approaches based on iPSCs and their applications, taking into account the more innovative technologies, which include tissue engineering or microfluidics.

scholarly journals Intrinsic light responses of retinal ganglion cells projecting to the circadian system

2003 ◽  
Vol 17 (9) ◽  
pp. 1727-1735 ◽  
Author(s):  
Erin J. Warren ◽  
Charles N. Allen ◽  
R. Lane Brown ◽  
David W. Robinson
Keyword(s):  
Retinal Ganglion Cells ◽  
Ganglion Cells ◽  
Circadian System ◽  
Retinal Ganglion ◽  
Light Responses

Investigating visual mechanisms underlying scene brightness

2016 ◽  
Vol 49 (1) ◽  
pp. 16-32 ◽  
Author(s):  
UC Besenecker ◽  
JD Bullough
Keyword(s):  
Retinal Ganglion Cells ◽  
Spectral Sensitivity ◽  
Short Wavelength ◽  
Ganglion Cells ◽  
Forced Choice ◽  
Light Sources ◽  
Retinal Ganglion ◽  
Brightness Perception ◽  
Light Levels ◽  
Relative Brightness

Short-wavelength (<500 nm) output of light sources enhances scene brightness perception in the low-to-moderate photopic range. This appears to be partially explained by a contribution from short-wavelength cones. Recent evidence from experiments on humans suggests that intrinsically photosensitive retinal ganglion cells (ipRGCs) containing the photopigment melanopsin might also contribute to spectral sensitivity for scene brightness perception. An experiment was conducted to investigate this possibility at two different light levels, near 10 lx and near 100 lx. Subjects provided forced-choice brightness judgments and relative brightness magnitude judgments when comparing two different amber-coloured stimuli with similar chromaticities. A provisional brightness metric including an ipRGC contribution was able to predict the data with substantially smaller errors than a metric based on cone input only.

scholarly journals Tailoring of the axon initial segment shapes the conversion of synaptic inputs into spiking output in OFF-α T retinal ganglion cells

2020 ◽  
Vol 6 (37) ◽  
pp. eabb6642
Author(s):  
Paul Werginz ◽  
Vineeth Raghuram ◽  
Shelley I. Fried
Keyword(s):  
Retinal Ganglion Cells ◽  
Initial Segment ◽  
Ganglion Cells ◽  
Axon Initial Segment ◽  
Retinal Ganglion ◽  
Light Responses ◽  
Synaptic Inputs ◽  
Dorsal Cells ◽  
Axon Initial Segments ◽  
Dorsal Retina

Recently, mouse OFF-α transient (OFF-α T) retinal ganglion cells (RGCs) were shown to display a gradient of light responses as a function of position along the dorsal-ventral axis; response differences were correlated to differences in the level of excitatory presynaptic input. Here, we show that postsynaptic differences between cells also make a strong contribution to response differences. Cells in the dorsal retina had longer axon initial segments (AISs)—the greater number of Nav1.6 channels in longer AISs directly mediates higher rates of spiking and helps avoid depolarization block that terminates spiking in ventral cells with shorter AISs. The pre- and postsynaptic specializations that shape the output of OFF-α T RGCs interact in different ways: In dorsal cells, strong inputs and the long AISs are both necessary to generate their strong, sustained spiking outputs, while in ventral cells, weak inputs or the short AISs are both sufficient to limit the spiking signal.

scholarly journals Loss of Responses to Visual But Not Electrical Stimulation in Ganglion Cells of Rats With Severe Photoreceptor Degeneration

2009 ◽  
Vol 102 (6) ◽  
pp. 3260-3269 ◽  
Author(s):  
Chris Sekirnjak ◽  
Clare Hulse ◽  
Lauren H. Jepson ◽  
Pawel Hottowy ◽  
Alexander Sher ◽  
...  
Keyword(s):  
Electrical Stimulation ◽  
Retinal Ganglion Cells ◽  
Vision Loss ◽  
Ganglion Cells ◽  
Transgenic Rat ◽  
Direct Electrical Stimulation ◽  
Retinal Ganglion ◽  
Photoreceptor Degeneration ◽  
Wild Type ◽  
Light Responses

Retinal implants are intended to help patients with degenerative conditions by electrically stimulating surviving cells to produce artificial vision. However, little is known about how individual retinal ganglion cells respond to direct electrical stimulation in degenerating retina. Here we used a transgenic rat model to characterize ganglion cell responses to light and electrical stimulation during photoreceptor degeneration. Retinas from pigmented P23H-1 rats were compared with wild-type retinas between ages P37 and P752. During degeneration, retinal thickness declined by 50%, largely as a consequence of photoreceptor loss. Spontaneous electrical activity in retinal ganglion cells initially increased two- to threefold, but returned to nearly normal levels around P600. A profound decrease in the number of light-responsive ganglion cells was observed during degeneration, culminating in retinas without detectable light responses by P550. Ganglion cells from transgenic and wild-type animals were targeted for focal electrical stimulation using multielectrode arrays with electrode diameters of ∼10 microns. Ganglion cells were stimulated directly and the success rate of stimulation in both groups was 60–70% at all ages. Surprisingly, thresholds (∼0.05 mC/cm2) and latencies (∼0.25 ms) in P23H rat ganglion cells were comparable to those in wild-type ganglion cells at all ages and showed no change over time. Thus ganglion cells in P23H rats respond normally to direct electrical stimulation despite severe photoreceptor degeneration and complete loss of light responses. These findings suggest that high-resolution epiretinal prosthetic devices may be effective in treating vision loss resulting from photoreceptor degeneration.

Light adaptation in the primate retina: Analysis of changes in gain and dynamics of monkey retinal ganglion cells

1990 ◽  
Vol 4 (1) ◽  
pp. 75-93 ◽  
Author(s):  
Keith Purpura ◽  
Daniel Tranchina ◽  
Ehud Kaplan ◽  
Robert M. Shapley
Keyword(s):  
Retinal Ganglion Cells ◽  
Negative Feedback ◽  
Light Adaptation ◽  
Ganglion Cells ◽  
Human Subjects ◽  
Light Level ◽  
Retinal Ganglion ◽  
M Cell ◽  
Feedback Model ◽  
Light Levels

AbstractThe responses of monkey retinal ganglion cells to sinusoidal stimuli of various temporal frequencies were measured and analyzed at a number of mean light levels. Temporal modulation tuning functions (TMTFs) were measured at each mean level by varying the drift rate of a sine-wave grating of fixed spatial frequency and contrast. The changes seen in ganglion cell temporal responses with changes in adaptation state were similar to those observed in human subjects and in turtle horizontal cells and cones tested with sinusoidally flickering stimuli; “Weber's Law” behavior was seen at low temporal frequencies but not at higher temporal frequencies. Temporal responses were analyzed in two ways: (1) at each light level, the TMTFs were fit by a model consisting of a cascade of low- and high-pass filters; (2) the family of TMTFs collected over a range of light levels for a given cell was fit by a linear negative feedback model in which the gain of the feedback was proportional to the mean light level. Analysis (1) revealed that the temporal responses of one class of monkey ganglion cells (M cells) were more phasic at both photopic and mesopic light levels than the responses of P ganglion cells. In analysis (2), the linear negative feedback model accounted reasonably well for changes in gain and dynamics seen in three P cells and one M cell. From the feedback model, it was possible to estimate the light level at which the dark-adapted gain of the cone pathways in the primate retina fell by a factor of two. This value was two to three orders of magnitude lower than the value estimated from recordings of isolated monkey cones. Thus, while a model which includes a single stage of negative feedback can account for the changes in gain and dynamics associated with light adaptation in the photopic and mesopic ranges of vision, the underlying physical mechanisms are unknown and may involve elements in the primate retina other than the cone.

scholarly journals Retinal Ganglion Cells With a Glaucoma OPTN(E50K) Mutation Exhibit Neurodegenerative Phenotypes when Derived from Three-Dimensional Retinal Organoids

2020 ◽  
Vol 15 (1) ◽  
pp. 52-66 ◽  
Author(s):  
Kirstin B. VanderWall ◽  
Kang-Chieh Huang ◽  
Yanling Pan ◽  
Sailee S. Lavekar ◽  
Clarisse M. Fligor ◽  
...  
Keyword(s):  
Retinal Ganglion Cells ◽  
Ganglion Cells ◽  
Three Dimensional ◽  
Retinal Ganglion
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