scholarly journals Multiple mechanisms of photoreceptor spectral tuning following loss of UV color vision in Heliconius butterflies

2021 ◽  
Author(s):  
Kyle J. McCulloch ◽  
Aide Macias-Muñoz ◽  
Ali Mortazavi ◽  
Adriana D. Briscoe
Keyword(s):  
Visual System ◽  
Color Vision ◽  
Adaptive Evolution ◽  
Color Discrimination ◽  
Butterfly Species ◽  
Intracellular Recordings ◽  
Spectral Tuning ◽  
Antibody Staining ◽  
Visual Systems ◽  
Rapid Divergence

AbstractColor vision modifications occur in animals via a process known as spectral tuning. In Heliconius butterflies, a genus-specific UVRh opsin duplication led to the evolution of UV color discrimination in Heliconius erato females, a rare trait among butterflies. In the H. melpomene and H. ismenius lineages, the UV2 receptor has been lost. Here we compare how loss of the UV2 photoreceptor has altered the visual system of these butterflies. We compare visual system evolution in three Heliconius butterfly species using a combination of intracellular recordings, ATAC-seq, and antibody staining. We identify several spectral tuning mechanisms including adaptive evolution of opsins, deployment of two types of filtering pigments, and co-expression of two distinct opsins in the same cell. Our data show that opsin gain and loss is driving rapid divergence in Heliconius visual systems via tuning of multiple spectral classes of photoreceptor in distinct lineages, potentially contributing to ongoing speciation in this genus.

The revolt of the clay

2021 ◽  
pp. 165-196
Author(s):  
Arlin Stoltzfus
Keyword(s):  
Local Adaptation ◽  
Color Vision ◽  
Adaptive Evolution ◽  
Molecular Level ◽  
Neutral Evolution ◽  
Mutation Rates ◽  
Spectral Tuning ◽  
Evolution Of Resistance ◽  
Altitude Adaptation

Chapter 9 presents an empirical case for the importance of mutational biases, based on studies of adaptation traced to the molecular level. Where Chapter 8 identified a variational cause of bias that does not depend on neutral evolution, absolute constraints, or high mutation rates, this chapter focuses on how quantitative biases in ordinary nucleotide mutations influence adaptive evolution. It uses published studies of parallel adaptation in nature and in the laboratory. The natural studies include both (1) cases of recent local adaptation, e.g., evolution of resistance to insecticides and herbicides, and (2) cases of fixed changes, e.g., altitude adaptation via changes in hemoglobins, spectral tuning of photoreceptors used in color vision, and so on. The results indicate that the kinds of changes that happen most often in adaptation are the kinds favored by simple biases in mutation, e.g., transition-transversion bias.

scholarly journals Complementary shifts in photoreceptor spectral tuning unlock the full adaptive potential of ultraviolet vision in birds

eLife ◽  
2016 ◽  
Vol 5 ◽  
Author(s):  
Matthew B Toomey ◽  
Olle Lind ◽  
Rikard Frederiksen ◽  
Robert W Curley ◽  
Ken M Riedl ◽  
...  
Keyword(s):  
Color Vision ◽  
Color Discrimination ◽  
Wavelength Shift ◽  
Spectral Tuning ◽  
Cell Type ◽  
Adaptive Potential ◽  
Light Spectrum ◽  
Avian Evolution ◽  
Spectral Filters ◽  
Ultraviolet Vision

Color vision in birds is mediated by four types of cone photoreceptors whose maximal sensitivities (λmax) are evenly spaced across the light spectrum. In the course of avian evolution, the λmax of the most shortwave-sensitive cone, SWS1, has switched between violet (λmax > 400 nm) and ultraviolet (λmax < 380 nm) multiple times. This shift of the SWS1 opsin is accompanied by a corresponding short-wavelength shift in the spectrally adjacent SWS2 cone. Here, we show that SWS2 cone spectral tuning is mediated by modulating the ratio of two apocarotenoids, galloxanthin and 11’,12’-dihydrogalloxanthin, which act as intracellular spectral filters in this cell type. We propose an enzymatic pathway that mediates the differential production of these apocarotenoids in the avian retina, and we use color vision modeling to demonstrate how correlated evolution of spectral tuning is necessary to achieve even sampling of the light spectrum and thereby maintain near-optimal color discrimination.

scholarly journals Image Content Enhancement Through Salient Regions Segmentation for People With Color Vision Deficiencies

i-Perception ◽  
2019 ◽  
Vol 10 (3) ◽  
pp. 204166951984107 ◽  
Author(s):  
Alessandro Bruno ◽  
Francesco Gugliuzza ◽  
Edoardo Ardizzone ◽  
Calogero Carlo Giunta ◽  
Roberto Pirrone
Keyword(s):  
Visual System ◽  
Eye Tracking ◽  
Color Vision ◽  
Human Visual System ◽  
Color Images ◽  
Color Mapping ◽  
Visual Systems ◽  
Salient Regions ◽  
Color Blind ◽  
Color Vision Deficiencies

Color vision deficiencies affect visual perception of colors and, more generally, color images. Several sciences such as genetics, biology, medicine, and computer vision are involved in studying and analyzing vision deficiencies. As we know from visual saliency findings, human visual system tends to fix some specific points and regions of the image in the first seconds of observation summing up the most important and meaningful parts of the scene. In this article, we provide some studies about human visual system behavior differences between normal and color vision-deficient visual systems. We eye-tracked the human fixations in first 3 seconds of observation of color images to build real fixation point maps. One of our contributions is to detect the main differences between the aforementioned human visual systems related to color vision deficiencies by analyzing real fixation maps among people with and without color vision deficiencies. Another contribution is to provide a method to enhance color regions of the image by using a detailed color mapping of the segmented salient regions of the given image. The segmentation is performed by using the difference between the original input image and the corresponding color blind altered image. A second eye-tracking of color blind people with the images enhanced by using recoloring of segmented salient regions reveals that the real fixation points are then more coherent (up to 10%) with the normal visual system. The eye-tracking data collected during our experiments are in a publicly available dataset called Eye-Tracking of Color Vision Deficiencies.

HOW DO INSECT POLLINATORS DISCRIMINATE COLORS?

1997 ◽  
Vol 45 (2-3) ◽  
pp. 103-113 ◽  
Author(s):  
Misha Vorobyev ◽  
Robert Brandt
Keyword(s):  
Color Vision ◽  
Color Discrimination ◽  
Visual Systems ◽  
Insect Pollinators ◽  
Basic Concepts ◽  
Practical Recommendations

Basic concepts of color vision in animals and, in particular in the honeybee, are reviewed. Four models of color discrimination in honeybees are presented. Because visual systems in Hymenoptera are similar to that of the honeybee, such models can also be used to describe color discrimination in many hymenopteran pollinators. We compare predictive capacities of the models and give practical recommendations for their usage. Although models have different mathematical formulations, in most cases they give similar predictions. Examples where predictions of different models deviate are discussed.

Bipolar cell pathways for color vision in non-primate dichromats

2010 ◽  
Vol 28 (1) ◽  
pp. 51-60 ◽  
Author(s):  
CHRISTIAN PULLER ◽  
SILKE HAVERKAMP
Keyword(s):  
Color Vision ◽  
Bipolar Cell ◽  
Ganglion Cells ◽  
Color Discrimination ◽  
Model Systems ◽  
Retinal Ganglion ◽  
Retinal Pathways ◽  
Retinal Information Processing ◽  
Cone Opsins ◽  
Retinal Information

AbstractColor vision in mammals is based on the expression of at least two cone opsins that are sensitive to different wavelengths of light. Furthermore, retinal pathways conveying color-opponent signals are required for color discrimination. Most of the primates are trichromats, and “color-coded channels” of their retinas are unveiled to a large extent. In contrast, knowledge of cone-selective pathways in nonprimate dichromats is only slowly emerging, although retinas of dichromats like mice or rats are extensively studied as model systems for retinal information processing. Here, we review recent progress of research on color-coded pathways in nonprimate dichromats to identify differences or similarities between di- and trichromatic mammals. In addition, we applied immunohistochemical methods and confocal microscopy to retinas of different species and present data on their neuronal properties, which are expected to contribute to color vision. Basic neuronal features such as the “blue cone bipolar cell” exist in every species investigated so far. Moreover, there is increasing evidence for chromatic OFF channels in dichromats and retinal ganglion cells that relay color-opponent signals to the brain. In conclusion, di- and trichromats share similar retinal pathways for color transmission and processing.

Visual Systems and the Role of Vision in Subterranean Rodents: Diversity of Retinal Properties and Visual System Designs

2007 ◽  
pp. 129-160 ◽  
Author(s):  
Pavel Němec ◽  
Pavla Cveková ◽  
Hynek Burda ◽  
Oldřich Benada ◽  
Leo Peichl
Keyword(s):  
Visual System ◽  
Subterranean Rodents ◽  
Visual Systems ◽  
System Designs

The Insect Visual System: Correspondence with Vertebrates and with Olfactory Processing

2017 ◽  
pp. 293-306
Author(s):  
Nicholas J. Strausfeld
Keyword(s):  
Visual Cortex ◽  
Visual System ◽  
Nobel Prize ◽  
Insect Visual System ◽  
Dendritic Trees ◽  
Optic Lobes ◽  
Visual Systems ◽  
Valid Comparison ◽  
Olfactory Processing ◽  
Lateral Protocerebrum

A 1915 monograph by the Nobel Prize–winning neuroanatomist Santiago Ramón y Cajal and Domingo Sánchez y Sánchez, describing neurons and their organization in the optic lobes of insects, is now standard fare for those studying the microcircuitry of the insect visual system. The work contains prescient assumptions about possible functional arrangements, such as lateral interactions, centrifugal pathways, and the convergence of neurons onto wider dendritic trees, to provide central integration of information processed at peripheral levels of the system. This chapter will consider further indications of correspondence between the insect-crustacean and the vertebrate visual systems, with particular reference to the deep organization of the optic lobe’s third optic neuropil, the lobula, and part of the lateral forebrain (protocerebrum) that receives inputs from it. Together, the lobula and lateral protocerebrum suggest valid comparison with the visual cortex and olfactory centers.

AWAVS, a Research Facility for Defining Flight Trainer Visual System Requirements

1978 ◽  
Vol 22 (1) ◽  
pp. 99-104 ◽  
Author(s):  
Stanley C. Collyer ◽  
Walter S. Chambers
Keyword(s):  
Visual System ◽  
Wide Angle ◽  
Experimental Facility ◽  
Research Facility ◽  
Pilot Performance ◽  
System Parameters ◽  
Systems Research ◽  
Visual Systems ◽  
System Requirements ◽  
And Training

The objective of the Navy's Aviation Wide Angle Visual System (AWAVS) program is to recommend design criteria for future flight simulator visual systems. Research leading to this goal will have two facets: improving visual system technology, and determining the effects of visual system parameters on pilot performance and training. The experimental facility is described, and the behavioral research plans are discussed, with emphasis on the carrier landing studies to be conducted during the first phase of the program.

scholarly journals The visual ecology of Holocentridae, a nocturnal coral reef fish family with a deep-sea-like multibank retina

2020 ◽  
pp. jeb.233098
Author(s):  
Fanny de Busserolles ◽  
Fabio Cortesi ◽  
Lily Fogg ◽  
Sara M. Stieb ◽  
Martin Luehrmann ◽  
...  
Keyword(s):  
Visual System ◽  
Reef Fish ◽  
Deep Sea ◽  
Colour Vision ◽  
Ganglion Cells ◽  
Light Sensitivity ◽  
Fish Family ◽  
Visual Systems ◽  
Retinal Topography ◽  
Dim Light

The visual systems of teleost fishes usually match their habitats and lifestyles. Since coral reefs are bright and colourful environments, the visual systems of their diurnal inhabitants have been more extensively studied than those of nocturnal species. In order to fill this knowledge gap, we conducted a detailed investigation of the visual system of the nocturnal reef fish family Holocentridae. Results showed that the visual system of holocentrids is well adapted to their nocturnal lifestyle with a rod-dominated retina. Surprisingly, rods in all species were arranged into 6-17 well-defined banks, a feature most commonly found in deep-sea fishes, that may increase the light sensitivity of the eye and/or allow colour discrimination in dim-light. Holocentrids also have the potential for dichromatic colour vision during the day with the presence of at least two spectrally different cone types: single cones expressing the blue-sensitive SWS2A gene, and double cones expressing one or two green-sensitive RH2 genes. Some differences were observed between the two subfamilies, with Holocentrinae (squirrelfish) having a slightly more developed photopic visual system than Myripristinae (soldierfish). Moreover, retinal topography of both ganglion cells and cone photoreceptors showed specific patterns for each cell type, likely highlighting different visual demands at different times of the day, such as feeding. Overall, their well-developed scotopic visual systems and the ease of catching and maintaining holocentrids in aquaria, make them ideal models to investigate teleost dim-light vision and more particularly shed light on the function of the multibank retina and its potential for dim-light colour vision.

scholarly journals Why are “What” and “Where” Processed by Separate Cortical Visual Systems? A Computational Investigation

1989 ◽  
Vol 1 (2) ◽  
pp. 171-186 ◽  
Author(s):  
Jay G. Rueckl ◽  
Kyle R. Cave ◽  
Stephen M. Kosslyn
Keyword(s):  
Visual System ◽  
Spatial Information ◽  
Systems Design ◽  
Computational Investigation ◽  
Connectionist Models ◽  
Internal Representations ◽  
Visual Systems ◽  
Computational Resources ◽  
Computational Properties ◽  
Hidden Nodes

In the primate visual system, the identification of objects and the processing of spatial information are accomplished by different cortical pathways. The computational properties of this “two-systems” design were explored by constructing simplifying connectionist models. The models were designed to simultaneously classify and locate shapes that could appear in multiple positions in a matrix, and the ease of forming representations of the two kinds of information was measured. Some networks were designed so that all hidden nodes projected to all output nodes, whereas others had the hidden nodes split into two groups, with some projecting to the output nodes that registered shape identity and the remainder projecting to the output nodes that registered location. The simulations revealed that splitting processing into separate streams for identifying and locating a shape led to better performance only under some circumstances. Provided that enough computational resources were available in both streams, split networks were able to develop more efficient internal representations, as revealed by detailed analyses of the patterns of weights between connections.

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