scholarly journals Vision in an abundant North American bird: The Red-winged Blackbird

The Auk ◽  
2019 ◽  
Vol 136 (3) ◽  
Author(s):  
Esteban Fernández-Juricic ◽  
Patrice E Baumhardt ◽  
Luke P Tyrrell ◽  
Amanda Elmore ◽  
Shelagh T DeLiberto ◽  
...  
Keyword(s):  
Visual Acuity ◽  
Visual System ◽  
Color Vision ◽  
Human Vision ◽  
Multiple Traits ◽  
Binocular Field ◽  
Visual Behaviors ◽  
North American Bird ◽  
Species Specific ◽  
Visual Coverage

Abstract Avian vision is fundamentally different from human vision; however, even within birds there are substantial between-species differences in visual perception in terms of visual acuity, visual coverage, and color vision. However, there are not many species that have all these visual traits described, which can constrain our ability to study the evolution of visual systems in birds. To start addressing this gap, we characterized multiple traits of the visual system (visual coverage, visual acuity, centers of acute vision, and color vision) of the Red-winged Blackbird (Agelaius phoeniceus), one of the most abundant and studied birds in North America. We found that Red-winged Blackbirds have: wide visual coverage; one center of acute vision per eye (fovea) projecting fronto-laterally with high density of single and double cones, making it the center of both chromatic and achromatic vision; a wide binocular field that does not have the input of the centers of acute vision; and an ultraviolet sensitive visual system. With this information, we parameterized a Red-winged Blackbird-specific perceptual model considering different plumage patches. We found that the male red epaulet was chromatically conspicuous but with minimal achromatic signal, but the male yellow patch had a lower chromatic but a higher achromatic signal, which may be explained by the pigment composition of the feathers. However, the female epaulet was not visually conspicuous in both the chromatic and achromatic dimensions compared with other female feather patches. We discuss the implications of this visual system configuration relative to the foraging, antipredator, mate choice, and social behaviors of Red-winged Blackbirds. Our findings can be used for comparative studies as well as for making more species-specific predictions about different visual behaviors for future empirical testing.

scholarly journals Ecological trait differences are associated with gene expression in the primary visual cortex of primates

2020 ◽  
Author(s):  
Trisha Marie Zintel ◽  
John J. Ely ◽  
Mary Ann Raghanti ◽  
William D. Hopkins ◽  
Patrick R. Hof ◽  
...  
Keyword(s):  
Gene Expression ◽  
Visual Cortex ◽  
Visual System ◽  
Color Vision ◽  
Primary Visual Cortex ◽  
Brain Regions ◽  
Primate Species ◽  
Tissue Samples ◽  
Synaptic Signaling ◽  
Species Specific

Abstract Background : Primate species differ drastically from most other mammals in how they visually perceive their environments, which is important for foraging, predator avoidance, and detection of social cues. Although it is well established that primates display diversity in color vision and various ecological specializations, it is not understood how visual system characteristics and ecological adaptations may be associated with gene expression levels within the primary visual cortex (V1). Results : We performed RNA-Seq on V1 tissue samples from 28 individuals, representing 13 species of anthropoid primates, including hominoids, cercopithecoids, and platyrrhines. We explored trait-dependent differential expression (DE) by contrasting species with different visual system phenotypes and ecological traits. Between 4-25% of genes were determined to be differentially expressed in primates that varied in type of color vision (trichromatic or polymorphic di/trichromatic), habitat use (arboreal or terrestrial), group size (large or small), and primary diet (frugivorous, folivorous, or omnivorous). DE analyses revealed that humans and chimpanzees showed the most marked differences between any two species, despite the fact that they are only separated by 6-8 million years of independent evolution. Pathway enrichment analyses of DE genes demonstrated that changes in cellular metabolic pathways (e.g. glycolysis) contribute to altered gene expression in primate V1 more than neuron-specific processes (e.g. synaptic signaling). The exception to this trend is between human and chimpanzee, which exhibited DE for a number of processes related to cholinergic and GABAergic synaptic signaling. Conclusions : Our data significantly expand the number of primate species for which V1 expression data exists. These results show a combination of species-specific and trait-dependent differences in the evolution of gene expression in primate V1. We also show that human-specific changes in brain gene expression extend to the primary visual cortex in a manner similar to that reported of other brain regions.

scholarly journals Multiple Roles for Nogo Receptor 1 in Visual System Plasticity

2016 ◽  
Vol 22 (6) ◽  
pp. 653-666 ◽  
Author(s):  
Céleste-Élise Stephany ◽  
Michael G. Frantz ◽  
Aaron W. McGee
Keyword(s):  
Visual Acuity ◽  
Visual System ◽  
Critical Period ◽  
Ocular Dominance ◽  
Mouse Genetics ◽  
Multiple Roles ◽  
Neural Function ◽  
Visual Plasticity ◽  
Species Specific ◽  
Abnormal Visual

During the developmental critical period for visual plasticity, discordant vision alters the responsiveness of neurons in visual cortex. The subsequent closure of the critical period not only consolidates neural function but also limits recovery of acuity from preceding abnormal visual experience. Despite species-specific differences in circuitry of the visual system, these characteristics are conserved. The nogo-66 receptor 1 ( ngr1) is one of only a small number of genes identified thus far that is essential to closing the critical period. Mice lacking a functional ngr1 gene retain developmental visual plasticity as adults and their visual acuity spontaneously improves after prolonged visual deprivation. Experiments employing conditional mouse genetics have revealed that ngr1 restricts plasticity within distinct circuits for ocular dominance and visual acuity. However, the mechanisms by which NgR1 limits plasticity have not been elucidated, in part because the subcellular localization and signal transduction of the protein are only partially understood. Here we explore potential mechanisms for NgR1 function in relation to manipulations that reactivate visual plasticity in adults and propose lines of investigation to address relevant gaps in knowledge.

scholarly journals EFFECTS OF ENVIRONMENTAL EXPOSURE TO TOBACCO ON MODULATION OF COLOR VISION

2020 ◽  
Vol 8 (7) ◽  
pp. 211-224
Author(s):  
Mariana Nunes Fabricio ◽  
Bruna Sthefanny Da Cunha Ferreira ◽  
Helena Beatriz Moura Martins ◽  
Ruan Carlos Silva de Jesus ◽  
Mauro César De Oliveira ◽  
...  
Keyword(s):  
Visual Acuity ◽  
Visual System ◽  
Color Vision ◽  
Control Group ◽  
Daily Consumption ◽  
Cross Sectional ◽  
Functional Changes ◽  
Test Version ◽  
Psychophysical Evaluation ◽  
Oxidative Effects

The chronic use of cigarettes causes toxic and oxidative effects on the visual system, which can cause changes in color vision. Although there are studies on the harmful effects of tobacco in active smokers, the literature on secondhand/passive smokers (or environmental tobacco smoke) is still scarce. Therefore, the aim of this study was to investigate the ability of color vision in active and passive smokers. This is a cross-sectional observational study in which 103 individuals were divided pseudorandomly into 3 groups: control group (CG) n = 44 individuals (72 eyes), with a mean age of 28.65 ± 7.90; group of passive smokers (GPS) n = 28 (56 eyes), mean age 28.74 ± 9.42; group of active smokers (GAS) n = 31 (60 eyes), mean age 34.91 ± 11.30. The psychophysical evaluation of color vision was performed using the Ishihara pseudoisochromatic plates, the computer program of the Freiburg Visual Acuity & Contrast Test, version 3.7, and the desaturated Lanthony D15 ordering test. The results indicate that there was no correlation in GAS and GPS with age, time of exposure to tobacco and daily consumption. It was observed that both GAS and GPS showed changes in visual acuity (P <0.05), and only GPS showed changes in color vision (P <0.05); GFP showed a deficit in visual acuity and worse color vision when compared to GAS (P <0.05). These results are discussed in relation to the biochemical and pathophysiological effects that exposure to cigarettes may have on the visual system, which would explain the functional changes observed. We conclude that passive and active smokers have impaired color vision and that the psychophysical methods used in this study are effective for the subclinical tracking of changes in color vision.

scholarly journals Capsule Networks as Recurrent Models ofGrouping and Segmentation

2019 ◽  
Author(s):  
Adrien Doerig ◽  
Lynn Schmittwilken ◽  
Bilge Sayim ◽  
Mauro Manassi ◽  
Michael H. Herzog
Keyword(s):  
Neural Networks ◽  
Visual System ◽  
Convolutional Neural Networks ◽  
Human Vision ◽  
Global Shape ◽  
Grouping And Segmentation ◽  
Segmentation Process ◽  
Shape Processing ◽  
Visual Crowding ◽  
Recurrent Connections

AbstractClassically, visual processing is described as a cascade of local feedforward computations. Feedforward Convolutional Neural Networks (ffCNNs) have shown how powerful such models can be. However, using visual crowding as a well-controlled challenge, we previously showed that no classic model of vision, including ffCNNs, can explain human global shape processing (1). Here, we show that Capsule Neural Networks (CapsNets; 2), combining ffCNNs with recurrent grouping and segmentation, solve this challenge. We also show that ffCNNs and standard recurrent CNNs do not, suggesting that the grouping and segmentation capabilities of CapsNets are crucial. Furthermore, we provide psychophysical evidence that grouping and segmentation are implemented recurrently in humans, and show that CapsNets reproduce these results well. We discuss why recurrence seems needed to implement grouping and segmentation efficiently. Together, we provide mutually reinforcing psychophysical and computational evidence that a recurrent grouping and segmentation process is essential to understand the visual system and create better models that harness global shape computations.Author SummaryFeedforward Convolutional Neural Networks (ffCNNs) have revolutionized computer vision and are deeply transforming neuroscience. However, ffCNNs only roughly mimic human vision. There is a rapidly expanding body of literature investigating differences between humans and ffCNNs. Several findings suggest that, unlike humans, ffCNNs rely mostly on local visual features. Furthermore, ffCNNs lack recurrent connections, which abound in the brain. Here, we use visual crowding, a well-known psychophysical phenomenon, to investigate recurrent computations in global shape processing. Previously, we showed that no model based on the classic feedforward framework of vision can explain global effects in crowding. Here, we show that Capsule Neural Networks (CapsNets), combining ffCNNs with recurrent grouping and segmentation, solve this challenge. ffCNNs and recurrent CNNs with lateral and top-down recurrent connections do not, suggesting that grouping and segmentation are crucial for human-like global computations. Based on these results, we hypothesize that one computational function of recurrence is to efficiently implement grouping and segmentation. We provide psychophysical evidence that, indeed, grouping and segmentation is based on time consuming recurrent processes in the human brain. CapsNets reproduce these results too. Together, we provide mutually reinforcing computational and psychophysical evidence that a recurrent grouping and segmentation process is essential to understand the visual system and create better models that harness global shape computations.

scholarly journals Visual Acuity, Contrast Sensitivity and Color Vision Three Years After Iodine-125 Brachytherapy for Choroidal and Ciliary Body Melanoma

2015 ◽  
Vol 9 (1) ◽  
pp. 131-135 ◽  
Author(s):  
Irena Tsui ◽  
Robert M Beardsley ◽  
Tara A McCannel ◽  
Scott C Oliver ◽  
Melissa W Chun ◽  
...  
Keyword(s):  
Visual Acuity ◽  
Contrast Sensitivity ◽  
Color Vision ◽  
Ciliary Body ◽  
Case Series ◽  
Vision Measurement ◽  
Corrected Visual Acuity ◽  
Iodine 125 ◽  
Decrease In Visual Acuity ◽  
Ciliary Body Melanoma

Purpose : To report visual acuity, contrast sensitivity and color vision prior to, 1 year after, 2 years after and 3 years after iodine-125 brachytherapy for choroidal and ciliary body melanoma (CCM). Design : Prospective interventional case series. Participants : Thirty-seven patients (37 eyes) with CCM. Methods : Patients had best-corrected Early Treatment Diabetic Retinopathy Study (ETDRS) visual acuity, Pelli-Robson contrast sensitivity and Hardy-Rand-Rittler color vision measurement; comprehensive ophthalmology examination; optical coherence tomography; and ultrasonography at baseline prior to, 1 year after, 2 years after and 3 years after I-125 brachytherapy. Main Outcome Measures : Visual acuity, contrast sensitivity and color vision prior to, 1 year after, 2 years after and 3 years after brachytherapy. Results : Nineteen (19) men and 18 women with mean age of 58 years (SD 13, range 30-78) prior to, 1 year after, 2 years after and 3 years after brachytherapy had mean best-corrected visual acuity of 77 letters (20/32), 65 letters (20/50), 56 letters (20/80) and 47 letters (20/125); contrast sensitivity of 30, 26, 22 and 19 letters; color vision of 26, 20, 17 and 14 test figures, respectively. Decrease in visual acuity, contrast sensitivity and color vision was statistically significant from baseline at 1 year, 2 years, and 3 years after brachytherapy. Decreased acuity at 3 years was associated with mid-choroid and macula melanoma location, ≥ 4.1 mm melanoma height, radiation maculopathy and radiation optic neuropathy. Conclusion : 1, 2 and 3 years after brachytherapy, eyes with CCM had significantly decreased visual acuity, contrast sensitivity and color vision.

Utilization of Visual Acuity Retroilluminated Charts for the Assessment of Afferent Visual System Dysfunction in a Pediatric Neuroimmunology Population

2020 ◽  
Vol Publish Ahead of Print ◽  
Author(s):  
Peter V. Sguigna ◽  
Morgan C. McCreary ◽  
Darrel L. Conger ◽  
Jennifer S. Graves ◽  
Leslie A. Benson ◽  
...  
Keyword(s):  
Visual Acuity ◽  
Visual System ◽  
Afferent Visual System

Retinal toxicity after high-dose cisplatin therapy.

1985 ◽  
Vol 3 (12) ◽  
pp. 1683-1689 ◽  
Author(s):  
G Wilding ◽  
R Caruso ◽  
T S Lawrence ◽  
Y Ostchega ◽  
E J Ballintine ◽  
...  
Keyword(s):  
Visual Acuity ◽  
Ovarian Carcinoma ◽  
Causal Relationship ◽  
Color Vision ◽  
Retinal Toxicity ◽  
High Dose ◽  
Visual Dysfunction ◽  
Blurred Vision ◽  
Cone Dysfunction ◽  
Cisplatin Therapy

Because of increasing complaints of visual dysfunction, 13 patients with refractory or recently diagnosed ovarian carcinoma were evaluated for possible cisplatin-induced ophthalmologic toxicity. All patients had received high-dose cisplatin (200 mg/m2 in five divided daily doses) over two to four cycles. Eight patients (62%) developed symptoms of blurred vision and three (23%) also developed altered color perception. Retinal toxicity in the form of cone dysfunction was documented by electroretinography and color vision testing in 11 patients. Three patients were studied prospectively. Two patients who developed cone dysfunction had normal ophthalmologic exams before the initiation of chemotherapy or after one cycle of cisplatin, suggesting a causal relationship between cisplatin therapy and subsequent retinal abnormalities. Though visual acuity improved off therapy, color vision abnormalities persisted as long as 16 months beyond therapy.

The Study of Spatial Frequency Channels for Human Visual System

2019 ◽  
Vol 33 (06) ◽  
pp. 1955007
Author(s):  
Xiangyang Xu ◽  
Qiao Chen ◽  
Ruixin Xu
Keyword(s):  
Receptive Field ◽  
Spatial Frequency ◽  
Visual System ◽  
Human Visual System ◽  
Frequency Tuning ◽  
Tuning Curve ◽  
Vision System ◽  
Human Vision ◽  
Psychophysical Experiment ◽  
Human Vision System

Similar to auditory perception of sound system, color perception of the human visual system also presents a multi-frequency channel property. In order to study the multi-frequency channel mechanism of how the human visual system processes color information, the paper proposed a psychophysical experiment to measure the contrast sensitivities based on 17 color samples of 16 spatial frequencies on CIELAB opponent color space. Correlation analysis was carried out on the psychophysical experiment data, and the results show obvious linear correlations of observations for different spatial frequencies of different observers, which indicates that a linear model can be used to model how human visual system processes spatial frequency information. The results of solving the model based on the experiment data of color samples show that 9 spatial frequency tuning curves can exist in human visual system with each lightness, R–G and Y–B color channel and each channel can be represented by 3 tuning curves, which reflect the “center-around” form of the human visual receptive field. It is concluded that there are 9 spatial frequency channels in human vision system. The low frequency tuning curve of a narrow-frequency bandwidth shows the characteristics of lower level receptive field for human vision system, the medium frequency tuning curve shows a low pass property of the change of medium frequent colors and the high frequency tuning curve of a width-frequency bandwidth, which has a feedback effect on the low and medium frequency channels and shows the characteristics of higher level receptive field for human vision system, which represents the discrimination of details.

Visual Acuity Affected by Size Perception Based on Convergence Cue

Perception ◽  
1997 ◽  
Vol 26 (1_suppl) ◽  
pp. 354-354
Author(s):  
H Shinoda ◽  
M Ikeda
Keyword(s):  
Visual Acuity ◽  
Visual System ◽  
Retinal Image ◽  
White Paper ◽  
Retinal Size ◽  
Size Perception ◽  
Convergence Angle ◽  
Threshold Size

Increasing (or decreasing) the convergence angle can shrink (or expand) the perceived size of an object without changing its retinal size (Oyama, 1974 Perception & Psychophysics16 175 – 182). Here we address the question whether such a change in perceived size affects visual acuity. We investigated the effects of perceived size on the legibility of letters, using a telestereoscope consisting of four mirrors to control the observer's convergence angle while keeping the size of the retinal image constant. The targets were photocopies of ordinary Japanese books containing both types of Japanese characters, kana and kanji. The former is a phonetic character and simpler than the latter. Letters were printed in black on white paper. First, we demonstrated that letters do become more legible (illegible) as perceived size expands (shrinks), although their retinal size does not change. Then, we measured the size of the convergence angle at which letters became legible. The ‘threshold’ size of the convergence angle was obtained for several retinal sizes (0.1 to 0.2 deg) of letters, and for kana and kanji, respectively. Four subjects participated in the experiment. The result shows that the threshold convergence angle for legibility decreases as the retinal size of letters decreases, so that the minimum retinal size of legible letters depends linearly on the convergence angle. The results implicate contributions from higher levels of the visual system to the determination of visual acuity.

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