(photopia) articles in PubMed
- RETINAL DETACHMENT ASSOCIATED WITH PERIPHERAL TEAR OF THE RETINAL PIGMENT EPITHELIUM IN PACHYCHOROID SPECTRUM DISEASE. [Journal Article]
- Retin Cases Brief Rep 2016 Sep 28RC
- CONCLUSIONS: Peripheral retinal pigment epithelium tear-associated retinal detachment can be seen in patients with pachychoroid spectrum disease. Scleral window surgery may be considered in the management of these retinal detachments.
- Seeing without knowing: Operational principles along the early visual pathway. [Journal Article]
- Psych J 2016; 5(3):145-60PJ
- Single cases may lead to unexpected hypotheses in psychology. We retrospectively analyzed single case studies that suggested organizational principles along the early visual pathway, which have remai...
Single cases may lead to unexpected hypotheses in psychology. We retrospectively analyzed single case studies that suggested organizational principles along the early visual pathway, which have remained unanswered until now.
- QUININE TOXICITY: MULTIMODAL RETINAL IMAGING AND ELECTRORETINOGRAPHY FINDINGS. [Journal Article]
- Retin Cases Brief Rep 2016 Sep 21RC
- CONCLUSIONS: Quinine toxicity may be associated with vision loss secondary to inner retinal atrophy. We report two cases with a clear history of acute quinine exposure leading to similar retinal imaging findings and distinctive ERG abnormalities. Clinicians should be aware of this uncommon condition as ingestion history may be remote.
- Imperfect past and present progressive: beak color reflects early-life and adult exposure to antigen. [Journal Article]
- Behav Ecol 2016 Sep-Oct; 27(5):1320-1330BE
- Secondary sexual traits may convey information about individual condition. We assessed the capacity for immune challenge with lipopolysaccharide (LPS) or keyhole limpet hemocyanin (KLH) during the pr...
Secondary sexual traits may convey information about individual condition. We assessed the capacity for immune challenge with lipopolysaccharide (LPS) or keyhole limpet hemocyanin (KLH) during the prenatal and early postnatal stages to impact beak color development and expression in captive zebra finches. In addition, we tested whether adult immune challenge impacted beak color, and if early-life experience was influential. Immune challenge with KLH early in life slowed development of red beak coloration, and males challenged with KLH as nestlings had reduced red coloration as adults. Following adult KLH challenge, males exhibited a decline in beak redness. Birds challenged with KLH during development produced more anti-KLH antibodies after adult challenge. There was a significant interaction between young treatment and anti-KLH antibody production; for males not challenged with KLH early in life, individuals that mounted a weaker antibody response lost more red coloration after challenge than males mounting a stronger antibody response. Based on models of avian vision, these differences in beak coloration should be detectable to the finches. In contrast to previous studies, we found no effect of early-life or adult challenge with LPS on any aspects of beak coloration. These results provide evidence that beak color reflects developmental and current conditions, and that the signal is linked to critical physiological processes.
- Photoreception and vision in the ultraviolet. [Review]
- J Exp Biol 2016 Sep 15; 219(Pt 18):2790-2801JE
- Ultraviolet (UV) light occupies the spectral range of wavelengths slightly shorter than those visible to humans. Because of its shorter wavelength, it is more energetic (and potentially more photodam...
Ultraviolet (UV) light occupies the spectral range of wavelengths slightly shorter than those visible to humans. Because of its shorter wavelength, it is more energetic (and potentially more photodamaging) than 'visible light', and it is scattered more efficiently in air and water. Until 1990, only a few animals were recognized as being sensitive to UV light, but we now know that a great diversity, possibly even the majority, of animal species can visually detect and respond to it. Here, we discuss the history of research on biological UV photosensitivity and review current major research trends in this field. Some animals use their UV photoreceptors to control simple, innate behaviors, but most incorporate their UV receptors into their general sense of vision. They not only detect UV light but recognize it as a separate color in light fields, on natural objects or living organisms, or in signals displayed by conspecifics. UV visual pigments are based on opsins, the same family of proteins that are used to detect light in conventional photoreceptors. Despite some interesting exceptions, most animal species have a single photoreceptor class devoted to the UV. The roles of UV in vision are manifold, from guiding navigation and orientation behavior, to detecting food and potential predators, to supporting high-level tasks such as mate assessment and intraspecific communication. Our current understanding of UV vision is restricted almost entirely to two phyla: arthropods and chordates (specifically, vertebrates), so there is much comparative work to be done.
- Effect of overlaid luminance contrast on perceived color contrast: Shadows enhance, borders suppress. [Journal Article]
- J Vis 2016 Sep 1; 16(11):15JV
- Natural scenes contain both color and luminance variations at different sizes and orientations that are sometimes spatially overlaid and sometimes not. Here, we explore visual interactions between ov...
Natural scenes contain both color and luminance variations at different sizes and orientations that are sometimes spatially overlaid and sometimes not. Here, we explore visual interactions between overlaid color and luminance contrast that are both suprathreshold and highly visible. We used a color-luminance plaid in which the perception of the color contrast and luminance contrast components were measured separately using a method of constant stimuli, to reveal how overlaid cross-oriented luminance contrast affects perceived color contrast, and how color contrast affects perceived luminance contrast. Binocular, monocular, and dichoptic viewing conditions were used for different spatial frequencies (0.375-1.5 cpd, 2 Hz) and base contrasts. We find that overlaid, cross-oriented luminance contrast enhances perceived color contrast by an average of 32% (monocularly and binocularly) across a wide range of luminance contrasts, but interocularly suppresses color contrast. For the reverse condition, we found no effect of color contrast on perceived luminance contrast. If, however, the cross-oriented arrangement is changed to co-oriented, specifically with the color and luminance borders aligned and in-phase, the color enhancement disappears and becomes mild suppression. Likewise, if the phase of the co-aligned components is varied, color enhancement returns once the color and luminance borders are misaligned and out of phase. Thus the relative position of the color and luminance borders is a crucial factor in determining the type of interaction, with color suppression occurring when the luminance and color borders coincide, as when demarcating an object boundary, and color enhancement when they do not coincide, as occurs in shadows and shading.
- The elementary representation of spatial and color vision in the human retina. [Journal Article]
- Sci Adv 2016; 2(9):e1600797SA
- The retina is the most accessible element of the central nervous system for linking behavior to the activity of isolated neurons. We unraveled behavior at the elementary level of single input units-t...
The retina is the most accessible element of the central nervous system for linking behavior to the activity of isolated neurons. We unraveled behavior at the elementary level of single input units-the visual sensation generated by stimulating individual long (L), middle (M), and short (S) wavelength-sensitive cones with light. Spectrally identified cones near the fovea of human observers were targeted with small spots of light, and the type, proportion, and repeatability of the elicited sensations were recorded. Two distinct populations of cones were observed: a smaller group predominantly associated with signaling chromatic sensations and a second, more numerous population linked to achromatic percepts. Red and green sensations were mainly driven by L- and M-cones, respectively, although both cone types elicited achromatic percepts. Sensations generated by cones were rarely stochastic; rather, they were consistent over many months and were dominated by one specific perceptual category. Cones lying in the midst of a pure spectrally opponent neighborhood, an arrangement purported to be most efficient in producing chromatic signals in downstream neurons, were no more likely to signal chromatic percepts. Overall, the results are consistent with the idea that the nervous system encodes high-resolution achromatic information and lower-resolution color signals in separate pathways that emerge as early as the first synapse. The lower proportion of cones eliciting color sensations may reflect a lack of evolutionary pressure for the chromatic system to be as fine-grained as the high-acuity achromatic system.
- Improving access to vision screening in urban Philadelphia elementary schools. [Journal Article]
- J AAPOS 2016 Sep 16JA
- CONCLUSIONS: The program described herein can provide comprehensive vision screening, with eyeglasses and/or referrals, to children within an underserved community.
- Level of visual acuity necessary to avoid false-positives on the HRR and Ishihara color vision tests. [Journal Article]
- Eur J Ophthalmol 2016 Sep 7; :0EJ
- CONCLUSIONS: Based on the plate in each test that was found to be the least tolerant to blur, the average minimum VAs needed to identify the screening plates were approximately 20/180 for the Ishihara test and 20/50 for the HRR test. Identifying the demonstration plate in the Ishihara and HRR tests does not ensure FPs will be avoided.
New Search Next
- Electrophysiological correlates of visual binding errors after bilateral parietal damage. [Journal Article]
- Neuroscience 2016 Sep 17N
- Illusory conjunctions (e.g. the confusion between the shape of one stimulus with the color of another stimulus) are the most dramatic expression of binding failures in vision. Under brief exposure or...
Illusory conjunctions (e.g. the confusion between the shape of one stimulus with the color of another stimulus) are the most dramatic expression of binding failures in vision. Under brief exposure or when attention is diverted illusory conjunctions may be observed in healthy participants, but they only represent a real-life problem for patients with parietal damage. However, it is unclear whether such failures reflect the impairment of early or late stages of visual processing. Here, we examined the time-course of visual processing using evoked potential measures in a patient with bilateral damage to the posterior parietal cortex presenting prominent binding failures. The patient was asked to identify colored letters that were briefly flashed to the left or right hemifield. When only one item was presented she adequately identified color or shape of left and right letters. In contrast, when presentation was bilateral she either identified the correct right shape-color combination and missed the item in the left hemifield (extinction) or combined incorrectly the right shape with the left color (illusory conjunction). Evoked potential analyses revealed a specific electrophysiological signature of illusory conjunctions, starting ∼105ms after stimulus onset over the right frontal cortex. These findings indicate that binding errors reflect failures of early stages of attentional filtering relying on the integrity of the posterior parietal cortex.