567 results on '"Visual sensitivity"'
Search Results
2. A Study of Expressinging Symbolic Sculptures of Roundabout Considering the Visual Sensitivity of Drivers - Based on Symbolic Sculptures Installed at Small-size Roundabout in Korea from 2010 to 2021
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Jun Ho Kwon
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Sculpture ,media_common.quotation_subject ,Roundabout ,Art ,Visual sensitivity ,media_common ,Visual arts - Published
- 2021
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3. Visual performance and reaction time measures for object-based attention
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Shurygina, Olga and Rolfs, Martin
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object-based attantion ,visual sensitivity ,Life Sciences ,exogenous attention - Abstract
We will explore spread of covert exogenous attention along objects, in a double-rectangle cueing paradigm by measuring response time and performance in a visual discrimination task. We will compare the sensitivity of these measures for targets given different levels of noise. In their classical study, Egly, Driver & Rafal (1994) showed that visual attention spreads along attended objects (rectangles) by measuring the simple response time to visual probe stimuli. Since then, their double-rectangle cueing paradigm was extensively used in research studying different aspects of object-based attention (e.g., Lamy & Egeth, 2002; Jurissen, Roelfsema, 2016; McCarley et al., 2002; Theeuwes & Mathot, 2010; Pilz et al., 2012; Drummond & Shomstein, 2010) In most of these studies the main measure of the attention was a response time in a simple detection task. The question whether the spread of attention along the object can be observed in increased visual sensitivity (measured as improved performance in a visual discrimination task) remains unclear. In the current experiment, we have three aims. Our first aim is to compare two well-established methods of measuring visual attention — response time and performance in a visual discrimination task — in order to estimate which of these measures is more sensitive for object-based attention depending on the signal to noise ratio of the stimulus that is to be detected (henceforth, probe). The second aim of our study to bring the measurement of object-based attention closer to natural vision in real-world scenes. That’s why we will probe attention in different signal-to-noise ratios (SNRs) as the objects in real life will have different textures. Finally, the majority of the above mentioned studies used a hybrid cue that had both exogenous (it was a sudden onset flash in the visual periphery) and endogenous components (the probe was presented more often at the cued location than elsewhere). We will make the cue irrelevant for the task, allowing us to measure the spread of purely automatic, exogenous attention. In our previous study we showed increased visual sensitivity at locations that were perceptually grouped with a location that was attended as the saccade target (Shurygina et al., 2020 – under review). In the current experiment, we will use grouping features from that study (color, pattern of the movement) to strengthen the perception of the objects as separate items. more...
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- 2022
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4. The Attraction of Stored Grain Pests Toward Various Colour Surfaces
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Shafique Ahmed Memon, Muhammad Abuzar Jaffar, Gulkhanda Parwaiz, Ghulam Khaliq, Intazar Ali, and Ghulam Ali Bugti
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genetic structures ,Stored grain ,ved/biology ,fungi ,ved/biology.organism_classification_rank.species ,Biology ,biology.organism_classification ,Visual sensitivity ,Attraction ,Retinal image ,Horticulture ,Pigment ,visual_art ,visual_art.visual_art_medium ,Red flour beetle ,Callosobruchus chinensis ,Green colour - Abstract
Colour vision is common phenomenon in living animals, but varies in insect species, depending on their vision sensitivity and photoreceptors involved. The sensitivity of the photoreceptor is determined through the absorption of visual colour pigments expressed. Photoreceptors are involved in filtering pigments, transverse wavelength, retinal image and colour signals. We have evaluated the colour attraction of two important stored grains insects, Red flour beetle (Tribolium castaneum H) and Pulse beetle (Callosobruchus chinensis L) to determine their visual sensitivity toward various colour surfaces. The data was recorded after 24hrs of releasing the insects in a chamber in which various colour surfaces were provided. The results showed that the T. castaneum was highly attracted toward green colour with maximum (17.3%) and (8.7%) of insects observed outside and inside the bags respectively. Whereas, minimum (4.3%) and (3.0%) T. castaneum found outside and inside the blue colour bags respectively. Similarly, C. chinensis was greatly attracted toward blue colour with the maximum (16.0%) and (7.7%) insects found attached outside and inside the bags respectively. Whereas, minimum (9.0%) and (2.0%) C. chinensis were recorded outside and inside the black colour bags respectively. more...
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- 2021
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5. 34‐3: Visual Sensitivity to 'Perfect' Black
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Michael J. Murdoch, Fu Jiang, Ben Bodner, and Susan P. Farnand
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Optics ,business.industry ,Computer science ,Organic Chemistry ,Glare (vision) ,Sensitivity (control systems) ,business ,Biochemistry ,Visual sensitivity - Published
- 2021
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6. Characteristics of visual sensitivity in familial cortical myoclonic tremor and epilepsy
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Yujia Cao, Wenjuan Zhang, Xiaoli Wang, Jiang Zhu, Yonghong Liu, Jin-Xiang Wang, and Bi Wang
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medicine.medical_specialty ,genetic structures ,medicine.diagnostic_test ,business.industry ,Electroencephalography ,Epilepsies, Myoclonic ,Video sequence ,General Medicine ,Audiology ,medicine.disease ,Visual sensitivity ,eye diseases ,Pedigree ,Epilepsy ,Neurology ,Neuroimaging ,Tremor ,medicine ,Reflex ,Humans ,In patient ,Photosensitivity Disorders ,Neurology (clinical) ,business - Abstract
The aim of the study was to describe the electroclinical features of visual sensitivity in patients with familial cortical myoclonic tremor and epilepsy. We searched the EEG database using the terms "familial cortical myoclonic tremor and epilepsy" and "visual sensitivity" over a seven-year period from March 2013 to April 2020 in the Xijing hospital, Xi'an, China. The inclusion criteria were demonstrable electroclinical visual sensitivity in the form of eye-opening sensitivity, eye-closure sensitivity, eyes-closed sensitivity and photosensitivity. Clinical, EEG and imaging records of patients were screened, and subsequently, detailed analysis of their data was undertaken. We enrolled six patients with visual sensitivity, five of whom suffered with rare generalized tonic-clonic seizures. Neuroimaging was negative in all cases. All patients demonstrated photosensitivity; eye-opening sensitivity associated with cortical myoclonic in one patient, eyes-closed sensitivity associated with cortical myoclonic tremor status in three patients, and eye-closure sensitivity in two patients. At the last follow-up visit, cortical myoclonic tremor and epilepsy in all patients was well controlled with first-line treatment. Visual sensitivity is therefore likely to be an important reflex trait in some patients with familial cortical myoclonic tremor and epilepsy, and should be routinely evaluated in order to better define the electroclinical features in FCMTE syndrome. [Published with video sequences]. more...
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- 2021
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7. Short-wavelength visual sensitivity and sexual differences in plumage colouration of ovenbirds (Aves: Furnariinae)
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Ana S. Barreira, Cecilia Kopuchian, Pablo L. Tubaro, Elisabet Vilacoba, and Muir D. Eaton
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0106 biological sciences ,Ovenbird ,genetic structures ,Dichromatism ,biology ,Zoology ,biology.organism_classification ,010603 evolutionary biology ,01 natural sciences ,Visual sensitivity ,010605 ornithology ,Synallaxis spixi ,Plumage ,Clade ,Sexual difference ,Phleocryptes melanops - Abstract
Ovenbirds represent a clade of exclusively Neotropical birds that are exceptionally diverse, despite their rather dull, melanin-based plumage. In general, sexes are considered monomorphic in size and colour, but several authors have reported females of some species within this family as being slightly paler than their conspecific counterparts. Our aim was to assess levels of sexual dichromatism in a set of ovenbird species representing a diversity of genera and plumage patterns; Furnarius rufus, Phleocryptes melanops, Synallaxis spixi and Schoeniophylax phryganophilus. For each species, we quantified sexual differences in brightness and colouration among 8–10 different plumage regions through modelling avian perceptual colour-space distances. To best inform our visual modelling parameters, we successfully sequenced the SWS1 gene fragment (associated with short-wavelength, including ultraviolet, visual sensitivity in birds) for one species, P. melanops, and found it possessed an amino acid sequence consistent with the VS-type SWS1 visual system. This provides further evidence supporting the presence of VS-sensitive opsin in ovenbirds. Among all four species, females were consistently brighter than males in at least one plumage patch, but chromatic colour differences between sexes were significant only for the throat patches of Schoeniophylax phryganophilus. Overall, we interpret ovenbirds to exhibit very low levels of sexual dichromatism, manifest mainly by achromatic colour differences. more...
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- 2021
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8. Variability of chromatic visual sensitivity: discrimination according to daily shifts
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Maria Thalita Cardoso Rezende, Bruna Gabrielli Damascena de Figueiredo, Thiago Augusto de Souza Bonifácio, Natanael Antonio dos Santos, and Michael Jackson Oliveira de Andrade
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medicine.medical_specialty ,Physiology ,Color vision ,0402 animal and dairy science ,Healthy subjects ,04 agricultural and veterinary sciences ,Audiology ,040201 dairy & animal science ,Visual sensitivity ,03 medical and health sciences ,0302 clinical medicine ,Variation (linguistics) ,Physiology (medical) ,medicine ,Chromatic scale ,Psychology ,030217 neurology & neurosurgery ,Ecology, Evolution, Behavior and Systematics - Abstract
This study aimed to verify the daily variation in the chromatic visual sensitivity of healthy subjects. The study included 35 male adults, aged between 20 and 40 years old (M = 24.97; SD = 4.9). Th... more...
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- 2020
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9. UV sensitive vision in cardinals and tanagers is ubiquitous
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Pablo D Lavinia, Belén Casalía, Pablo L. Tubaro, Ana S. Barreira, and Elisabet Vilacoba
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Physics ,Optics ,genetic structures ,business.industry ,Colour Vision ,Animal Science and Zoology ,Photopigment ,sense organs ,business ,Visual sensitivity ,Cone (formal languages) ,Ecology, Evolution, Behavior and Systematics ,Nature and Landscape Conservation - Abstract
Short wavelength visual sensitivity in birds is determined mostly by the type of photopigment present in the short-wavelength sensitive cone 1 (SWS1) which varies between clades and takes two main forms: the violet sensitive type (VS) and ultraviolet sensitive type (UVS). The common ancestor of passerines is thought to have been UVS, but there were at least 8 transitions between both types of visual sensitivity, even within species of the same family (Maluridae). The type of visual system a species has is a key parameter of avian visual models employed to describe chromatic visual perception and assess if colour differences are discernible by birds. Cardinalidae and Thraupidae together include more than 400 very diverse species that were model organisms in many bird colouration studies. However, visual sensitivity has been characterised for only one species of each of these families so far. Here, we obtained partial genetic sequences of the SWS1 opsin gene that determines the spectral sensitivity of the photopigment for a phylogenetically broad species sample of these families. All cardinals and tanagers studied here have SWS1 sequences corresponding with UVS sensitivity, suggesting that this character is conserved in these bird families despite their highly diverse range of plumage colours and habitat types. more...
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- 2020
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10. Obstacle avoidance in bumblebees is robust to changes in light intensity
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Emily Baird
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030110 physiology ,0301 basic medicine ,Forage (honey bee) ,Light ,Vision ,Computer science ,Short Communication ,Dusk ,Experimental and Cognitive Psychology ,Motion ,03 medical and health sciences ,0302 clinical medicine ,Obstacle avoidance ,Animals ,Computer vision ,Bumblebee ,Ecology, Evolution, Behavior and Systematics ,Light intensity ,business.industry ,Bees ,Visual sensitivity ,Visual field ,Flight ,Flight, Animal ,Obstacle ,Artificial intelligence ,Visual Fields ,Fast motion ,business ,Insect ,030217 neurology & neurosurgery - Abstract
Flying safely and avoiding obstacles in low light is crucial for the bumblebees that forage around dawn and dusk. Previous work has shown that bumblebees overcome the limitations of their visual system—typically adapted for bright sunlight—by increasing the time over which they sample photons. While this improves visual sensitivity, it decreases their capacity to resolve fast motion. This study investigates what effect this has on obstacle avoidance in flight, a task that requires the bees to reliably detect obstacles in the frontal visual field and to make a timely diversion to their flight path. In both bright and dim light, bumblebees avoided the 5 cm diameter obstacle at a consistent distance (22 cm) although in dim light they approached it more slowly from a distance of at least at least 80 cm. This suggests that bumblebees have an effective strategy for avoiding obstacles in all light conditions under which they are naturally active, and it is hypothesised that this is based on a time-to-contact prediction. Electronic supplementary material The online version of this article (10.1007/s10071-020-01421-z) contains supplementary material, which is available to authorized users. more...
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- 2020
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11. Unilateral increased visual sensitivity in cluster headache: a cross-sectional study
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Roemer B Brandt, Victor M Cnossen, Patty GG Doesborg, Ilse Frederieke de Coo, Matthijs J L. Perenboom, Johannes A Carpay, Roy Meilof, Gisela Marie Terwindt, Michel D Ferrari, and Rolf Fronczek
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photophobia ,primary headache disorder ,Cross-Sectional Studies ,visual sensitivity ,Migraine Disorders ,Surveys and Questionnaires ,Humans ,Pain ,Cluster Headache ,Neurology (clinical) ,General Medicine ,headache - Abstract
Background and Objectives Increased sensitivity to light and patterns is typically associated with migraine, but has also been anecdotally reported in cluster headache, leading to diagnostic confusion. We wanted to assess whether visual sensitivity is increased ictally and interictally in cluster headache. Methods We used the validated Leiden Visual Sensitivity Scale (L-VISS) questionnaire (range 0-36 points) to measure visual sensitivity in people with episodic or chronic cluster headache: (i) during attacks; (ii) in-between attacks; and in episodic cluster headache (iii) in-between bouts. The L-VISS scores were compared with the L-VISS scores obtained in a previous study in healthy controls and participants with migraine. Results Mean L-VISS scores were higher for: (i) ictal vs interictal cluster headache (episodic cluster headache: 11.9 ± 8.0 vs. 5.2 ± 5.5, chronic cluster headache: 13.7 ± 8.4 vs 5.6 ± 4.8; p Conclusion Cluster headache is associated with increased ictal and interictal visual sensitivity. In contrast to migraine, this is mostly unilateral and ipsilateral on the side of the ictal pain. more...
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- 2022
12. [Untitled]
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photophobia ,primary headache disorder ,Cluster headache ,visual sensitivity ,headache - Abstract
Background and Objectives Increased sensitivity to light and patterns is typically associated with migraine, but has also been anecdotally reported in cluster headache, leading to diagnostic confusion. We wanted to assess whether visual sensitivity is increased ictally and interictally in cluster headache.Methods We used the validated Leiden Visual Sensitivity Scale (L-VISS) questionnaire (range 0-36 points) to measure visual sensitivity in people with episodic or chronic cluster headache: (i) during attacks; (ii) in-between attacks; and in episodic cluster headache (iii) in-between bouts. The L-VISS scores were compared with the L-VISS scores obtained in a previous study in healthy controls and participants with migraine.Results Mean L-VISS scores were higher for: (i) ictal vs interictal cluster headache (episodic cluster headache: 11.9 +/- 8.0 vs. 5.2 +/- 5.5, chronic cluster headache: 13.7 +/- 8.4 vs 5.6 +/- 4.8; p < 0.001); (ii) interictal cluster headache vs controls (5.3 +/- 5.2 vs 3.6 +/- 2.8, p < 0.001); (iii) interictal chronic cluster headache vs interictal ECH in bout (5.9 +/- 0.5 vs 3.8 +/- 0.5, p = 0.009), and (iv) interictal episodic cluster headache in bout vs episodic cluster headache out-of-bout (5.2 +/- 5.5 vs. 3.7 +/- 4.3, p < 0.001). Subjective visual hypersensitivity was reported by 110/121 (91%; 9 missing) participants with cluster headache and was mostly unilateral in 70/110 (64%) and ipsilateral to the ictal pain in 69/70 (99%) participants.Conclusion Cluster headache is associated with increased ictal and interictal visual sensitivity. In contrast to migraine, this is mostly unilateral and ipsilateral on the side of the ictal pain. more...
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- 2022
13. Visual space curves before eye movements
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Ifedayo-EmmanuEL Adeyefa-Olasupo
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Visual processing ,business.industry ,Computer science ,Visual space ,Eye movement ,Computer vision ,Artificial intelligence ,Percept ,business ,Visual sensitivity ,Gaze - Abstract
In most experiments within the field of cognitive and systems neuroscience, fixation is often required prior to the onset of an experimental trial. However, the term “fixation” is rather misleading since our eyes are constantly moving. One type of transient miniature movement ubiquitously observed during fixation is commonly referred to as fixational eye movements or microsaccades. Perimicrosaccadic compression of visual space — the ability of retinotopic cells to transiently exhibit predictive spatiotemporal retinotopic compressive shifts toward the target of an impending microsaccade — is known to dramatically alter visual perception. However, whether perimicrosaccadic compressive shifts can become spatially asymmetric, that is, continuously directed toward a specific foveal region over another (e.g., an upper over a lower region in the fovea) and for what purpose, remains poorly understood. Assuming that these transient shifts are indeed asymmetric under certain conditions, the perceptual and oculomotor consequences such asymmetricity might accompany across visual space is poorly understood. Equally unaccounted for is a mechanistic account of the neural computation and architecture that could support these transient asymmetric shifts while the visual system actively maintains retinotopic organization. Here, we systematically measured visual sensitivity in human subjects to faint probes presented during fixation and around the time of saccadic eye movement at geometrically symmetric retinotopic locations in the foveal, parafoveal, and peripheral regions of visual space. Remarkably, we observed transient local asymmetric visual sensitivity differences between these symmetric retinotopic locations where none should be observed. Equally surprising, we observed the trajectories of saccadic eye movements, which are expected to travel along a linear path, routinely deviate along a curved path toward orthogonal eccentric locations. To provide a mechanistic account of the neural computation and architecture that may explain our results, we proposed a novel neurobiologically inspired phenomenological force field model in which underlying attentional and oculomotor signals are modulated by transient eccentric error signals that manifest as temporally overlapping predictive forces and impinge on the retinotopic visual cortex. These forces, which transiently bias putative population sensitivity toward an orthogonal retinotopic foveal region and, around the time of a saccadic eye movement, along an axis orthogonal to the saccade direction toward a mislocalized peripheral region, succinctly capture the essence of our empirical observations. more...
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- 2021
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14. Ultraviolet Visual Sensitivity in the Larvae of Two Species of Marine Atherinid Fishes
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William N. McFarland, Florence A. McAlary, and Ellis R. Loew
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Larva ,medicine ,Zoology ,Biology ,medicine.disease_cause ,Visual sensitivity ,Ultraviolet - Published
- 2021
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15. A perceptual rate control algorithm based on luminance adaptation for HEVC encoders
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Dong-Gyu Sim and Woong Lim
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Pixel ,Computer science ,Quantization (signal processing) ,media_common.quotation_subject ,Rate control ,020206 networking & telecommunications ,02 engineering and technology ,Visual sensitivity ,Luminance ,Perception ,Signal Processing ,0202 electrical engineering, electronic engineering, information engineering ,020201 artificial intelligence & image processing ,Electrical and Electronic Engineering ,Subjective quality ,Algorithm ,Encoder ,media_common - Abstract
This paper proposes a rate control algorithm by selecting a proper quantization parameter (QP) based on perceptual luminance adaptation in a single-loop encoding fashion. In this paper, the proposed algorithm uses the visual characteristics of humans to adaptively decide the number of bits available for a pixel. Then, a base QP is selected based on the proposed R–λ model. The proposed rate control determines the range of QP based on the base QP and calculates the maximum and minimum bpps within that range. The optimal bpp is obtained from the bpp range by considering the visual characteristics of the human being, and the QP value is determined by the optical bpp through the proposed R–λ model. In the proposed rate control algorithm, the QP value is selected based on the R–λ model by considering the perceptual luminance adaptation model at the CTU level. The number of target bits is decided to decide the QP, subject to visual sensitivity based on JND thresholds. With the use of the proposed rate control algorithm, bits for non-noticeable regions can be saved, and the remaining bits can be consumed for perceptually noticeable regions to enhance the overall subjective quality with the similar amount of total bits. The proposed method shows lower average variances of bits and PSNR fluctuations. Also, the proposed method achieves an approximately 0.19 higher MOS value on average under DSCQS test, compared with the conventional R–λ model-based rate control algorithm. more...
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- 2020
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16. Cortical Hyper‐Excitability in Migraine in Response to Chromatic Patterns
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Pulkit Grover, Sarah M. Haigh, Alireza Chamanzar, and Marlene Behrmann
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Adult ,Male ,medicine.medical_specialty ,genetic structures ,Aura ,Migraine Disorders ,Audiology ,Young Adult ,03 medical and health sciences ,Neural activity ,0302 clinical medicine ,Humans ,Medicine ,030212 general & internal medicine ,Chromatic scale ,Chromaticity ,Hue ,Cerebral Cortex ,business.industry ,Electroencephalography ,Middle Aged ,medicine.disease ,Visual sensitivity ,Neurology ,Migraine ,Cortical Excitability ,Evoked Potentials, Visual ,Female ,Neurology (clinical) ,business ,Color Perception ,Photic Stimulation ,030217 neurology & neurosurgery - Abstract
Objective Individuals with migraine exhibit heightened sensitivity to visual input that continues beyond their migraine episodes. However, the contribution of color to visual sensitivity, and how it relates to neural activity, has largely been unexplored in these individuals. Background Previously, it has been shown that, in non-migraine individuals, patterns with greater chromaticity separation evoked greater cortical activity, regardless of hue, even when colors were isoluminant. Therefore, to investigate whether individuals with migraine experienced increased visual sensitivity, we compared the behavioral and neural responses to chromatic patterns of increasing separation in migraine and non-migraine individuals. Methods Seventeen individuals with migraine (12 with aura) and 18 headache-free controls viewed pairs of colored horizontal grating patterns that varied in chromaticity separation. Color pairs were either blue-green, red-green, or red-blue. Participants rated the discomfort of the gratings and electroencephalogram was recorded simultaneously. Results Both groups showed increased discomfort ratings and larger N1/N2 event-related potentials (ERPs) with greater chromaticity separation, which is consistent with increased cortical excitability. However, individuals with migraine rated gratings as being disproportionately uncomfortable and exhibited greater effects of chromaticity separation in ERP amplitude across occipital and parietal electrodes. Ratings of discomfort and ERPs were smaller in response to the blue-green color pairs than the red-green and red-blue gratings, but this was to an equivalent degree across the 2 groups. Conclusions Together, these findings indicate that greater chromaticity separation increases neural excitation, and that this effect is heightened in migraine, consistent with the theory that hyper-excitability of the visual system is a key signature of migraine. more...
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- 2019
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17. Wavelength‐specific thresholds of artificially reared Japanese eelAnguilla japonicalarvae determined from negative‐phototactic behaviours
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Keishi Matsuda, Masaaki Kamoshida, and Yoshitsugu Masuda
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0106 biological sciences ,Light ,Aquaculture ,Aquatic Science ,010603 evolutionary biology ,01 natural sciences ,Japonica ,Optics ,Japan ,Anguillidae ,Phototaxis ,Animals ,Japanese eel ,Ecology, Evolution, Behavior and Systematics ,Larva ,biology ,business.industry ,010604 marine biology & hydrobiology ,Anguilla ,biology.organism_classification ,Visual sensitivity ,Wavelength ,Spectral sensitivity ,business - Abstract
We report wavelength-specific thresholds of leptocephali of Japanese eels Anguilla japonica determined from their negative-phototactic behaviour. Leptocephali are most sensitive to wavelengths 400-500 nm and at very short wavelengths. Their visual sensitivity decreases more sharply at wavelengths >500 nm than it does at wavelengths more...
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- 2019
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18. Saccadic suppression measured by steady-state visual evoked potentials
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Matteo Valsecchi, Jing Chen, Karl R. Gegenfurtner, Chen J., Valsecchi M., and Gegenfurtner K.R.
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Adult ,Male ,Physics ,Steady state (electronics) ,Perception and action ,genetic structures ,Physiology ,General Neuroscience ,Spectrum analysi ,Saccadic eye movement ,Eye movement ,Neural Inhibition ,Visual evoked potentials ,Visual sensitivity ,Saccadic masking ,Reaction Time ,Saccades ,Visual Perception ,Evoked Potentials, Visual ,Humans ,Female ,Saccadic suppression ,Spectrum analysis ,Neuroscience ,SSVEP - Abstract
Visual sensitivity is severely impaired during the execution of saccadic eye movements. This phenomenon has been extensively characterized in human psychophysics and nonhuman primate single-neuron studies, but a physiological characterization in humans is less established. Here, we used a method based on steady-state visually evoked potential (SSVEP), an oscillatory brain response to periodic visual stimulation, to examine how saccades affect visual sensitivity. Observers made horizontal saccades back and forth, while horizontal black-and-white gratings flickered at 5–30 Hz in the background. We analyzed EEG epochs with a length of 0.3 s either centered at saccade onset (saccade epochs) or centered at fixations half a second before the saccade (fixation epochs). Compared with fixation epochs, saccade epochs showed a broadband power increase, which most likely resulted from saccade-related EEG activity. The execution of saccades, however, led to an average reduction of 57% in the SSVEP amplitude at the stimulation frequency. This result provides additional evidence for an active saccadic suppression in the early visual cortex in humans. Compared with previous functional MRI and EEG studies, an advantage of this approach lies in its capability to trace the temporal dynamics of neural activity throughout the time course of a saccade. In contrast to previous electrophysiological studies in nonhuman primates, we did not find any evidence for postsaccadic enhancement, even though simulation results show that our method would have been able to detect it. We conclude that SSVEP is a useful technique to investigate the neural correlates of visual perception during saccadic eye movements in humans. NEW & NOTEWORTHY We make fast ballistic saccadic eye movements a few times every second. At the time of saccades, visual sensitivity is severely impaired. The present study uses steady-state visually evoked potentials to reveal a neural correlate of the fine temporal dynamics of these modulations at the time of saccades in humans. We observed a strong reduction (57%) of visually driven neural activity associated with saccades but did not find any evidence for postsaccadic enhancement. more...
- Published
- 2019
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19. Microperimetry in Three Inherited Retinal Disorders
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Ronald M. Hansen, Anne B. Fulton, and Laura Bagdonaite-Bejarano
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medicine.medical_specialty ,Retinal Disorder ,genetic structures ,Retinoschisis ,Fixation, Ocular ,Macular Degeneration ,03 medical and health sciences ,0302 clinical medicine ,Ophthalmology ,medicine ,Humans ,Stargardt Disease ,Clinical Trials as Topic ,Retina ,business.industry ,Outcome measures ,Small sample ,General Medicine ,medicine.disease ,Visual sensitivity ,Stargardt disease ,Clinical trial ,medicine.anatomical_structure ,030221 ophthalmology & optometry ,Visual Field Tests ,Visual Fields ,business ,Microperimetry ,Choroideremia ,030217 neurology & neurosurgery - Abstract
Objective: Microperimetry (MP) is used to assess visual sensitivity mediated by the central retina. As such, MP performance is a candidate outcome measure for gene therapy trials. Herein, we review MP results in three inherited retinal disorders for which gene therapy trials have been initiated-choroideremia, Stargardt disease, and X-linked juvenile retinoschisis. Each of these disorders typically presents in childhood and each has distinct effects on the central retina. Outcomes and Results: Our review indicates that microperimetry is feasible in each of these conditions. The MP sensitivity maps vary among conditions consistent with known effects of each of the three conditions. There is, however, within each of the three disorders considerable variability in fixation stability and in the pattern of sensitivity loss. Conclusions: Microperimetry is a valuable tool for monitoring functional aspects of central retina in an individual patient, especially in combination with other modalities such as OCT, autofluorescence, and acuity and thus may contribute to evaluating the efficacy of gene treatments. Variability of the MP parameters raises some cautions in application of MP as an outcome measure in treatment trials that may have small sample sizes. Nonetheless, we suspect that MP will continue to have a rightful place in future gene therapy trials. more...
- Published
- 2019
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20. Caffeine improves contrast sensitivity of freely moving rats
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Satoshi Shimegi, Akinori Y Sato, Keisuke Tsunoda, Ryo Kurata, and Ryo Mizuyama
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Male ,media_common.quotation_subject ,Experimental and Cognitive Psychology ,Motor Activity ,Pharmacology ,Contrast Sensitivity ,03 medical and health sciences ,Behavioral Neuroscience ,chemistry.chemical_compound ,0302 clinical medicine ,Caffeine ,Sensation ,Animals ,Contrast (vision) ,Rats, Long-Evans ,0501 psychology and cognitive sciences ,050102 behavioral science & comparative psychology ,Staircase method ,media_common ,Chemistry ,Two-alternative forced choice ,05 social sciences ,Central nervous system stimulant ,Visual sensitivity ,Rats ,Central Nervous System Stimulants ,Sensitivity (electronics) ,030217 neurology & neurosurgery - Abstract
Caffeine (1, 3, 7-trimethylxanthine) is a well-known central nervous system stimulant that affects various brain functions such as attention, memory and sensation. However, it remains unclear whether and how caffeine modulates visual ability such as contrast sensitivity (CS) and the CS-spatial frequency (SF) relationship. To investigate these points, we tested the effects of caffeine on the perceptual CS of rats under three SF conditions. CS was measured using a two-alternative forced choice (2AFC) grating detection task combined with a staircase method. Intraperitoneal administration of caffeine 30 min prior to the task improved CS in an SF-dependent manner, in which the improving effect was observed at 0.1 cycles/degree (cpd) of the optimal SF for rats but not at 0.5 or 1 cpd. We concluded that caffeine, a representative ingredient contained in foods or drinks consumed daily, leads to an improvement of perceptual visual sensitivity. more...
- Published
- 2019
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21. Significant correlations between focal photopic negative response and focal visual sensitivity and ganglion cell complex thickness in glaucomatous eyes
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Atsushi Tada, Tomoharu Nishimura, Mana Gonmori, Masahiko Ishizuka, Yuji Hara, Shigeki Machida, and Satoshi Ebihara
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Retinal Ganglion Cells ,medicine.medical_specialty ,genetic structures ,Open angle glaucoma ,Cell complex ,Glaucoma ,chemistry.chemical_compound ,Ophthalmology ,medicine ,Electroretinography ,Humans ,business.industry ,Retinal ,General Medicine ,medicine.disease ,Visual sensitivity ,eye diseases ,Ganglion ,medicine.anatomical_structure ,chemistry ,Visual Field Tests ,sense organs ,Visual Fields ,business ,Microperimetry ,Glaucoma, Open-Angle ,Tomography, Optical Coherence ,Photopic vision - Abstract
PURPOSE To determine whether there are significant correlations between the focal photopic negative response (PhNR), the focal visual sensitivity and the ganglion cell complex (GCC) thickness in glaucomatous eyes. STUDY DESIGN Single-center observational study. METHODS Fifty-two eyes of 52 patients (71.4 ± 9.42 years) with clinically diagnosed open angle glaucoma were studied. Thirty-six age-matched normal subjects served as controls. The focal PhNR of the focal macular electroretinograms (fmERGs) were elicited by a 15° circular, a superior semicircular or an inferior semicircular stimulus centered on the fovea. The thickness of the GCC was measured in the corresponding retinal areas in the spectral-domain optical coherence tomographic images. The visual sensitivities (dB) were measured by microperimetry at the retinal area where the fmERGs were elicited and were converted to liner values (1/Lambert). RESULTS The focal PhNR amplitudes were significantly correlated with the visual sensitivities of the full-circle (R = 0.532), the superior (R = 0.530) and inferior (R = 0.526) semicircular responses (P more...
- Published
- 2021
22. Parallel shifts of visual sensitivity and body colouration in replicate populations of extremophile fish
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Thor Veen, Michael Tobler, Dylan R. Moxley, Lenin Arias-Rodriguez, Diana J. Rennison, and Gregory L. Owens
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0106 biological sciences ,genetic structures ,Zoology ,Biology ,010603 evolutionary biology ,01 natural sciences ,Poecilia mexicana ,Extremophiles ,03 medical and health sciences ,Genetics ,Animals ,Extremophile ,Hydrogen Sulfide ,14. Life underwater ,Selection, Genetic ,Ecology, Evolution, Behavior and Systematics ,030304 developmental biology ,Poecilia ,0303 health sciences ,Natural selection ,Replicate ,Adaptation, Physiological ,Visual sensitivity ,Mate choice ,Habitat ,Sexual selection ,sense organs ,Adaptation - Abstract
Visual sensitivity and body pigmentation are often shaped by both natural selection from the environment and sexual selection from mate choice. One way of quantifying the impact of the environment is by measuring how traits have changed after colonization of a novel habitat. To do this, we studied Poecilia mexicana populations that have repeatedly adapted to extreme sulphidic (H2S containing) environments. We measured visual sensitivity using opsin gene expression, as well as body pigmentation and water transmission for populations in four independent drainages. Both visual sensitivity and body pigmentation showed significant parallel shifts towards greater medium wavelength sensitivity and reflectance in sulphidic populations. The light spectrum was only subtly different between environments and overall, we found no significant correlations between the light environment and visual sensitivity or body pigmentation. Altogether we found that sulphidic habitats select for differences in visual sensitivity and pigmentation; our data suggest that this effect is unlikely to be driven purely by the water’s spectral properties and may instead be from other correlated ecological changes. more...
- Published
- 2021
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23. Shedding light on dark adaptation
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Ellen R. Weiss
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Physics ,Retina ,Dark room ,Light sensitivity ,genetic structures ,Colour Vision ,Adaptation (eye) ,Visual sensitivity ,General Biochemistry, Genetics and Molecular Biology ,eye diseases ,Article ,medicine.anatomical_structure ,medicine ,Biophysics ,sense organs ,Bright light ,Vertebrate retina - Abstract
The retina is famous for its ability to operate under a broad range of light intensities. This is partly due to the presence of two types of photoreceptor cells, rods and cones. Rods are used mostly for dim light vision, and cones are used for bright light and colour vision. These cells are also able to adapt to a broad range of light intensities using light- and dark-adaptation mechanisms. Dark adaptation is used by the vertebrate retina to increase its visual sensitivity when moving from a brightly lit environment to a dark environment. The brighter the surrounding light, the longer it takes for the retina to adapt to the dark. Most retina biologists have studied dark adaptation by exposing animals to a 90% bleach, meaning that 90% of the light-sensing proteins in these photoreceptor cells have been activated, followed by transfer of these animals to a dark room and analysis of their light sensitivity using electrophysiological methods. In this report, we introduce the basic elements of the visual system and describe how the system might operate during dark adaptation. We also introduce a novel role for cAMP-mediated phosphorylation of G protein-coupled receptor kinase 1 (GRK1), a major kinase in visual signalling. more...
- Published
- 2021
24. Visual sensitivity to parallel configurations of contours compared with sensitivity to other configurations
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Ekaterina Koshmanova, Maria Dvoeglazova, and Tadamasa Sawada
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Physics ,Orientation (computer vision) ,Orthographic projection ,Geometry ,Collinearity ,Visual sensitivity ,Sensory Systems ,Form Perception ,Ophthalmology ,Pattern Recognition, Visual ,Orientation ,Convergence (routing) ,Perpendicular ,Psychophysics ,Humans ,3d perception ,Sensitivity (control systems) - Abstract
People can perceive 3D information from contour drawings and some types of configurations of contours in such drawings are important for 3D perception. We know that our visual system is sensitive to these configurations. Koshmanova & Sawada (2019, Vision Research, 154, 97–104) showed that the sensitivity is higher to a parallel configuration of contours than to a perpendicular configuration of contours. In this study, two psychophysical experiments were conducted that compared the sensitivity to a parallel configuration to two different configurations. In Experiment 1, orientation thresholds were measured with parallel and converging configurations composed of three contours. In Experiment 2, orientation thresholds of configurations composed of two contours were measured with parallel, collinear, and perpendicular configurations. The results of Experiment 1 showed that the visual system is more sensitive to parallel configurations than to converging configurations. The results of Experiment 2 showed that the sensitivity to the parallel configuration is analogous to the sensitivity to the collinear configuration, and it is higher than the sensitivity to the perpendicular configuration. The role that the parallel configuration plays in the 3D perception of contour-drawings is discussed. more...
- Published
- 2021
25. Author response for 'Low pre-stimulus EEG alpha power amplifies visual awareness but not visual sensitivity'
- Author
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Monika Harvey, Andra Coldea, Christopher S.Y. Benwell, and Gregor Thut
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Stimulus (psychology) ,medicine.medical_specialty ,medicine ,Audiology ,Visual awareness ,Psychology ,Visual sensitivity ,Power (physics) ,Eeg alpha - Published
- 2021
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26. Foveal vision at the time of microsaccades
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Janis Intoy, Naghmeh Mostofi, and Michele Rucci
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Retina ,genetic structures ,media_common.quotation_subject ,Visual sensitivity ,Saccadic masking ,Foveola ,medicine.anatomical_structure ,Foveal ,Fixation (visual) ,medicine ,Contrast (vision) ,Microsaccade ,Psychology ,Neuroscience ,media_common - Abstract
Humans use rapid eye movements (saccades) to inspect stimuli with the foveola, the region of the retina where receptors are most densely packed. It is well established that visual sensitivity is generally attenuated during these movements, a phenomenon known as saccadic suppression. This effect is commonly studied with large, often peripheral, stimuli presented during instructed saccades. However, little is known about how saccades modulate the foveola and how the resulting dynamics unfold during natural visual exploration. Here we measured the foveal dynamics of saccadic suppression in a naturalistic high-acuity task, a task designed after primate’s social grooming, which—like most explorations of fine patterns—primarily elicits minute saccades (microsaccades). Leveraging on recent advances in gaze-contingent display control, we were able to systematically map the peri-saccadic time-course of sensitivity across the foveola. We show that contrast sensitivity is not uniform across this region and that both the extent and dynamics of saccadic suppression vary within the foveola. Suppression is stronger and faster in the most central portion, where sensitivity is generally higher and selectively rebounds at the onset of a new fixation. These results shed new light on the modulations experienced by foveal vision during the saccade-fixation cycle and explain some of the benefits of microsaccades. more...
- Published
- 2021
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27. Two-photon visual sensitivity of cataract patients
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Katarzyna Komar, Bartosz L. Sikorski, Anna Matuszak, Maciej Wojtkowski, and Marcin Marzejon
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medicine.medical_specialty ,genetic structures ,Two-photon excitation microscopy ,Intraocular lenses ,business.industry ,Ophthalmology ,Refractive surgery ,medicine.medical_treatment ,medicine ,sense organs ,business ,Visual sensitivity ,eye diseases - Abstract
The two- and one-photon visual sensitivities (2phS and 1phS) of cataract patients were tested before and after IOL surgery. Mean change in 2phS was twice smaller than 1phS indicating that 2phS is less affected by cataract. more...
- Published
- 2021
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28. Photosensitive and Pattern-Sensitive Epilepsy: A Guide for Patients and Caregivers
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Athanasios Covanis and Jessica Solodar
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medicine.medical_specialty ,Epilepsy ,Visual perception ,business.industry ,Reflex Epilepsy ,Medicine ,Audiology ,business ,medicine.disease ,Visual sensitivity ,Pattern sensitivity ,Safety guidelines - Abstract
Photsensitive epilepsy is the most common type of reflex epilepsy. Seizures in people with photosensitive or patter-sensitive occur in response to specific visual stimuli such as strobe lights, or flashing computer graphics, or, in some people, fixed stripes and gemetric patterns. The risk of these seizures has grown due to the tremendous increse in electronic screen exposure in daily life. This guide describes photosensitivity and pattern sensitivity and how they are diagnosed, managed and treated. It provides patient and caregivers with recommendations regarding strategies and environmental modifications that can reduce seizures triggered by common visual stimuli. Cobalt blue eyeglasses or sunglasses are strongly recommended for seizure protection. more...
- Published
- 2020
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29. Review for 'Low pre-stimulus EEG alpha power amplifies visual awareness but not visual sensitivity'
- Author
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Elio Balestrieri
- Subjects
Stimulus (psychology) ,medicine.medical_specialty ,medicine ,Audiology ,Visual awareness ,Psychology ,Visual sensitivity ,Power (physics) ,Eeg alpha - Published
- 2020
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30. Review for 'Low pre-stimulus EEG alpha power amplifies visual awareness but not visual sensitivity'
- Author
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Jason Samaha
- Subjects
Stimulus (psychology) ,medicine.medical_specialty ,medicine ,Visual awareness ,Audiology ,Psychology ,Visual sensitivity ,Power (physics) ,Eeg alpha - Published
- 2020
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31. Fundus-controlled perimetry (microperimetry): Application as outcome measure in clinical trials
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Frank G. Holz, Monika Fleckenstein, Zhichao Wu, Steffen Schmitz-Valckenberg, Robyn H. Guymer, Eleonora M. Lad, Maximilian Pfau, Jonathan Denniss, and Jasleen K Jolly
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0301 basic medicine ,Fixation stability ,Visual acuity ,Computer science ,Fundus Oculi ,Visual Acuity ,Retina ,03 medical and health sciences ,0302 clinical medicine ,Disease severity ,Outcome Assessment, Health Care ,medicine ,Humans ,Outcome measures ,Visual sensitivity ,Sensory Systems ,Clinical trial ,Ophthalmology ,030104 developmental biology ,Fixation (visual) ,030221 ophthalmology & optometry ,Optometry ,Visual Field Tests ,medicine.symptom ,Visual Fields ,Microperimetry - Abstract
Fundus-controlled perimetry (FCP, also called 'microperimetry') allows for spatially-resolved mapping of visual sensitivity and measurement of fixation stability, both in clinical practice as well as research. The accurate spatial characterization of visual function enabled by FCP can provide insightful information about disease severity and progression not reflected by best-corrected visual acuity in a large range of disorders. This is especially important for monitoring of retinal diseases that initially spare the central retina in earlier disease stages. Improved intra- and inter-session retest-variability through fundus-tracking and precise point-wise follow-up examinations even in patients with unstable fixation represent key advantages of these technique. The design of disease-specific test patterns and protocols reduces the burden of extensive and time-consuming FCP testing, permitting a more meaningful and focused application. Recent developments also allow for photoreceptor-specific testing through implementation of dark-adapted chromatic and photopic testing. A detailed understanding of the variety of available devices and test settings is a key prerequisite for the design and optimization of FCP protocols in future natural history studies and clinical trials. Accordingly, this review describes the theoretical and technical background of FCP, its prior application in clinical and research settings, data that qualify the application of FCP as an outcome measure in clinical trials as well as ongoing and future developments. more...
- Published
- 2020
32. How flower colour signals allure bees and hummingbirds: a community‐level test of the bee avoidance hypothesis
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Maria Gabriela Gutierrez Camargo, Sebastian Brings, Leonor Patrícia Cerdeira Morellato, Vinícius Lourenço Garcia de Brito, Marco Antônio Batalha, and Klaus Lunau
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0106 biological sciences ,0301 basic medicine ,Attractiveness ,Pollination ,Physiology ,Color ,Zoology ,Flowers ,Plant Science ,Biology ,Models, Biological ,01 natural sciences ,Birds ,03 medical and health sciences ,Species Specificity ,Pollinator ,Avoidance Learning ,Animals ,Community level ,Pigmentation ,Bees ,Visual sensitivity ,Reflectivity ,030104 developmental biology ,Trait ,Colour contrast ,010606 plant biology & botany - Abstract
Colour signals are the main floral trait for plant-pollinator communication. Owing to visual specificities, flower visitors exert different selective pressures on flower colour signals of plant communities. Although they evolved to attract pollinators, matching their visual sensitivity and colour preferences, floral signals may also evolve to avoid less efficient pollinators and antagonistic flower visitors. We evaluated evidence for the bee avoidance hypothesis in a Neotropical community pollinated mainly by bees and hummingbirds, the campo rupestre. We analysed flower reflectance spectra, compared colour variables of bee-pollinated flowers (bee-flowers; 244 species) and hummingbird-pollinated flowers (hummingbird-flowers; 39 species), and looked for evidence of bee sensorial exclusion in hummingbird-flowers. Flowers were equally contrasting for hummingbirds. Hummingbird-flowers were less conspicuous to bees, reflecting mainly long wavelengths and avoiding red-blind visitors. Bee-flowers reflected more short wavelengths, were more conspicuous to bees (higher contrasts and spectral purity) than hummingbird-flowers and displayed floral guides more frequently, favouring flower attractiveness, discrimination and handling by bees. Along with no phylogenetic signal, the differences in colour signal strategies between bee- and hummingbird-flowers are the first evidence of the bee avoidance hypothesis at a community level and reinforce the role of pollinators as a selective pressure driving flower colour diversity. more...
- Published
- 2018
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33. Photoreceptors and eyes of pikeperch Sander lucioperca , pike Esox lucius , perch Perca fluviatilis and roach Rutilus rutilus from a clear and a brown lake
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Kristian Donner, Martta Leena Maria Viljanen, Christer Brönmark, Noora E. Nevala, and Mirka Jokela-Määttä
- Subjects
0106 biological sciences ,Light transmission ,Light ,genetic structures ,Cyprinidae ,Zoology ,Aquatic Science ,Eye ,010603 evolutionary biology ,01 natural sciences ,Species Specificity ,Visual range ,Animals ,14. Life underwater ,Finland ,Vision, Ocular ,Ecology, Evolution, Behavior and Systematics ,Esox ,Pike ,computer.programming_language ,Perch ,biology ,010604 marine biology & hydrobiology ,biology.organism_classification ,Visual sensitivity ,Lakes ,Visual pigments ,Perches ,Esocidae ,sense organs ,Rutilus ,computer ,Photoreceptor Cells, Vertebrate - Abstract
The photoreceptors and eyes of four fish species commonly cohabiting Fennoscandian lakes with different light transmission properties were compared: pikeperch Sander lucioperca, pike Esox lucius, perch Perca fluviatilis and roach Rutilus rutilus. Each species was represented by individuals from a clear (greenish) and a humic (dark brown) lake in southern Finland: Lake Vesijarvi (LV; peak transmission around 570 nm) and Lake Tuusulanjarvi (LT; peak transmission around 630 nm). In the autumn, all species had almost purely A2-based visual pigments. Rod absorption spectra peaked at c.526 nm (S. lucioperca), c. 533 nm (E. lucius) and c. 540 nm (P. fluviatilis and R. rutilus), with no differences between the lakes. Esox lucius rods had remarkably long outer segments, 1.5–2.8-fold longer than those of the other species. All species possessed middle-wavelength-sensitive (MWS) and long-wavelength-sensitive (LWS) cone pigments in single, twin or double cones. Rutilus rutilus also had two types of short-wavelength sensitive (SWS) cones: UV-sensitive [SWS1] and blue-sensitive (SWS2) cones, although in the samples from LT no UV cones were found. No other within-species differences in photoreceptor cell complements, absorption spectra or morphologies were found between the lakes. However, E. lucius eyes had a significantly lower focal ratio in LT compared with LV, enhancing sensitivity at the expense of acuity in the dark-brown lake. Comparing species, S. lucioperca was estimated to have the highest visual sensitivity, at least two times higher than similar-sized E. lucius, thanks to the large relative size of the eye (pupil) and the presence of a reflecting tapetum behind the retina. High absolute sensitivity will give a competitive edge also in terms of short reaction times and long visual range. (Less) more...
- Published
- 2018
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34. Second-order visual sensitivity in the aging population
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Alexandre Reynaud, Yong Tang, Robert F. Hess, and Yifeng Zhou
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Male ,Aging ,media_common.quotation_subject ,Motion Perception ,Biology ,Contrast Sensitivity ,03 medical and health sciences ,0302 clinical medicine ,Extrastriate cortex ,medicine ,Humans ,Contrast (vision) ,030212 general & internal medicine ,Sensitivity (control systems) ,Aged ,Visual Cortex ,media_common ,Cognition ,Middle Aged ,Visual sensitivity ,medicine.anatomical_structure ,Order (biology) ,Female ,Spatial frequency ,Geriatrics and Gerontology ,Neuroscience ,Photic Stimulation ,030217 neurology & neurosurgery - Abstract
Most visual and cognitive functions are affected by aging over the lifespan. In this study, our aim was to investigate the loss in sensitivity to different classes of second-order stimuli-a class of stimuli supposed to be mainly processed in extrastriate cortex-in the aging population. These stimuli will then allow one to identify specific cortical deficit independently of visibility losses in upstream parts of the visual pathway. For this purpose, we measured the sensitivity to first-order stimuli and second-order stimuli: orientation-modulated, motion-modulated or contrast-modulated as a function of spatial frequency in 50 aged participants. Overall, we observed a sensitivity loss for all classes of stimuli, but this loss differentially affects the three classes of second-order stimuli tested. It involves all modulation spatial frequencies in the case of motion modulation, but just high modulation spatial frequencies in the case of contrast- and orientation modulations. These observations imply that aging selectively affects the sensitivity to second-order stimuli depending on their type. Since there is evidence that these different second-order stimuli are processed in different regions of extrastriate cortex, this result may suggest that some visual cortical areas are more susceptible to aging effects than others. more...
- Published
- 2018
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35. Precues’ elevation of sensitivity is not only preattentive, but largely monocular
- Author
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Joshua A. Solomon and Michael J. Morgan
- Subjects
Adult ,Male ,Linguistics and Language ,Vision Disparity ,genetic structures ,media_common.quotation_subject ,Experimental and Cognitive Psychology ,01 natural sciences ,Article ,050105 experimental psychology ,Language and Linguistics ,010309 optics ,Vision, Monocular ,0103 physical sciences ,Reaction Time ,Humans ,Contrast (vision) ,Attention ,0501 psychology and cognitive sciences ,Sensitivity (control systems) ,media_common ,Monocular ,05 social sciences ,Precueing ,Visual sensitivity ,Sensory Systems ,Space-based attention ,Facilitation ,Female ,RE ,Cues ,Psychology ,Neuroscience - Abstract
Visual sensitivity can be heightened in the vicinity of an appropriate precue. Experiments with multiple, noninformative precues suggest that this facilitation should not be attributed to focal attention. The number of simultaneously appearing precues seems to be irrelevant; contrast thresholds are lowest for targets that appear in a precued position. Here we report that precues become less effective when they and the target are delivered to different eyes. We conclude that the mechanism responsible for such heightened sensitivity has largely monocular input. Electronic supplementary material The online version of this article (10.3758/s13414-018-1564-1) contains supplementary material, which is available to authorized users. more...
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- 2018
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36. The study of urban landscape visual sensitivity assessments: a case study in the Zhongshan District of Dalian
- Author
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Fangxiong Wang and Xinyu Qu
- Subjects
Atmospheric Science ,General Energy ,Geography ,Geography, Planning and Development ,0211 other engineering and technologies ,021107 urban & regional planning ,02 engineering and technology ,010501 environmental sciences ,Urban landscape ,01 natural sciences ,Cartography ,Visual sensitivity ,0105 earth and related environmental sciences - Abstract
This paper uses slope, distance,visual probability and remarkableness as evaluation indices to study urban landscape visual sensitivity in the Zhongshan District of Dalian. The results show that ar... more...
- Published
- 2018
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37. Relationship of Macular Thickness and Function to Optical Microangiography Measurements in Glaucoma
- Author
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Srilakshmi Dasari, Robert N. Weinreb, Mohammed Riyazuddin, Harsha L. Rao, Narendra K. Puttaiah, Carroll A.B. Webers, Zia S. Pradhan, Kaweh Mansouri, RS: MHeNs - R3 - Neuroscience, Oogheelkunde, MUMC+: *MA Oogheelkunde (3), and MUMC+: MA UECM Oogartsen MUMC (9) more...
- Subjects
Male ,Retinal Ganglion Cells ,primary open-angle glaucoma ,genetic structures ,Glaucoma ,PROGRESSION ,perfusion density ,optical microangiography ,Nerve Fibers ,0302 clinical medicine ,Macula Lutea ,VESSEL DENSITY ,RETINA ,Aged, 80 and over ,medicine.diagnostic_test ,Angiography ,Organ Size ,DEFECTS ,Middle Aged ,Visual sensitivity ,Visual field ,medicine.anatomical_structure ,COHERENCE TOMOGRAPHY ANGIOGRAPHY ,Female ,Visual field loss ,OPEN-ANGLE GLAUCOMA ,Glaucoma, Open-Angle ,Tomography, Optical Coherence ,Adult ,medicine.medical_specialty ,ganglion cell-inner plexiform layer thickness ,Open angle glaucoma ,VISUAL-FIELD LOSS ,03 medical and health sciences ,Optical coherence tomography ,Ophthalmology ,medicine ,Humans ,EYES ,HEALTHY ,Intraocular Pressure ,Aged ,vessel length density ,Retina ,PERIPAPILLARY ,business.industry ,medicine.disease ,eye diseases ,Cross-Sectional Studies ,Microangiography ,030221 ophthalmology & optometry ,sense organs ,business ,030217 neurology & neurosurgery - Abstract
Purpose:The purpose of this article was to evaluate the relationship between macular optical microangiography (OMAG), ganglion cell-inner plexiform layer (GCIPL) thickness, and visual sensitivity measurements of different macular sectors in primary open-angle glaucoma.Methods:In a cross-sectional study, 39 eyes of 26 primary open-angle glaucoma patients underwent optical coherence tomography imaging and 10-2 visual field examination of the macula in the same session. Linear regression models were used to evaluate the relationships between OMAG, GCIPL thickness, and visual sensitivity measurements in different macular sectors. Strength of relationship was reported as coefficient of determination (R-2).Results:R-2 values for the associations between OMAG and GCIPL thickness measurements ranged from 0.37 in the temporal sector to 0.56 in the inferior macular sector. R-2 values for the association between OMAG and visual sensitivity measurements ranged from 0.23 in the superior to 0.53 in the inferior macular sector. R-2 values for the association between GCIPL thickness and visual sensitivity measurements ranged from 0.15 in the superior to 0.62 in the temporal sector.Conclusions:The strongest associations between OMAG, GCIPL thickness, and visual sensitivity measurements were found in the inferior macular sector. The association of OMAG with GCIPL thickness measurements was as strong as the association between OMAG and visual sensitivity measurements in the inferior macular sector. more...
- Published
- 2018
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38. Rich Structural Index for Stereoscopic Image Quality Assessment
- Author
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Hua, Zhang, Xinwen, Hu, Ruoyun, Gou, Lingjun, Zhang, Bolun, Zheng, and Zhuonan, Shen
- Subjects
Support Vector Machine ,Databases, Factual ,image pyramid ,Chemical technology ,ComputingMethodologies_IMAGEPROCESSINGANDCOMPUTERVISION ,TP1-1185 ,Biochemistry ,Article ,structural index ,Atomic and Molecular Physics, and Optics ,Analytical Chemistry ,cyclopean map ,visual sensitivity ,depth information ,Humans ,Electrical and Electronic Engineering ,Instrumentation ,Algorithms ,Vision, Ocular - Abstract
The human visual system (HVS), affected by viewing distance when perceiving the stereo image information, is of great significance to study of stereoscopic image quality assessment. Many methods of stereoscopic image quality assessment do not have comprehensive consideration for human visual perception characteristics. In accordance with this, we propose a Rich Structural Index (RSI) for Stereoscopic Image objective Quality Assessment (SIQA) method based on multi-scale perception characteristics. To begin with, we put the stereo pair into the image pyramid based on Contrast Sensitivity Function (CSF) to obtain sensitive images of different resolution. Then, we obtain local Luminance and Structural Index (LSI) in a locally adaptive manner on gradient maps which consider the luminance masking and contrast masking. At the same time we use Singular Value Decomposition (SVD) to obtain the Sharpness and Intrinsic Structural Index (SISI) to effectively capture the changes introduced in the image (due to distortion). Meanwhile, considering the disparity edge structures, we use gradient cross-mapping algorithm to obtain Depth Texture Structural Index (DTSI). After that, we apply the standard deviation method for the above results to obtain contrast index of reference and distortion components. Finally, for the loss caused by the randomness of the parameters, we use Support Vector Machine Regression based on Genetic Algorithm (GA-SVR) training to obtain the final quality score. We conducted a comprehensive evaluation with state-of-the-art methods on four open databases. The experimental results show that the proposed method has stable performance and strong competitive advantage. more...
- Published
- 2022
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39. Optimum Space-Frequency Partition in Subband Image Coding with Human Visual Sensitivity and Region-of-Interest
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Haruhiko Miyazaki and Masashi Kameda
- Subjects
Image coding ,Region of interest ,Computer science ,business.industry ,Frequency partition of a graph ,Pattern recognition ,Artificial intelligence ,business ,Space (mathematics) ,Visual sensitivity - Published
- 2018
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40. Optimizing the Quantization Parameters of the JPEG Compressor to a High Quality of Fine-Detail Rendition
- Author
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S. V. Sai
- Subjects
Computer science ,ComputingMethodologies_IMAGEPROCESSINGANDCOMPUTERVISION ,Data_CODINGANDINFORMATIONTHEORY ,02 engineering and technology ,computer.file_format ,Color space ,01 natural sciences ,Computer Graphics and Computer-Aided Design ,JPEG ,Visual sensitivity ,010309 optics ,Visual contrast sensitivity ,0103 physical sciences ,0202 electrical engineering, electronic engineering, information engineering ,Discrete cosine transform ,020201 artificial intelligence & image processing ,Computer Vision and Pattern Recognition ,Quantization (image processing) ,Recognition algorithm ,computer ,Algorithm ,Gas compressor - Abstract
This paper describes a new algorithm for adaptive selection of DCT quantization parameters in the JPEG compressor. The quantization parameters are selected by classification of blocks based on the composition of fine details whose contrast exceeds the threshold visual sensitivity. Fine details are identified by an original search and recognition algorithm in the N-CIELAB normalized color space, which allows us to take visual contrast sensitivity into account. A distortion assessment metric and an optimization criterion for quantization of classified blocks to a high visual quality are proposed. A comparative analysis of test images in terms of compression parameters and quality degradation is presented. The new algorithm is experimentally shown to improve the compression of photorealistic images by 30% on average while preserving their high visual quality. more...
- Published
- 2018
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41. Luminance modulations from eye movements predict visual sensitivity
- Author
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Janis Intoy, Martina Poletti, Michele Rucci, Norick R. Bowers, and Jonathan D. Victor
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Ophthalmology ,business.industry ,Computer science ,Eye movement ,Computer vision ,Artificial intelligence ,business ,Visual sensitivity ,Luminance ,Sensory Systems - Published
- 2021
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42. Through the looking-glass: Visual sensitivity to chirality
- Author
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Ziv Epstein, Tal Boger, Matthew Groh, and Chaz Firestone
- Subjects
Physics ,Ophthalmology ,Condensed matter physics ,Chirality (chemistry) ,Visual sensitivity ,Sensory Systems - Published
- 2021
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43. A Model of the Post-saccadic Dynamics of Visual Sensitivity
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Bin Yang, Scott Murdison, Michele Rucci, Michele A. Cox, Zhetuo Zhao, Yuanhao Li, and Janis Intoy
- Subjects
Ophthalmology ,Computer science ,Dynamics (mechanics) ,Visual sensitivity ,Neuroscience ,Sensory Systems ,Saccadic masking - Published
- 2021
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44. Visual sensitivity and reaction time measures show no evidence for purely exogenous object-based attention
- Author
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Martin Rolfs and Olga Shurygina
- Subjects
Ophthalmology ,Computer science ,business.industry ,Computer vision ,Artificial intelligence ,business ,Visual sensitivity ,Sensory Systems ,Object-based attention - Published
- 2021
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45. Post-saccadic dynamics of visual sensitivity across the visual field
- Author
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T. Scott Murdison, Michele Rucci, Michele A. Cox, Bin Yang, Zhetuo Zhao, Yuanhao Li, and Janis Intoy
- Subjects
Ophthalmology ,Computer science ,Dynamics (music) ,Neuroscience ,Visual sensitivity ,Sensory Systems ,Saccadic masking ,Visual field - Published
- 2021
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46. Adaptive Optimization of Visual Sensitivity
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Sergei Gepshtein and Thomas D. Albright
- Subjects
Multidisciplinary ,Adaptive optimization ,business.industry ,Computer science ,05 social sciences ,Sensory system ,Observer (special relativity) ,Machine learning ,computer.software_genre ,Visual sensitivity ,Article ,050105 experimental psychology ,03 medical and health sciences ,0302 clinical medicine ,Premise ,Normative ,Visual motion perception ,0501 psychology and cognitive sciences ,Artificial intelligence ,Environmental statistics ,business ,computer ,030217 neurology & neurosurgery - Abstract
Sensory systems adapt to environmental change. It has been argued that adaptation should have the effect of optimizing sensitivity to the new environment. Here we consider a framework in which this premise is made concrete using an economic normative theory of visual motion perception. In this framework, visual systems adapt to the environment by reallocating their limited neural resources. The allocation is optimal when uncertainties about different aspects of stimulation are balanced. This theory makes predictions about visual sensitivity as a function of environmental statistics. Adaptive optimization of the visual system should be manifested as a change in sensitivity for an observer and for the underlying motion-sensitive neurons. We review evidence supporting these predictions and examine effects of adaptation on the neuronal representation of visual motion. more...
- Published
- 2017
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47. Rod and frame test and posture under optokinetic stimulation used to explore two complementary aspects of the visual influence in postural control after stroke
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Isabelle V. Bonan, S. Tasseel-Ponche, Hélène Le Liepvre, Alain-Pierre Yelnik, Pierre-Paul Vidal, F. Colle, and C. Andriantsifanetra
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Adult ,Male ,030506 rehabilitation ,medicine.medical_specialty ,Adolescent ,medicine.medical_treatment ,Posture ,Biophysics ,Rod and frame test ,Developmental psychology ,Young Adult ,03 medical and health sciences ,0302 clinical medicine ,Physical medicine and rehabilitation ,medicine ,Postural Balance ,Humans ,Orthopedics and Sports Medicine ,Stroke ,Aged ,Balance (ability) ,Aged, 80 and over ,Rehabilitation ,Stroke Rehabilitation ,Middle Aged ,medicine.disease ,Visual sensitivity ,Functional Independence Measure ,Visual Perception ,Female ,0305 other medical science ,Psychology ,Photic Stimulation ,030217 neurology & neurosurgery ,Optokinetic stimulation - Abstract
Background Balance rehabilitation should consider individual comportments according to visual input (VI). Indeed, visual dependence (VD), defined as the predominance given to the VI whatever the circumstances, frequent after stroke it could disturb balance. Because the term VD is a bit restrictive and cannot be deduced from clinical tests, the term visual sensitivity (VS) is preferred here. Hypothesis VI could have different influence depending on the task for a given individual. Methods We retrospectively compared 2 VS tests routinely used: the rod and frame test (RFT) and optokinetic stimulation (OKS). In RFT, VS was defined by a misperception of the visual verticality induced by a tilted frame (VS RFT) and in OKS by tilted sitting posture induced by rotational OKS (VS OKS). We studied the relations between VS RFT and VS OKS. Results We analysed data for 84 patients, mean age 55 ± 10 years, 45 ± 30 days after stroke. Scores for both tests were correlated with autonomy measured by the functional independence measure (r = −0.3, p = 0.01 and r = −0.2, p = 0.02). VS OKS score was also correlated with balance measured by the postural assessment scale for stroke (r = −0.3, p = 0.03). VS RFT score was not correlated with VS OKS score (p = 0.4, r = 0.04). Discussion - conclusion A patient may display VS for one test without sensitivity for the other because these tests investigate different neural organisation — perception for RFT or action for OKS. Their relation to balance disorders should be further investigated to build individualized rehabilitation programs. more...
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- 2017
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48. Saccadic Suppression Is Embedded Within Extended Oscillatory Modulation of Sensitivity
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Maria Concetta Morrone and Alessandro Benedetto
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Adult ,Male ,genetic structures ,Visual Acuity ,Visual oscillations ,Fixation, Ocular ,Sensorimotor integration ,Horizontal saccades ,050105 experimental psychology ,03 medical and health sciences ,0302 clinical medicine ,Biological Clocks ,Saccadic suppression of image displacement ,Long period ,Saccades ,Humans ,0501 psychology and cognitive sciences ,Contrast sensitivity ,Saccadic suppression ,Research Articles ,Communication ,Neuroscience (all) ,business.industry ,General Neuroscience ,05 social sciences ,Eye movement ,Neural Inhibition ,Action and perception ,Eye movements ,Visual sensitivity ,Saccadic masking ,Visual field ,Saccade ,action and perception ,contrast sensitivity ,eye movements ,saccadic suppression ,sensorimotor integration ,visual oscillations ,Female ,Psychology ,business ,Neuroscience ,Psychomotor Performance ,030217 neurology & neurosurgery - Abstract
Action and perception are intimately coupled systems. One clear case is saccadic suppression, the reduced visibility around the time of saccades, which is important in mediating visual stability; another is the oscillatory modulation of visibility synchronized with hand action. To suppress effectively the spurious retinal motion generated by the eye movements, it is crucial that saccadic suppression and saccadic onset be temporally synchronous. However, the mechanisms that determine this temporal synchrony are unknown. We investigated the effect of saccades on contrast discrimination sensitivity over a long period stretching over >1 s before and after saccade execution. Human subjects made horizontal saccades at will to two stationary saccadic targets separated by 20°. At a random interval, a brief Gabor patch was displayed between the two fixations in either the upper or lower visual field and the subject had to detect its location. Strong saccadic suppression was measured between −50 and 50 ms from saccadic onset. However, the suppression was systematically embedded in a trough of oscillations of contrast sensitivity that fluctuated rhythmically in the delta range (at ∼3 Hz), commencing ∼1 s before saccade execution and lasting for up to 1 s after the saccade. The results show that saccadic preparation and visual sensitivity oscillations are coupled and the coupling might be instrumental in temporally aligning the initiation of the saccade with the visual suppression.SIGNIFICANCE STATEMENTSaccades are known to produce a suppression of contrast sensitivity at saccadic onset and an enhancement after saccadic offset. Here, we show that these dynamics are systematically embedded in visual oscillations of contrast sensitivity that fluctuate rhythmically in the delta range (at ∼3 Hz), commencing ∼1 s before saccade execution and lasting for up to 1 s after the saccade. The results show that saccadic preparation and visual sensitivity oscillations are coupled and the coupling might be instrumental in aligning temporally the initiation of the saccade with the visual suppression. more...
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- 2017
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49. Sensory Processing: Visual Sensitivity Gets High at Night
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Christophe P. Ribelayga and Iris Fahrenfort
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0301 basic medicine ,Visual perception ,genetic structures ,Sensory processing ,medicine.medical_treatment ,Biology ,General Biochemistry, Genetics and Molecular Biology ,Retina ,03 medical and health sciences ,chemistry.chemical_compound ,Mice ,0302 clinical medicine ,medicine ,Animals ,skin and connective tissue diseases ,Vision, Ocular ,Retinal ,Visual sensitivity ,eye diseases ,030104 developmental biology ,medicine.anatomical_structure ,chemistry ,Visual Perception ,sense organs ,General Agricultural and Biological Sciences ,Neuroscience ,030217 neurology & neurosurgery - Abstract
Every day and night, the retina undergoes dramatic changes in its physiology and function. The prevailing view is that these daily changes affect the retinal output and thereby visual perception. Recent evidence suggests that modifications in higher-order processing centers, and not in retinal computations, account for variations in visual sensitivity. more...
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- 2020
50. Useful Field of View Performance in the Intact Visual Field of Hemianopia Patients
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Jeroen Goossens, Albert V. van den Berg, Anna C. Geuzebroek, and Karlijn Woutersen
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Adult ,Male ,medicine.medical_specialty ,genetic structures ,Audiology ,050105 experimental psychology ,Young Adult ,03 medical and health sciences ,All institutes and research themes of the Radboud University Medical Center ,0302 clinical medicine ,Quality of life ,Healthy control ,medicine ,Humans ,0501 psychology and cognitive sciences ,Hemianopsia ,Ocular pain ,Aged ,Aged, 80 and over ,Blind spot ,Humphrey field analyzer ,05 social sciences ,ipsilesional visual field ,Middle Aged ,Disorders of movement Donders Center for Medical Neuroscience [Radboudumc 3] ,medicine.disease ,Visual sensitivity ,eye diseases ,Visual field ,useful field of view ,Useful field of view ,Quality of Life ,homonymous hemianopia ,Female ,Visual Neuroscience ,Visual Fields ,Psychology ,National Eye Institute Visual Quality of Life-25 ,030217 neurology & neurosurgery ,postchiasmatic lesions - Abstract
Purpose Postchiasmatic brain damage commonly results in an area of reduced visual sensitivity or blindness in the contralesional hemifield. Previous studies have shown that the ipsilesional visual field can be impaired too. Here, we examine whether assessing visual functioning of the "intact" ipsilesional visual field can be useful to understand difficulties experienced by patients with visual field defects. Methods We compared the performance of 14 patients on a customized version of the useful field of view test that presents stimuli in both hemifields but only assesses functioning of their intact visual half-field (iUFOV) with that of equivalent hemifield assessments in 17 age-matched healthy control participants. In addition, we mapped visual field sensitivity with the Humphrey Field Analyzer. Last, we used an adapted version of the National Eye Institute Visual Quality of Life-25 to measure their experienced visual quality of life. Results We found that patients performed worse on the second and third iUFOV subtests, but not on the first subtest. Furthermore, patients scored significantly worse on almost every subscale, except ocular pain. Summed iUFOV scores (assessing the intact hemifield only) and Humphrey field analyzer scores (assessing both hemifields combined) showed almost similar correlations with the subscale scores of the adapted National Eye Institute Visual Quality of Life-25. Conclusions The iUFOV test is sensitive to deficits in the visual field that are not picked up by traditional perimetry. We therefore believe this task is of interest for patients with postchiasmatic brain lesions and should be investigated further. more...
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- 2020
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