Journal articles on the topic 'Visual discrimination'

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1

Haagensen, Annika M. J., Nanna Grand, Signe Klastrup, Christina Skytte, and Dorte B. Sørensen. "Spatial discrimination and visual discrimination." Behavioural Pharmacology 24, no. 3 (June 2013): 172–79. http://dx.doi.org/10.1097/fbp.0b013e32836104fd.

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2

Pérez-González, Luis Antonio, and Héctor Martínez. "Emergence of Third-Order Conditional Discriminations from Learning Discriminations with Unrelated Stimuli." Psychological Record 72, no. 1 (November 17, 2021): 75–88. http://dx.doi.org/10.1007/s40732-021-00461-2.

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AbstractThis study explored learning and generalization of a third-order conditional discrimination. Two 8-year-old children learned two auditory–visual conditional discriminations in which they selected visual Japanese syllabic symbols in response to syllables spoken by the experimenter. Then, they learned a third-order conditional discrimination in which they selected between two visual symbols after being exposed to two spoken syllables and one visual symbol. Thereafter, we probed generalization with novel symbols and names by teaching two additional conditional discriminations with Nahuatl symbols and spoken words and probing without reinforcement a new third-order conditional discrimination in which they had to select between two visual Nahuatl symbols after being exposed to two spoken Nahuatl words and one visual Nahuatl symbol. The two children responded in a predicted way to the novel third-order conditional discrimination. The emergent performance was possible because the set of relations established among the stimuli of the third-order conditional discrimination with Japanese syllables was analogous to the set of relations established among the stimuli of the third-order conditional discriminations with Nahuatl words. These results demonstrated a novel type of emergent responding in third-order conditional discrimination with arbitrary relations.
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3

Merigan, William H. "Basic visual capacities and shape discrimination after lesions of extrastriate area V4 in macaques." Visual Neuroscience 13, no. 1 (January 1996): 51–60. http://dx.doi.org/10.1017/s0952523800007124.

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Abstractlbotenic acid lesions were made in four macaque monkeys in a region of cortical area V4 that corresponds to the lower quadrant of one hemifield. For visual testing, fixation locus was monitoredwith scleral search coils and controlled behaviorally to place test stimuli either in the lesionedquadrant or in a control location in the opposite hemifield. Some basic visual capacities were slightly altered by the lesions; there was a two-fold reduction of luminance contrast sensitivity as well as red-green chromatic contrast sensitivity, both tested with stationary gratings. On the other hand, little or no loss was found when contrast sensitivity for detection or direction discrimination was tested with 10–Hz drifting gratings nor was there a reliable change in visual acuity. Hue and luminance matching were tested with a spatially more complex matching-to-sample task, but monkeys could not learn this task in the visual field locus of a V4 lesion. If previously trained at this locus, performance was not affected by the lesion. In contrast to the small effects on basic visual capabilities, performance on two form discrimination tasks was devastated by V4 lesions. The first involved discriminating the orientation of colinear groups of dots on a background of randomly placed dots. The second involved discriminating the orientation of a group of three line segments surrounded by differently oriented line segments. Some selectivity of the deficitsfor form discrimination was shown by the lack of an effect of the lesions on a global motion discrimination. These results show that while V4 lesions cause only slight disruptions of basic visual capacities, they profoundly disrupt form discriminations.
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4

Hopf, Jens-Max, Edward Vogel, Geoffrey Woodman, Hans-Jochen Heinze, and Steven J. Luck. "Localizing Visual Discrimination Processes in Time and Space." Journal of Neurophysiology 88, no. 4 (October 1, 2002): 2088–95. http://dx.doi.org/10.1152/jn.2002.88.4.2088.

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Previous studies of visual processing in humans using event-related potentials (ERPs) have demonstrated that task-related modulations of an early component called the “N1” wave (140–200 ms) reflect the operation of a voluntary discrimination process. Specifically, this component is larger in tasks requiring target discrimination than in tasks requiring simple detection. The present study was designed to localize this discriminative process in both time and space by means of combined magnetoencephalographic (MEG) and ERP recordings. Discriminative processing led to differential ERP and MEG activity beginning within 150 ms of stimulus onset. Source localization of the combined ERP/MEG data was performed using anatomical constraints from structural magnetic resonance images. These analyses revealed highly reliable and focused activity in regions of inferior occipital-temporal cortex. These findings indicate that the earliest measurable correlates of discriminative operations in the visual system appear as neural activity in circumscribed regions of the ventral processing stream.
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5

SCULLY, ERIN N., MARTIN J. ACERBO, and OLGA F. LAZAREVA. "Bilateral lesions of nucleus subpretectalis/interstitio-pretecto-subpretectalis (SP/IPS) selectively impair figure–ground discrimination in pigeons." Visual Neuroscience 31, no. 1 (October 9, 2013): 105–10. http://dx.doi.org/10.1017/s0952523813000424.

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AbstractEarlier, we reported that nucleus rotundus (Rt) together with its inhibitory complex, nucleus subpretectalis/interstitio-pretecto-subpretectalis (SP/IPS), had significantly higher activity in pigeons performing figure–ground discrimination than in the control group that did not perform any visual discriminations. In contrast, color discrimination produced significantly higher activity than control in the Rt but not in the SP/IPS. Finally, shape discrimination produced significantly lower activity than control in both the Rt and the SP/IPS. In this study, we trained pigeons to simultaneously perform three visual discriminations (figure–ground, color, and shape) using the same stimulus displays. When birds learned to perform all three tasks concurrently at high levels of accuracy, we conducted bilateral chemical lesions of the SP/IPS. After a period of recovery, the birds were retrained on the same tasks to evaluate the effect of lesions on maintenance of these discriminations. We found that the lesions of the SP/IPS had no effect on color or shape discrimination and that they significantly impaired figure–ground discrimination. Together with our earlier data, these results suggest that the nucleus Rt and the SP/IPS are the key structures involved in figure–ground discrimination. These results also imply that thalamic processing is critical for figure–ground segregation in avian brain.
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MERIGAN, WILLIAM H., and HONG AN PHAM. "V4 lesions in macaques affect both single- and multiple-viewpoint shape discriminations." Visual Neuroscience 15, no. 2 (February 1998): 359–67. http://dx.doi.org/10.1017/s0952523898152112.

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The role of cortical area V4 in complex shape discriminations was studied by testing the effects of V4 lesions in macaques on the ability to visually discriminate between images of three-dimensional (3D) objects from different viewpoints. Stimuli were presented in pairs in the lower left or lower right visual field quadrants about 4 deg from the fovea, and the monkeys judged on each trial whether the two views were of the same or of different objects. Object similarity was varied to determine a threshold shape difference. V4 lesions caused profound, retinotopic, and apparently permanent disruptions of discrimination, regardless of whether the images represented single or multiple viewpoints. In V4 lesioned portions of the visual field, monkeys could discriminate objects only when they differed much more grossly in shape than was true in control locations. These effects of the lesion were virtually identical for discriminations that had been learned before lesions were placed and for those learned afterwards. As in previous studies, V4 lesions elevated contrast thresholds by approximately a factor of two, but control observations showed that this was not the basis of the disruption of shape discrimination. Manipulation of cues to shape showed that in control locations, monkeys maintained excellent shape discrimination despite a variety of stimulus alterations, whereas in V4 lesioned areas their performance was easily disrupted. This finding suggests that V4 may support visual shape discriminations by facilitating the use of multiple visual cues. However, the fact that single-viewpoint and multiple-viewpoint discriminations were similarly affected indicates that the disruption was not specific to 3D shape discrimination, but may apply to a variety of subtle discriminations.
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7

Fukuda, Kyosuke. "Analysis of Eyeblink Activity during Discriminative Tasks." Perceptual and Motor Skills 79, no. 3_suppl (December 1994): 1599–608. http://dx.doi.org/10.2466/pms.1994.79.3f.1599.

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To evaluate the blinking pattern during and after cognitive processing, 10 subjects' eyeblinks were recorded by a videotape recording camera placed 100 cm from the subjects' side. The subjects' task was to discriminate two kinds of auditory tones presented serially and to discriminate two kinds of visual stimuli presented serially. Treatments were composed of the baseline condition preexperiment, the visual task with no discrimination, the visual discriminative task, the auditory task with no discrimination, and the auditory discriminative task. The blink rate in each treatment, the temporal distribution of blinks poststimulus, and the blink waveform were evaluated. Although blinks were not inhibited during tasks, frequent blinks after tasks were observed in both modalities. Blinks concentrated between 300 msec. and 800 msec. after the discriminated stimulus and formulated the blink-rate peak. The closing velocity of lid in the blink rate peak was lower after auditory stimulus. Moreover, the lid's opening velocity after the auditory discrimination was higher. These results indicated that the eyelid closed slowly and opened quickly after the auditory discriminative stimulus.
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8

Seider, T., E. Porges, A. Woods, and R. Cohen. "C-19 An fMRI Study of Age-Associated Changes in Basic Visual Discrimination." Archives of Clinical Neuropsychology 34, no. 6 (July 25, 2019): 1048. http://dx.doi.org/10.1093/arclin/acz034.181.

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Abstract Objective The study was conducted to determine age-associated changes in functional brain response, measured with fMRI, during visual discrimination with regard to three elementary components of visual perception: shape, location, and velocity. A secondary aim was to validate the method used to isolate the hypothesized brain regions associated with these perceptual functions. Method Items from the Visual Assessment Battery (VAB), a simultaneous match-to-sample task, assessed visual discrimination in 40 healthy adults during fMRI. Participants were aged 51-91 and recruited from a larger community sample for a study on normal aging. The tasks were designed to isolate neural recruitment during discrimination of either location, shape, or velocity by using tasks that were identical aside from the perceptual skill required to complete them. Results The Location task uniquely activated the dorsal visual processing stream, the Shape task the ventral stream, and the Velocity task V5/MT. Greater age was associated with greater neural recruitment, particularly in frontal areas (uncorrected voxel-level p < .001, family-wise error cluster-level p□.05). Conclusions Results validated the specialization of brain regions for spatial, perceptual, and movement discriminations and the use of the VAB to assess functioning localized to these regions. Anterior neural recruitment during visual discrimination increases with age.
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9

Feng, W., V. S. Stormer, A. Martinez, J. J. McDonald, and S. A. Hillyard. "Sounds Activate Visual Cortex and Improve Visual Discrimination." Journal of Neuroscience 34, no. 29 (July 16, 2014): 9817–24. http://dx.doi.org/10.1523/jneurosci.4869-13.2014.

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10

Goldstein, Laura H., and David A. Oakley. "Visual discrimination in the absence of visual cortex." Behavioural Brain Research 24, no. 3 (June 1987): 181–93. http://dx.doi.org/10.1016/0166-4328(87)90056-8.

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11

Pas, Susan F. te, and Jan J. Koenderink. "Visual Discrimination of Spectral Distributions." Perception 33, no. 12 (December 2004): 1483–97. http://dx.doi.org/10.1068/p5324.

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12

Norman, J. Farley, Elizabeth Y. Wiesemann, Hideko F. Norman, M. Jett Taylor, and Warren D. Craft. "The Visual Discrimination of Bending." Perception 36, no. 7 (July 2007): 980–89. http://dx.doi.org/10.1068/p5641.

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The sensitivity of observers to nonrigid bending was evaluated in two experiments. In both experiments, observers were required to discriminate on any given trial which of two bending rods was more elastic. In experiment 1, both rods bent within the same oriented plane, and bent either in a frontoparallel plane or bent in depth. In experiment 2, the two rods within any given trial bent in different, randomly chosen orientations in depth. The results of both experiments revealed that human observers are sensitive to, and can reliably detect, relatively small differences in bending (the average Weber fraction across experiments 1 and 2 was 9.0%). The performance of the human observers was compared to that of models that based their elasticity judgments upon either static projected curvature or mean and maximal projected speed. Despite the fact that all of the observers reported compelling 3-D perceptions of bending in depth, their judgments were both qualitatively and quantitatively consistent with the performance of the models. This similarity suggests that relatively straightforward information about the elasticity of simple bending objects is available in projected retinal images.
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Weikum, W. M., A. Vouloumanos, J. Navarra, S. Soto-Faraco, N. Sebastian-Galles, and J. F. Werker. "Visual Language Discrimination in Infancy." Science 316, no. 5828 (May 25, 2007): 1159. http://dx.doi.org/10.1126/science.1137686.

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14

LIDESTAM, BJÖRN. "Visual discrimination of vowel duration." Scandinavian Journal of Psychology 50, no. 5 (October 2009): 427–35. http://dx.doi.org/10.1111/j.1467-9450.2009.00746.x.

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15

Passino, Enrica, and Martine Ammassari–Teule. "Visual Discrimination in Inbred Mice." Physiology & Behavior 67, no. 3 (September 1999): 393–99. http://dx.doi.org/10.1016/s0031-9384(99)00076-1.

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16

Heuer, Herbert. "Visual discrimination and response programming." Psychological Research 49, no. 2-3 (August 1987): 91–98. http://dx.doi.org/10.1007/bf00308673.

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17

Wesley, Frank, and F. D. Klopfer. "Visual Discrimination Learning in Swine1." Zeitschrift für Tierpsychologie 19, no. 1 (April 26, 2010): 93–104. http://dx.doi.org/10.1111/j.1439-0310.1962.tb00764.x.

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18

Gaillard, B., and J. Feng. "Modelling a visual discrimination task." Neurocomputing 65-66 (June 2005): 203–9. http://dx.doi.org/10.1016/j.neucom.2004.10.008.

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19

Browse, Roger A., and Rick Gurnsey. "Asymmetries in visual texture discrimination." Spatial Vision 4, no. 1 (1989): 31–44. http://dx.doi.org/10.1163/156856889x00031.

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20

Ptito, Alain, Maryse Lassonde, Franco Leporé, and Maurice Ptito. "Visual discrimination in hemispherectomized patients." Neuropsychologia 25, no. 6 (January 1987): 869–79. http://dx.doi.org/10.1016/0028-3932(87)90092-3.

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21

MUNTZ, W. R. A., and J. GWYTHER. "Visual Acuity in Octopus Pallidus and Octopus Australis." Journal of Experimental Biology 134, no. 1 (January 1, 1988): 119–29. http://dx.doi.org/10.1242/jeb.134.1.119.

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Specimens of Octopus pallidus and O. australis were trained to discriminate vertical from horizontal rectangles, vertical from horizontal gratings, and vertical and horizontal gratings from uniform grey. In the discriminations that involved gratings a conditional simultaneous discrimination procedure was used, in which the two stimuli to be discriminated were presented stationary at the two ends of the tank, and a moving white disc was shown in front of each of them. Attacks on a disc were then rewarded or punished depending on the background against which it was shown. Animals rapidly reached performance levels of better than 80% correct responses on all discriminations. With one specimen of O. pallidus and three of O. australis when progressively finer gratings were used the discrimination broke down with stripe widths between 4.4′ and 9.7′, showing that for both species the minimum separable visual acuity is less than 9.7′. The behaviour of the two species is very similar to that of O. vulgaris, except that they accept less food per day, so fewer trials could be given.
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MERIGAN, WILLIAM H. "Cortical area V4 is critical for certain texture discriminations, but this effect is not dependent on attention." Visual Neuroscience 17, no. 6 (November 2000): 949–58. http://dx.doi.org/10.1017/s095252380017614x.

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This study examined the question of which features of a complex grouping discrimination make it vulnerable to permanent elimination by V4 lesions. We first verified that the line element grouping discrimination, which we previously reported to be devastated by V4 lesions, was similarly affected in the monkeys of this study. The permanence of the deficit was established by mapping its visual field distribution and then testing this discrimination for an extended period at a locus on the border of the deficit. Also, a staircase procedure was used to provide the monkey with within session instruction in the grouping discrimination, but this did not improve V4 lesion performance. Grouping was then compared with several discriminations that shared some features with it, but which were found not to be permanently eliminated by V4 lesions. This comparison suggested that grouping (rather than segmentation or response to a single element) was one feature that made the discrimination vulnerable, a second was the similarity in shape of the texture elements to be grouped. Finally, we tested visual crowding, a property of peripheral vision that is thought to reflect neuronal interactions early in visual cortex, possibly in area V1, and found no effect of V4 lesions. A control experiment with human observers tested whether the elimination of grouping by V4 lesions might be due to an alteration of attention, but found no evidence to support this hypothesis. These results show that severe disruption of texture discriminations by V4 lesions depends on both the nature of the discrimination and the type of texture elements involved, but does not necessarily involve the disruption of attention.
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Cross, Ginger W., Stephanie M. Doane, and David L. Alderton. "Training for Optimal Strategic Skills." Proceedings of the Human Factors and Ergonomics Society Annual Meeting 46, no. 25 (September 2002): 2054–58. http://dx.doi.org/10.1177/154193120204602513.

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The present research examined the impact of discrimination difficulty on the acquisition and transfer of strategic visual discrimination skills for meaningful stimuli. Participants were trained to discriminate between airplane silhouettes that varied in similarity. Some participants were trained to make difficult discriminations between similar airplane silhouettes, whereas others were trained to make easy discriminations between dissimilar airplane silhouettes. Participants were then transferred to making discrimination judgments at all similarity levels. The results suggest that initial training difficulty influences strategic skills even when participants have a priori strategies for processing stimuli. The findings improve our understanding of strategic skill acquisition, and training suggestions are discussed.
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Matar, Elie, Joseph R. Phillips, Kaylena A. Ehgoetz Martens, Glenda M. Halliday, and Simon J. G. Lewis. "Impaired Color Discrimination—A Specific Marker of Hallucinations in Lewy Body Disorders." Journal of Geriatric Psychiatry and Neurology 32, no. 5 (April 29, 2019): 257–64. http://dx.doi.org/10.1177/0891988719845501.

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There is emerging evidence indicating that color discrimination impairments can predict the development of Lewy body dementia in patients with rapid eye movement sleep behavior disorder, Parkinson disease, and in patients with mild cognitive impairment. Despite this clear relationship, color vision deficits are not seen uniformly in patients with dementia with Lewy bodies (DLB), suggesting a more nuanced association with the underlying neuropathology. Visual hallucinations represent a discriminating feature of DLB, and recent evidence implicates visual pathway dysfunction as a significant contributor to this phenomenon. In this study, we examined the relationship between color vision impairment and visual hallucinations, along with other clinical and neuropsychological features in 24 well-characterized patients with DLB alongside 25 healthy controls. Color discrimination impairment was seen in 16 (67%) of 24 DLB participants with a higher error score relative to controls ( P = .001). We demonstrate for the first time a strong association between color discrimination errors on the Farnsworth-Munsell 100 hue test and both the presence and severity of hallucinatory symptoms in DLB based on clinician-derived ( P = .008) and questionnaire-derived ( P = .03) measures. Correlation with clinical and neuropsychological variables revealed that color discrimination is significantly related to visuospatial difficulties measured by the clock-drawing task ( P = .02) but not to global measures of cognition, motor severity, age, or disease duration in our cohort. Factor analysis confirmed a unique relationship between color discrimination, visual hallucinations, and visuospatial function. Our results suggest that color discrimination does not simply relate to dementia but rather indexes higher order perceptual deficits that may predict visual hallucinations in Lewy body disorders and share a common pathophysiological substrate.
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Bridwell, David A., Elizabeth A. Hecker, John T. Serences, and Ramesh Srinivasan. "Individual differences in attention strategies during detection, fine discrimination, and coarse discrimination." Journal of Neurophysiology 110, no. 3 (August 1, 2013): 784–94. http://dx.doi.org/10.1152/jn.00520.2012.

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Interacting with the environment requires the ability to flexibly direct attention to relevant features. We examined the degree to which individuals attend to visual features within and across Detection, Fine Discrimination, and Coarse Discrimination tasks. Electroencephalographic (EEG) responses were measured to an unattended peripheral flickering (4 or 6 Hz) grating while individuals ( n = 33) attended to orientations that were offset by 0°, 10°, 20°, 30°, 40°, and 90° from the orientation of the unattended flicker. These unattended responses may be sensitive to attentional gain at the attended spatial location, since attention to features enhances early visual responses throughout the visual field. We found no significant differences in tuning curves across the three tasks in part due to individual differences in strategies. We sought to characterize individual attention strategies using hierarchical Bayesian modeling, which grouped individuals into families of curves that reflect attention to the physical target orientation (“on-channel”) or away from the target orientation (“off-channel”) or a uniform distribution of attention. The different curves were related to behavioral performance; individuals with “on-channel” curves had lower thresholds than individuals with uniform curves. Individuals with “off-channel” curves during Fine Discrimination additionally had lower thresholds than those assigned to uniform curves, highlighting the perceptual benefits of attending away from the physical target orientation during fine discriminations. Finally, we showed that a subset of individuals with optimal curves (“on-channel”) during Detection also demonstrated optimal curves (“off-channel”) during Fine Discrimination, indicating that a subset of individuals can modulate tuning optimally for detection and discrimination.
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Matar, Elie, Joseph R. Phillips, Kaylena A. Ehgoetz Martens, Glenda M. Halliday, and Simon JG Lewis. "060 Impaired color discrimination is associated with hallucinations in dementia with lewy bodies." Journal of Neurology, Neurosurgery & Psychiatry 90, e7 (July 2019): A19.3—A20. http://dx.doi.org/10.1136/jnnp-2019-anzan.52.

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IntroductionEmerging evidence indicates that color discrimination impairments can predict the development of dementia across a range of prodromal Lewy body conditions. However, color vision deficits are not seen uniformly in patients with Dementia with Lewy Bodies (DLB), suggesting a more nuanced association. Visual hallucinations(VH) represent a discriminating feature of DLB, and recent evidence implicates visual pathway dysfunction as a significant contributor to this phenomenon. We therefore hypothesized that color impairment will more closely associate with VH in DLB rather than general cognition.MethodsIn this study, we examined the relationship between color vision impairment and VH, along with other clinical and neuropsychological features in 24 patients with DLB alongside 25 age-matched controls. Color discrimination was assessed using the Farnsworth-Munsell-100 Hue (FM-100) test.ResultsColor discrimination impairment was seen in 16/24 DLB participants (67%) with a higher error score relative to controls(p=0.001). We demonstrate for the first time a strong association between color discrimination errors and both the presence and severity of VH in DLB based on clinician-derived(p=0.008) and questionnaire-derived(p=0.03) measures. Correlation with clinical and neuropsychological variables revealed that color discrimination is significantly related to visuospatial impairment(p=0.02) but not to global measures of cognition, motor severity, age or disease duration. Factor analysis confirmed a unique relationship between color discrimination, visual hallucinations and visuospatial function.ConclusionOur results suggest that color impairments may be a specific biomarker of visual hallucinations and associated visuoperceptual deficits in evolving Lewy body disorders rather than dementia per se and thus providing insight into a shared pathophysiological substrate.
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Adab, Hamed Zivari, Ivo D. Popivanov, Wim Vanduffel, and Rufin Vogels. "Perceptual Learning of Simple Stimuli Modifies Stimulus Representations in Posterior Inferior Temporal Cortex." Journal of Cognitive Neuroscience 26, no. 10 (October 2014): 2187–200. http://dx.doi.org/10.1162/jocn_a_00641.

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Practicing simple visual detection and discrimination tasks improves performance, a signature of adult brain plasticity. The neural mechanisms that underlie these changes in performance are still unclear. Previously, we reported that practice in discriminating the orientation of noisy gratings (coarse orientation discrimination) increased the ability of single neurons in the early visual area V4 to discriminate the trained stimuli. Here, we ask whether practice in this task also changes the stimulus tuning properties of later visual cortical areas, despite the use of simple grating stimuli. To identify candidate areas, we used fMRI to map activations to noisy gratings in trained rhesus monkeys, revealing a region in the posterior inferior temporal (PIT) cortex. Subsequent single unit recordings in PIT showed that the degree of orientation selectivity was similar to that of area V4 and that the PIT neurons discriminated the trained orientations better than the untrained orientations. Unlike in previous single unit studies of perceptual learning in early visual cortex, more PIT neurons preferred trained compared with untrained orientations. The effects of training on the responses to the grating stimuli were also present when the animals were performing a difficult orthogonal task in which the grating stimuli were task-irrelevant, suggesting that the training effect does not need attention to be expressed. The PIT neurons could support orientation discrimination at low signal-to-noise levels. These findings suggest that extensive practice in discriminating simple grating stimuli not only affects early visual cortex but also changes the stimulus tuning of a late visual cortical area.
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Jaén, EM, EM Colombo, and CF Kirschbaum. "A simple visual task to assess flicker effects on visual performance." Lighting Research & Technology 43, no. 4 (July 11, 2011): 457–71. http://dx.doi.org/10.1177/1477153511405409.

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Temporal modulation of lighting at frequencies higher than the critical fusion frequency can affect human efficiency in diverse ways that are not understood. A simple visual search task was used to assess visual performance under lighting with low (3%) and high (32%) temporal modulation and compared with the results of a conventional discrimination task in an identical situation. Even when side-by-side subjective appraisal corroborates that there are no visually perceptible differences between the two forms of lighting, both tasks show a reduction in visual performance when temporal modulation increases. Significantly larger relative differences between the two levels of modulation and better discrimination between individuals were obtained with the visual search task, demonstrating that the search task could be more useful for identifying individuals sensitive to flicker. The reasons why the visual search task might be more sensitive to flicker than the discrimination task are discussed.
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Orban, G. A. "Human Brain Regions Involved in Visual Discriminations." Perception 26, no. 1_suppl (August 1997): 298. http://dx.doi.org/10.1068/v970012.

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We have used simple visual discriminations as a tool to investigate the human visual system with PET and fMRI. In discrimination tasks, stimuli in which an attribute is defined by a cue are presented in a position in the visual field and the subjects compare the stimuli with each other or with a standard. We have manipulated each of these four aspects. Manipulation of stimulus position engages visuo-spatial attention mechanisms in parietal and frontal cortex (Vandenberghe et al, 1996 Brain119 1263 – 1276; 1997 Journal of Neuroscience in press). Manipulation of the cue has revealed the kinetic occipital (KO) region involved in the processing of kinetic contours (Orban et al, 1995 Proceedings of the National Academy of Sciences of the USA92 993 – 997; Dupont et al, 1997 Cerebral Cortex in press). Using luminance-defined patterns presented centrally and contrasting successive orientation discrimination with identification we have demonstrated the involvement of right fusiform cortex in temporal comparison of orientation (Orban et al, 1997 European Journal of Neurosciences9 246 – 259). The same region is involved in spatial comparison of orientation as well as in temporal comparison of speed and direction of random-dot motion. This set of experiments shows that processing in the human visual system depends not only on the attribute used but also on the nature of the task to be performed. The direction and speed discrimination experiments also reveal the involvement of the lingual motion area in these tasks, but surprisingly very little involvement of human MT/V5.
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Hinson, John M., and Linda R. Tennison. "WITHIN-SESSION ANALYSIS OF VISUAL DISCRIMINATION." Journal of the Experimental Analysis of Behavior 72, no. 3 (November 1999): 385–405. http://dx.doi.org/10.1901/jeab.1999.72-385.

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31

Nissani, Moti, Donna Hoefler-Nissani, U. Tin Lay, and U. Wan Htun. "SIMULTANEOUS VISUAL DISCRIMINATION IN ASIAN ELEPHANTS." Journal of the Experimental Analysis of Behavior 83, no. 1 (January 2005): 15–29. http://dx.doi.org/10.1901/jeab.2005.34-04.

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32

MUNTZ, W. R. A., and J. GWYTHER. "Visual Discrimination of Distance by Octopuses." Journal of Experimental Biology 140, no. 1 (November 1, 1988): 345–53. http://dx.doi.org/10.1242/jeb.140.1.345.

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If two stimuli are presented to an octopus simultaneously, but at different distances from the animal, the nearer of the two is usually attacked. This preference was used to test the ability of octopuses to discriminate distance. White discs, 37 mm in diameter, were used as stimuli, and two parameters were varied: the distance of the farther stimulus from the animal (D), and the difference between the distances of the farther and nearer stimulus (d). Animals chose the nearer stimulus on 70% of occasions under the most difficult conditions used, where D was 370 mm and d was 50mm. This percentage increased as D decreased or d increased. Further tests showed that varying the size of the discs, or using white vertical or horizontal rectangles instead of discs as stimuli, did not affect performance. The most likely cue being used by the animals to discriminate distances is accommodation. If this is the case octopuses can detect blurring of points on the retinal image comparable in size to a single retinal receptor, and lens displacements of around 10 μm
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33

Barraclough, Nick E., Steve A. Page, and Bruce D. Keefe. "Visual adaptation enhances action sound discrimination." Attention, Perception, & Psychophysics 79, no. 1 (September 7, 2016): 320–32. http://dx.doi.org/10.3758/s13414-016-1199-z.

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34

Ross, John. "Visual Discrimination of Number without Counting." Perception 32, no. 7 (July 2003): 867–70. http://dx.doi.org/10.1068/p5029.

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Observers in this study judged which of two fields contained the greater number of spots. Spots had difference-of-Gaussian luminance profiles and could differ in contrast polarity or were of uniform luminance and could differ in size. Weber fractions for all observers except one varied little except when spots varied in size. It is suggested that the results of this and previous studies might be explained by the existence of neurons tuned for number.
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35

Wilson, H. R. "Nonlinear processes in visual pattern discrimination." Proceedings of the National Academy of Sciences 90, no. 21 (November 1, 1993): 9785–90. http://dx.doi.org/10.1073/pnas.90.21.9785.

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36

Saarinen, Jukka. "Focal Visual Attention and Pattern Discrimination." Perception 22, no. 5 (May 1993): 509–15. http://dx.doi.org/10.1068/p220509.

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Pattern discrimination in the presence of distractor patterns is improved when the stimulus display is preceded by a precue designating the location of the target pattern. Experiments were conducted to determine how big an improvement the precue produced. The specific question of whether the observer is able to process selectively the stimulus pattern in the cued location of the display and ignore the patterns of the noncued locations was addressed. In order to study this, reaction time for pattern discrimination on a blank background (no distractors) was compared with the reaction time when the observer performed the same discrimination task in the presence of distractors and a precue had indicated the location of the stimulus pattern to be discriminated. The results showed that these two reaction times were equal if the cue preceded the stimulus patterns at intervals which were longer than some minimum time. Hence, stimuli outside the ‘aperture’ of focal attention can be ignored. These results could not be attributed to eye movements, because the longest duration of the whole sequence of precue and stimulus patterns was only 200 ms.
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37

Durgin, F. H., K. M. Gigone, and E. Schaffer. "Improved visual speed discrimination while walking." Journal of Vision 4, no. 8 (August 1, 2004): 802. http://dx.doi.org/10.1167/4.8.802.

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38

Miles, Fiona, and James W. Meehan. "Visual discrimination of pigmented skin lesions." Health Psychology 14, no. 2 (1995): 171–77. http://dx.doi.org/10.1037/0278-6133.14.2.171.

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39

Sato, Hiromi, Takumi Oide, Ryuto Yashiro, and Isamu Motoyoshi. "Visual discrimination of spatiotemporal average orientation." Journal of Vision 19, no. 10 (September 6, 2019): 48b. http://dx.doi.org/10.1167/19.10.48b.

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40

Greenlee, Mark W., and Svein Magnussen. "Limited-capacity mechanisms of visual discrimination." Vision Research 38, no. 3 (February 1998): 375–85. http://dx.doi.org/10.1016/s0042-6989(97)00161-2.

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41

Simpson, William A., and Barbara A. Finsten. "Pedestal effect in visual motion discrimination." Journal of the Optical Society of America A 12, no. 12 (December 1, 1995): 2555. http://dx.doi.org/10.1364/josaa.12.002555.

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42

Rehkämper, G., and A. Görlach. "Visual Discrimination in Adult Dairy Bulls." Journal of Dairy Science 80, no. 8 (August 1997): 1613–21. http://dx.doi.org/10.3168/jds.s0022-0302(97)76092-2.

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43

Allen, Anne, Jon Michels, and J. Z. Young. "Memory and visual discrimination by squids." Marine Behaviour and Physiology 11, no. 4 (July 1985): 271–82. http://dx.doi.org/10.1080/10236248509387052.

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44

Shalev, Lee, Rony Paz, and Galia Avidan. "Visual Aversive Learning Compromises Sensory Discrimination." Journal of Neuroscience 38, no. 11 (February 8, 2018): 2766–79. http://dx.doi.org/10.1523/jneurosci.0889-17.2017.

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45

Charpentier, Marie J. E., Mélanie Harté, Barthélémy Ngoubangoye, Anais Herbert, and Peter M. Kappeler. "Visual Discrimination of Kin in Mandrills." Ethology 123, no. 3 (February 14, 2017): 251–59. http://dx.doi.org/10.1111/eth.12596.

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46

Ezzo, Rania, Jonathan Winawer, Marisa Carrasco, and Bas Rokers. "Motion discrimination around the visual field." Journal of Vision 22, no. 14 (December 5, 2022): 3433. http://dx.doi.org/10.1167/jov.22.14.3433.

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47

Anselmo, Sandra. "Developing visual comprehension: Figure-ground discrimination." Day Care & Early Education 12, no. 3 (March 1985): 44. http://dx.doi.org/10.1007/bf01620064.

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48

Allik, J�ri, Tiia Tuulmets, and Piet G. Vos. "Size invariance in visual number discrimination." Psychological Research 53, no. 4 (1991): 290–95. http://dx.doi.org/10.1007/bf00920482.

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49

Vyazovska, Olga V., Victor M. Navarro, and Edward A. Wasserman. "Stagewise multidimensional visual discrimination by pigeons." Journal of the Experimental Analysis of Behavior 106, no. 1 (July 2016): 58–74. http://dx.doi.org/10.1002/jeab.217.

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50

O'Riordan, Michelle, and Kate Plaisted. "Enhanced discrimination in autism." Quarterly Journal of Experimental Psychology Section A 54, no. 4 (November 2001): 961–79. http://dx.doi.org/10.1080/713756000.

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Children with autism are superior to typically developing children at visual search tasks (O'Riordan, Plaisted, Driver, & Baron-Cohen, in press; Plaisted, O'Riordan, & Baron-Cohen, l998b). This study investigates the reasons for this phenomenon. The performance of children with autism and of typically developing children was compared on a series of visual search tasks to investigate two related problems. The first issue was whether the critical determinant of search rate in children is the discriminability of the display items, as it is in normal adults. The second question investigated was whether the superior performance of individuals with autism on visual search tasks is due to an enhanced ability to discriminate between display items. The results demonstrated that discriminability is the rate-determining factor for children with and without autism, replicating earlier findings with normal adults, and that children with autism have an enhanced ability to discriminate between display items. Thus, it seems that an enhanced ability to discriminate between display items underlies superior visual search in autism.
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