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Maehara G, Wang Y, Murakami I. Effects of binocular disparity on binocular luminance combination. J Vis 2024; 24:4. [PMID: 38376853 PMCID: PMC10883336 DOI: 10.1167/jov.24.2.4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/21/2024] Open
Abstract
This study aimed to examine the effects of binocular disparity on binocular combination of brightness information coming from luminance increments and decrements. The point of subjective equality was determined by asking the observers to judge which stimulus appeared brighter-a bar stimulus with variable disparity or another stimulus with zero disparity. For the bar stimulus, the interocular luminance ratio was varied to trace an equal brightness curve. Binocular disparity had no effect on luminance increments presented on a gray or black background. In contrast, when luminance decrements were presented on a gray background, non-zero disparities elevated points of subjective equality for stimuli with interocular luminance differences. This means that the binocular brightness combination of the two monocular signals shifted from winner-take-all summation toward linear averaging. It has been argued that this effect may be caused by non-zero binocular disparities attenuating interocular suppression, which is deemed to operate normally with zero disparity.
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Affiliation(s)
- Goro Maehara
- Department of Human Science, Kanagawa University, Kanagawa, Japan
| | - Yiqian Wang
- Department of Psychology, The University of Tokyo, Tokyo, Japan
| | - Ikuya Murakami
- Department of Psychology, The University of Tokyo, Tokyo, Japan
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Clayton R, Siderov J. Differences in stereoacuity between crossed and uncrossed disparities reduce with practice. Ophthalmic Physiol Opt 2022; 42:1353-1362. [PMID: 35997266 PMCID: PMC9804356 DOI: 10.1111/opo.13040] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2022] [Revised: 07/22/2022] [Accepted: 07/22/2022] [Indexed: 01/05/2023]
Abstract
INTRODUCTION Stereoacuity, like many forms of hyperacuity, improves with practice. We investigated the effects of repeated measurements over multiple visits on stereoacuity using two commonly utilised clinical stereotests, for both crossed and uncrossed disparity stimuli. METHODS Participants were adults with normal binocular vision (n = 17) aged between 18 and 50 years. Stereoacuity was measured using the Randot and TNO stereotests on five separate occasions over a six week period. We utilised both crossed and uncrossed stimuli to separately evaluate stereoacuity in both disparity directions. A subset of the subject group also completed a further five visits over an additional six week period. Threshold stereoacuity was determined by the lowest disparity level at which the subjects could correctly identify both the position and disparity direction (crossed or uncrossed) of the stimulus. Data were analysed by repeated measures analysis of variance. RESULTS Stereoacuity for crossed and uncrossed stimuli improved significantly across the first five visits (F1,21 = 4.24, p = 0.05). The main effect of disparity direction on stereoacuity was not significant (F1 = 0.02, p = 0.91). However, a significant interaction between disparity direction and stereotest was identified (F1 = 7.92, p = 0.01). CONCLUSIONS Stereoacuity measured with both the TNO and Randot stereotests improved significantly over the course of five repetitions. Although differences between crossed and uncrossed stereoacuity were evident, they depended on the stereotest used and reduced or disappeared after repeated measurements. A single measure of stereoacuity is inadequate for properly evaluating adult stereopsis clinically.
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Affiliation(s)
- Robin Clayton
- Centre for Vision across the Life Span, Department of Optometry and Vision SciencesUniversity of HuddersfieldHuddersfieldUK
| | - John Siderov
- Centre for Vision across the Life Span, Department of Optometry and Vision SciencesUniversity of HuddersfieldHuddersfieldUK
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Ale Magar JB, Shah SP, Sleep MG, Willett FA, Dai SH. Validity and repeatability of contour-based visotec distance stereoacuity test. Clin Exp Optom 2022; 106:283-289. [PMID: 35125046 DOI: 10.1080/08164622.2022.2033599] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022] Open
Abstract
CLINICAL RELEVANCE The clinical assessment of distance stereoacuity is important in some ocular conditions. Given the different neurophysiological mechanism for crossed and uncrossed stereoacuities, evaluation of both may provide additional insight into binocular vision disorders. BACKGROUND Clinical devices measuring distance crossed and uncrossed stereopsis are not readily available. Visotec Distance Stereo Test (VDST) is a contour-based device designed to measure both forms of distance stereoacuity. This study assesses the validity and test-retest reliability of the device in comparison to the random dot-based Randot Distance Stereo Test (RDST). METHOD VDST and RDST were administered to a total of 107 children, that included 51 'normal' and 56 'abnormal' (37 intermittent exotropia and 19 amblyopia) between the ages of 5 and 15 years. Two examiners retested stereoacuities in a sub-set of 62 randomly selected subjects. Stereoacuity was transformed to log scale. 95% limits of agreement were calculated for test-retest reliability. The Bland-Altman plot was used to demonstrate the agreement between the tests and the examiners. RESULTS The mean ± SD crossed distance stereoacuities using VDST in normal, intermittent exotropia and amblyopic children were 93.1 ± 43.8, 161.9 ± 89.8 and 236.3 ± 122.4 arcseconds, respectively. For uncrossed stereoacuity, these were 104.7 ± 54.0, 187.6 ± 89.6 and 265.5 ± 144.0 arcseconds, respectively. Crossed stereoacuity was significantly better than uncrossed stereoacuity. 95% limits of test-retest agreement for crossed and uncrossed stereoacuities using the VDST were 0.27 and 0.30, respectively. An exact test-retest match using VDST was 84% in normals and 77% in abnormals for crossed and 83% in normal and 74% in abnormal for uncrossed stereoacuities. CONCLUSION VDST is a reliable, valid and easy-to-administer distance crossed and uncrossed stereoacuity measuring device. Further studies are required to establish the clinical importance of assessing these two forms stereoacuities in relation to various binocular vision disorders.
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Affiliation(s)
- Jit B Ale Magar
- Ophthalmology Department, Queensland Children's Hospital, Brisbane, Australia
| | - Shaheen P Shah
- Ophthalmology Department, Queensland Children's Hospital, Brisbane, Australia.,School of Clinical Medicine, The University of Queensland, Brisbane, Australia
| | - Michael G Sleep
- Ophthalmology Department, Queensland Children's Hospital, Brisbane, Australia
| | - Faren A Willett
- Ophthalmology Department, Queensland Children's Hospital, Brisbane, Australia
| | - Shuan H Dai
- Ophthalmology Department, Queensland Children's Hospital, Brisbane, Australia.,School of Clinical Medicine, The University of Queensland, Brisbane, Australia
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Kim NG, Lee HW. Stereoscopic Depth Perception and Visuospatial Dysfunction in Alzheimer's Disease. Healthcare (Basel) 2021; 9:healthcare9020157. [PMID: 33546119 PMCID: PMC7913121 DOI: 10.3390/healthcare9020157] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2020] [Revised: 01/21/2021] [Accepted: 01/29/2021] [Indexed: 11/16/2022] Open
Abstract
With visuospatial dysfunction emerging as a potential marker that can detect Alzheimer's disease (AD) even in its earliest stages and with disturbance in stereopsis suspected to be the prime contributor to visuospatial deficits in AD, we assessed stereoscopic abilities of patients with AD and mild cognitive impairment (MCI). Whereas previous research assessing patients' stereoacuity has yielded mixed results, we assessed patients' capacity to process coarse disparities that can convey adequate depth information about objects in the environment. We produced two virtual cubes at two different distances from the observer by manipulating disparity type (absolute vs. relative), disparity direction (crossed vs. uncrossed) and disparity magnitude, then had participants judge the object that appeared closer to them. Two patient groups performed as well as, or even better than elderly controls, suggesting that AD patients' coarse disparity processing capacity is capable of supporting common tasks involving reaching, grasping, driving, and navigation. Results may help researchers narrow down the exact cause(s) of visuospatial deficits in AD and develop and validate measures to assess visuospatial dysfunction in clinical trials and disease diagnosis.
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Affiliation(s)
- Nam-Gyoon Kim
- Department of Psychology, Keimyung University, Daegu 42601, Korea
- Correspondence: ; Tel.: +82-53-580-5415
| | - Ho-Won Lee
- Department of Neurology, School of Medicine & Brain Science and Engineering Institute, Kyungpook National University, Daegu 41566, Korea;
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Alarcon Carrillo S, Baldwin AS, Hess RF. Factors limiting sensitivity to binocular disparity in human vision: Evidence from a noise-masking approach. J Vis 2020; 20:9. [PMID: 32232374 PMCID: PMC7405759 DOI: 10.1167/jov.20.3.9] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2019] [Accepted: 11/15/2019] [Indexed: 11/24/2022] Open
Abstract
Our visual system uses the disparity between the images received by the two eyes to judge three-dimensional distance to surfaces. We can measure this ability by having subjects discriminate the disparity of rendered surfaces. We wanted to know the basis of the individual differences in this ability. We tested 53 adults with normal vision using a relative disparity detection task. Targets were wedge-shaped surfaces formed from random dots. These were presented in either crossed or uncrossed disparity relative to a random dot background. The threshold disparity ranged from 24 arc seconds in the most-able subject to 275 arc seconds in the least-able subject. There was a small advantage for detecting crossed-disparity targets. We used the noise-masking paradigm to partition subject performance into two factors. These were the subject's equivalent internal noise and their processing efficiency. The parameters were estimated by fitting the linear amplifier model. We found both factors contributed to the individual differences in stereoacuity. Within subjects, those showing an advantage for one disparity direction had enhanced efficiency for that direction. Some subjects had a higher equivalent internal noise for one direction that was balanced out by an increased efficiency. Our approach provides a more thorough account of the stereo-ability of our subjects compared with measuring thresholds alone. We present a normative set of results that can be compared with clinical populations.
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Affiliation(s)
- Sara Alarcon Carrillo
- McGill Vision Research, Department of Ophthalmology & Visual Sciences, McGill University, Montreal, Quebec, Canada
| | - Alex S. Baldwin
- McGill Vision Research, Department of Ophthalmology & Visual Sciences, McGill University, Montreal, Quebec, Canada
| | - Robert F. Hess
- McGill Vision Research, Department of Ophthalmology & Visual Sciences, McGill University, Montreal, Quebec, Canada
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Chopin A, Bavelier D, Levi DM. The prevalence and diagnosis of 'stereoblindness' in adults less than 60 years of age: a best evidence synthesis. Ophthalmic Physiol Opt 2019; 39:66-85. [PMID: 30776852 DOI: 10.1111/opo.12607] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2018] [Accepted: 01/23/2019] [Indexed: 12/21/2022]
Abstract
PURPOSE Stereoscopic vision (or stereopsis) is the ability to perceive depth from binocular disparity - the difference of viewpoints between the two eyes. Interestingly, there are large individual differences as to how well one can appreciate depth from such a cue. The total absence of stereoscopic vision, called 'stereoblindness', has been associated with negative behavioural outcomes such as poor distance estimation. Surprisingly, the prevalence of stereoblindness remains unclear, as it appears highly dependent on the way in which stereopsis is measured. RECENT FINDINGS This review highlights the fact that stereopsis is not a unitary construct, but rather implies different systems. The optimal conditions for measuring these varieties of stereoscopic information processing are discussed given the goal of detecting stereoblindness, using either psychophysical or clinical stereotests. In that light, we then discuss the estimates of stereoblindness prevalence of past studies. SUMMARY We identify four different approaches that all converge toward a prevalence of stereoblindness of 7% (median approach: 7%; unambiguous-stereoblindness-criteria approach: 7%; visual-defect-included approach: 7%; multiple-criteria approach: 7%). We note that these estimates were derived considering adults of age <60 years old. Older adults may have a higher prevalence. Finally, we make recommendations for a new ecological definition of stereoblindness and for efficient clinical methods for determining stereoblindness by adapting existing tools.
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Affiliation(s)
- Adrien Chopin
- Faculte de Psychologie et Sciences de l'Education, University of Geneva, Geneva, Switzerland.,Campus Biotech, Geneva, Switzerland
| | - Daphne Bavelier
- Faculte de Psychologie et Sciences de l'Education, University of Geneva, Geneva, Switzerland.,Campus Biotech, Geneva, Switzerland
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Excessive Crossed Disparity Detection by Visual Evoked Potentials to Reduce Visual Discomfort in 3D Viewing. COMPUTATIONAL INTELLIGENCE AND NEUROSCIENCE 2018; 2018:7098389. [PMID: 30515201 PMCID: PMC6236968 DOI: 10.1155/2018/7098389] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/31/2018] [Revised: 09/05/2018] [Accepted: 09/20/2018] [Indexed: 11/27/2022]
Abstract
As excessive crossed disparity is known to cause visual discomfort, this study aims to establish a classification model to discriminate excessive crossed disparity in stereoscopic viewing in combination with subjective assessment of visual discomfort. A stereo-visual evoked potentials (VEPs) experimental system was built up to obtain the VEPs evoked by stereoscopic stimulus with different disparities. Ten volunteers participated in this experiment, and forty VEP datasets in total were extracted when the viewers were under comfortable viewing conditions. Six features of VEPs from three electrodes at the occipital lobe were chosen, and the classification was established using the Fisher's linear discriminant (FLD). Based on FLD results, the correct rate for determining the excessive crossed disparity was 70%, and it reached 80% for other stimuli. The study demonstrated cost-effective discriminant classification modelling to distinguish the stimulus with excessive crossed disparity which inclines to cause visual discomfort.
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Fixating at far distance shortens reaction time to peripheral visual stimuli at specific locations. Neurosci Lett 2018; 664:15-19. [PMID: 29126774 DOI: 10.1016/j.neulet.2017.11.006] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2017] [Revised: 11/04/2017] [Accepted: 11/06/2017] [Indexed: 11/24/2022]
Abstract
The purpose of the present study was to examine whether the fixation distance in real three-dimensional space affects manual reaction time to peripheral visual stimuli. Light-emitting diodes were used for presenting a fixation point and four peripheral visual stimuli. The visual stimuli were located at a distance of 45cm and at 25° in the left, right, upper, and lower directions from the sagittal axis including the fixation point. Near (30cm), Middle (45cm), Far (90cm), and Very Far (300cm) fixation distance conditions were used. When one of the four visual stimuli was randomly illuminated, the participants released a button as quickly as possible. Results showed that overall peripheral reaction time decreased as the fixation distance increased. The significant interaction between fixation distance and stimulus location indicated that the effect of fixation distance on reaction time was observed at the left, right, and upper locations but not at the lower location. These results suggest that fixating at far distance would contribute to faster reaction and that the effect is specific to locations in the peripheral visual field. The present findings are discussed in terms of viewer-centered representation, the focus of attention in depth, and visual field asymmetry related to neurological and psychological aspects.
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Dorman R, van Ee R. 50 Years of Stereoblindness: Reconciliation of a Continuum of Disparity Detectors With Blindness for Disparity in Near or Far Depth. Iperception 2017; 8:2041669517738542. [PMID: 29201340 PMCID: PMC5697597 DOI: 10.1177/2041669517738542] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
Whitman Richards (1932–2016) discovered some 50 years ago that about 30% of observers from the normal population exhibit stereoblindness: the disability to process binocular disparities in either far or near depth. We review the literature on stereoblindness entailing two insights. First, contemporary scholars in stereopsis undervalue the comprehension that disparity processing studies require precise assessments of observers’ stereoblindness. We argue that this frequently leads to suboptimal interpretations. Second, there is still an open conundrum: How can the established finding that disparity is processed by a continuum of detectors be reconciled with the disability of many observers to process a whole class of far or near disparities? We propose, based upon integration of literature, that an asymmetry between far and near disparity detection at birth—being present for a variety of reasons—can suppress the typical formation of binocular correlation during the critical period for the development of stereopsis early in life, thereby disabling a whole class of far or near disparities.
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Affiliation(s)
- Reinder Dorman
- Cognitive and Systems Neuroscience Group, Swammerdam Institute for Life Science, University of Amsterdam, The Netherlands; Donders Institute for Brain, Cognition and Behavior, Radboud University, Nijmegen, The Netherlands
| | - Raymond van Ee
- Donders Institute for Brain, Cognition and Behavior, Radboud University, Nijmegen, The Netherlands; Department of Brain and Cognition, University of Leuven, Belgium; Department of Brain, Behavior and Cognition, Philips Research, Eindhoven, The Netherlands
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The effects of the binocular disparity differences between targets and maskers on visual search. Atten Percept Psychophys 2016; 79:459-472. [PMID: 27943121 DOI: 10.3758/s13414-016-1252-y] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
A visual search for targets is facilitated when the target objects are on a different depth plane than other masking objects cluttering the scene. The ability of observers to determine whether one of four letters presented stereoscopically at four symmetrically located positions on the fixation plane differed from the other three was assessed when the target letters were masked by other randomly positioned and oriented letters appearing on the same depth plane as the target letters, or in front, or behind it. Three additional control maskers, derived from the letter maskers, were also presented on the same three depth planes: (1) random-phase maskers (same spectral amplitude composition as the letter masker but with the phase spectrum randomized); (2) random-pixel maskers (the locations of the letter maskers' pixel amplitudes were randomized); (3) letter-fragment maskers (the same letters as in the letter masker but broken up into fragments). Performance improved with target duration when the target-letter plane was in front of the letter-masker plane, but not when the target letters were on the same plane as the masker, or behind it. A comparison of the results for the four different kinds of maskers indicated that maskers consisting of recognizable objects (letters or letter fragments) interfere more with search and comparison judgments than do visual noise maskers having the same spatial frequency profile and contrast. In addition, performance was poorer for letter maskers than for letter-masker fragments, suggesting that the letter maskers interfered more with performance than the letter-fragment maskers because of the lexical activity they elicit.
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Nasr S, Tootell RBH. Visual field biases for near and far stimuli in disparity selective columns in human visual cortex. Neuroimage 2016; 168:358-365. [PMID: 27622398 DOI: 10.1016/j.neuroimage.2016.09.012] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2016] [Revised: 08/27/2016] [Accepted: 09/06/2016] [Indexed: 10/21/2022] Open
Abstract
When visual objects are located in the lower visual field, human observers perceive objects to be nearer than their real physical location. Conversely, objects in the upper visual field are viewed farther than their physical location. This bias may be linked to the statistics of natural scenes, and perhaps the ecological relevance of objects in the upper and lower visual fields (Previc, 1990; Yang and Purves, 2003). However, the neural mechanisms underlying such perceptual distortions have remained unknown. To test for underlying brain mechanisms, we presented visual stimuli at different perceptual distances, while measuring high-resolution fMRI in human subjects. First, we localized disparity-selective thick stripes and thick-type columns in secondary and third visual cortical areas, respectively. Consistent with the perceptual bias, we found that the thick stripe/columns that represent the lower visual field also responded more selectively to near rather than far visual stimuli. Conversely, thick stripe/columns that represent the upper visual field show a complementary bias, i.e. selectively higher activity to far rather than near stimuli. Thus, the statistics of natural scenes may play a significant role in the organization of near- and far-selective neurons within V2 thick stripes and V3 thick-type columns.
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Affiliation(s)
- Shahin Nasr
- Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Boston, MA, USA; Department of Radiology, Harvard Medical School, Boston, MA, USA.
| | - Roger B H Tootell
- Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Boston, MA, USA; Department of Radiology, Harvard Medical School, Boston, MA, USA
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Functional architecture for disparity in macaque inferior temporal cortex and its relationship to the architecture for faces, color, scenes, and visual field. J Neurosci 2015; 35:6952-68. [PMID: 25926470 DOI: 10.1523/jneurosci.5079-14.2015] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Binocular disparity is a powerful depth cue for object perception. The computations for object vision culminate in inferior temporal cortex (IT), but the functional organization for disparity in IT is unknown. Here we addressed this question by measuring fMRI responses in alert monkeys to stimuli that appeared in front of (near), behind (far), or at the fixation plane. We discovered three regions that showed preferential responses for near and far stimuli, relative to zero-disparity stimuli at the fixation plane. These "near/far" disparity-biased regions were located within dorsal IT, as predicted by microelectrode studies, and on the posterior inferotemporal gyrus. In a second analysis, we instead compared responses to near stimuli with responses to far stimuli and discovered a separate network of "near" disparity-biased regions that extended along the crest of the superior temporal sulcus. We also measured in the same animals fMRI responses to faces, scenes, color, and checkerboard annuli at different visual field eccentricities. Disparity-biased regions defined in either analysis did not show a color bias, suggesting that disparity and color contribute to different computations within IT. Scene-biased regions responded preferentially to near and far stimuli (compared with stimuli without disparity) and had a peripheral visual field bias, whereas face patches had a marked near bias and a central visual field bias. These results support the idea that IT is organized by a coarse eccentricity map, and show that disparity likely contributes to computations associated with both central (face processing) and peripheral (scene processing) visual field biases, but likely does not contribute much to computations within IT that are implicated in processing color.
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Mast F, Frings C, Spence C. Response interference in touch, vision, and crossmodally: beyond the spatial dimension. Exp Brain Res 2014; 232:2325-36. [DOI: 10.1007/s00221-014-3929-6] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2014] [Accepted: 03/20/2014] [Indexed: 11/29/2022]
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Kavšek M. The onset of sensitivity to horizontal disparity in infancy: a short-term longitudinal study. Infant Behav Dev 2013; 36:329-43. [PMID: 23558013 DOI: 10.1016/j.infbeh.2013.02.002] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2012] [Revised: 11/15/2012] [Accepted: 02/21/2013] [Indexed: 11/17/2022]
Abstract
In this short-term longitudinal study, infants were examined for their natural preference of a square defined by crossed horizontal disparity (either 1° or 0.5°) over a square defined by a vertical disparity (either 1° or 0.5°). The square targets were embedded in a dynamic random dot stereogram. The stimuli were presented on an autostereoscopic monitor equipped with a face-tracking device. The infants were tested weekly between 6 and 16 weeks of age. Four experiments were conducted. In two experiments, the infants were examined with the forced-choice preferential looking (FPL) method for their ability to perceive either 1° or 0.5° horizontal disparity. In the remaining two experiments, the classical natural preference (CNP) method (measurement of looking times) was applied. According to the results of the FPL experiments, mean relative preference for the horizontal disparity square became significant at 8 weeks of age. The CNP data indicated an onset of stereopsis at 12-15 weeks. The mean relative preferences for horizontal disparity indicated by the CNP method were smaller than those found in the FPL experiments. Thus, the FPL method was more sensitive than the CNP method in the measurement of infant responsiveness to crossed horizontal disparity.
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Affiliation(s)
- Michael Kavšek
- University of Bonn, Department of Psychology, Unit of Developmental and Educational Psychology, Kaiser-Karl-Ring 9, 53111 Bonn, Germany.
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Harris JM, Chopin A, Zeiner K, Hibbard PB. Perception of Relative Depth Interval: Systematic Biases in Perceived Depth. Q J Exp Psychol (Hove) 2012; 65:73-91. [DOI: 10.1080/17470218.2011.589520] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
Given an estimate of the binocular disparity between a pair of points and an estimate of the viewing distance, or knowledge of eye position, it should be possible to obtain an estimate of their depth separation. Here we show that, when points are arranged in different vertical geometric configurations across two intervals, many observers find this task difficult. Those who can do the task tend to perceive the depth interval in one configuration as very different from depth in the other configuration. We explore two plausible explanations for this effect. The first is the tilt of the empirical vertical horopter: Points perceived along an apparently vertical line correspond to a physical line of points tilted backwards in space. Second, the eyes can rotate in response to a particular stimulus. Without compensation for this rotation, biases in depth perception would result. We measured cyclovergence indirectly, using a standard psychophysical task, while observers viewed our depth configuration. Biases predicted from error due either to cyclovergence or to the tilted vertical horopter were not consistent with the depth configuration results. Our data suggest that, even for the simplest scenes, we do not have ready access to metric depth from binocular disparity.
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Affiliation(s)
- Julie M Harris
- Vision Lab, School of Psychology, University of St Andrews, St Andrews, UK.
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Different regions of space or different spaces altogether: What are the dorsal/ventral systems processing? Behav Brain Sci 2011. [DOI: 10.1017/s0140525x00080183] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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Functional specialization in the lower and upper visual fields in humans: Its ecological origins and neurophysiological implications. Behav Brain Sci 2011. [DOI: 10.1017/s0140525x00080018] [Citation(s) in RCA: 420] [Impact Index Per Article: 32.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
AbstractFunctional specialization in the lower and upper visual fields in humans is analyzed in relation to the origins of the primate visual system. Processing differences between the vertical hemifields are related to the distinction between near (peripersonal) and far (extrapersonal) space, which are biased toward the lower and upper visual fields, respectively. Nonlinear/global processing is required in the lower visual field in order to pergeive the optically degraded and diplopic images in near vision, whereas objects in far vision are searched for and recognized primarily using linear/local perceptual mechanisms. The functional differences between near and far visual space are correlated with their disproportionate representations in the dorsal and ventral divisions of visual association cortex, respectively, and in the magnocellular and parvocellular pathways that project to them. Advances in far visual capabilities and forelimb manipulatory skills may have led to a significant enhancement of these functional specializations.
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Transition from monocular motion perception to dichoptic motion perception as a function of the stimulus duration. Exp Brain Res 2008; 190:499-502. [DOI: 10.1007/s00221-008-1542-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2008] [Accepted: 08/04/2008] [Indexed: 10/21/2022]
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Norman JF, Norman HF, Craft AE, Walton CL, Bartholomew AN, Burton CL, Wiesemann EY, Crabtree CE. Stereopsis and aging. Vision Res 2008; 48:2456-65. [PMID: 18771680 DOI: 10.1016/j.visres.2008.08.008] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2008] [Revised: 08/11/2008] [Accepted: 08/12/2008] [Indexed: 11/16/2022]
Abstract
Three experiments investigated whether and to what extent increases in age affect the functionality of stereopsis. The observers' ages ranged from 18 to 83 years. The overall goal was to challenge the older stereoscopic visual system by utilizing high magnitudes of binocular disparity, ambiguous binocular disparity [cf., Julesz, B., & Chang, J. (1976). Interaction between pools of binocular disparity detectors tuned to different disparities. Biological Cybernetics, 22, 107-119], and by making binocular matching more difficult. In particular, Experiment 1 evaluated observers' abilities to discriminate ordinal depth differences away from the horopter using standing disparities of 6.5-46 min arc. Experiment 2 assessed observers' abilities to discriminate stereoscopic shape using line-element stereograms. The direction (crossed vs. uncrossed) and magnitude of the binocular disparity (13.7 and 51.5 min arc) were manipulated. Binocular matching was made more difficult by varying the orientations of corresponding line elements across the two eyes' views. The purpose of Experiment 3 was to determine whether the aging stereoscopic system can resolve ambiguous binocular disparities in a manner similar to that of younger observers. The results of all experiments demonstrated that older observers' stereoscopic vision is functionally comparable to that of younger observers in many respects. For example, both age groups exhibited a similar ability to discriminate depth and surface shape. The results also showed, however, that age-related differences in stereopsis do exist, and they become most noticeable when the older stereoscopic system is challenged by multiple simultaneous factors.
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Affiliation(s)
- J Farley Norman
- Department of Psychology, 1906 College Heights Boulevard #21030, Western Kentucky University, Bowling Green, KY 42101-1030, USA.
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Devisme C, Drobe B, Monot A, Droulez J. Stereoscopic depth perception in peripheral field and global processing of horizontal disparity gradient pattern. Vision Res 2008; 48:753-64. [DOI: 10.1016/j.visres.2007.12.003] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2006] [Revised: 10/22/2007] [Accepted: 12/09/2007] [Indexed: 11/16/2022]
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Wilmer JB. How to use individual differences to isolate functional organization, biology, and utility of visual functions; with illustrative proposals for stereopsis. SPATIAL VISION 2008; 21:561-79. [PMID: 19017483 PMCID: PMC2586597 DOI: 10.1163/156856808786451408] [Citation(s) in RCA: 83] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
This paper is a call for greater use of individual differences in the basic science of visual perception. Individual differences yield insights into visual perception's functional organization, underlying biological/environmental mechanisms, and utility. I first explain the general approach advocated and where it comes from. Second, I describe five principles central to learning about the nature of visual perception through individual differences. Third, I elaborate on the use of individual differences to gain insights into the three areas mentioned above (function, biology/environment, utility), in each case describing the approach advocated, presenting model examples from the literature, and laying out illustrative research proposals for the case of stereopsis.
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Affiliation(s)
- Jeremy B Wilmer
- SUNY State College of Optometry, Vision Sciences, 33 West 42nd Street, New York, NY 10036, USA.
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Tanabe S, Doi T, Umeda K, Fujita I. Disparity-Tuning Characteristics of Neuronal Responses to Dynamic Random-Dot Stereograms in Macaque Visual Area V4. J Neurophysiol 2005; 94:2683-99. [PMID: 16000525 DOI: 10.1152/jn.00319.2005] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Stereo processing begins in the striate cortex and involves several extrastriate visual areas. We quantitatively analyzed the disparity-tuning characteristics of neurons in area V4 of awake, fixating monkeys. Approximately half of the analyzed V4 cells were tuned for horizontal binocular disparities embedded in dynamic random-dot stereograms (RDSs). Their response preferences were strongly biased for crossed disparities. To characterize the disparity-tuning profile, we fitted a Gabor function to the disparity-tuning data. The distribution of V4 cells showed a single dense cluster in a joint parameter space of the center and the phase parameters of the fitted Gabor function; most V4 neurons were maximally sensitive to fine stereoscopic depth increments near zero disparity. Comparing single-cell responses with background multiunit responses at the same sites showed that disparity-sensitive cells were clustered within V4 and that nearby cells possessed similar preferred disparities. Consistent with a recent report by Hegdé and Van Essen, the disparity tuning for an RDS drastically differed from that for a solid-figure stereogram (SFS). Disparity-tuning curves were generally broader for SFSs than for RDSs, and there was no correlation between the fitted Gabor functions' amplitudes, widths, or peaks for the two types of stereograms. The differences were partially attributable to shifts in the monocular images of an SFS. Our results suggest that the representation of stereoscopic depth in V4 is suited for detecting fine structural features protruding from a background. The representation is not generic and differs when the stimulus is broad-band noise or a solid figure.
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Affiliation(s)
- Seiji Tanabe
- Laboratory for Cognitive Neuroscience, Graduate School of Frontier Biosciences, Osaka University, Toyonaka, Japan
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Levine MW, McAnany JJ. The relative capabilities of the upper and lower visual hemifields. Vision Res 2005; 45:2820-30. [PMID: 16051308 DOI: 10.1016/j.visres.2005.04.001] [Citation(s) in RCA: 104] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2004] [Revised: 01/11/2005] [Accepted: 04/07/2005] [Indexed: 11/30/2022]
Abstract
Visual performance is better in the lower visual hemifield than in the upper field for many classes of stimuli. The origin of this difference is unclear. One theory associates it with finer-grained attention in the lower field, an idea consistent with a change in relative efficacy with task difficulty. The first experiment in this study confirmed a lower hemifield advantage for discriminating a range of stimuli, including those that differ in contrast, hue, and motion. An identical paradigm revealed an upper field advantage when stimuli differed in their apparent distances from the observer. Presentations of stimuli in the upper or lower hemifield were interlaced to reduce the likelihood of possible artifacts or biases. A second experiment varied the difficulty of these discriminations, showing that difficulty does not determine field preference. Thus, an attentional mechanism is not a likely explanation for these preferences.
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Affiliation(s)
- Michael W Levine
- Department of Psychology, The University of Illinois at Chicago, M/C 285, 1007 West Harrison Street, Chicago, IL 60607-7137, USA.
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Cisarik PM, Harwerth RS. Stereoscopic depth magnitude estimation: effects of stimulus spatial frequency and eccentricity. Behav Brain Res 2005; 160:88-98. [PMID: 15836903 DOI: 10.1016/j.bbr.2004.11.019] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2004] [Revised: 11/10/2004] [Accepted: 11/15/2004] [Indexed: 11/25/2022]
Abstract
To determine the effects of stimulus spatial frequency and retinal eccentricity on the perception of depth magnitude derived from disparity cues alone, subjects were asked to estimate the magnitude of depth of a stereoscopically viewed Gabor patch presented to the central or peripheral field with either crossed or uncrossed absolute disparity. Disparity vergence responses to the same Gabor stimuli were separately estimated subjectively by determining the offset required for dichoptic nonius alignment following presentation of the stimulus. The normalized stereoscopic magnitude estimation data generally showed that crossed disparities were perceived with greater depth than uncrossed disparities of the same magnitude, whether presented to the central or peripheral field. Asymmetries in magnitude of depth perception ranged from mild differences between depth directions to complete lack of depth perception for one direction. Disparity vergence response functions varied from (1) appropriate initiation of vergence to both directions of disparity, (2) initiation of vergence to only one direction of disparity, or (3) an attenuated initiation of vergence response to either direction of disparity. Within subjects, their asymmetries in magnitude of depth perception did not correlate with their asymmetries in vergence initiation. The similarity of the asymmetric depth magnitude estimation for a given individual at both stimulus locations tested suggests that common neural mechanisms are responsible for central and peripheral depth magnitude estimation. The lack of correlation between the perceptual and motor responses to the same stimuli suggests that the neural pathways for these responses diverge shortly after the detection of disparity in primary visual cortex.
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Affiliation(s)
- Patricia M Cisarik
- University of Houston, College of Optometry, 505 J. Davis Armistead Building, Houston, TX 77004-2020, USA.
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Mitsudo H, Nakamizo S, Ono H. Greater depth seen with phantom stereopsis is coded at the early stages of visual processing. Vision Res 2005; 45:1365-74. [PMID: 15743607 DOI: 10.1016/j.visres.2004.12.002] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2004] [Revised: 12/08/2004] [Accepted: 12/08/2004] [Indexed: 11/22/2022]
Abstract
A visual search task was used to investigate the spatially parallel coding of depth from binocular disparity and from binocularly unmatched features. Experiment 1, using disparity noise, showed that detectability is higher for illusory phantom targets defined by unmatched features than for disparity-defined targets, although the two targets were equated as to theoretically minimum depth. Experiment 2, using binocularly unmatched noise whose width was equal to the disparity of the noise used in Experiment 1, showed that noise severely interferes with the detection of both the disparity and the phantom targets. These results are consistent with the idea that the greater depth seen with phantom stereopsis is coded at the early stages of visual processing.
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Affiliation(s)
- Hiroyuki Mitsudo
- Centre for Vision Research, York University, 4700 Keele Street, Toronto, Ont., Canada M3J 1P3.
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van Ee R. Correlation between stereoanomaly and perceived depth when disparity and motion interact in binocular matching. Perception 2003; 32:67-84. [PMID: 12613787 DOI: 10.1068/p3459] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
The aim of this study was to find out to what extent binocular matching is facilitated by motion when stereoanomalous and normal subjects estimate the perceived depth of a 3-D stimulus containing excessive matching candidates. Thirty subjects viewed stimuli that consisted of bars uniformly distributed inside a volume. They judged the perceived depth-to-width ratio of the volume by adjusting the aspect ratio of an outline rectangle (a metrical 3-D task). Although there were large inter-subject differences in the depth perceived, the experimental results yielded a good correlation with stereoanomaly (the inability to distinguish disparities of different magnitudes and/or signs in part of the disparity spectrum). The results cannot be explained solely by depth-cue combination. Since up to 30% of the population is stereoanomalous, stereoscopic experiments would yield more informative results if subjects were first characterized with regard to their stereo capacities. Intriguingly, it was found that motion does not help to define disparities in subjects who are able to perceive depth-from-disparity in half of the disparity spectrum. These stereoanomalous subjects were found to rely completely on the motion signals. This suggests that the perception of volumetric depth in subjects with normal stereoscopic vision requires the joint processing of crossed and uncrossed disparities.
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Affiliation(s)
- Raymond van Ee
- Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology, NE 20-451, 77 Massachusetts Avenue, Cambridge, MA 02139, USA.
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Abstract
Stereoanomaly is the failure to see differences in depth when the viewer is presented with stimuli having different magnitudes of stereoscopic disparity. In the absence of eye movements, everyone suffers from stereoanomaly for extremely large disparities. Typically, such disparities are seen at the same depth as monocular stimuli. However, about 30%, of the population exhibit some form of stereoanomaly even for very small disparities, provided eye movements are avoided. In some cases, the sign of the disparity will be confused, and the perceived depth will be incorrectly seen as 'behind' rather than 'in front of' the fixation point, for example. Because anomalies provide useful information about perceptual mechanisms, tests that measure and quantify the extent of a blindness are important investigative tools for research. Here we offer two easy-to-administer tests for stereoanomaly. The first test is based on depth judgments of two bars relative to a fixation point. The second test involves judgments of volumetric stimuli, seen stereoscopically. In each case, subjects indicate depth by setting a rectangle (with fixed base) to match the perceived depth. Although both tests are correlated, some differences in stereo processing are seen, depending upon whether or not the stimuli are presented near the point of fixation.
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Affiliation(s)
- Raymond van Ee
- Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology, Cambridge 02139-4307, USA.
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Lam AKC, Tse P, Choy E, Chung M. Crossed and uncrossed stereoacuity at distance and the effect from heterophoria. Ophthalmic Physiol Opt 2002; 22:189-93. [PMID: 12090632 DOI: 10.1046/j.1475-1313.2002.00030.x] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
BACKGROUND Previous studies have found that crossed disparities give better stereoacuity than uncrossed. When near phoria is considered, exophores had a better crossed stereoacuity and esophores had a better uncrossed stereoacuity. The current study investigated the effect of heterophoria on distant crossed and uncrossed stereoacuity. METHODS Seventy-two subjects were recruited and their distant heterophoria measured. Heterophoria within two prism dioptres was considered as orthophoric. Esophoric group had esophoria greater than two prism dioptres. Exophoric group had exophoria greater than two prism dioptres. There were 40 orthophores, 23 exophores and nine esophores. Their stereoacuity was measured with a three-rod apparatus at 6 m. RESULTS The mean crossed stereoacuity was 4.8" and uncrossed stereoacuity was 7.2" (t = -3.03, p < 0.01). The mean stereoacuity for orthophoric subjects was 5.31", 6.02" for exophores and 8.91" for esophores. The distant crossed stereoacuity is better than uncrossed stereoacuity in all three groups but the difference is only significant for the exophores. Exophoric subjects demonstrated a significant difference between crossed (4.10") and uncrossed (7.95") stereoacuity. CONCLUSIONS Orthophores have the best stereoacuity, followed by exophores and esophores. Exophoric subjects have a better crossed than uncrossed stereoacuity. More esophoric subjects should be recruited to confirm the difference between crossed and uncrossed stereoacuity.
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Affiliation(s)
- Andrew K C Lam
- Department of Optometry and Radiography, The Hong Kong Polytechnic University, Hong Kong SAR, China.
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Becker S, Bowd C, Shorter S, King K, Patterson R. Occlusion contributes to temporal processing differences between crossed and uncrossed stereopsis in random-dot displays. Vision Res 1999; 39:331-9. [PMID: 10326139 DOI: 10.1016/s0042-6989(98)00110-2] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
Stereoscopic depth discrimination was investigated in crossed and uncrossed directions using stimuli defined by binocular disparity differences embedded in dynamic random-dot stereograms. Across three experiments, fixation was directed to a point on the display screen (which placed crossed stimuli in front of and uncrossed stimuli behind, the background dots of the stereogram), to a point in front of the display screen (which placed both crossed and uncrossed stimuli in front of the background dots), and to a point behind the display screen (which placed both crossed and uncrossed stimuli behind the background dots). Results showed that depth discrimination was always good when the stimuli appeared in front of the background dots of the stereogram, whereas discrimination was always poor when the stimuli appeared behind the background dots. These results suggest that differences between crossed and uncrossed stereopsis as reported in past research arose, in part, from effects related to occlusion.
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Affiliation(s)
- S Becker
- Department of Psychology, Washington State University, Pullman 99164-4820, USA
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35
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Landers DD, Cormack LK. Asymmetries and errors in perception of depth from disparity suggest a multicomponent model of disparity processing. PERCEPTION & PSYCHOPHYSICS 1997; 59:219-31. [PMID: 9055617 DOI: 10.3758/bf03211890] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
In three experiments, asymmetries between the processing of crossed and uncrossed disparities were investigated. The target was a luminance-defined circle concentric to a fixation mark, viewed stereoscopically on a computer monitor for 105 msec. Fifteen disparities were presented according to the method of constant stimuli. Observers indicated the apparent direction of target depth relative to fixation. All experiments measured both the accuracy and latency of this response. Experiment 1 showed fewer errors and shorter reaction times for identifying crossed disparities. Experiments 2 and 3 replicated Experiment 1 and also showed that observers may often perceive a target in the direction opposite that prescribed by the disparity information. We propose that the asymmetries and reversals result from differences in computation of sign, not of magnitude. This notion is consistent with a scheme of continuous disparity tuning and accounts for such asymmetries and errors without positing disparity pooling mechanisms.
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Affiliation(s)
- D D Landers
- Department of Psychology, University of Texas, Austin 78712-1189, USA.
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Patterson R, Cayko R, Short GL, Flanagan R, Moe L, Taylor E, Day P. Temporal integration differences between crossed and uncrossed stereoscopic mechanisms. PERCEPTION & PSYCHOPHYSICS 1995; 57:891-7. [PMID: 7651812 DOI: 10.3758/bf03206803] [Citation(s) in RCA: 41] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
In this study, we investigated temporal integration of disparity information for crossed and uncrossed stereopsis. Across three experiments, exposure duration thresholds were measured for stereoscopic stimuli created from dynamic random-dot stereograms. In Experiment 1, an investigation of disparity detection showed that detection thresholds were equal for the crossed and uncrossed directions. In Experiment 2, an examination of duration limits for depth perception showed that critical durations were lower, and depth more veridical, for crossed depth than for uncrossed depth. In Experiment 3, an investigation of depth discrimination revealed that discrimination thresholds were lower for crossed depth than for uncrossed depth. These results suggest that crossed and uncrossed mechanisms differ in terms of their temporal integration properties at processing levels involving the computation and discrimination of depth.
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Affiliation(s)
- R Patterson
- Department of Psychology, Washington State University, Pullman 99164-4820, USA
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Previc FH, Breitmeyer BG, Weinstein LF. Discriminability of random-dot stereograms in three-dimensional space. Int J Neurosci 1995; 80:247-53. [PMID: 7775051 DOI: 10.3109/00207459508986103] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
The discriminability of crossed-disparity (near) and uncrossed-disparity as a function of their location in the upper-left, upper-right, lower-left, and lower-right quadrants of the visual field. Discriminability was assessed using choice reaction-time (RT) and accuracy measures. While near targets were recognized equally well in the upper and lower fields, far targets were perceived more easily in the upper visual field. The discriminability of far targets was particularly poor in the lower left quadrant. These results point to the existence of fundamental asymmetries in perceiving crossed and uncrossed disparities along the vertical and lateral axes.
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Affiliation(s)
- F H Previc
- Crew Technology Division, Armstrong Laboratory, Brooks Air Force Base, Texas 78235, USA
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Manning ML, Finlay DC, Dewis SA, Dunlop DB. Detection duration thresholds and evoked potential measures of stereosensitivity. Doc Ophthalmol 1992; 79:161-75. [PMID: 1591970 DOI: 10.1007/bf00156575] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Visual evoked potentials have been proposed by some researchers to be more useful than behavioral techniques to evaluate stereo performance in children and certain clinical populations. Stimulus duration detection thresholds, visual evoked potentials, and scalp electrical potential distribution maps to dynamic random dot stereograms were studied. A high degree of correspondence was found between visual evoked potential amplitudes and behaviorally determined detection thresholds. Upper field stimuli had higher detection thresholds and generated lower-amplitude visual evoked potential responses than did centrally presented stimuli. For the most eccentrically presented stimuli, lower detection thresholds were found for stimuli presented in the right visual field than the left visual field. This finding was consistent with the pattern of VEP responses to be lateralized, with higher-amplitude responses recorded over left-hemisphere sites. The study examined a proposal that the major negative component of the stereoscopic visual evoked potential originates in cortical area V1. The results failed to support the proposal and were consistent with the main negative component of the VEP being generated in V2, rather than V1.
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Affiliation(s)
- M L Manning
- Department of Psychology, University of Western Australia, Nedlands
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Moraglia G, Schneider B. Effects of direction and magnitude of horizontal disparities on binocular unmasking. Perception 1990; 19:581-93. [PMID: 2102993 DOI: 10.1068/p190581] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Conditions under which binocular unmasking (BU), as an analogue of binaural unmasking, occurs have been explored. Observers were to detect through a stereoscope a Gabor signal in patches of two-dimensional broadband gaussian noise surrounded by a frame of uniform noise. The right-eye gaussian field was displaced relative to the left eye so that it appeared either in front of or behind the frame. Performance when signal disparity was equal to that of the noise--a condition functionally equivalent to monocular processing--was compared to that obtained when signal disparity was zero--a case in which BU should occur. Enhanced signal detectability of up to 12 dB and of nearly constant magnitude was observed in the latter condition when uncrossed disparities of up to 67.60 min visual angle and display durations of 1 s were employed. Signal detectability declined appreciably with increasing disparity (both crossed and uncrossed) when display duration was reduced to 90 ms, thus preventing the occurrence of compensatory vergence eye movements. It is suggested that BU effects may result from a process of linear summation of monocular inputs.
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Affiliation(s)
- G Moraglia
- Department of Psychology, University of Toronto, Mississauga, Ontario, Canada
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40
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The ups and downs of visual fields. Behav Brain Sci 1990. [DOI: 10.1017/s0140525x00080109] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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41
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Functional specialization in the visual system: Retinotopic or body centered? Behav Brain Sci 1990. [DOI: 10.1017/s0140525x00080080] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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42
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Properties of neurons in the dorsal visual pathway of the monkey. Behav Brain Sci 1990. [DOI: 10.1017/s0140525x00080171] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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43
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44
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Seeing double: Dichotomizing the visual system. Behav Brain Sci 1990. [DOI: 10.1017/s0140525x00080031] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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45
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Ecology and functional specialization: The whole is less than the sum of the parts. Behav Brain Sci 1990. [DOI: 10.1017/s0140525x00080110] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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46
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The role of dorsal/ventral processing dissociation in the economy of the primate brain. Behav Brain Sci 1990. [DOI: 10.1017/s0140525x00080146] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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47
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Visual information in the upper and lower visual fields may be processed differently, but how and why remains to be established. Behav Brain Sci 1990. [DOI: 10.1017/s0140525x00080092] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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48
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The primary visual system does not care about Previc's near-far dichotomy. Why not? Behav Brain Sci 1990. [DOI: 10.1017/s0140525x00080195] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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49
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Does visual-field specialization really have implications for coordinated visual-motor behavior? Behav Brain Sci 1990. [DOI: 10.1017/s0140525x0008002x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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50
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