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Zhang S, Morrison J, Sun T, Kowal DR, Greene E. Evaluating integration of letter fragments through contrast and spatially targeted masking. J Vis 2024; 24:9. [PMID: 38856981 PMCID: PMC11174100 DOI: 10.1167/jov.24.6.9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2023] [Accepted: 04/02/2024] [Indexed: 06/11/2024] Open
Abstract
Four experiments were conducted to gain a better understanding of the visual mechanisms related to how integration of partial shape cues provides for recognition of the full shape. In each experiment, letters formed as outline contours were displayed as a sequence of adjacent segments (fragments), each visible during a 17-ms time frame. The first experiment varied the contrast of the fragments. There were substantial individual differences in contrast sensitivity, so stimulus displays in the masking experiments that followed were calibrated to the sensitivity of each participant. Masks were displayed either as patterns that filled the entire screen (full field) or as successive strips that were sliced from the pattern, each strip lying across the location of the letter fragment that had been shown a moment before. Contrast of masks were varied to be lighter or darker than the letter fragments. Full-field masks, whether light or dark, provided relatively little impairment of recognition, as was the case for mask strips that were lighter than the letter fragments. However, dark strip masks proved to be very effective, with the degree of recognition impairment becoming larger as mask contrast was increased. A final experiment found the strip masks to be most effective when they overlapped the location where the letter fragments had been shown a moment before. They became progressively less effective with increased spatial separation from that location. Results are discussed with extensive reference to potential brain mechanisms for integrating shape cues.
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Affiliation(s)
- Sherry Zhang
- Department of Psychology, University of Southern California, Los Angeles, CA, USA
| | | | - Thomas Sun
- Department of Statistics, Rice University, Houston, TX, USA
| | - Daniel R Kowal
- Department of Statistics, Rice University, Houston, TX, USA
| | - Ernest Greene
- Department of Psychology, University of Southern California, Los Angeles, CA, USA
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Karampatakis V, P. Papadopoulou E, Almpanidou S, Karamitopoulos L, Almaliotis D. Evaluation of contrast sensitivity in visually impaired individuals using K-CS test. A novel smartphone-based contrast sensitivity test-Design and validation. PLoS One 2024; 19:e0288512. [PMID: 38330096 PMCID: PMC10852338 DOI: 10.1371/journal.pone.0288512] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2022] [Accepted: 06/29/2023] [Indexed: 02/10/2024] Open
Abstract
BACKGROUND To describe the development and investigate the accuracy of a novel smartphone-based Contrast Sensitivity (CS) application, the K-CS test. METHODS A total of 67 visually impaired and 50 normal participants were examined monocularly using the novel digital K-CS test and the Pelli-Robson (PR) chart. The K-CS test examines letter contrast sensitivity in logarithmic units, using eight levels of contrast from logCS = ~0,1 to logCS = ~2,1 at two spatial frequencies of 1.5 and 3 cycles per degree (cpd). The K-CS test was compared to the gold standard, PR test and intra-session test repeatability was also examined. RESULTS The K-CS test in normally sighted was found to agree well with the PR, providing comparable mean scores in logCS (±SD) (K-CS = 1.908 ± 0.06 versus PR = 1.93 ± 0.05) at 1.5 cpd and mean (± SD) logCS at 3 cpd (K-CS = 1.83 ± 0.13 versus PR = 1.86 ± 0.07). The mean best corrected visual acuity of visually impaired participants was 0.67 LogMAR (SD = 0.21) and the K-CS was also found to agree well with the Pelli-Robson in this group, with an equivalent mean (±SD) logCS at 1.5 cpd: (K-CS = 1.19 ± 0.27, PR = 1.15 ± 0.31), 3 cpd: K-CS = 1.01 ± 0.33, PR = 0.94 ± 0.34. Regarding the intra-session test repeatability, both the K-CS test and the PR test showed good repeatability in terms of the 95% limits of agreement (LoA): K-CS = ±0.112 at 1.5 cpd and ±0.133 at 3 cpd, PR = ±0.143 at 1.5 cpd and ±0.183 in 3 cpd in visually impaired individuals. CONCLUSION The K-CS test provides a quick assessment of the CS both in normally sighted and visually impaired individuals. The K-CS could serve as an alternative tool to assess contrast sensitivity function using a smartphone and provides results that agree well with the commonly used PR test.
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Affiliation(s)
- Vasileios Karampatakis
- Laboratory of Experimental Ophthalmology, School of Medicine, Aristotle University of Thessaloniki, Thessaloniki, Greece
| | - Eleni P. Papadopoulou
- Laboratory of Experimental Ophthalmology, School of Medicine, Aristotle University of Thessaloniki, Thessaloniki, Greece
| | - Stavroula Almpanidou
- Laboratory of Experimental Ophthalmology, School of Medicine, Aristotle University of Thessaloniki, Thessaloniki, Greece
| | - Leonidas Karamitopoulos
- Laboratory of Experimental Ophthalmology, School of Medicine, Aristotle University of Thessaloniki, Thessaloniki, Greece
| | - Diamantis Almaliotis
- Laboratory of Experimental Ophthalmology, School of Medicine, Aristotle University of Thessaloniki, Thessaloniki, Greece
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A comparison of equivalent noise methods in investigating local and global form and motion integration. Atten Percept Psychophys 2023; 85:152-165. [PMID: 36380147 DOI: 10.3758/s13414-022-02595-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/08/2022] [Indexed: 11/16/2022]
Abstract
Static and dynamic cues within certain spatiotemporal proximity are used to evoke respective global percepts of form and motion. The limiting factors in this process are, first, internal noise, which indexes local orientation/direction detection, and, second, sampling efficiency, which relates to the processing and the representation of global orientation/direction. These parameters are quantified using the equivalent noise (EN) paradigm. EN has been implemented with just two levels: high and low noise. However, when using this simplified version, one must assume the shape of the overall noise dependence, as the intermediate points are missing. Here, we investigated whether two distinct EN methods, the 8-point and the simplified 2-point version, reveal comparable parameter estimates. This was performed for three different types of stimuli: random dot kinematograms, and static and dynamic translational Glass patterns, to investigate how constant internal noise estimates are, and how sampling efficiency might vary over tasks. The results indicated substantial compatibility between estimates over a wide range of external noise levels sampled with eight data points, and a simplified version producing two highly informative data points. Our findings support the use of a simplified procedure to estimate essential form-motion integration parameters, paving the way for rapid and critical applications to populations that cannot tolerate protracted measurements.
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Zhang S, Morrison J, Wang W, Greene E. Recognition of letters displayed as successive contour fragments. AIMS Neurosci 2022; 9:491-515. [PMID: 36660071 PMCID: PMC9826752 DOI: 10.3934/neuroscience.2022028] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2022] [Revised: 12/01/2022] [Accepted: 12/04/2022] [Indexed: 12/14/2022] Open
Abstract
Shapes can be displayed as parts but perceived as a whole through feedforward and feedback mechanisms in the visual system, though the exact spatiotemporal relationships for this process are still unclear. Our experiments examined the integration of letter fragments that were displayed as a rapid sequence. We examined the effects of timing and masking on integration, hypothesizing that increasing the timing interval between frames would impair recognition by disrupting contour linkage. We further used different mask types, a full-field pattern mask and a smaller strip mask, to examine the effects of global vs local masking on integration. We found that varying mask types and contrast produced a greater decline in recognition than was found when persistence or mask density was manipulated. The study supports prior work on letter recognition and provides greater insight into the spatiotemporal factors that contribute to the identification of shapes.
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Affiliation(s)
- Sherry Zhang
- Department of Psychology, University of Southern California, Los Angeles, CA 90007, United States of America,* Correspondence:
| | - Jack Morrison
- Neuropsychology Foundation, Sun Valley, CA 91353, United States of America
| | - Wei Wang
- Departments of Medicine and Neurology, Brigham and Women's Hospital. Division of Sleep Medicine, Harvard Medical School, Boston, MA 02115, United States of America
| | - Ernest Greene
- Department of Psychology, University of Southern California, Los Angeles, CA 90007, United States of America
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Bariya S, Ichhpujani P, Rehman O, Kumar S. Normative database for Spaeth Richman contrast sensitivity test for Indian eyes. Indian J Ophthalmol 2022; 70:3476-3482. [PMID: 36190030 PMCID: PMC9789830 DOI: 10.4103/ijo.ijo_491_22] [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] [Indexed: 11/05/2022] Open
Abstract
Purpose To ascertain normative database of contrast sensitivity (CS) using Spaeth/Richman CS test (SPARCS) in the Indian population. Methods This cross-sectional study enrolled 200 healthy individuals, and CS was tested in both eyes of each participant using SPARCS. A detailed ocular examination was done before enrollment to rule out pathologies that may affect CS. A practice test was performed in the right eye (OD), followed by uniocular testing in each eye and a final binocular test. Results Data of 400 eyes of 200 subjects who fulfilled the inclusion criteria was evaluated. The average age of subjects was 46.57 ± 16.77 years (range 21-79 years), with a slight female preponderance (53%, n = 106). A statistically significant decline in average SPARCS scores was noted with increasing age (P < 0.05), ranging from 86.68 (20-29 years age group) to 67.44 (70-79 years age group). Higher scores were noted in binocular testing than uniocular testing (Interclass correlation coefficient [ICC] = 0.83; P < 0.001). Females achieved statistically significant higher total scores in uniocular SPARCS testing (both OD and OS), but there was no significant difference noted between the two genders in binocular testing. Correlation between practice and main tests was statistically Significant with an interclass correlation coefficient of 0.54 (P < 0.001). Conclusion Normative database for SPARCS was established for Indian eyes, with a decreasing trend noted in peripheral as well as central CS scores with increasing age.
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Affiliation(s)
- Sonia Bariya
- Department of Ophthalmology, Government Medical College and Hospital, Chandigarh, India
| | - Parul Ichhpujani
- Department of Ophthalmology, Government Medical College and Hospital, Chandigarh, India,Correspondence to: Dr. Parul Ichhpujani, Department of Ophthalmology, Government Medical College and Hospital, Sector 32, Chandigarh - 160 030, India. E-mail:
| | - Obaidur Rehman
- Department of Ophthalmology, Government Medical College and Hospital, Chandigarh, India
| | - Suresh Kumar
- Department of Ophthalmology, Government Medical College and Hospital, Chandigarh, India
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Mechanisms of Surround Suppression Effect on the Contrast Sensitivity of V1 Neurons in Cats. Neural Plast 2022; 2022:5677655. [PMID: 35299618 PMCID: PMC8923783 DOI: 10.1155/2022/5677655] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2021] [Revised: 01/30/2022] [Accepted: 02/19/2022] [Indexed: 12/14/2022] Open
Abstract
Surround suppression (SS) is a phenomenon that a neuron’s response to visual stimuli within the classical receptive field (cRF) is suppressed by a concurrent stimulation in the surrounding receptive field (sRF) beyond the cRF. Studies show that SS affects neuronal response contrast sensitivity in the primary visual cortex (V1). However, the underlying mechanisms remain unclear. Here, we examined SS effect on the contrast sensitivity of cats’ V1 neurons with different preferred SFs using external noise-masked visual stimuli and perceptual template model (PTM) analysis at the system level. The contrast sensitivity was evaluated by the inverted threshold contrast of neurons in response to circular gratings of different contrasts in the cRF with or without an annular grating in the sRF. Our results showed that SS significantly reduced the contrast sensitivity of cats’ V1 neurons. The SS-induced reduction of contrast sensitivity was not correlated with SS strength but was dependent on neuron’s preferred SF, with a larger reduction for neurons with low preferred SFs than those with high preferred SFs. PTM analysis of threshold versus external noise contrast (TvC) functions indicated that SS decreased contrast sensitivity by increasing both the internal additive noise and impact of external noise for neurons with low preferred SFs, but improving only internal additive noise for neurons with high preferred SFs. Furthermore, the SS effect on the contrast-response function of low- and high-SF neurons also exhibited different mechanisms in contrast gain and response gain. Collectively, these results suggest that the mechanisms of SS effect on neuronal contrast sensitivity may depend on neuronal populations with different SFs.
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Ding J, Ye Z, Xu F, Hu X, Yu H, Zhang S, Tu Y, Zhang Q, Sun Q, Hua T, Lu ZL. Effects of top-down influence suppression on behavioral and V1 neuronal contrast sensitivity functions in cats. iScience 2022; 25:103683. [PMID: 35059603 PMCID: PMC8760559 DOI: 10.1016/j.isci.2021.103683] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2021] [Revised: 11/16/2021] [Accepted: 12/20/2021] [Indexed: 02/09/2023] Open
Abstract
To explore the relative contributions of higher-order and primary visual cortex (V1) to visual perception, we compared cats' behavioral and V1 neuronal contrast sensitivity functions (CSF) and threshold versus external noise contrast (TvC) functions before and after top-down influence of area 7 (A7) was modulated with transcranial direct current stimulation (tDCS). We found that suppressing top-down influence of A7 with cathode-tDCS, but not sham-tDCS, reduced behavioral and neuronal contrast sensitivity in the same range of spatial frequencies and increased behavioral and neuronal contrast thresholds in the same range of external noise levels. The neuronal CSF and TvC functions were highly correlated with their behavioral counterparts both before and after the top-down suppression. Analysis of TvC functions using the Perceptual Template Model (PTM) indicated that top-down influence of A7 increased both behavioral and V1 neuronal contrast sensitivity by reducing internal additive noise and the impact of external noise. Top-down suppression lowers both behavioral and V1 neuronal CSF functions Top-down suppression raises both behavioral and V1 neuronal TvC functions The neuronal CSFs and TvCs are highly correlated with their behavioral counterparts Top-down influence lowers internal additive noise and impact of external noise in V1
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Affiliation(s)
- Jian Ding
- College of Life Sciences, Anhui Normal University, Wuhu, Anhui 241000, China
| | - Zheng Ye
- College of Life Sciences, Anhui Normal University, Wuhu, Anhui 241000, China
| | - Fei Xu
- College of Life Sciences, Anhui Normal University, Wuhu, Anhui 241000, China
| | - Xiangmei Hu
- College of Life Sciences, Anhui Normal University, Wuhu, Anhui 241000, China
| | - Hao Yu
- College of Life Sciences, Anhui Normal University, Wuhu, Anhui 241000, China
| | - Shen Zhang
- College of Life Sciences, Anhui Normal University, Wuhu, Anhui 241000, China
| | - Yanni Tu
- College of Life Sciences, Anhui Normal University, Wuhu, Anhui 241000, China
| | - Qiuyu Zhang
- College of Life Sciences, Anhui Normal University, Wuhu, Anhui 241000, China
| | - Qingyan Sun
- College of Life Sciences, Anhui Normal University, Wuhu, Anhui 241000, China
| | - Tianmiao Hua
- College of Life Sciences, Anhui Normal University, Wuhu, Anhui 241000, China
| | - Zhong-Lin Lu
- Divison of Arts and Sciences, NYU Shanghai, Shanghai 200122, China.,Center for Neural Science and Department of Psychology, New York University, New York, NY 10003, USA.,NYU-ECNU Institute of Brain and Cognitive Science, NYU Shanghai, Shanghai 200062, China
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8
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Ding J, Hu X, Xu F, Yu H, Ye Z, Zhang S, Pan H, Pan D, Tu Y, Zhang Q, Sun Q, Hua T. Suppression of top-down influence decreases neuronal excitability and contrast sensitivity in the V1 cortex of cat. Sci Rep 2021; 11:16034. [PMID: 34362965 PMCID: PMC8346540 DOI: 10.1038/s41598-021-95407-7] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2021] [Accepted: 07/26/2021] [Indexed: 12/18/2022] Open
Abstract
How top-down influence affects neuronal activity and information encoding in the primary visual cortex (V1) remains elusive. This study examined changes of neuronal excitability and contrast sensitivity in cat V1 cortex after top-down influence of area 7 (A7) was modulated by transcranial direct current stimulation (tDCS). The neuronal excitability in V1 cortex was evaluated by visually evoked field potentials (VEPs), and contrast sensitivity (CS) was assessed by the inverse of threshold contrast of neurons in response to visual stimuli at different performance accuracy. We found that the amplitude of VEPs in V1 cortex lowered after top-down influence suppression with cathode-tDCS in A7, whereas VEPs in V1 did not change after sham-tDCS in A7 and nonvisual cortical area 5 (A5) or cathode-tDCS in A5 and lesioned A7. Moreover, the mean CS of V1 neurons decreased after cathode-tDCS but not sham-tDCS in A7, which could recover after tDCS effect vanished. Comparisons of neuronal contrast-response functions showed that cathode-tDCS increased the stimulus contrast required to generate the half-maximum response, with a weakly-correlated reduction in maximum response but not baseline response. Therefore, top-down influence of A7 enhanced neuronal excitability in V1 cortex and improved neuronal contrast sensitivity by both contrast gain and response gain.
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Affiliation(s)
- Jian Ding
- College of Life Sciences, Anhui Normal University, Wuhu, 241000, Anhui, China
| | - Xiangmei Hu
- College of Life Sciences, Anhui Normal University, Wuhu, 241000, Anhui, China
| | - Fei Xu
- College of Life Sciences, Anhui Normal University, Wuhu, 241000, Anhui, China
| | - Hao Yu
- College of Life Sciences, Anhui Normal University, Wuhu, 241000, Anhui, China
| | - Zheng Ye
- College of Life Sciences, Anhui Normal University, Wuhu, 241000, Anhui, China
| | - Shen Zhang
- College of Life Sciences, Anhui Normal University, Wuhu, 241000, Anhui, China
| | - Huijun Pan
- College of Life Sciences, Anhui Normal University, Wuhu, 241000, Anhui, China
| | - Deng Pan
- College of Life Sciences, Anhui Normal University, Wuhu, 241000, Anhui, China
| | - Yanni Tu
- College of Life Sciences, Anhui Normal University, Wuhu, 241000, Anhui, China
| | - Qiuyu Zhang
- College of Life Sciences, Anhui Normal University, Wuhu, 241000, Anhui, China
| | - Qingyan Sun
- College of Life Sciences, Anhui Normal University, Wuhu, 241000, Anhui, China
| | - Tianmiao Hua
- College of Life Sciences, Anhui Normal University, Wuhu, 241000, Anhui, China.
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9
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Tulver K. The factorial structure of individual differences in visual perception. Conscious Cogn 2019; 73:102762. [PMID: 31176848 DOI: 10.1016/j.concog.2019.102762] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2019] [Revised: 05/02/2019] [Accepted: 05/27/2019] [Indexed: 12/25/2022]
Abstract
Although at first glance the way we perceive the world is similar for most individuals and resembles a veridical interpretation of the environment, the persistent individual differences found in many perceptual processes continue to inspire and confuse researchers. Despite numerous attempts to map out the reliable factors and correlates of individual variance in perception, the factorial structure of vision has remained elusive. The current article reviews recent developments in the study of individual differences in perception with a focus on work that has applied latent variable techniques for analysing performance across multiple visual paradigms. As this overview reveals, studies that have attempted to answer the question whether one general or several specific factors best describe vision tend to reject the monolithic view. Some general notes are also provided regarding pitfalls that should be taken into account when designing such research in the future.
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Affiliation(s)
- Kadi Tulver
- Institute of Psychology, University of Tartu, Estonia.
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10
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Affiliation(s)
- Koen V. Haak
- Donders Institute for Brain Cognition and Behaviour Centre for Cognitive Neuroimaging Radboud University Nijmegen The Netherlands
- Department of Cognitive Neuroscience Radboud University Medical Centre Nijmegen The Netherlands
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11
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Individual differences in internal noise are consistent across two measurement techniques. Vision Res 2017; 141:30-39. [DOI: 10.1016/j.visres.2016.10.008] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2016] [Revised: 09/16/2016] [Accepted: 10/25/2016] [Indexed: 11/22/2022]
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12
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Abstract
Background Migraine is a common neurological condition that often involves differences in visual processing. These sensory processing differences provide important information about the underlying causes of the condition, and for the development of treatments. Review of psychophysical literature Psychophysical experiments have shown consistent impairments in contrast sensitivity, orientation acuity, and the perception of global form and motion. They have also established that the addition of task-irrelevant visual noise has a greater effect, and that surround suppression, masking and adaptation are all stronger in migraine. Theoretical signal processing model We propose utilising an established model of visual processing, based on signal processing theory, to account for the behavioural differences seen in migraine. This has the advantage of precision and clarity, and generating clear, falsifiable predictions. Conclusion Increased effects of noise and differences in excitation and inhibition can account for the differences in migraine visual perception. Consolidating existing research and creating a unified, defined theoretical account is needed to better understand the disorder.
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Affiliation(s)
- Louise O'Hare
- School of Psychology, College of Social Science, University of Lincoln, UK
| | - Paul B Hibbard
- Department of Psychology, University of Essex, UK
- School of Psychology and Neuroscience, University of St Andrews, UK
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13
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Baldwin AS, Baker DH, Hess RF. What Do Contrast Threshold Equivalent Noise Studies Actually Measure? Noise vs. Nonlinearity in Different Masking Paradigms. PLoS One 2016; 11:e0150942. [PMID: 26953796 PMCID: PMC4783112 DOI: 10.1371/journal.pone.0150942] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2015] [Accepted: 02/22/2016] [Indexed: 11/21/2022] Open
Abstract
The internal noise present in a linear system can be quantified by the equivalent noise method. By measuring the effect that applying external noise to the system's input has on its output one can estimate the variance of this internal noise. By applying this simple "linear amplifier" model to the human visual system, one can entirely explain an observer's detection performance by a combination of the internal noise variance and their efficiency relative to an ideal observer. Studies using this method rely on two crucial factors: firstly that the external noise in their stimuli behaves like the visual system's internal noise in the dimension of interest, and secondly that the assumptions underlying their model are correct (e.g. linearity). Here we explore the effects of these two factors while applying the equivalent noise method to investigate the contrast sensitivity function (CSF). We compare the results at 0.5 and 6 c/deg from the equivalent noise method against those we would expect based on pedestal masking data collected from the same observers. We find that the loss of sensitivity with increasing spatial frequency results from changes in the saturation constant of the gain control nonlinearity, and that this only masquerades as a change in internal noise under the equivalent noise method. Part of the effect we find can be attributed to the optical transfer function of the eye. The remainder can be explained by either changes in effective input gain, divisive suppression, or a combination of the two. Given these effects the efficiency of our observers approaches the ideal level. We show the importance of considering these factors in equivalent noise studies.
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Affiliation(s)
- Alex S. Baldwin
- McGill Vision Research, Department of Ophthalmology, McGill University, Montreal, Canada
| | | | - Robert F. Hess
- McGill Vision Research, Department of Ophthalmology, McGill University, Montreal, Canada
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14
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Manning C, Baker DH. Response to Davis and Plaisted-Grant: psychophysical data do not support the low-noise account of autism. AUTISM : THE INTERNATIONAL JOURNAL OF RESEARCH AND PRACTICE 2014; 19:365-6. [PMID: 25492972 DOI: 10.1177/1362361314557164] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
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15
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Hess RF, Thompson B, Baker DH. Binocular vision in amblyopia: structure, suppression and plasticity. Ophthalmic Physiol Opt 2014; 34:146-62. [PMID: 24588532 DOI: 10.1111/opo.12123] [Citation(s) in RCA: 118] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2013] [Accepted: 01/17/2014] [Indexed: 02/04/2023]
Abstract
The amblyopic visual system was once considered to be structurally monocular. However, it now evident that the capacity for binocular vision is present in many observers with amblyopia. This has led to new techniques for quantifying suppression that have provided insights into the relationship between suppression and the monocular and binocular visual deficits experienced by amblyopes. Furthermore, new treatments are emerging that directly target suppressive interactions within the visual cortex and, on the basis of initial data, appear to improve both binocular and monocular visual function, even in adults with amblyopia. The aim of this review is to provide an overview of recent studies that have investigated the structure, measurement and treatment of binocular vision in observers with strabismic, anisometropic and mixed amblyopia.
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Affiliation(s)
- Robert F Hess
- Department of Ophthalmology, McGill Vision Research, McGill University, Montreal, Canada
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