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Marmoy OR, Tekavčič Pompe M, Kremers J. Chromatic visual evoked potentials: A review of physiology, methods and clinical applications. Prog Retin Eye Res 2024; 101:101272. [PMID: 38761874 DOI: 10.1016/j.preteyeres.2024.101272] [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: 07/20/2023] [Revised: 05/06/2024] [Accepted: 05/10/2024] [Indexed: 05/20/2024]
Abstract
Objective assessment of the visual system can be performed electrophysiologically using the visual evoked potential (VEP). In many clinical circumstances, this is performed using high contrast achromatic patterns or diffuse flash stimuli. These methods are clinically valuable but they may only assess a subset of possible physiological circuitries within the visual system, particularly those involved in achromatic (luminance) processing. The use of chromatic VEPs (cVEPs) in addition to standard VEPs can inform us of the function or dysfunction of chromatic pathways. The chromatic VEP has been well studied in human health and disease. Yet, to date our knowledge of their underlying mechanisms and applications remains limited. This likely reflects a heterogeneity in the methodology, analysis and conclusions of different works, which leads to ambiguity in their clinical use. This review sought to identify the primary methodologies employed for recording cVEPs. Furthermore cVEP maturation and application in understanding the function of the chromatic system under healthy and diseased conditions are reviewed. We first briefly describe the physiology of normal colour vision, before describing the methodologies and historical developments which have led to our understanding of cVEPs. We thereafter describe the expected maturation of the cVEP, followed by reviewing their application in several disorders: congenital colour vision deficiencies, retinal disease, glaucoma, optic nerve and neurological disorders, diabetes, amblyopia and dyslexia. We finalise the review with recommendations for testing and future directions.
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Affiliation(s)
- Oliver R Marmoy
- Clinical and Academic Department of Ophthalmology, Great Ormond Street Hospital for Children, London, UK; UCL-GOS Institute of Child Health, University College London, London, UK.
| | - Manca Tekavčič Pompe
- University Eye Clinic, University Medical Centre Ljubljana, Ljubljana, Slovenia; Faculty of Medicine, University of Ljubljana, Slovenia
| | - Jan Kremers
- Section of Retinal Physiology, University Hospital Erlangen, Germany
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Zhang Y, Valsecchi M, Gegenfurtner KR, Chen J. The time course of chromatic adaptation in human early visual cortex revealed by SSVEPs. J Vis 2023; 23:17. [PMID: 37223943 PMCID: PMC10214868 DOI: 10.1167/jov.23.5.17] [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: 01/19/2022] [Accepted: 04/26/2023] [Indexed: 05/25/2023] Open
Abstract
Previous studies have identified at least two components of chromatic adaptation: a rapid component with a time scale between tens of milliseconds to a few seconds, and a slow component with a half-life of about 10 to 30 seconds. The basis of the rapid adaptation probably lies in receptor adaptation at the retina. The neural substrate for the slow adaptation remains unclear, although previous psychophysical results hint at the early visual cortex. A promising approach to investigate adaptation effects in the visual cortex is to analyze steady-state visual evoked potentials (SSVEPs) elicited by chromatic stimuli, which typically use long durations of stimulation. Here, we re-analyzed the data from two previous pattern-reversal SSVEP studies. In these experiments (N = 49 observers in total), SSVEPs were elicited by counter-phase flickering color- or luminance-defined grating stimuli for 150 seconds in each trial. By analyzing SSVEPs with short time windows, we found that chromatic SSVEP responses decreased with increasing stimulation duration and reached a lower asymptote within a minute of stimulation. The luminance SSVEPs did not show any systematic adaptation. The time course of chromatic SSVEPs can be well described by an exponential decay function with a half-life of about 20 seconds, which is very close to previous psychophysical reports. Despite the difference in stimuli between the current and previous studies, the coherent time course may indicate a more general adaptation mechanism in the early visual cortex. In addition, the current result also provides a guide for future color SSVEP studies in terms of either avoiding or exploiting this adaptation effect.
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Affiliation(s)
- Yuan Zhang
- School of Psychology, Shanghai University of Sport, Shanghai, China
| | - Matteo Valsecchi
- Dipartimento di Psicologia, Universitá di Bologna, Bologna, Italy
- https://www.unibo.it/sitoweb/matteo.valsecchi
| | - Karl R Gegenfurtner
- Abteilung Allgemeine Psychologie and Center for Mind, Brain & Behavior, Justus-Liebig-Universität Giessen, Giessen, Germany
- https://www.allpsych.uni-giessen.de/karl/
| | - Jing Chen
- School of Psychology, Shanghai University of Sport, Shanghai, China
- https://orcid.org/0000-0002-3038-1786
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Tcheslavski GV, Vasefi M. An "Instantaneous" Response of a Human Visual System to Hue: An EEG-Based Study. SENSORS (BASEL, SWITZERLAND) 2022; 22:8484. [PMID: 36366181 PMCID: PMC9657469 DOI: 10.3390/s22218484] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/15/2022] [Revised: 10/28/2022] [Accepted: 10/31/2022] [Indexed: 06/16/2023]
Abstract
(1) The article presents a new technique to interpret biomedical data (EEG) to assess cortical responses to continuous color/hue variations. We propose an alternative approach to analyze EEG activity evoked by visual stimulation. This approach may augment the traditional VEP analysis. (2) Considering ensembles of EEG epochs as multidimensional spatial vectors evolving over time (rather than collections of time-domain signals) and evaluating the similarity between such vectors across different EEG epochs may result in a more accurate detection of colors that evoke greater responses of the visual system. To demonstrate its suitability, the developed analysis technique was applied to the EEG data that we previously collected from 19 participants with normal color vision, while exposing them to stimuli of continuously varying hue. (3) Orange/yellow and dark blue/violet colors generally aroused better-pronounced cortical responses. The selection of EEG channels allowed for assessing the activity that predominantly originates from specific cortical regions. With such channel selection, the strongest response to the hue was observed from Parieto-Temporal region of the right hemisphere. The statistical test-Kruskal-Wallis one-way analysis of variance-indicates that the distance evaluated for spatial EEG vectors at different post-stimulus latencies generally originate from different statistical distributions with a probability exceeding 99.9% (α = 0.001).
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Affiliation(s)
- Gleb V. Tcheslavski
- Drayer Department of Electrical Engineering, Lamar University, Beaumont, TX 77710, USA
| | - Maryam Vasefi
- Department of Biology, Lamar University, Beaumont, TX 77710, USA
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Sutterer DW, Coia AJ, Sun V, Shevell SK, Awh E. Decoding chromaticity and luminance from patterns of EEG activity. Psychophysiology 2021; 58:e13779. [PMID: 33550667 DOI: 10.1111/psyp.13779] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2020] [Revised: 01/08/2021] [Accepted: 01/11/2021] [Indexed: 11/28/2022]
Abstract
A long-standing question in the field of vision research is whether scalp-recorded EEG activity contains sufficient information to identify stimulus chromaticity. Recent multivariate work suggests that it is possible to decode which chromaticity an observer is viewing from the multielectrode pattern of EEG activity. There is debate, however, about whether the claimed effects of stimulus chromaticity on visual evoked potentials (VEPs) are instead caused by unequal stimulus luminances, which are achromatic differences. Here, we tested whether stimulus chromaticity could be decoded when potential confounds with luminance were minimized by (1) equating chromatic stimuli in luminance using heterochromatic flicker photometry for each observer and (2) independently varying the chromaticity and luminance of target stimuli, enabling us to test whether the pattern for a given chromaticity generalized across wide variations in luminance. We also tested whether luminance variations can be decoded from the topography of voltage across the scalp. In Experiment 1, we presented two chromaticities (appearing red and green) at three luminance levels during separate trials. In Experiment 2, we presented four chromaticities (appearing red, orange, yellow, and green) at two luminance levels. Using a pattern classifier and the multielectrode pattern of EEG activity, we were able to accurately decode the chromaticity and luminance level of each stimulus. Furthermore, we were able to decode stimulus chromaticity when we trained the classifier on chromaticities presented at one luminance level and tested at a different luminance level. Thus, EEG topography contains robust information regarding stimulus chromaticity, despite large variations in stimulus luminance.
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Affiliation(s)
- David W Sutterer
- Department of Psychology, University of Chicago, Chicago, IL, USA.,Institute for Mind and Biology, University of Chicago, Chicago, IL, USA.,Department of Psychology, Vanderbilt University, Nashville, TN, USA
| | - Andrew J Coia
- Department of Psychology, University of Chicago, Chicago, IL, USA.,Institute for Mind and Biology, University of Chicago, Chicago, IL, USA
| | - Vincent Sun
- Center for Visual Communication and Color Research, Chinese Culture University, Taipei, Taiwan
| | - Steven K Shevell
- Department of Psychology, University of Chicago, Chicago, IL, USA.,Institute for Mind and Biology, University of Chicago, Chicago, IL, USA.,Department of Ophthalmology and Visual Science, University of Chicago, Chicago, IL, USA
| | - Edward Awh
- Department of Psychology, University of Chicago, Chicago, IL, USA.,Institute for Mind and Biology, University of Chicago, Chicago, IL, USA
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Vanston JE, Crognale MA. Effects of eccentricity on color contrast. JOURNAL OF THE OPTICAL SOCIETY OF AMERICA. A, OPTICS, IMAGE SCIENCE, AND VISION 2018; 35:B122-B129. [PMID: 29603965 DOI: 10.1364/josaa.35.00b122] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/20/2017] [Accepted: 01/24/2018] [Indexed: 06/08/2023]
Abstract
Using near-threshold stimuli, human color sensitivity has been shown to decrease across the visual field, likely due in part to physiological differences between the fovea and periphery. It remains unclear to what extent this holds true for suprathreshold stimuli. The current study used suprathreshold contrast matching to examine how perceived contrast varies with eccentricity along the cardinal axes in a cone-opponent space. Our data show that, despite increasing stimulus size in the periphery, the LM axis stimuli were still perceived as reduced in contrast, whereas the S axis perceived contrast was observed to increase with eccentricity.
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Rabin J, Kryder A, Lam D. Binocular facilitation of cone-specific visual evoked potentials in colour deficiency. Clin Exp Optom 2017. [PMID: 28636141 DOI: 10.1111/cxo.12567] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
Abstract
BACKGROUND Neural compensatory mechanisms have been proposed, which preserve the binocular visual field in glaucoma, as well as cognition in Alzheimer's disease and motor function in Parkinson's disease. It is conceivable that comparable mechanisms operate to preserve function in congenital and/or dystrophic disease. In hereditary colour vision deficiency (CVD), we observed significant facilitation in the amplitude of the binocular cone-specific visual evoked potential (VEP) compared to the monocular amplitude for the cone type corresponding to the CVD. We propose that this finding may reflect preservation of function in hereditary colour vision deficiency. METHODS Binocular and monocular L, M and S cone-specific VEPs were recorded from 12 colour vision deficient subjects and 17 with normal colour vision, confirmed to be CVD or normal on a battery of colour vision tests. Binocular VEP amplitudes were compared to monocular amplitudes within subjects and between subject groups. RESULTS Subjects with CVDs showed binocular facilitation of VEP amplitude (enhancement more than 2.0 times; mean: 2.8 times, p = 0.0003) for the cone type corresponding to their CVD. Mean facilitation of 2.8 times exceeded binocular enhancement for other cone types within CVDs (2.8 times versus 1.2 times) and compared to colour vision normals (2.8 times versus 1.2 times). CONCLUSIONS Hereditary CVDs show binocular facilitation of cone VEP signals for the cone type corresponding to their CVD. As CVD is typically assessed with foveal stimuli, our findings using wider-field binocular stimulation suggest that enhanced colour perception may occur in CVD across a more extensive area of visual field. These results may relate to binocular visual field enhancement in glaucoma and improved colour vision in CVD at supra-threshold levels of stimulation.
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Affiliation(s)
- Jeff Rabin
- The Rosenberg School of Optometry, University of the Incarnate Word, San Antonio, Texas, USA
| | - Andrew Kryder
- The Rosenberg School of Optometry, University of the Incarnate Word, San Antonio, Texas, USA
| | - Dan Lam
- The Rosenberg School of Optometry, University of the Incarnate Word, San Antonio, Texas, USA
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Rabin JC, Kryder AC, Lam D. Diagnosis of Normal and Abnormal Color Vision with Cone-Specific VEPs. Transl Vis Sci Technol 2016; 5:8. [PMID: 27226932 PMCID: PMC4874451 DOI: 10.1167/tvst.5.3.8] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2016] [Accepted: 04/19/2016] [Indexed: 11/24/2022] Open
Abstract
Purpose Normal color vision depends on normal long wavelength (L), middle wavelength (M), and short wavelength sensitive (S) cones. Hereditary “red-green” color vision deficiency (CVD) is due to a shift in peak sensitivity or lack of L or M cones. Hereditary S cone CVD is rare but can be acquired as an early sign of disease. Current tests detect CVD but few diagnose type or severity, critical for linking performance to real-world demands. The anomaloscope and newer subjective tests quantify CVD but are not applicable to infants or cognitively impaired patients. Our purpose was to develop an objective test of CVD with sensitivity and specificity comparable to current tests. Methods A calibrated visual-evoked potential (VEP) display and Food and Drug Administration-approved system was used to record L, M, and S cone-specific pattern-onset VEPs from 18 color vision normals (CVNs) and 13 hereditary CVDs. VEP amplitudes and latencies were compared between groups to establish VEP sensitivity and specificity. Results Cone VEPs show 100% sensitivity for diagnosis of CVD and 94% specificity for confirming CVN. L cone (protan) CVDs showed a significant increase in L cone latency (53.1 msec, P < 0.003) and decreased amplitude (10.8 uV, P < 0.0000005) but normal M and S cone VEPs (P > 0.31). M cone (deutan) CVDs showed a significant increase in M cone latency (31.0 msec, P < 0.000004) and decreased amplitude (8.4 uV, P < 0.006) but normal L and S cone VEPs (P > 0.29). Conclusions Cone-specific VEPs offer a rapid, objective test to diagnose hereditary CVD and show potential for detecting acquired CVD in various diseases. Translational Relevance This paper describes the efficacy of cone-specific color VEPs for quantification of normal and abnormal color vision. The rapid, objective nature of this approach makes it suitable for detecting color sensitivity loss in infants and the cognitively impaired.
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Affiliation(s)
- Jeff C Rabin
- University of the Incarnate Word Rosenberg School of Optometry San Antonio, TX, USA
| | - Andrew C Kryder
- University of the Incarnate Word Rosenberg School of Optometry San Antonio, TX, USA
| | - Dan Lam
- University of the Incarnate Word Rosenberg School of Optometry San Antonio, TX, USA
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