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Adhikari P, Uprety S, Feigl B, Zele AJ. Melanopsin-mediated amplification of cone signals in the human visual cortex. Proc Biol Sci 2024; 291:20232708. [PMID: 38808443 DOI: 10.1098/rspb.2023.2708] [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: 11/30/2023] [Accepted: 05/02/2024] [Indexed: 05/30/2024] Open
Abstract
The ambient daylight variation is coded by melanopsin photoreceptors and their luxotonic activity increases towards midday when colour temperatures are cooler, and irradiances are higher. Although melanopsin and cone photoresponses can be mediated via separate pathways, the connectivity of melanopsin cells across all levels of the retina enables them to modify cone signals. The downstream effects of melanopsin-cone interactions on human vision are however, incompletely understood. Here, we determined how the change in daytime melanopsin activation affects the human cone pathway signals in the visual cortex. A 5-primary silent-substitution method was developed to evaluate the dependence of cone-mediated signals on melanopsin activation by spectrally tuning the lights and stabilizing the rhodopsin activation under a constant cone photometric luminance. The retinal (white noise electroretinogram) and cortical responses (visual evoked potential) were simultaneously recorded with the photoreceptor-directed lights in 10 observers. By increasing the melanopsin activation, a reverse response pattern was observed with cone signals being supressed in the retina by 27% (p = 0.03) and subsequently amplified by 16% (p = 0.01) as they reach the cortex. We infer that melanopsin activity can amplify cone signals at sites distal to retinal bipolar cells to cause a decrease in the psychophysical Weber fraction for cone vision.
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Affiliation(s)
- Prakash Adhikari
- Centre for Vision and Eye Research, Queensland University of Technology (QUT), Brisbane, Queensland 4059, Australia
| | - Samir Uprety
- Centre for Vision and Eye Research, Queensland University of Technology (QUT), Brisbane, Queensland 4059, Australia
| | - Beatrix Feigl
- Centre for Vision and Eye Research, Queensland University of Technology (QUT), Brisbane, Queensland 4059, Australia
- School of Biomedical Sciences, Queensland University of Technology (QUT), Brisbane, Queensland 4059, Australia
- Queensland Eye Institute, Brisbane, Queensland 4101, Australia
| | - Andrew J Zele
- Centre for Vision and Eye Research, Queensland University of Technology (QUT), Brisbane, Queensland 4059, Australia
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Adhikari P, Zele AJ, Cao D, Kremers J, Feigl B. The melanopsin-directed white noise electroretinogram (wnERG). Vision Res 2019; 164:83-93. [DOI: 10.1016/j.visres.2019.08.007] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2018] [Revised: 08/07/2019] [Accepted: 08/22/2019] [Indexed: 10/26/2022]
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Test-retest repeatability of the pattern electroretinogram and flicker electroretinogram. Doc Ophthalmol 2019; 139:185-195. [PMID: 31312944 DOI: 10.1007/s10633-019-09707-5] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2018] [Accepted: 06/27/2019] [Indexed: 10/26/2022]
Abstract
PURPOSE To evaluate the repeatability of the steady-state pattern electroretinogram (PERG) and full-field flicker electroretinogram (Flicker ERG) protocols, delivered by the office-based Neuro Optic Vision Assessment (NOVA)™ testing platform, in healthy subjects. METHODS Healthy individuals underwent PERG (16° and 24°) and Flicker ERG [fixed luminance (FL) and multi-luminance (ML)] testing protocols. Test-retest repeatability of protocols was calculated using intra-class correlation coefficients (ICC). Reference values of the parameters of the aforementioned tests were also calculated. RESULTS The ICCs for the PERG parameters ranged from 0.793 to 0.911 (p < 0.001). The ICCs for the Flicker ERG parameters ranged from 0.968 to 0.994 (p < 0.001). A linear regression analysis was applied to assess the impact of age on ERG responses. Age had a significant impact on all PERG parameters (16° or 24°). The phase response of the FL Flicker ERG significantly decreased with age (β = - 0.837, p ≤ 0.001). The FL Flicker ERG Magnitude was also impacted with a significant quadratic effect of age (β = - 0.0047, p = 0.0004). Similarly, the Phase Area Under the Curve (Phase AUC) of the ML Flicker ERG significantly declined with age (β = - 0.007, p = 0.009), and the impact on the Magnitude AUC was significant as well, with a negative quadratic age effect. CONCLUSIONS The PERG and Flicker ERG protocols, delivered by an office-based testing platform, were shown to have good-to-excellent test-retest repeatability when tests were performed in the same order and in immediate succession.
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Zele AJ, Adhikari P, Cao D, Feigl B. Melanopsin and Cone Photoreceptor Inputs to the Afferent Pupil Light Response. Front Neurol 2019; 10:529. [PMID: 31191431 PMCID: PMC6540681 DOI: 10.3389/fneur.2019.00529] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2018] [Accepted: 05/03/2019] [Indexed: 11/20/2022] Open
Abstract
Background: Retinal photoreceptors provide the main stage in the mammalian eye for regulating the retinal illumination through changes in pupil diameter, with a small population of melanopsin-expressing intrinsically photosensitive retinal ganglion cells (ipRGCs) forming the primary afferent pathway for this response. The purpose of this study is to determine how melanopsin interacts with the three cone photoreceptor classes in the human eye to modulate the light-adapted pupil response. Methods: We investigated the independent and combined contributions of the inner and outer retinal photoreceptor inputs to the afferent pupil pathway in participants with trichromatic color vision using a method to independently control the excitations of ipRGCs, cones and rods in the retina. Results: We show that melanopsin-directed stimuli cause a transient pupil constriction generated by cones in the shadow of retinal blood vessels; desensitizing these penumbral cone signals uncovers a signature melanopsin pupil response that includes a longer latency (292 ms) and slower time (4.1x) and velocity (7.7x) to constriction than for cone-directed stimuli, and which remains sustained post-stimulus offset. Compared to melanopsin-mediated pupil responses, the cone photoreceptor-initiated pupil responses are more transient with faster constriction latencies, higher velocities and a secondary constriction at light offset. The combined pupil responses reveal that melanopsin signals are additive with the cone signals. Conclusions: The visual system uses the L–, M–, and S–cone photoreceptor inputs to the afferent pupil pathway to accomplish the tonic modulations of pupil size to changes in image contrast. The inner retinal melanopsin-expressing ipRGCs mediate the longer-term, sustained pupil constriction to set the light-adapted pupil diameter during extended light exposures.
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Affiliation(s)
- Andrew J Zele
- Institute of Health and Biomedical Innovation, Queensland University of Technology (QUT), Brisbane, QLD, Australia.,School of Optometry and Vision Science, Queensland University of Technology (QUT), Brisbane, QLD, Australia
| | - Prakash Adhikari
- Institute of Health and Biomedical Innovation, Queensland University of Technology (QUT), Brisbane, QLD, Australia.,School of Optometry and Vision Science, Queensland University of Technology (QUT), Brisbane, QLD, Australia
| | - Dingcai Cao
- Department of Ophthalmology and Visual Sciences, University of Illinois at Chicago, Chicago, IL, United States
| | - Beatrix Feigl
- Institute of Health and Biomedical Innovation, Queensland University of Technology (QUT), Brisbane, QLD, Australia.,School of Biomedical Sciences, Queensland University of Technology (QUT), Brisbane, QLD, Australia.,Queensland Eye Institute, Brisbane, QLD, Australia
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Monsalve P, Ren S, Triolo G, Vazquez L, Henderson AD, Kostic M, Gordon P, Feuer WJ, Porciatti V. Steady-state PERG adaptation: a conspicuous component of response variability with clinical significance. Doc Ophthalmol 2018; 136:157-164. [PMID: 29779071 DOI: 10.1007/s10633-018-9633-2] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2018] [Accepted: 05/01/2018] [Indexed: 11/27/2022]
Abstract
PURPOSE To investigate within-test variability of the steady-state PERG (SS-PERG). METHODS SS-PERGs were recorded in response to black-white horizontal gratings (1.6 cycles/deg, 98% contrast, 15.63 reversals/s, LED display, 25 deg square field, 800 cd/sqm mean luminance) using skin electrodes. PERG and noise (± reference) signals were averaged over 1024 epochs (~ 2.2 min) and Fourier analyzed to retrieve SS-PERG amplitude and phase. SS-PERGs were split into 16 partial averages (samples) of 64 epochs each, and corresponding amplitudes and phases combined in polar coordinates to assess their dispersion (within-test variability). To assess time-dependent variability, samples were clustered in four successive time segments of ~ 33 s each. Amplitude adaptation was defined as amplitude difference between initial and final clusters, and PERG phase adaptation as the corresponding phase difference. To determine the dynamic range of SS-PERG adaptation, recording was performed in normal controls of different age (n = 32) and patients with different severity of optic nerve dysfunction (early manifest glaucoma, EMG, n = 7; non-arteritic ischemic optic neuropathy, NAION, n = 5). RESULTS Amplitude adaptation was largest in younger controls (amplitude adaptation ÷ noise, SNR = 9.5, 95% CI 13.1, 5.9) and progressively decreased with increasing age (older subjects, SNR = 5.5, 95% CI 9.2, 1.8) and presence of disease (EMG: SNR = 2.4, 95% CI 3.5, 1.4; NAION: SNR = 1.9, 95% CI 6.5,-2.2). In 11 young subjects, amplitude adaptation was repeatable (test-retest in two sessions a week apart; intraclass correlation coefficient = 0.59). Phase adaptation was not significantly different from zero in all groups. CONCLUSIONS SS-PERG adaptation accounts for a sizeable portion of the within-test variability. As it has robust SNR, sufficient test-retest variability, and is altered in disease, it may have physiological and clinical significance. This study suggests that SS-PERG protocols should include adaptation in addition to SS-PERG amplitude and phase/latency.
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Affiliation(s)
- P Monsalve
- Bascom Palmer Eye Institute, University of Miami Miller School of Medicine, Miami, FL, USA
| | - S Ren
- Bascom Palmer Eye Institute, University of Miami Miller School of Medicine, Miami, FL, USA
| | - G Triolo
- Head and Neck Department, IRCCS St. Raffaele Hospital, Milan, Italy
| | - L Vazquez
- Bascom Palmer Eye Institute, University of Miami Miller School of Medicine, Miami, FL, USA
| | - A D Henderson
- Johns Hopkins Wilmer Eye Institute, Columbia, MD, USA
| | - M Kostic
- Bascom Palmer Eye Institute, University of Miami Miller School of Medicine, Miami, FL, USA
| | - P Gordon
- Bascom Palmer Eye Institute, University of Miami Miller School of Medicine, Miami, FL, USA
| | - W J Feuer
- Bascom Palmer Eye Institute, University of Miami Miller School of Medicine, Miami, FL, USA
| | - V Porciatti
- Bascom Palmer Eye Institute, University of Miami Miller School of Medicine, Miami, FL, USA.
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Zele AJ, Feigl B, Kambhampati PK, Aher A, McKeefry D, Parry N, Maguire J, Murray I, Kremers J. A Temporal White Noise Analysis for Extracting the Impulse Response Function of the Human Electroretinogram. Transl Vis Sci Technol 2017; 6:1. [PMID: 29109907 PMCID: PMC5666911 DOI: 10.1167/tvst.6.6.1] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2017] [Accepted: 09/23/2017] [Indexed: 12/22/2022] Open
Abstract
PURPOSE We introduce a method for determining the impulse response function (IRF) of the ERG derived from responses to temporal white noise (TWN) stimuli. METHODS This white noise ERG (wnERG) was recorded in participants with normal trichromatic vision to full-field (Ganzfeld) and 39.3° diameter focal stimuli at mesopic and photopic mean luminances and at different TWN contrasts. The IRF was obtained by cross-correlating the TWN stimulus with the wnERG. RESULTS We show that wnERG recordings are highly repeatable, with good signal-to-noise ratio, and do not lead to blink artifacts. The wnERG resembles a flash ERG waveform with an initial negativity (N1) followed by a positivity (P1), with amplitudes that are linearly related to stimulus contrast. These N1 and N1-P1 components showed commonalties in implicit times with the a- and b-waves of flash ERGs. There was a clear transition from rod- to cone-driven wnERGs at ∼1 photopic cd.m-2. We infer that oscillatory potentials found with the flash ERG, but not the wnERG, may reflect retinal nonlinearities due to the compression of energy into a short time period during a stimulus flash. CONCLUSION The wnERG provides a new approach to study the physiology of the retina using a stimulation method with adaptation and contrast conditions similar to natural scenes to allow for independent variation of stimulus strength and mean luminance, which is not possible with the conventional flash ERG. TRANSLATIONAL RELEVANCE The white noise ERG methodology will be of benefit for clinical studies and animal models in the evaluation of hypotheses related to cellular redundancy to understand the effects of disease on specific visual pathways.
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Affiliation(s)
- Andrew J. Zele
- Visual Science Laboratory, Institute of Health and Biomedical Innovation, School of Optometry and Vision Science, Queensland University of Technology (QUT), Brisbane, Australia
| | - Beatrix Feigl
- Medical Retina Laboratory, Institute of Health and Biomedical Innovation, School of Biomedical Sciences, Queensland University of Technology (QUT), Brisbane, Australia
- Queensland Eye Institute, South Brisbane, Australia
| | - Pradeep K. Kambhampati
- Medical Retina Laboratory, Institute of Health and Biomedical Innovation, School of Biomedical Sciences, Queensland University of Technology (QUT), Brisbane, Australia
| | - Avinash Aher
- Laboratory for Retinal Physiology, Department of Ophthalmology, University Hospital Erlangen, Erlangen, Germany
| | - Declan McKeefry
- University of Bradford, Bradford School of Optometry and Vision Sciences, West Yorkshire, UK
| | - Neil Parry
- University of Bradford, Bradford School of Optometry and Vision Sciences, West Yorkshire, UK
- Vision Science Centre, Manchester Royal Eye Hospital, Central Manchester University Hospitals NHS Foundation Trust, Manchester Academic Health Science Centre, Manchester, UK
| | - John Maguire
- University of Bradford, Bradford School of Optometry and Vision Sciences, West Yorkshire, UK
| | - Ian Murray
- Vision Science Centre, Manchester Royal Eye Hospital, Central Manchester University Hospitals NHS Foundation Trust, Manchester Academic Health Science Centre, Manchester, UK
| | - Jan Kremers
- Laboratory for Retinal Physiology, Department of Ophthalmology, University Hospital Erlangen, Erlangen, Germany
- University of Bradford, Bradford School of Optometry and Vision Sciences, West Yorkshire, UK
- Department of Anatomy II, Friedrich-Alexander University Erlangen Nürnberg, Erlangen, Germany
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Hathibelagal AR, Feigl B, Kremers J, Zele AJ. Correlated and uncorrelated invisible temporal white noise alters mesopic rod signaling. JOURNAL OF THE OPTICAL SOCIETY OF AMERICA. A, OPTICS, IMAGE SCIENCE, AND VISION 2016; 33:A93-A103. [PMID: 26974946 DOI: 10.1364/josaa.33.000a93] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
We determined how rod signaling at mesopic light levels is altered by extrinsic temporal white noise that is correlated or uncorrelated with the activity of one (magnocellular, parvocellular, or koniocellular) postreceptoral pathway. Rod and cone photoreceptor excitations were independently controlled using a four-primary photostimulator. Psychometric (Weibull) functions were measured for incremental rod pulses (50 to 250 ms) in the presence (or absence; control) of perceptually invisible subthreshold extrinsic noise. Uncorrelated (rod) noise facilitates rod detection. Correlated postreceptoral pathway noise produces differential changes in rod detection thresholds and decreases the slope of the psychometric functions. We demonstrate that invisible extrinsic noise changes rod-signaling characteristics within the three retinogeniculate pathways at mesopic illumination depending on the temporal profile of the rod stimulus and the extrinsic noise type.
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