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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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Mahroo OA. Visual electrophysiology and "the potential of the potentials". Eye (Lond) 2023; 37:2399-2408. [PMID: 36928229 PMCID: PMC10397240 DOI: 10.1038/s41433-023-02491-2] [Citation(s) in RCA: 9] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2023] [Revised: 02/09/2023] [Accepted: 03/06/2023] [Indexed: 03/18/2023] Open
Abstract
Visual electrophysiology affords direct, quantitative, objective assessment of visual pathway function at different levels, and thus yields information complementary to, and not necessarily obtainable from, imaging or psychophysical testing. The tests available, and their indications, have evolved, with many advances, both in technology and in our understanding of the neural basis of the waveforms, now facilitating more precise evaluation of physiology and pathophysiology. After summarising the visual pathway and current standard clinical testing methods, this review discusses, non-exhaustively, several developments, focusing particularly on human electroretinogram recordings. These include new devices (portable, non-mydiatric, multimodal), novel testing protocols (including those aiming to separate rod-driven and cone-driven responses, and to monitor retinal adaptation), and developments in methods of analysis, including use of modelling and machine learning. It is likely that several tests will become more accessible and useful in both clinical and research settings. In future, these methods will further aid our understanding of common and rare eye disease, will help in assessing novel therapies, and will potentially yield information relevant to neurological and neuro-psychiatric conditions.
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Affiliation(s)
- Omar A Mahroo
- Institute of Ophthalmology, University College London, 11-43 Bath Street, London, UK.
- Retinal and Genetics Services, Moorfields Eye Hospital, 162 City Road, London, UK.
- Section of Ophthalmology and Department of Twin Research and Genetic Epidemiology, King's College London, St Thomas' Hospital Campus, Westminster Bridge Road, London, UK.
- Physiology, Development and Neuroscience, University of Cambridge, Downing Street, Cambridge, UK.
- Department of Translational Ophthalmology, Wills Eye Hospital, Philadelphia, PA, USA.
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Stallwitz N, Joachimsthaler A, Kremers J. Single opsin driven white noise ERGs in mice. Front Neurosci 2023; 17:1211329. [PMID: 37583414 PMCID: PMC10423813 DOI: 10.3389/fnins.2023.1211329] [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: 04/24/2023] [Accepted: 07/17/2023] [Indexed: 08/17/2023] Open
Abstract
Purpose Electroretinograms elicited by photopigment isolating white noise stimuli (wnERGs) in mice were measured. The dependency of rod- and cone-opsin-driven wnERGs on mean luminance was studied. Methods Temporal white noise stimuli (containing all frequencies up to 20 Hz, equal amplitudes, random phases) that modulated either rhodopsin, S-opsin or L*-opsin, using the double silent substitution technique, were used to record wnERGs in mice expressing a human L*-opsin instead of the native murine M-opsin. Responses were recorded at 4 mean luminances (MLs).Impulse response functions (IRFs) were obtained by cross-correlating the wnERG recordings with the corresponding modulation of the photopigment excitation elicited by the stimulus. So-called modulation transfer functions (MTFs) were obtained by performing a Fourier transform on the IRFs.Potentials of two repeated wnERG recordings at corresponding time points were plotted against each other. The correlation coefficient (r2repr) of the linear regression through these data was used to quantify reproducibility. Another correlation coefficient (r2ML) was used to quantify the correlations of the wnERGs obtained at different MLs with those at the highest (for cone isolating stimuli) or lowest (for rod isolating stimuli) ML. Results IRFs showed an initial negative (a-wave like) trough N1 and a subsequent positive (b-wave like) peak P1. No oscillatory potential-like components were observed. At 0.4 and 1.0 log cd/m2 ML robust L*- and S-opsin-driven IRFs were obtained that displayed similar latencies and dependencies on ML. L*-opsin-driven IRFs were 2.5-3 times larger than S-opsin-driven IRFs. Rhodopsin-driven IRFs were observed at -0.8 and - 0.2 log cd/m2 and decreased in amplitude with increasing ML. They displayed an additional pronounced late negativity (N2), which may be a correlate of retinal ganglion cell activity.R2repr and r2ML values increased for cones with increasing ML whereas they decreased for rods. For rhodopsin-driven MTFs at low MLs and L*-opsin-driven MTFs at high MLs amplitudes decreased with increasing frequency, with much faster decreasing amplitudes for rhodopsin. A delay was calculated from MTF phases showing larger delays for rhodopsin- vs. low delays for L*-opsin-driven responses. Conclusion Opsin-isolating wnERGs in mice show characteristics of different retinal cell types and their connected pathways.
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Affiliation(s)
- Nina Stallwitz
- Department of Ophthalmology, University Hospital Erlangen, Erlangen, Germany
- Animal Physiology, Department of Biology, Friedrich-Alexander-University Erlangen-Nürnberg, Erlangen, Germany
| | - Anneka Joachimsthaler
- Department of Ophthalmology, University Hospital Erlangen, Erlangen, Germany
- Animal Physiology, Department of Biology, Friedrich-Alexander-University Erlangen-Nürnberg, Erlangen, Germany
| | - Jan Kremers
- Department of Ophthalmology, University Hospital Erlangen, Erlangen, Germany
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Barboni MTS, Joachimsthaler A, Roux MJ, Nagy ZZ, Ventura DF, Rendon A, Kremers J, Vaillend C. Retinal dystrophins and the retinopathy of Duchenne muscular dystrophy. Prog Retin Eye Res 2022:101137. [DOI: 10.1016/j.preteyeres.2022.101137] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2022] [Revised: 10/25/2022] [Accepted: 11/03/2022] [Indexed: 11/21/2022]
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Kremers J, Aher AJ, Parry NRA, Patel NB, Frishman LJ. Electroretinographic responses to luminance and cone-isolating white noise stimuli in macaques. Front Neurosci 2022; 16:925405. [PMID: 35968368 PMCID: PMC9372266 DOI: 10.3389/fnins.2022.925405] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2022] [Accepted: 06/27/2022] [Indexed: 11/30/2022] Open
Abstract
Electroretinograms (ERGs) are mass potentials with a retinal origin that can be measured non-invasively. They can provide information about the physiology of the retina. Often, ERGs are measured to flashes that are highly unnatural stimuli. To obtain more information about the physiology of the retina, we measured ERGs with temporal white noise (TWN) stimuli that are more natural and keep the retina in a normal range of operation. The stimuli can be combined with the silent substitution stimulation technique with which the responses of single photoreceptor types can be isolated. We characterized electroretinogram (ERG) responses driven by luminance activity or by the L- or the M-cones. The ERGs were measured from five anesthetized macaques (two females) to luminance, to L-cone isolating and to M-cone isolating stimuli in which luminance or cone excitation were modulated with a TWN profile. The responses from different recordings were correlated with each other to study reproducibility and inter-individual variability. Impulse response functions (IRFs) were derived by cross-correlating the response with the stimulus. Modulation transfer functions (MTFs) were the IRFs in the frequency domain. The responses to luminance and L-cone isolating stimuli showed the largest reproducibility. The M-cone driven responses showed the smallest inter-individual variability. The IRFs and MTFs showed early (high frequency) components that were dominated by L-cone driven signals. A late component was equally driven by L- and M-cone activity. The IRFs showed characteristic similarities and differences relative to flash ERGs. The responses to TWN stimuli can be used to characterize the involvement of retinal cells and pathways to the ERG response. It can also be used to identify linear and non-linear processes.
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Affiliation(s)
- Jan Kremers
- Section for Retinal Physiology, University Hospital Erlangen, Erlangen, Germany
- *Correspondence: Jan Kremers,
| | - Avinash J. Aher
- Section for Retinal Physiology, University Hospital Erlangen, Erlangen, Germany
| | - Neil R. A. Parry
- Vision Science Centre, Manchester Academic Health Science Centre, Manchester Royal Eye Hospital, Manchester University NHS Foundation Trust, Manchester, United Kingdom
- Faculty of Biology, Medicine and Health, University of Manchester, Manchester, United Kingdom
| | - Nimesh B. Patel
- Department of Vision Sciences, College of Optometry, University of Houston, Houston, TX, United States
| | - Laura J. Frishman
- Department of Vision Sciences, College of Optometry, University of Houston, Houston, TX, United States
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Zhang M, Yang J, Ji K, He X, He T, Xing Y. Inhibition of p66Shc attenuates retinal ischemia-reperfusion injury-induced damage by activating the akt pathway. Exp Eye Res 2022; 220:109082. [PMID: 35513040 DOI: 10.1016/j.exer.2022.109082] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2021] [Revised: 03/08/2022] [Accepted: 04/13/2022] [Indexed: 11/26/2022]
Abstract
Retinal ganglion cell (RGC) death is the direct cause of several optic neuropathies. Several studies have reported that the loss of p66Shc ameliorates neuronal injury and vascular abnormalities in ischemia-reperfusion (I/R) injury. However, whether p66Shc is involved in the loss of RGC remains unclear. Therefore, this study aimed to investigate the function of p66Shc due to retinal ischemia in mice. The retinal I/R model was constructed after an intravitreal injection of recombinant adeno-associated viruses (rAAV-EGFP or rAAV-p66Shc-EGFP) for 4 weeks. The expression of p66Shc was detected by western blotting, quantitative real-time polymerase chain reaction, and immunofluorescence staining. The survival of RGCs was determined using immunofluorescence staining. Retinal function was analyzed based on electroretinogram (ERG) findings. Retinal cell apoptosis was detected by TdT-mediated dUTP nick-end labeling staining. The protein expressions of Akt, phospho-Akt, Bax, and PARP were analyzed by western blotting. After rAAVs were successfully transfected, enhanced green fluorescent protein was expressed in all retinal cell layers, and the level of p66Shc after I/R injury was successfully reduced. We found that inhibition of p66Shc expression remarkably decreased the death of RGCs and prevented the loss of ERG a- and b-wave amplitudes caused by retinal ischemia. Mechanistically, downregulation of p66Shc resulted in reduced Bax, whereas increased phospho-Akt and PARP. Taken together, our study revealed that p66Shc acts through the Akt pathway to protect RGCs from retinal I/R injury-induced apoptosis and retinal dysfunction, making p66Shc a possible therapeutic target for glaucoma treatment.
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Affiliation(s)
- Min Zhang
- Department of Ophthalmology, Renmin Hospital of Wuhan University, Hubei, China
| | - Jiayi Yang
- Department of Ophthalmology, Renmin Hospital of Wuhan University, Hubei, China
| | - Kaibao Ji
- Department of Ophthalmology, Renmin Hospital of Wuhan University, Hubei, China
| | - Xuejun He
- Department of Ophthalmology, Renmin Hospital of Wuhan University, Hubei, China
| | - Tao He
- Department of Ophthalmology, Renmin Hospital of Wuhan University, Hubei, China.
| | - Yiqiao Xing
- Department of Ophthalmology, Renmin Hospital of Wuhan University, Hubei, China.
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Pasmanter N, Occelli LM, Komáromy AM, Petersen-Jones SM. Use of extended protocols with nonstandard stimuli to characterize rod and cone contributions to the canine electroretinogram. Doc Ophthalmol 2022; 144:81-97. [PMID: 35247111 PMCID: PMC10426558 DOI: 10.1007/s10633-022-09866-y] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2021] [Accepted: 02/08/2022] [Indexed: 11/03/2022]
Abstract
PURPOSE In this study, we assessed several extended electroretinographic protocols using nonstandard stimuli. Our aim was to separate and quantify the contributions of different populations of retinal cells to the overall response, both to assess normal function and characterize dogs with inherited retinal disease. METHODS We investigated three different protocols for measuring the full-field flash electroretinogram-(1) chromatic dark-adapted red and blue flashes, (2) increasing luminance blue-background, (3) flicker with fixed frequency and increasing luminance, and flicker with increasing frequency at a fixed luminance-to assess rod and cone contributions to electroretinograms recorded in phenotypically normal control dogs and dogs lacking rod function. RESULTS Temporal separation of the rod- and cone-driven responses is possible in the fully dark-adapted eye using dim red flashes. A- and b-wave amplitudes decrease at different rates with increasing background luminance in control dogs. Flicker responses elicited with extended flicker protocols are well fit with mathematical models in control dogs. Dogs lacking rod function demonstrated larger amplitude dark-adapted compared to light-adapted flicker responses. CONCLUSIONS Using extended protocols of the full-field electroretinogram provides additional characterization of the health and function of different populations of cells in the normal retina and enables quantifiable comparison between phenotypically normal dogs and those with retinal disease.
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Affiliation(s)
- Nate Pasmanter
- Department of Small Animal Clinical Sciences, College of Veterinary Medicine, Michigan State University, 736 Wilson Road, D-208, East Lansing, MI, 48824, USA
| | - Laurence M Occelli
- Department of Small Animal Clinical Sciences, College of Veterinary Medicine, Michigan State University, 736 Wilson Road, D-208, East Lansing, MI, 48824, USA
| | - András M Komáromy
- Department of Small Animal Clinical Sciences, College of Veterinary Medicine, Michigan State University, 736 Wilson Road, D-208, East Lansing, MI, 48824, USA
| | - Simon M Petersen-Jones
- Department of Small Animal Clinical Sciences, College of Veterinary Medicine, Michigan State University, 736 Wilson Road, D-208, East Lansing, MI, 48824, USA.
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Yang JJ, Huang CH, Yang CH, Yang CM, Lin CW, Ho TC, Lin CP, Hsieh YT, Yeh PT, Lai TT, Chen PL, Chen TC. The Clinical Contribution of Full-Field Electroretinography and 8-Year Experiences of Application in a Tertiary Medical Center. J Pers Med 2021; 11:jpm11101022. [PMID: 34683163 PMCID: PMC8539721 DOI: 10.3390/jpm11101022] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2021] [Revised: 10/05/2021] [Accepted: 10/09/2021] [Indexed: 12/15/2022] Open
Abstract
Electroretinography (ERG) is an important and well-established examination for retinal and visual pathway diseases. This study reviewed the medical records of patients who received full-field ERG (ffERG) at a single medical center between 2012 and 2019, which was an 8-year experience in the clinical contribution of ERG. Based on the indication for scheduling ffERG and the final diagnosis, patients could be classified into six groups: ‘retinal dystrophies’, ‘other retinal or macular diseases’, ‘optic neuropathies’, ‘visual complaints’, ‘systemic diseases’, and ‘others’. A total of 1921 full-field electroretinograms (ffERGs) (1655 patients) were included. The average number of ffERGs performed per year was 262 and the number of annual ffERGs was constant. The ‘retinal dystrophies’ group accounted for 36.5% of the studied population, followed by the ‘other retinal or macular diseases’ group (20.2%). The most common systemic disease was central nervous system disease. The rates of abnormal ffERGs in the ‘systemic diseases’, ‘optic neuropathies’, and ‘visual complaints’ groups were 27.3%, 22.6%, and 10.1%, respectively (p < 0.001). Higher rates were found in patients <20 years old in the ‘systemic diseases’ and ‘optic neuropathies’ groups; epilepsy and optic nerve atrophy were the most common diagnoses, respectively. In brief, by quantifying the functional response in the retina, ffERG is indispensable for diagnosis and prognosis in ophthalmologic and multidisciplinary practice.
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Affiliation(s)
- Jung-Je Yang
- Department of Medical Education, National Taiwan University Hospital, Taipei 10002, Taiwan;
| | - Chu-Hsuan Huang
- Department of Ophthalmology, Cathay General Hospital, Taipei 10002, Taiwan;
| | - Chang-Hao Yang
- Department of Ophthalmology, National Taiwan University Hospital, Taipei 10002, Taiwan; (C.-H.Y.); (C.-M.Y.); (C.-W.L.); (T.-C.H.); (C.-P.L.); (Y.-T.H.); (P.-T.Y.); (T.-T.L.)
- Department of Ophthalmology, College of Medicine, National Taiwan University, Taipei 10002, Taiwan
| | - Chung-May Yang
- Department of Ophthalmology, National Taiwan University Hospital, Taipei 10002, Taiwan; (C.-H.Y.); (C.-M.Y.); (C.-W.L.); (T.-C.H.); (C.-P.L.); (Y.-T.H.); (P.-T.Y.); (T.-T.L.)
- Department of Ophthalmology, College of Medicine, National Taiwan University, Taipei 10002, Taiwan
| | - Chao-Wen Lin
- Department of Ophthalmology, National Taiwan University Hospital, Taipei 10002, Taiwan; (C.-H.Y.); (C.-M.Y.); (C.-W.L.); (T.-C.H.); (C.-P.L.); (Y.-T.H.); (P.-T.Y.); (T.-T.L.)
| | - Tzyy-Chang Ho
- Department of Ophthalmology, National Taiwan University Hospital, Taipei 10002, Taiwan; (C.-H.Y.); (C.-M.Y.); (C.-W.L.); (T.-C.H.); (C.-P.L.); (Y.-T.H.); (P.-T.Y.); (T.-T.L.)
- Department of Ophthalmology, College of Medicine, National Taiwan University, Taipei 10002, Taiwan
| | - Chang-Ping Lin
- Department of Ophthalmology, National Taiwan University Hospital, Taipei 10002, Taiwan; (C.-H.Y.); (C.-M.Y.); (C.-W.L.); (T.-C.H.); (C.-P.L.); (Y.-T.H.); (P.-T.Y.); (T.-T.L.)
- Department of Ophthalmology, College of Medicine, National Taiwan University, Taipei 10002, Taiwan
| | - Yi-Ting Hsieh
- Department of Ophthalmology, National Taiwan University Hospital, Taipei 10002, Taiwan; (C.-H.Y.); (C.-M.Y.); (C.-W.L.); (T.-C.H.); (C.-P.L.); (Y.-T.H.); (P.-T.Y.); (T.-T.L.)
- Department of Ophthalmology, College of Medicine, National Taiwan University, Taipei 10002, Taiwan
| | - Po-Ting Yeh
- Department of Ophthalmology, National Taiwan University Hospital, Taipei 10002, Taiwan; (C.-H.Y.); (C.-M.Y.); (C.-W.L.); (T.-C.H.); (C.-P.L.); (Y.-T.H.); (P.-T.Y.); (T.-T.L.)
- Department of Ophthalmology, College of Medicine, National Taiwan University, Taipei 10002, Taiwan
| | - Tso-Ting Lai
- Department of Ophthalmology, National Taiwan University Hospital, Taipei 10002, Taiwan; (C.-H.Y.); (C.-M.Y.); (C.-W.L.); (T.-C.H.); (C.-P.L.); (Y.-T.H.); (P.-T.Y.); (T.-T.L.)
| | - Pei-Lung Chen
- Graduate Institute of Clinical Medicine, College of Medicine, National Taiwan University, Taipei 10002, Taiwan;
- Graduate Institute of Medical Genomics and Proteomics, College of Medicine, National Taiwan University, Taipei 10002, Taiwan
- Department of Medical Genetics, National Taiwan University Hospital, Taipei 10002, Taiwan
| | - Ta-Ching Chen
- Department of Ophthalmology, National Taiwan University Hospital, Taipei 10002, Taiwan; (C.-H.Y.); (C.-M.Y.); (C.-W.L.); (T.-C.H.); (C.-P.L.); (Y.-T.H.); (P.-T.Y.); (T.-T.L.)
- Graduate Institute of Clinical Medicine, College of Medicine, National Taiwan University, Taipei 10002, Taiwan;
- Correspondence: ; Tel.: +886-2-23123456 (ext. 63783)
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Aher AJ, Horn FK, Huchzermeyer C, Lämmer R, Kremers J. Responses of Postreceptoral Pathways Elicited by L- and M-Cone Isolating ON- and OFF-Electroretinograms in Glaucoma Patients. Invest Ophthalmol Vis Sci 2021; 62:14. [PMID: 34241626 PMCID: PMC8287051 DOI: 10.1167/iovs.62.9.14] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Purpose To compare the electroretinographical (ERG) responses elicited by L- and M-cone isolating ON- and OFF-sawtooth stimuli in normal subjects and glaucoma patients. Methods Twenty-one normal subjects and 44 primary open-angle glaucoma patients participated in the study. L- and M-cone isolating (18% cone contrast; 284 cd/m2) rapid ON- and rapid OFF-sawtooth (4 Hz) stimuli with two stimulus sizes (full-field (FF) and central 70° diameter) were generated using the triple silent substitution technique. ON- and OFF-response asymmetries were studied by adding the two (to obtain L-add and M-add responses). The initial positive (P) and subsequent late negative (LN) components of the L-add and M-add ERGs were compared between the subject groups and correlated with retinal nerve fiber layer thickness (RNFLT) and pattern ERG responses. Results The responses to L-ON and to M-OFF stimuli and vice versa resembled each other particularly with 70° stimuli. The PL-add amplitudes were not significantly different between the normal subjects and glaucoma patients, whereas the LNL-add amplitude was significantly (P < 0.01) smaller in the glaucoma patients. Both PM-add and LNM-add were not significantly different between the subject groups. The PERG amplitude with 0.8° check sizes and the 0.8°/16° amplitude ratio (PERG ratio) were significantly (P < 0.05) different between the subject groups. The 70° LNL-add amplitude and the 0.8° PERG amplitude were significantly correlated with RNFLT. Conclusions The ERGs to 70° cone isolating sawtooth stimuli reflect cone opponency. The cone opponent ERG responses were not significantly different between glaucoma patients and normal subjects. Luminance driven L-add responses were significantly different, indicating that central luminance signals are mainly affected in glaucoma.
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Affiliation(s)
- Avinash J Aher
- Section for Retinal Physiology, University Hospital Erlangen, Erlangen, Germany
| | - Folkert K Horn
- Department of Ophthalmology, University Hospital Erlangen, Erlangen, Germany
| | - Cord Huchzermeyer
- Department of Ophthalmology, University Hospital Erlangen, Erlangen, Germany
| | - Robert Lämmer
- Department of Ophthalmology, University Hospital Erlangen, Erlangen, Germany
| | - Jan Kremers
- Section for Retinal Physiology, University Hospital Erlangen, Erlangen, Germany.,School of Optometry and Vision Science, University of Bradford, Bradford, West Yorkshire, United Kingdom.,Department of Anatomy II, University of Erlangen-Nürnberg, Erlangen, Germany
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Li Z, Xie F, Yang N, Yang J, Luo J, Hua D, He T, Xing Y. Krüppel-like factor 7 protects retinal ganglion cells and promotes functional preservation via activating the Akt pathway after retinal ischemia-reperfusion injury. Exp Eye Res 2021; 207:108587. [PMID: 33891954 DOI: 10.1016/j.exer.2021.108587] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2020] [Revised: 03/22/2021] [Accepted: 04/12/2021] [Indexed: 10/21/2022]
Abstract
OBJECTIVE The purpose of this study is to investigate the effects of Krüppel-like factor 7 (KLF7) on retinal ganglion cells (RGCs) and retinal function after retinal ischemia-reperfusion (RIR) injury in mice. METHODS Male C57BL/6J mice were intravitreally injected with recombinant adeno-associated vectors (rAAV-KLF7-EGFP or rAAV-EGFP), and subsequently used to induce RIR injury. Retinal cryosections were used to access the efficacy of virus transfection, 1, 2, 3, and 4 weeks after rAAV-KLF7-EGFP transfer. RGCs survival rate was observed and quantified by immunofluorescent staining, 7 days after RIR injury. Meanwhile, electroretinogram (ERG) and optomotor response were used to evaluate the electrophysiological functions and visual acuity. Apoptosis was evaluated by TUNEL staining 1 day after RIR injury. Expression of KLF7, Akt, phospho-Akt, Bcl-2, and Bax were further detected by western blot to excavate the underlying mechanism. RESULTS The transfection efficiency of rAAV-KLF7-EGFP was increased in a time-dependent manner, and the number of EGFP-positive cells was increased significantly 3 weeks after rAAV-KLF7-EGFP transfer. RGCs survival rates, amplitudes of ERG a-, b-wave, Ops, PhNR, and visual acuity of mice were decreased after RIR injury. With the increase of light intensity, the amplitudes of scotopic ERG a- and b-wave were gradually increased while the incubation period was gradually shortened. RGCs survival rates, amplitudes of ERG a-, b-wave, Ops, PhNR, and visual acuity of mice were increased after rAAV-KLF7-EGFP transfer. The protein level of KLF7 was up-regulated after rAAV-KLF7-EGFP transfer. Up-regulation of KLF7 significantly inhibited cells apoptosis, increased phospho-Akt and Bcl-2 expression, and decreased Bax expression. There were no significant changes in Akt expression. CONCLUSION Overexpression of KLF7 can not only prevent the loss of RGCs, but also preserve the electrophysiological function. In addition, overexpression of KLF7 can ameliorate the retinal dysfunction after RIR injury, and ultimately improve the visual acuity of mice. The activation of Akt pathway and the suppression of the mitochondrial apoptotic pathway contribute to the neuroprotection of KLF7.
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Affiliation(s)
- Zongyuan Li
- Eye Center, Renmin Hospital of Wuhan University, 238 Jiefang Road, Wuhan, 430060, Hubei Province, China.
| | - Feijia Xie
- Eye Center, Renmin Hospital of Wuhan University, 238 Jiefang Road, Wuhan, 430060, Hubei Province, China
| | - Ning Yang
- Eye Center, Renmin Hospital of Wuhan University, 238 Jiefang Road, Wuhan, 430060, Hubei Province, China
| | - Jiayi Yang
- Eye Center, Renmin Hospital of Wuhan University, 238 Jiefang Road, Wuhan, 430060, Hubei Province, China
| | - Jinyuan Luo
- Eye Center, Renmin Hospital of Wuhan University, 238 Jiefang Road, Wuhan, 430060, Hubei Province, China
| | - Dihao Hua
- Eye Center, Renmin Hospital of Wuhan University, 238 Jiefang Road, Wuhan, 430060, Hubei Province, China
| | - Tao He
- Eye Center, Renmin Hospital of Wuhan University, 238 Jiefang Road, Wuhan, 430060, Hubei Province, China.
| | - Yiqiao Xing
- Eye Center, Renmin Hospital of Wuhan University, 238 Jiefang Road, Wuhan, 430060, Hubei Province, China.
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Kremers J, Aher AJ, Parry NRA, Patel NB, Frishman LJ. Comparison of macaque and human L- and M-cone driven electroretinograms. Exp Eye Res 2021; 206:108556. [PMID: 33794198 DOI: 10.1016/j.exer.2021.108556] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2020] [Revised: 03/05/2021] [Accepted: 03/22/2021] [Indexed: 11/30/2022]
Abstract
PURPOSE The macaque retina is often used as a model for the human retina. However, there are only a handful of direct in vivo comparisons of the retinal physiology in humans and macaques. In the current study, ERG responses to luminance, L-cone isolating and M-cone isolating stimuli with sinusoidal, sawtooth and square wave temporal profiles were measured. The results were compared with those obtained from human observers. METHODS The responses from five anesthetized adult macaques were measured. Full field stimuli were created. L- and M-cone isolating stimuli were based on the triple silent substitution technique. Sinusoidal stimuli had temporal frequencies between 4 and 56 Hz in 4 Hz steps. Sawtooth stimuli with rapid-on ramp-off and with rapid-off ramp-on excitation profiles had a frequency of 4 Hz. Square stimuli were presented at 2 Hz. RESULTS Macaque and human ERGs in response to L- and M-cone isolating stimuli reflect L/M opponency and luminance activity. In responses to sine waves, cone opponency dominates at low temporal frequencies (4-12 Hz); luminance dominates at high temporal frequencies. The responses to sawtooth and square wave stimuli reflect a mixture of chromatic and luminance activity. L:M response ratios vary between individuals both in macaques and humans. Macaques show more complex responses, including greater second harmonic contributions than those in humans. CONCLUSIONS Macaque and human ERGs share basic underlying mechanisms reflecting L/M opponency and luminance activity. There may be quantitative differences possibly reflecting differences in contributions of inner retinal mechanisms to the ERGs.
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Affiliation(s)
- Jan Kremers
- Section for Retinal Physiology, University Hospital Erlangen, 91054, Erlangen, Germany.
| | - Avinash J Aher
- Section for Retinal Physiology, University Hospital Erlangen, 91054, Erlangen, Germany
| | - Neil R A Parry
- Vision Science Centre, Manchester Royal Eye Hospital, Central Manchester University Hospitals NHS Foundation Trust, Manchester Academic Health Science Centre, Manchester, UK; Faculty of Biology, Medicine and Health, University of Manchester, UK
| | - Nimesh B Patel
- Department of Vision Sciences, College of Optometry, University of Houston, Houston, TX, USA
| | - Laura J Frishman
- Department of Vision Sciences, College of Optometry, University of Houston, Houston, TX, USA
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12
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Huchzermeyer C, Fars J, Stöhr H, Kremers J. [New techniques for quantification of color vision in disorders of cone function : Cambridge color test and photoreceptor-specific temporal contrast sensitivity in patients with heterozygous RP1L1 and RPGR mutations]. Ophthalmologe 2021; 118:144-153. [PMID: 32458067 PMCID: PMC7862517 DOI: 10.1007/s00347-020-01119-0] [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] [Indexed: 11/07/2022]
Abstract
Hintergrund Erbliche Netzhauterkrankungen mit Zapfendysfunktion können trotz relativ unauffälligem Fundusbefund ausgeprägte Visusminderung und deutliche Farbsinnstörungen aufweisen. Beispiele hierfür sind die autosomal-dominante okkulte Makuladystrophie (RP1L1-Gen) und die X‑chromosomale Retinitis pigmentosa (RPGR-Gen) – Letztere auch bei heterozygoten, weiblichen Merkmalsträgerinnen (Konduktorinnen). Neue Untersuchungsmethoden erlauben es, das Ausmaß der Farbsinnstörung zu quantifizieren. Methoden Nach einer umfangreichen klinischen Untersuchung führten wir Messungen zur Quantifizierung der Farbdiskriminierung und der Zapfenfunktion durch. Beim Cambridge-Color-Test werden pseudoisochromatische Tafeln mit Landolt-C-Figuren computergesteuert generiert, um die Farbunterscheidungsschwelle entlang mehrerer Achsen im Farbraum zu bestimmen. Bei der Untersuchung der photorezeptorspezifischen zeitlichen Kontrastempfindlichkeit kann durch geschickte zyklische Veränderung der spektralen Zusammensetzung eines Lichtreizes die Kontrastwahrnehmungsschwelle isolierter Photorezeptortypen bestimmt werden. Die molekulargenetische Diagnostik erfolgte mithilfe von Next Generation Sequencing(NGS)-basierter gezielter Genpanelanalyse sowie Sanger-Sequenzierung. Ergebnisse Bei 2 Patienten mit okkulter Makuladystrophie und 2 heterozygoten Trägerinnen von RPGR-Mutationen zeigten sich eine deutlich verminderte Fähigkeit zur Farbdiskriminierung und eine verminderte photorezeptorspezifische zeitliche Kontrastempfindlichkeit. Diskussion Bei erblichen Netzhauterkrankungen sind neben den modernen bildgebenden Verfahren (okuläre Kohärenztomographie [OCT] und Fundusautofluoreszenz) auch die sinnesphysiologischen Untersuchungen diagnostisch wegweisend – der Nachweis von Farbsinnstörungen spielt hierbei eine wichtige Rolle. Neuere Methoden erlauben eine Quantifizierung der Farbsinnstörungen und könnten in klinischen Studien zu gen- und stammzellbasierter Therapie zur Messung des Therapieerfolges dienen.
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Affiliation(s)
- Cord Huchzermeyer
- Augenklinik mit Poliklinik, Universitätsklinik Erlangen, Erlangen, Deutschland.
| | - Julien Fars
- Augenklinik mit Poliklinik, Universitätsklinik Erlangen, Erlangen, Deutschland
| | - Heidi Stöhr
- Institut für Humangenetik, Universität Regensburg, Regensburg, Deutschland
| | - Jan Kremers
- Augenklinik mit Poliklinik, Universitätsklinik Erlangen, Erlangen, Deutschland
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13
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Relationship between stimulus size and different components of the electroretinogram (ERG) elicited by flashed stimuli. Doc Ophthalmol 2020; 142:213-231. [PMID: 33063285 DOI: 10.1007/s10633-020-09797-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2020] [Accepted: 10/01/2020] [Indexed: 10/23/2022]
Abstract
PURPOSE To investigate how light stimulus conditions of varying spatial sizes affect components of the flash and long-flash electroretinogram (ERG) in normal subjects. METHOD Three stimulus conditions were generated by a Ganzfeld stimulator: a white flash on white background (WoW), a red flash on a blue background (RoB) and an L+M-cone isolating on-off (long flash) stimulus (Cone Iso). ERGs were recorded from six subjects (5 M, 1 F) with DTL electrodes to full-field (FF), 70°, 60°, 50°, 40°, 30° and 20° diameter circular stimuli. Amplitudes and peak times for a-, b-, d- and i-wave, and PhNR were examined. PhNR amplitudes were estimated in two different ways: from baseline (fB) and from preceding b-wave peak (fP). RESULTS With decreasing stimulus size, amplitudes for all ERG waveform components attenuated and peak times increased, although the effect varied across different components. An exponential fit described the relationship between amplitudes and size of stimulated retinal area well for most components and conditions (R2= 0.75-0.99), except for PhNR(fB) (R2= - 0.16-0.88). For peak times, an exponential decay function also fitted the data well (R2= 0.81-0.97), except in a few cases where the exponential constant was too small and a linear regression function was applied instead (a-wave Cone Iso, b- and i-wave WoW). The exponential constants for RoB amplitudes (b-wave, PhNR(fB), PhNR(fP)) were larger compared to their counterparts under WoW (p < 0.05), while there was no difference between the constants for a-wave amplitudes and peak times and for PhNR peak times. The exponential constants of amplitudes vs. area under WoW and Cone Iso were remarkably similar, while under RoB PhNR(fB) showed larger constants compared to either a- or b-wave (p < 0.05). CONCLUSION ERG components change in a predictable way with stimulus size and spectral characteristics of the stimulus under these conditions. This predictability could allow a modified version of these sets of stimuli to be tested for clinical applicability.
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14
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Developments in non-invasive visual electrophysiology. Vision Res 2020; 174:50-56. [PMID: 32540518 DOI: 10.1016/j.visres.2020.05.003] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2020] [Revised: 05/12/2020] [Accepted: 05/13/2020] [Indexed: 01/23/2023]
Abstract
To study the physiology of the primate visual system, non-invasive electrophysiological techniques are of major importance. Two main techniques are available: the electroretinogram (ERG), a mass potential originating in the retina, and the visual evoked potential (VEP), which reflects activity in the primary visual cortex. In this overview, the history and the state of the art of these techniques are briefly presented as an introduction to the special issue "New Developments in non-invasive visual electrophysiology". The overview and the special issue can be used as the starting point for exciting new developments in the electrophysiology of primate and mammalian vision.
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15
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Kamar S, Howlett MHC, Kamermans M. Silent-substitution stimuli silence the light responses of cones but not their output. J Vis 2020; 19:14. [PMID: 31100130 DOI: 10.1167/19.5.14] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Chromatic vision starts at the retinal photoreceptors but photoreceptors are themselves color-blind, responding only to their effective quantal catch and not to the wavelength of the caught photon per se. Mitchell and Rushton (1971) termed this phenomenon the univariance concept, and it is widely used in designing silent-substitution stimuli to test the unique contributions of specific photoreceptor types to vision. In principle, this procedure controls the effective quantal catch of photoreceptors well and hence works at the phototransduction-cascade level of vision. However, both phototransduction-cascade modulation and the horizontal-cell-mediated feedback signal determine photoreceptor output. Horizontal cells receive input from, and send feedback to, more than one photoreceptor type. This should mean that silent-substitution stimuli do not silence horizontal-cell activity, and that this activity is fed back to the silenced cones. This in turn will modulate the output of silenced cones, making them not so silent after all. Here we tested this idea and found that silent-substitution stimuli can adequately silence cone-membrane potential responses. However, these cones still received a feedback signal from horizontal cells, which modulates their Ca2+ current and thus their output. These feedback-induced Ca2+-current changes are substantial, as they are of the same order of magnitude as Ca2+-current changes that occur when cones are directly stimulated with light. This illustrates that great care needs to be taken in interpreting results obtained with silent-substitution stimuli. In the discussion, we outline two basic types of interpretation pitfalls that can occur.
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Affiliation(s)
- Sizar Kamar
- Netherlands Institute for Neuroscience, Amsterdam, the Netherlands
| | | | - Maarten Kamermans
- Netherlands Institute for Neuroscience, Amsterdam, the Netherlands.,Academic Medical Center, University of Amsterdam, Amsterdam, the Netherlands
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16
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Mowat FM, Wise E, Oh A, Foster ML, Kremers J. In vivo electroretinographic differentiation of rod, short-wavelength and long/medium-wavelength cone responses in dogs using silent substitution stimuli. Exp Eye Res 2019; 185:107673. [PMID: 31128103 DOI: 10.1016/j.exer.2019.05.013] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2019] [Revised: 05/20/2019] [Accepted: 05/21/2019] [Indexed: 02/05/2023]
Abstract
The canine species has dichromatic color vision comprising short-wavelength (S-) and long/medium (L/M-) wavelength-sensitive cones with peak spectral sensitivity of 429-435 nm and 555 nm respectively. Although differentiation of rod- and cone-mediated responses by electroretinogram (ERG) in dogs is commonly performed, and standards have been developed based on standards for human observers, methods to differentiate S- and L/M-cone responses in dogs have not been described. We developed flicker protocols derived from previously published rod and cone spectral sensitivities. We used a double silent substitution paradigm to isolate responses from each of the 3 photoreceptor subclasses. ERG responses were measured to sine-wave modulation of photoreceptor excitation at different temporal frequencies (between 4 and 56 Hz) and mean luminance (between 3.25 and 130 cd/m2) on 6 different normal dogs (3 adult female, and 3 adult male beagles) and one female beagle dog with suspected hereditary congenital stationary night blindness (CSNB). Peak rod driven response amplitudes were achieved with low frequency (4 Hz, maximal range 4-12 Hz) and low mean luminance (3.25 cd/m2). In contrast, peak L/M-cone driven response amplitudes were achieved with high frequency (32 Hz, maximal range 28-44 Hz) and high mean luminance (32.5-130 cd/m2). Maximal S-cone driven responses were obtained with low frequency stimuli (4 Hz, maximal range 4-12 Hz) and 32.5-130 cd/m2 mean luminance. The dog with CSNB had reduced rod- and S-cone-driven responses, but normal/supernormal L/M cone-driven responses. We have developed methods to differentiate rod, S- and L/M-cone function in dogs using silent substitution methods. The influence of temporal frequency and mean luminance on the ERGs originating in each photoreceptor type can now be studied independently. Dogs and humans have similar L/M cone responses, whereas mice have significantly different L/M responses. This work will facilitate a greater understanding of canine retinal electrophysiology and will complement the study of canine models of human hereditary photoreceptor disorders.
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Affiliation(s)
- Freya M Mowat
- Department of Clinical Sciences, College of Veterinary Medicine, North Carolina State University, Raleigh, NC, USA.
| | - Elisabeth Wise
- Department of Clinical Sciences, College of Veterinary Medicine, North Carolina State University, Raleigh, NC, USA
| | - Annie Oh
- Department of Clinical Sciences, College of Veterinary Medicine, North Carolina State University, Raleigh, NC, USA
| | - Melanie L Foster
- Department of Clinical Sciences, College of Veterinary Medicine, North Carolina State University, Raleigh, NC, USA
| | - Jan Kremers
- University Hospital Erlangen, Erlangen, Germany
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17
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Joachimsthaler A, Kremers J. Mouse Cones Adapt Fast, Rods Slowly In Vivo. Invest Ophthalmol Vis Sci 2019; 60:2152-2164. [PMID: 31100107 DOI: 10.1167/iovs.18-26356] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Purpose To study rod- and cone-driven adaptation dynamics separately, we used the silent substitution technique to selectively stimulate rods or cones in the Opn1lwLIAIS (LIAIS) mouse, in which the native M-cone pigment is replaced by a human L-cone pigment (L*). Methods ERG recordings were performed on anesthetized LIAIS mice. ERG stimuli were sinusoidally modulated. After 10 minutes of adaptation to 0.4 candela per square meter (cd/m2) ERGs were measured, followed by 11-minute adaptation to 8.8 cd/m2 background and recordings directly after the luminance increase and every second minute. Finally, during adaptation to 0.4 cd/m2 for 32 minutes, ERG responses were recorded directly after the change in background and every second minute. This protocol was repeated with rod-isolating stimuli (8 Hz; 75% rod contrast), L*-cone-isolating stimuli (12 Hz; 55% cone contrast) and white light (8 Hz and 12 Hz; 100% Michelson contrast). Results At 8.8 cd/m2, responses directly displayed photopic response properties without further changes in either cone or white light responses. Rod-driven responses were very small. After the return to 0.4 cd/m2, both rod-driven and white light responses increased over a time course of about 30 minutes. Cone-driven responses were very small. Response phases changed directly after a change in background without further alterations. Conclusions Rod- and cone-driven signal pathways display strongly different adaptation characteristics: adaptation of cone-driven responses to photopic conditions is very fast, whereas rod-driven responses change with a time course up to 30 minutes during scotopic conditions. Luminance responses are cone-driven at 8.8 cd/m2 and rod-driven at 0.4 cd/m2.
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Affiliation(s)
- Anneka Joachimsthaler
- Department of Ophthalmology, University Hospital Erlangen, Erlangen, Germany.,Animal Physiology, Department of Biology, FAU Erlangen-Nürnberg, Erlangen, Germany
| | - Jan Kremers
- Department of Ophthalmology, University Hospital Erlangen, Erlangen, Germany.,Department of Anatomy II, FAU Erlangen-Nürnberg, Erlangen, Germany.,School of Optometry and Vision Science, University of Bradford, Bradford, United Kingdom
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18
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Aher AJ, Jacob MM, Kremers J. High-frequency characteristics of L- and M-cone driven electroretinograms. Vision Res 2019; 159:35-41. [PMID: 30926305 DOI: 10.1016/j.visres.2019.03.010] [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: 10/16/2018] [Revised: 03/14/2019] [Accepted: 03/25/2019] [Indexed: 10/27/2022]
Abstract
Electroretinograms (ERGs) elicited by high temporal frequency (26-95 Hz) L- and M-cone isolating sine-wave stimuli were investigated in human observers for full-field (FF) and different spatially restricted stimulus sizes (70°, 50°, 30°, and 10° diameter). Responses to L- and M-cone isolating FF stimuli were maximal around 48 Hz and decreased gradually with increasing temporal frequency up to 95 Hz. The response maximum was shifted to about 30-32 Hz for both L- and M-cone driven responses obtained with spatially restricted stimuli. The M-cone driven responses could only be measured up to 54 Hz with 70° stimuli. The response amplitudes for L- and M-cones and L-/M-cone amplitude ratios decreased with decreasing stimulus size. The ERG response phases to L- and M-cone isolating stimuli decreased with increasing temporal frequency and were about -160° apart for all stimulus sizes up to 34 Hz. Further increase in the temporal frequency displayed a positive correlation between stimulus size and L-M phase difference. The ERG data indicate that the responses evoked by high temporal frequency cone isolating stimuli reflect two mechanisms, one that is more centrally located and displays a maximum at about 30-32 Hz and a peripheral mechanism that is sensitive to higher temporal modulations. We propose that the peripheral mechanism (FF ERGs) reflects magnocellular activity, whereas the central mechanism (ERGs with spatially restricted stimuli) is based on a parvocellular activity up to about 30 Hz.
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Affiliation(s)
- Avinash J Aher
- Department of Ophthalmology, University Hospital Erlangen, Schwabachanlage 6, Erlangen 91054, Germany
| | - Mellina M Jacob
- Department of Ophthalmology, University Hospital Erlangen, Schwabachanlage 6, Erlangen 91054, Germany; Laboratory of Tropical Neurology, Institute of Biological Sciences, UFPA, Augusto Correa St., Number 01, Belém CEP 66075-110, Brazil
| | - Jan Kremers
- Department of Ophthalmology, University Hospital Erlangen, Schwabachanlage 6, Erlangen 91054, Germany; School of Optometry and Vision Science, University of Bradford, Richmond Rd., Bradford, West Yorkshire BD7 1DP, United Kingdom.
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19
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Barboni MTS, Hauzman E, Nagy BV, Martins CMG, Aher AJ, Tsai TI, Bonci DMO, Ventura DF, Kremers J. Electrodiagnosis of dichromacy. Vision Res 2019; 158:135-145. [PMID: 30844384 DOI: 10.1016/j.visres.2019.02.011] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2018] [Revised: 02/13/2019] [Accepted: 02/17/2019] [Indexed: 11/26/2022]
Abstract
Retinal and cortical signals initiated by a single cone type can be recorded using the spectral compensation (or silent substitution) paradigm. Moreover, responses to instantaneous excitation increments combined with gradual excitation decreases are dominated by the response to the excitation increment. Similarly, the response to a sudden excitation decrement dominates the overall response when combined with a gradual excitation increase. Here ERGs and VEPs were recorded from 34 volunteers [25.9 ± 10.4 years old (mean ± 1 SD); 25 males, 9 females] to sawtooth flicker (4 Hz) stimuli that elicited L- or M-cone responses using triple silent substitution. The mean luminance (284 cd/m2) and the mean chromaticity (x = 0.5686, y = 0.3716; CIE 1931 color space) remained constant and thus the state of adaptation was the same in all conditions. Color discrimination thresholds along protan, deutan, and tritan axes were obtained from all participants. Dichromatic subjects were genetically characterized by molecular analysis of their opsin genes. ERG responses to L-cone stimuli were absent in protanopes whereas ERG responses to M-cone stimuli were strongly reduced in deuteranopes. Dichromats showed generally reduced VEP amplitudes. Responses to cone-specific stimuli obtained with standard electrophysiological methods may give the same classification as that obtained with the Cambridge Colour Test and in some cases with the genetic analysis of the L- and M-opsin genes. Therefore, cone-specific ERGs and VEPs may be reliable methods to detect cone dysfunction. The present data confirm and emphasize the potential use of cone-specific stimulation, combined with standard visual electrodiagnostic protocols.
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Affiliation(s)
- Mirella Telles Salgueiro Barboni
- Department of Experimental Psychology, University of Sao Paulo, Brazil; Department of Ophthalmology, Semmelweis University, Budapest, Hungary.
| | - Einat Hauzman
- Department of Experimental Psychology, University of Sao Paulo, Brazil; Instituto Israelita de Ensino e Pesquisa Albert Einstein, Sao Paulo, Brazil
| | - Balázs Vince Nagy
- Department of Experimental Psychology, University of Sao Paulo, Brazil; Department of Mechatronics, Optics and Engineering Informatics, Budapest University of Technology and Economics, Budapest, Hungary
| | | | - Avinash J Aher
- Department of Ophthalmology, University Hospital, Erlangen, Germany
| | - Tina I Tsai
- Department of Ophthalmology, University Hospital, Erlangen, Germany
| | - Daniela Maria Oliveria Bonci
- Department of Experimental Psychology, University of Sao Paulo, Brazil; Instituto Israelita de Ensino e Pesquisa Albert Einstein, Sao Paulo, Brazil
| | - Dora Fix Ventura
- Department of Experimental Psychology, University of Sao Paulo, Brazil; Instituto Israelita de Ensino e Pesquisa Albert Einstein, Sao Paulo, Brazil
| | - Jan Kremers
- Department of Ophthalmology, University Hospital, Erlangen, Germany; Department of Biology, Animal Physiology, FAU Erlangen-Nürnberg, Erlangen, Germany
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20
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Brasil A, Tsai TI, da Silva Souza G, Herculano AM, Ventura DF, de Lima Silveira LC, Kremers J. Pathway-specific light adaptation in human electroretinograms. J Vis 2019; 19:12. [PMID: 30916727 DOI: 10.1167/19.3.12] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
The cellular origins of slow ERG changes during light adaptation following a dark-adapted state are still unclear. To study light adaptation, six healthy, normal trichromats were dark-adapted for 30 min prior to full-field ERG recordings to sinusoidal stimuli that isolate responses of the L- or M-cones or that stimulate luminance and chromatic mechanisms at 12 or 36 Hz. Recordings were performed for 16 min with 2-min intervals after onset of a constant background. Generally, the responses were sine-wave-like, and the first harmonic (fundamental) component dominated the Fourier spectrum except for the 12-Hz luminance stimulus in which two components, a sine-wave-like component and a transient component, determined the response profiles, leading to large second harmonic components. The amplitude of the first harmonic component (F) increased as a function of the light-adaptation time except for the 12-Hz luminance stimulus at which the F component decreased as a function of the light-adaptation period. The phase of the first harmonic component changed only slightly (less than 30°) during the light-adaptation period for all stimuli conditions. The L/M ratio in luminance reflecting ERGs decreased with increasing adaptation time. Our present data suggest that the light-adaptation process mainly reflects changes in the luminance pathway. The responses to 12-Hz luminance stimuli are determined by two different luminance driven pathways with different adaptation characteristics.
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Affiliation(s)
- Alódia Brasil
- Biological Sciences Institute, Federal University of Para, Belém, Brazil.,Department of Ophthalmology, University Hospital Erlangen, Erlangen, Germany
| | - Tina I Tsai
- Department of Ophthalmology, University Hospital Erlangen, Erlangen, Germany
| | - Givago da Silva Souza
- Biological Sciences Institute, Federal University of Para, Belém, Brazil.,Tropical Medicine Nucleus, Federal University of Para, Belém, Brazil
| | | | - Dora Fix Ventura
- Institute of Psychology, University of São Paulo, São Paulo, Brazil
| | - Luiz Carlos de Lima Silveira
- Biological Sciences Institute, Federal University of Para, Belém, Brazil.,Tropical Medicine Nucleus, Federal University of Para, Belém, Brazil.,Ceuma University, Sao Luis, Brazil
| | - Jan Kremers
- Department of Ophthalmology, University Hospital Erlangen, Erlangen, Germany
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21
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Huchzermeyer C, Martins CMG, Nagy B, Barboni MTS, Ventura DF, Costa MF, Kremers J. Photoreceptor-specific light adaptation of critical flicker frequency in trichromat and dichromat observers. JOURNAL OF THE OPTICAL SOCIETY OF AMERICA. A, OPTICS, IMAGE SCIENCE, AND VISION 2018; 35:B106-B113. [PMID: 29603928 DOI: 10.1364/josaa.35.00b106] [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: 01/12/2018] [Indexed: 06/08/2023]
Abstract
The silent substitution paradigm offers possibilities to investigate and compare the temporal properties of mechanisms driven by single photoreceptor types, including the critical flicker frequency (CFF), in which the state of adaptation can be kept as invariant. We have (1) measured CFFs using triple silent substitutions to isolate L-, M-, and S-cone as well as rod-driven pathways under identical mean luminances and chromaticities; (2) repeated the CFF measurements at different mean luminances in order to validate the Ferry-Porter law (stating that the relationship between CFF and the log retinal illuminance-log I-is linear); and (3) compared these CFF versus log I functions for L-, M-, S-cone-, and rod-isolating stimuli for five trichromats and four X-linked dichromats (two protanopes, two deuteranopes). We show that the effects of luminance on the CFFs with silent substitution are comparable to those measured previously with chromatic stimuli. We found that M-cone-driven CFFs are smaller in trichromats than in protanopes. Furthermore, the slopes of the M-cone-driven CFF versus log I functions are smaller in trichromats. Possibly, the lacking L-cones are replaced by M-cones in these two protanopes and the CFF depends on cone density. Furthermore, we found that in trichromats, the slopes of the CFF-log I functions are smaller for M-cone- than for L-cone-isolating stimuli. This contradicts the current interpretation of the CFF-log I functions for chromatic stimuli, which states that CFF is mediated by the most strongly modulated photoreceptor type. Thus, the larger slopes that were previously found with medium-wavelength chromatic stimuli compared with long-wavelength chromatic stimuli seem to be the result of an addition of signals from different photoreceptors and do not necessarily result from M-cones being inherently faster.
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Abstract
Electroretinography is a crucial assay for studying the function and the functional integrity of the retina. The mouse is an important animal model for studying the retinal neurons and circuitries. In addition, it is often used as animal model for human retinal disorders. Therefore, a good understanding of the procedures in animal handling, of the methods for data analysis and of the requirements for stimulators and for the data acquisition equipment is of importance. Here, the currently most common methods and materials for in vivo electroretinography in the mouse are discussed.
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Affiliation(s)
- Jan Kremers
- Department of Ophthalmology, University Hospital Erlangen, Erlangen, Germany.
| | - Naoyuki Tanimoto
- Department of Ophthalmology, University Hospital Schleswig-Holstein, Kiel, Germany
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23
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Aher AJ, McKeefry DJ, Parry NRA, Maguire J, Murray IJ, Tsai TI, Huchzermeyer C, Kremers J. Rod- versus cone-driven ERGs at different stimulus sizes in normal subjects and retinitis pigmentosa patients. Doc Ophthalmol 2017; 136:27-43. [PMID: 29134295 DOI: 10.1007/s10633-017-9619-5] [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] [Received: 07/19/2017] [Accepted: 11/02/2017] [Indexed: 10/18/2022]
Abstract
PURPOSE To study how rod- and cone-driven responses depend on stimulus size in normal subjects and patients with retinitis pigmentosa (RP), and to show that comparisons between responses to full-field (FF) and smaller stimuli can be useful in diagnosing and monitoring disorders of the peripheral retina without the need for lengthy dark adaptation periods. METHOD The triple silent substitution technique was used to isolate L-cone-, M-cone- and rod-driven ERGs with 19, 18 and 33% photoreceptor contrasts, respectively, under identical mean luminance conditions. Experiments were conducted on five normal subjects and three RP patients. ERGs on control subjects were recorded at nine different temporal frequencies (between 2 and 60 Hz) for five different stimulus sizes: FF, 70°, 60°, 50° and 40° diameter circular stimuli. Experiments on RP patients involved rod- and L-cone-driven ERG measurements with FF and 40° stimuli at 8 and 48 Hz. Response amplitudes were defined as those of the first harmonic component after Fourier analysis. RESULTS In normal subjects, rod-driven responses displayed a fundamentally different behavior than cone-driven responses, particularly at low temporal frequencies. At low and intermediate temporal frequencies (≤ 12 Hz), rod-driven signals increased by a factor of about four when measured with smaller stimuli. In contrast, L- and M-cone-driven responses in this frequency region did not change substantially with stimulus size. At high temporal frequencies (≥ 24 Hz), both rod- and cone-driven response amplitudes decreased with decreasing stimulus size. Signals obtained from rod-isolating stimuli under these conditions are likely artefactual. Interestingly, in RP patients, both rod-driven and L-cone-driven ERGs were similar using 40° and FF stimuli. CONCLUSION The increased responses with smaller stimuli in normal subjects to rod-isolating stimuli indicate that a fundamentally different mechanism drives the ERGs in comparison with the cone-driven responses. We propose that the increased responses are caused by stray light stimulating the peripheral retina, thereby allowing peripheral rod-driven function to be studied using the triple silent substitution technique at photopic luminances. The method is effective in studying impaired peripheral rod- and cone- function in RP patients.
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Affiliation(s)
- Avinash J Aher
- Department of Ophthalmology, University Hospital Erlangen, Erlangen, Germany
| | - Declan J McKeefry
- School of Optometry and Vision Science, University of Bradford, Bradford, UK
| | - Neil R A Parry
- School of Optometry and Vision Science, University of Bradford, Bradford, UK.,Center for Hearing and Vision Research, Institute of Human Development, University of Manchester, Manchester, UK.,Vision Science Center, Manchester Royal Eye Hospital, Central Manchester University Hospitals NHS Foundation Trust, Manchester Academic Health Science Center, Manchester, UK
| | - John Maguire
- School of Optometry and Vision Science, University of Bradford, Bradford, UK
| | - I J Murray
- Faculty of Life Sciences, University of Manchester, Manchester, UK
| | - Tina I Tsai
- Department of Ophthalmology, University Hospital Erlangen, Erlangen, Germany
| | - Cord Huchzermeyer
- Department of Ophthalmology, University Hospital Erlangen, Erlangen, Germany
| | - Jan Kremers
- Department of Ophthalmology, University Hospital Erlangen, Erlangen, Germany. .,School of Optometry and Vision Science, University of Bradford, Bradford, UK.
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Maguire J, Parry NRA, Kremers J, Murray IJ, McKeefry D. The morphology of human rod ERGs obtained by silent substitution stimulation. Doc Ophthalmol 2017; 134:11-24. [PMID: 28091887 PMCID: PMC5274650 DOI: 10.1007/s10633-017-9571-4] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2016] [Accepted: 01/05/2017] [Indexed: 11/10/2022]
Abstract
Purpose To record transient ERGs from the light-adapted human retina using silent substitution stimuli which selectively reflect the activity of rod photoreceptors. We aim to describe the morphology of these waveforms and examine how they are affected by the use of less selective stimuli and by retinal pathology. Methods Rod-isolating stimuli with square-wave temporal profiles (250/250 ms onset/offset) were presented using a 4 primary LED ganzfeld stimulator. Experiment 1: ERGs were recorded using a rod-isolating stimulus (63 ph Td, rod contrast, Crod = 0.25) from a group (n = 20) of normal trichromatic observers. Experiment 2: Rod ERGs were recorded from a group (n = 5) using a rod-isolating stimulus (Crod = 0.25) which varied in retinal illuminance from 40 to 10,000 ph Td. Experiment 3: ERGs were elicited using 2 kinds of non-isolating stimuli; (1) broadband and (2) rod-isolating stimuli which contained varying degrees of L- and M-cone excitation. Experiment 4: Rod ERGs were recorded from two patient groups with rod monochromacy (n = 3) and CSNB (type 1; n = 2). Results The rod-isolated ERGs elicited from normal subjects had a waveform with a positive onset component followed by a negative offset. Response amplitude was maximal at retinal illuminances <100 ph Td and was virtually abolished at 400 ph Td. The use of non-selective stimuli altered the ERG waveform eliciting more photopic-like ERG responses. Rod ERGs recorded from rod monochromats had similar features to those recorded from normal trichromats, in contrast to those recorded from participants with CSNB which had an electronegative appearance. Conclusions Our results demonstrate that ERGs elicited by silent substitution stimuli can selectively reflect the operation of rod photoreceptors in the normal, light-adapted human retina.
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Affiliation(s)
- J Maguire
- Bradford School of Optometry and Vision Sciences, University of Bradford, Bradford, W. Yorkshire, BD7 1DP, UK
| | - N R A Parry
- Bradford School of Optometry and Vision Sciences, University of Bradford, Bradford, W. Yorkshire, BD7 1DP, UK.,Vision Science Centre, Manchester Royal Eye Hospital, Central Manchester University Hospitals NHS Foundation Trust, Manchester Academic Health Science Centre, Manchester, UK.,Faculty of Biology, Medicine and Health, University of Manchester, Manchester, UK
| | - J Kremers
- Bradford School of Optometry and Vision Sciences, University of Bradford, Bradford, W. Yorkshire, BD7 1DP, UK.,Department of Ophthalmology, University Hospital Erlangen, Erlangen, Germany
| | - I J Murray
- Faculty of Biology, Medicine and Health, University of Manchester, Manchester, UK
| | - D McKeefry
- Bradford School of Optometry and Vision Sciences, University of Bradford, Bradford, W. Yorkshire, BD7 1DP, UK.
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Kremers J, Bhatt D. Towards an electroretinographic assay for studying colour vision in human observers. Doc Ophthalmol 2016; 133:109-120. [DOI: 10.1007/s10633-016-9561-y] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2016] [Accepted: 09/08/2016] [Indexed: 01/05/2023]
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Maguire J, Parry NRA, Kremers J, Kommanapalli D, Murray IJ, McKeefry DJ. Rod Electroretinograms Elicited by Silent Substitution Stimuli from the Light-Adapted Human Eye. Transl Vis Sci Technol 2016; 5:13. [PMID: 27617180 PMCID: PMC5015991 DOI: 10.1167/tvst.5.4.13] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2016] [Accepted: 06/16/2016] [Indexed: 11/24/2022] Open
Abstract
PURPOSE To demonstrate that silent substitution stimuli can be used to generate electroretinograms (ERGs) that effectively isolate rod photoreceptor function in humans without the need for dark adaptation, and that this approach constitutes a viable alternative to current clinical standard testing protocols. METHODS Rod-isolating and non-isolating sinusoidal flicker stimuli were generated on a 4 primary light-emitting diode (LED) Ganzfeld stimulator to elicit ERGs from participants with normal and compromised rod function who had not undergone dark-adaptation. Responses were subjected to Fourier analysis, and the amplitude and phase of the fundamental were used to examine temporal frequency and retinal illuminance response characteristics. RESULTS Electroretinograms elicited by rod-isolating silent substitution stimuli exhibit low-pass temporal frequency response characteristics with an upper response limit of 30 Hz. Responses are optimal between 5 and 8 Hz and between 10 and 100 photopic trolands (Td). There is a significant correlation between the response amplitudes obtained with the silent substitution method and current standard clinical protocols. Analysis of signal-to-noise ratios reveals significant differences between subjects with normal and compromised rod function. CONCLUSIONS Silent substitution provides an effective method for the isolation of human rod photoreceptor function in subjects with normal as well as compromised rod function when stimuli are used within appropriate parameter ranges. TRANSLATIONAL RELEVANCE This method of generating rod-mediated ERGs can be achieved without time-consuming periods of dark adaptation, provides improved isolation of rod- from cone-based activity, and will lead to the development of faster clinical electrophysiologic testing protocols with improved selectivity.
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Affiliation(s)
- John Maguire
- Bradford School of Optometry and Vision Sciences, Bradford University, UK
| | - Neil R A Parry
- Bradford School of Optometry and Vision Sciences, Bradford University, UK ; Vision Science Centre, Manchester Royal Eye Hospital, Central Manchester University Hospitals NHS Foundation Trust, Manchester Academic Health Science Centre, Manchester, UK ; Centre for Ophthalmology and Vision Sciences, Institute of Human Development, Faculty of Medical and Human Sciences, University of Manchester, UK
| | - Jan Kremers
- Department of Ophthalmology, University Hospital Erlangen, Germany
| | | | - Ian J Murray
- Faculty of Biology, Medicine & Health, University of Manchester, UK
| | - Declan J McKeefry
- Bradford School of Optometry and Vision Sciences, Bradford University, UK
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Tsai TI, Jacob MM, McKeefry D, Murray IJ, Parry NRA, Kremers J. Spatial properties of L- and M-cone driven incremental (On-) and decremental (Off-) electroretinograms: evidence for the involvement of multiple post-receptoral mechanisms. JOURNAL OF THE OPTICAL SOCIETY OF AMERICA. A, OPTICS, IMAGE SCIENCE, AND VISION 2016; 33:A1-A11. [PMID: 26974913 DOI: 10.1364/josaa.33.0000a1] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
An overview of electroretinogram response components to incremental and decremental steps in L- and M-cone excitation was obtained in human observers, while varying the spatial properties of the stimulus. Responses to L- and M-cone stimuli of opposite polarity resembled each other, particularly within the central 35° of the retina. All amplitudes grew as stimulus size increased; however, earlier and later components of the On- and Off-responses showed differing degrees of dependency on stimulus size. Thus, they may reflect different proportions of responses originating in parvocellular (less stimulus size-dependent) and magnocellular (more stimulus size-dependent) streams.
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Zele AJ, Feigl B, Kambhampati PK, Hathibelagal AR, Kremers J. A method for estimating intrinsic noise in electroretinographic (ERG) signals. Doc Ophthalmol 2015; 131:85-94. [PMID: 26286330 DOI: 10.1007/s10633-015-9510-1] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2015] [Accepted: 08/07/2015] [Indexed: 11/26/2022]
Abstract
PURPOSE To develop a signal processing paradigm for extracting ERG responses to temporal sinusoidal modulation with contrasts ranging from below perceptual threshold to suprathreshold contrasts and estimate the magnitude of intrinsic noise in ERG signals at different stimulus contrasts. METHODS Photopic test stimuli were generated using a 4-primary Maxwellian view optical system. The 4-primary lights were sinusoidally temporally modulated in-phase (36 Hz; 2.5-50% Michelson contrast). The stimuli were presented in 1-s epochs separated by a 1-ms blank interval and repeated 160 times (160.160-s duration) during the recording of the continuous flicker ERG from the right eye using DTL fibre electrodes. After artefact rejection, the ERG signal was extracted using Fourier transforms in each of the 1-s epochs where a stimulus was presented. The signal processing allows for computation of the intrinsic noise distribution in addition to the signal-to-noise (SNR) ratio. RESULTS We provide the initial report that the ERG intrinsic noise distribution is independent of stimulus contrast, whereas SNR decreases linearly with decreasing contrast until the noise limit at ~2.5%. The 1-ms blank intervals between epochs de-correlated the ERG signal at the line frequency (50 Hz) and thus increased the SNR of the averaged response. We confirm that response amplitude increases linearly with stimulus contrast. The phase response shows a shallow positive relationship with stimulus contrast. CONCLUSIONS This new technique will enable recording of intrinsic noise in ERG signals above and below perceptual visual threshold and is suitable for measurement of continuous rod and cone ERGs across a range of temporal frequencies, and post-receptoral processing in the primary retinogeniculate pathways at low stimulus contrasts. The intrinsic noise distribution may have application as a biomarker for detecting changes in disease progression or treatment efficacy.
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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, Brisbane, Australia.
| | - Beatrix Feigl
- Medical Retina Laboratory, Institute of Health and Biomedical Innovation, School of Biomedical Sciences, Queensland University of Technology, 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, Brisbane, Australia
| | - Amithavikram R Hathibelagal
- Visual Science Laboratory, Institute of Health and Biomedical Innovation, School of Optometry and Vision Science, Queensland University of Technology, Brisbane, Australia
| | - Jan Kremers
- Laboratory for Retinal Physiology, Department of Ophthalmology, University Hospital Erlangen, Erlangen, Germany.
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The spatial properties of L- and M-cone inputs to electroretinograms that reflect different types of post-receptoral processing. PLoS One 2015; 10:e0121218. [PMID: 25785459 PMCID: PMC4364754 DOI: 10.1371/journal.pone.0121218] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2014] [Accepted: 01/29/2015] [Indexed: 11/22/2022] Open
Abstract
We studied the spatial arrangement of L- and M-cone driven electroretinograms (ERGs) reflecting the activity of magno- and parvocellular pathways. L- and M-cone isolating sine wave stimuli were created with a four primary LED stimulator using triple silent substitution paradigms. Temporal frequencies were 8 and 12 Hz, to reflect cone opponent activity, and 30, 36 and 48 Hz to reflect luminance activity. The responses were measured for full-field stimuli and for different circular and annular stimuli. The ERG data confirm the presence of two different mechanisms at intermediate and high temporal frequencies. The responses measured at high temporal frequencies strongly depended upon spatial stimulus configuration. In the full-field conditions, the L-cone driven responses were substantially larger than the full-field M-cone driven responses and also than the L-cone driven responses with smaller stimuli. The M-cone driven responses at full-field and with 70° diameter stimuli displayed similar amplitudes. The L- and M-cone driven responses measured at 8 and 12 Hz were of similar amplitude and approximately in counter-phase. The amplitudes were constant for most stimulus configurations. The results indicate that, when the ERG reflects luminance activity, it is positively correlated with stimulus size. Beyond 35° retinal eccentricity, the retina mainly contains L-cones. Small stimuli are sufficient to obtain maximal ERGs at low temporal frequencies where the ERGs are also sensitive to cone-opponent processing.
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Kremers J, Pangeni G, Tsaousis KT, McKeefry D, Murray IJ, Parry NRA. Incremental and decremental L- and M-cone driven ERG responses: II. Sawtooth stimulation. JOURNAL OF THE OPTICAL SOCIETY OF AMERICA. A, OPTICS, IMAGE SCIENCE, AND VISION 2014; 31:A170-A178. [PMID: 24695166 DOI: 10.1364/josaa.31.00a170] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
L- and M-cone driven on- and off- ERG responses and their interactions were examined using full field stimuli with sawtooth temporal profiles. The effects of temporal frequency and contrast were studied. ERG recordings were obtained from 21 trichromatic, 1 protanopic, and 1 deuteranopic subjects. ERGs to L-cone increments and decrements resembled those to M-cone decrements and increments, respectively (i.e., of the opposite polarity). Temporal frequency and contrast had little effect on the implicit times. All response components varied linearly with contrast. When stimulated simultaneously, the responsivities of most components were larger for counterphase than for inphase modulation. The retinal processing leading to an ERG response is reversed for L- and M-cone driven responses.
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McKeefry D, Kremers J, Kommanapalli D, Challa NK, Murray IJ, Maguire J, Parry NRA. Incremental and decremental L- and M-cone-driven ERG responses: I. Square-wave pulse stimulation. JOURNAL OF THE OPTICAL SOCIETY OF AMERICA. A, OPTICS, IMAGE SCIENCE, AND VISION 2014; 31:A159-A169. [PMID: 24695165 DOI: 10.1364/josaa.31.00a159] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
Electroretinograms (ERGs) elicited by transient, square-wave L- and M-cone isolating stimuli were recorded from human trichromatic (n=19) and dichromatic (n=4) observers. The stimuli were generated on a four primary LED stimulator and were equated in terms of cone modulation (cone contrast=0.11) and retinal illuminance (12,000 trolands). L- and M-cone isolated ERGs had waveforms similar to those observed for luminance responses. However, M-cone ERGs exhibited a phase reversal in their responses to onset and offset stimuli relative to the L-cone responses. This on-off response reversal was observed in trichromats but not dichromats. Simultaneous counterphase and inphase combinations of L- and M-cone isolating stimuli generated responses that reflected chromatic and luminance processing, respectively. We conclude that L- and M-cone specific ERGs provide a measure of how photoreceptors contribute to postreceptoral mechanisms.
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Kuchenbecker JA, Greenwald SH, Neitz M, Neitz J. Cone-isolating ON-OFF electroretinogram for studying chromatic pathways in the retina. JOURNAL OF THE OPTICAL SOCIETY OF AMERICA. A, OPTICS, IMAGE SCIENCE, AND VISION 2014; 31:A208-A213. [PMID: 24695171 PMCID: PMC4143118 DOI: 10.1364/josaa.31.00a208] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
The electroretinogram (ERG) provides information about outer retina function in both clinical and research applications. ERG components elicited by light increments and decrements can be separated using a long-flash paradigm in which periods of light ON and OFF are alternated. Here, the ON-OFF ERG is combined with a silent substitution technique to elicit responses from individual cone photoreceptor classes by modulating the intensities of three color lights between the two periods. The results focus on the short wavelength (S) cone pathways since they are vulnerable to disease and because there are many unanswered questions about S-cone ON and OFF circuitry.
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Kommanapalli D, Murray IJ, Kremers J, Parry NRA, McKeefry DJ. Temporal characteristics of L- and M-cone isolating steady-state electroretinograms. JOURNAL OF THE OPTICAL SOCIETY OF AMERICA. A, OPTICS, IMAGE SCIENCE, AND VISION 2014; 31:A113-A120. [PMID: 24695158 DOI: 10.1364/josaa.31.00a113] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
Cone isolating stimuli were used to assess the temporal frequency response characteristics of L- and M-cone electroretinograms (ERGs) in nine trichromatic and four dichromatic human observers. The stimuli comprised sinusoidal temporal modulations varying from 5 to 100 Hz. ERGs were recorded using corneal fiber electrodes and subjected to fast Fourier transform analysis. At low temporal frequencies (<10 Hz) the L- and M-cone ERGs had similar amplitude and exhibited minimal differences in apparent latency. At higher flicker rates (>20 Hz) L-cone ERGs had greater amplitudes and shorter apparent latencies than the M-cone responses. These differences between the L- and M-cone ERGs are consistent with their mediation by chromatic and luminance postreceptoral processing pathways at low and high temporal frequencies, respectively.
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Parry NRA, Murray IJ, Panorgias A, McKeefry DJ, Lee BB, Kremers J. Simultaneous chromatic and luminance human electroretinogram responses. J Physiol 2012; 590:3141-54. [PMID: 22586211 DOI: 10.1113/jphysiol.2011.226951] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Abstract
The parallel processing of information forms an important organisational principle of the primate visual system. Here we describe experiments which use a novel chromatic–achromatic temporal compound stimulus to simultaneously identify colour and luminance specific signals in the human electroretinogram (ERG). Luminance and chromatic components are separated in the stimulus; the luminance modulation has twice the temporal frequency of the chromatic modulation. ERGs were recorded from four trichromatic and two dichromatic subjects (1 deuteranope and 1 protanope). At isoluminance, the fundamental (first harmonic) response was elicited by the chromatic component in the stimulus. The trichromatic ERGs possessed low-pass temporal tuning characteristics, reflecting the activity of parvocellular post-receptoral mechanisms. There was very little first harmonic response in the dichromats' ERGs. The second harmonic response was elicited by the luminance modulation in the compound stimulus and showed, in all subjects, band-pass temporal tuning characteristic of magnocellular activity. Thus it is possible to concurrently elicit ERG responses from the human retina which reflect processing in both chromatic and luminance pathways. As well as providing a clear demonstration of the parallel nature of chromatic and luminance processing in the human retina, the differences that exist between ERGs from trichromatic and dichromatic subjects point to the existence of interactions between afferent post-receptoral pathways that are in operation from the earliest stages of visual processing.
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Affiliation(s)
- Neil R A Parry
- University of Manchester, Academic Health Science Center, Faculty of Life Sciences, and Vision Science Centre, Manchester Royal Eye Hospital, Oxford Road, Manchester M13 9WH, UK.
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Kremers J, Pangeni G. Electroretinographic responses to photoreceptor specific sine wave modulation. JOURNAL OF THE OPTICAL SOCIETY OF AMERICA. A, OPTICS, IMAGE SCIENCE, AND VISION 2012; 29:A306-A313. [PMID: 22330394 DOI: 10.1364/josaa.29.00a306] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
Electroretinographic responses to cone and rod isolating stimuli and to simultaneous L- and M-cone modulation were measured at different temporal frequencies between 2 and 60 Hz and at two mean luminances using a four primary stimulator. The responses driven by each photoreceptor type had distinct characteristics. The responses to stimuli containing L- and/or M-cone stimulation indicated the presence of two underlying mechanisms that were active in distinct frequency regions. Between 2 and 12 Hz, the responses displayed properties that were reminiscent of the L-M-cone opponent system. At higher temporal frequencies, the electroretinograms were more determined by the luminance content in the stimuli.
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Affiliation(s)
- Jan Kremers
- Department of Ophthalmology, University of Erlangen-Nürnberg, Schwabachanlage 6, 91054 Erlangen, Germany. jan.kremers@uk‑erlangen.de
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Abstract
The electroretinographic response to L- and M-cone isolating stimuli was measured at different luminance levels to study the effect of retinal illuminance on amplitude and phase, and how this may influence estimates of L:M ratios in the retina. It was found that the amplitude of L- and M-cone driven responses increases differently with increasing retinal illuminance: L-cone responses increase more quickly than those of M-cones. The L:M ratio does not change strongly with retinal illuminance. The phase of both L- and M-cone driven responses advances with increasing retinal illuminance. There is considerable interindividual variability in the phase difference between the two, but generally M-cone driven responses are phase advanced.
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Challa NK, McKeefry D, Parry NRA, Kremers J, Murray IJ, Panorgias A. L- and M-cone input to 12Hz and 30Hz flicker ERGs across the human retina. Ophthalmic Physiol Opt 2010; 30:503-10. [PMID: 20883333 DOI: 10.1111/j.1475-1313.2010.00758.x] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
We recorded L- and M-cone isolating ERGs from human subjects using a silent substitution technique at temporal rates of 12 and 30 Hz. These frequencies isolate the activity of cone-opponent and non-opponent post-receptoral mechanisms, respectively. ERGs were obtained using a sequence of stimuli with different spatial configurations comprising; (1) circular stimuli of different sizes which increased in 10° steps up to 70°diameter, or (2) annular stimuli with a 70° outer diameter but with different sized central ablations from 10° up to 60°. L- and M-cone isolating ERGs were obtained from five colour normal subjects using a DTL fibre electrode. Fourier analysis of the ERGs was performed and we measured the amplitude of the first harmonic of the response. For 12 Hz ERGs the L:M cone response amplitude ratio (L:M(ERG)) was close to unity and remained stable irrespective of the spatial configuration of the stimulus. The maintenance of this balanced ratio points to the existence of cone selective input across the human retina for the L-M cone opponent mechanism. For 30 Hz the L:M(ERG) ratio was greater than unity but varied depending upon which region of the retina was being stimulated. This variation we consider to be a consequence of the global response properties of M-cone ERGs rather than representing a real variation in L:M cone ratios across the retina.
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Affiliation(s)
- N K Challa
- Bradford School of Optometry and Vision Sciences, University of Bradford, UK
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Tekavčič Pompe M, Stirn Kranjc B, Brecelj J. Chromatic VEP in children with congenital colour vision deficiency. Ophthalmic Physiol Opt 2010; 30:693-8. [DOI: 10.1111/j.1475-1313.2010.00739.x] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Abstract
Omitting a stimulus from a train of repetitive stimuli, by either interrupting or terminating the train, can elicit an electrophysiological response that occurs at the time appropriate for the omitted stimulus. This study investigated whether such an omitted stimulus response (OSR) is present in the flicker electroretinogram (ERG) of the human cone system. ERGs were recorded from 11 visually normal subjects in response to full-field sinusoidal flicker trains presented against a rod-desensitizing adapting field at frequencies ranging from 12.5 to 100 Hz. Recordings were synchronized with the onset of the stimulus trains, and the amplitude and relative delay of any additional ERG responses following the offset of the flicker train were analyzed. At stimulus frequencies below 35 Hz, the number of ERG responses always equaled the number of stimulus cycles. However, over the frequency range of 38.5 to 100 Hz, the ERG contained an extra response following flicker train offset. At stimulus frequencies from 38.5 to 62.5 Hz, there was a constant delay between the peak of the extra ERG response and the time at which the next stimulus would have occurred had the flicker train continued. This constant delay is characteristic of an OSR. In addition, an extra ERG response was apparent at these same stimulus frequencies if the flicker train was interrupted by omitting stimulus cycles from the middle of the train. The pattern of ERG findings is consistent with a recently proposed model of the OSR that attributes the phenomenon to a resonant oscillation in retinal bipolar cells.
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Feigl B. Age-related maculopathy – Linking aetiology and pathophysiological changes to the ischaemia hypothesis. Prog Retin Eye Res 2009; 28:63-86. [PMID: 19070679 DOI: 10.1016/j.preteyeres.2008.11.004] [Citation(s) in RCA: 100] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Affiliation(s)
- Beatrix Feigl
- Institute of Health and Biomedical Innovation, Queensland University of Technology, 60 Musk Avenue, Kelvin Grove, 4059 QLD, Australia.
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Rod and S-cone driven ERG signals at high retinal illuminances. Doc Ophthalmol 2008; 118:205-16. [PMID: 19101744 DOI: 10.1007/s10633-008-9159-0] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2008] [Accepted: 12/01/2008] [Indexed: 11/27/2022]
Abstract
The purpose of the present study was to investigate whether L- and M-cone driven responses can be influenced by concomitant modulation in the rods or the S-cones. In addition, it was studied whether a change in the state of adaptation in L- or M-cones can have a different influence on ERG data when simultaneously the mean number of photoisomerizations in either rods or S-cones is altered. It was found that rods and/or S-cones cannot be neglected when measuring L- or M-cone driven ERGs.
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Alexander KR, Rajagopalan AS, Raghuram A, Fishman GA. Activation phase of cone phototransduction and the flicker electroretinogram in retinitis pigmentosa. Vision Res 2006; 46:2773-85. [PMID: 16494917 DOI: 10.1016/j.visres.2006.01.007] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2005] [Revised: 01/10/2006] [Accepted: 01/10/2006] [Indexed: 11/18/2022]
Abstract
This study examined the relationship between the activation phase of cone phototransduction and the flicker electroretinogram (ERG) in 15 patients with retinitis pigmentosa (RP) and 12 age-equivalent, visually normal control subjects. Values of Rmp3 (maximum amplitude of P3, the massed cone photoreceptor response) and S (sensitivity of cone phototransduction) were derived from a delayed Gaussian model applied to the leading edge of the ERG a-wave. Fundamental amplitude and phase of the flicker ERG were derived from responses to sinusoidal flicker presented at temporal frequencies ranging from 7.8 to 100 Hz. Patients with RP who had a reduced value of Rmp3 alone had an overall reduction in flicker ERG amplitude with a normal response phase across temporal frequency. Patients with RP who had a reduced value of S, whether or not Rmp3 was reduced, had the greatest amplitude reduction at temporal frequencies above 40 Hz and phase lags across a range of temporal frequencies. At high temporal frequencies, the amplitude reduction of the flicker ERG was predicted by the product of Rmp3 and S for all of the subjects except the three patients with RP who had the lowest fundamental amplitudes. The results indicate that there is a systematic relationship between the derived parameters of the activation phase of cone phototransduction and the characteristics of the flicker ERG in patients with RP, although the phase changes in the flicker ERG were generally greater than predicted by the derived parameters alone.
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Affiliation(s)
- Kenneth R Alexander
- Department of Ophthalmology and Visual Sciences, University of Illinois at Chicago, 1855 W. Taylor St., Chicago, IL 60612, USA.
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