1
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Holiel HA, Fawzi SA, Al-Atabany W. Pre-processing visual scenes for retinal prosthesis systems: A comprehensive review. Artif Organs 2024. [PMID: 39023279 DOI: 10.1111/aor.14824] [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: 10/31/2023] [Revised: 05/13/2024] [Accepted: 06/21/2024] [Indexed: 07/20/2024]
Abstract
BACKGROUND Retinal prostheses offer hope for individuals with degenerative retinal diseases by stimulating the remaining retinal cells to partially restore their vision. This review delves into the current advancements in retinal prosthesis technology, with a special emphasis on the pivotal role that image processing and machine learning techniques play in this evolution. METHODS We provide a comprehensive analysis of the existing implantable devices and optogenetic strategies, delineating their advantages, limitations, and challenges in addressing complex visual tasks. The review extends to various image processing algorithms and deep learning architectures that have been implemented to enhance the functionality of retinal prosthetic devices. We also illustrate the testing results by demonstrating the clinical trials or using Simulated Prosthetic Vision (SPV) through phosphene simulations, which is a critical aspect of simulating visual perception for retinal prosthesis users. RESULTS Our review highlights the significant progress in retinal prosthesis technology, particularly its capacity to augment visual perception among the visually impaired. It discusses the integration between image processing and deep learning, illustrating their impact on individual interactions and navigations within the environment through applying clinical trials and also illustrating the limitations of some techniques to be used with current devices, as some approaches only use simulation even on sighted-normal individuals or rely on qualitative analysis, where some consider realistic perception models and others do not. CONCLUSION This interdisciplinary field holds promise for the future of retinal prostheses, with the potential to significantly enhance the quality of life for individuals with retinal prostheses. Future research directions should pivot towards optimizing phosphene simulations for SPV approaches, considering the distorted and confusing nature of phosphene perception, thereby enriching the visual perception provided by these prosthetic devices. This endeavor will not only improve navigational independence but also facilitate a more immersive interaction with the environment.
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Affiliation(s)
- Heidi Ahmed Holiel
- Medical Imaging and Image Processing Research Group, Center for Informatics Science, Nile University, Sheikh Zayed City, Egypt
| | - Sahar Ali Fawzi
- Medical Imaging and Image Processing Research Group, Center for Informatics Science, Nile University, Sheikh Zayed City, Egypt
- Systems and Biomedical Engineering Department, Cairo University, Giza, Egypt
| | - Walid Al-Atabany
- Medical Imaging and Image Processing Research Group, Center for Informatics Science, Nile University, Sheikh Zayed City, Egypt
- Biomedical Engineering Department, Helwan University, Helwan, Egypt
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2
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Ashtari M, Cook P, Lipin M, Yu Y, Ying GS, Maguire A, Bennett J, Gee J, Zhang H. Dynamic structural remodeling of the human visual system prompted by bilateral retinal gene therapy. CURRENT RESEARCH IN NEUROBIOLOGY 2023; 4:100089. [PMID: 37397812 PMCID: PMC10313860 DOI: 10.1016/j.crneur.2023.100089] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2022] [Revised: 02/03/2023] [Accepted: 05/01/2023] [Indexed: 07/04/2023] Open
Abstract
The impact of changes in visual input on neuronal circuitry is complex and much of our knowledge on human brain plasticity of the visual systems comes from animal studies. Reinstating vision in a group of patients with low vision through retinal gene therapy creates a unique opportunity to dynamically study the underlying process responsible for brain plasticity. Historically, increases in the axonal myelination of the visual pathway has been the biomarker for brain plasticity. Here, we demonstrate that to reach the long-term effects of myelination increase, the human brain may undergo demyelination as part of a plasticity process. The maximum change in dendritic arborization of the primary visual cortex and the neurite density along the geniculostriate tracks occurred at three months (3MO) post intervention, in line with timing for the peak changes in postnatal synaptogenesis within the visual cortex reported in animal studies. The maximum change at 3MO for both the gray and white matter significantly correlated with patients' clinical responses to light stimulations called full field sensitivity threshold (FST). Our results shed a new light on the underlying process of brain plasticity by challenging the concept of increase myelination being the hallmark of brain plasticity and instead reinforcing the idea of signal speed optimization as a dynamic process for brain plasticity.
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Affiliation(s)
- Manzar Ashtari
- Center for Advanced Retinal and Ocular Therapeutics (CAROT), University of Pennsylvania, Philadelphia, PA, 19104, United States
- Department of Ophthalmology, University of Pennsylvania, Philadelphia, PA, 19104, United States
- Department of Radiology, University of Pennsylvania, Philadelphia, PA, 19104, United States
| | - Philip Cook
- Department of Radiology, University of Pennsylvania, Philadelphia, PA, 19104, United States
| | - Mikhail Lipin
- Center for Advanced Retinal and Ocular Therapeutics (CAROT), University of Pennsylvania, Philadelphia, PA, 19104, United States
| | - Yinxi Yu
- Department of Ophthalmology, University of Pennsylvania, Philadelphia, PA, 19104, United States
| | - Gui-Shuang Ying
- Department of Ophthalmology, University of Pennsylvania, Philadelphia, PA, 19104, United States
| | - Albert Maguire
- Center for Advanced Retinal and Ocular Therapeutics (CAROT), University of Pennsylvania, Philadelphia, PA, 19104, United States
- Department of Ophthalmology, University of Pennsylvania, Philadelphia, PA, 19104, United States
| | - Jean Bennett
- Center for Advanced Retinal and Ocular Therapeutics (CAROT), University of Pennsylvania, Philadelphia, PA, 19104, United States
- Department of Ophthalmology, University of Pennsylvania, Philadelphia, PA, 19104, United States
| | - James Gee
- Department of Radiology, University of Pennsylvania, Philadelphia, PA, 19104, United States
| | - Hui Zhang
- Centre for Medical Image Computing, University College London, London, United Kingdom
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3
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Retinitis Pigmentosa Associated with EYS Gene Mutations: Disease Severity Staging and Central Retina Atrophy. Diagnostics (Basel) 2023; 13:diagnostics13050850. [PMID: 36899994 PMCID: PMC10000790 DOI: 10.3390/diagnostics13050850] [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: 12/31/2022] [Revised: 02/07/2023] [Accepted: 02/13/2023] [Indexed: 02/25/2023] Open
Abstract
BACKGROUND Eyes shut homolog (EYS) gene mutations are estimated to affect at least 5% of patients with autosomal recessive retinitis pigmentosa. Since there is no mammalian model of human EYS disease, it is important to investigate its age-related changes and the degree of central retinal impairment. METHODS A cohort of EYS patients was studied. They underwent full ophthalmic examination as well as assessment of retinal function and structure, by full-field and focal electroretinograms (ERGs) and spectral domain optical coherence tomography (OCT), respectively. The disease severity stage was determined by the RP stage scoring system (RP-SSS). Central retina atrophy (CRA) was estimated from the automatically calculated area of the sub-retinal pigment epithelium (RPE) illumination (SRI). RESULTS The RP-SSS was positively correlated with age, showing an advanced severity score (≥8) at an age of 45 and a disease duration of 15 years. The RP-SSS was positively correlated with the CRA area. LogMAR visual acuity and ellipsoid zone width, but not ERG, were correlated with CRA. CONCLUSIONS In EYS-related disease, the RP-SSS showed advanced severity at a relative early age and was correlated with the central area of the RPE/photoreceptor atrophy. These correlations may be relevant in view of therapeutic interventions aimed at rescuing rods and cones in EYS-retinopathy.
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4
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Chen Y, Gao Y, He Z, Sun Z, Mao Y, Hess RF, Zhang P, Zhou J. Internal neural states influence the short-term effect of monocular deprivation in human adults. eLife 2023; 12:83815. [PMID: 36705563 PMCID: PMC9910827 DOI: 10.7554/elife.83815] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2022] [Accepted: 01/26/2023] [Indexed: 01/28/2023] Open
Abstract
The adult human visual system maintains the ability to be altered by sensory deprivation. What has not been considered is whether the internal neural states modulate visual sensitivity to short-term monocular deprivation. In this study we manipulated the internal neural state and reported changes in intrinsic neural oscillations with a patched eye open or closed. We investigated the influence of eye open/eye closure on the unpatched eye's contrast sensitivity and ocular dominance (OD) shifts induced by short-term monocular deprivation. The results demonstrate that internal neural states influence not only baseline contrast sensitivity but also the extent to which the adult visual system can undergo changes in ocular dominance.
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Affiliation(s)
- Yiya Chen
- State Key Laboratory of Ophthalmology, Optometry and Visual Science, Wenzhou Medical UniversityWenzhouChina
- National Engineering Research Center of Ophthalmology and Optometry, Wenzhou Medical UniversityWenzhouChina
| | - Yige Gao
- State Key Laboratory of Brain and Cognitive Science, Institute of Biophysics, Chinese Academy of SciencesBeijingChina
- University of Chinese Academy of SciencesBeijingChina
| | - Zhifen He
- State Key Laboratory of Ophthalmology, Optometry and Visual Science, Wenzhou Medical UniversityWenzhouChina
- National Engineering Research Center of Ophthalmology and Optometry, Wenzhou Medical UniversityWenzhouChina
| | - Zhouyuan Sun
- State Key Laboratory of Brain and Cognitive Science, Institute of Biophysics, Chinese Academy of SciencesBeijingChina
- University of Chinese Academy of SciencesBeijingChina
| | - Yu Mao
- State Key Laboratory of Ophthalmology, Optometry and Visual Science, Wenzhou Medical UniversityWenzhouChina
- National Engineering Research Center of Ophthalmology and Optometry, Wenzhou Medical UniversityWenzhouChina
| | - Robert F Hess
- Department of Ophthalmology and Visual Sciences, McGill UniversityMontrealCanada
| | - Peng Zhang
- State Key Laboratory of Brain and Cognitive Science, Institute of Biophysics, Chinese Academy of SciencesBeijingChina
- University of Chinese Academy of SciencesBeijingChina
- Institute of Artificial Intelligence, Hefei Comprehensive National Science CenterHefeiChina
| | - Jiawei Zhou
- State Key Laboratory of Ophthalmology, Optometry and Visual Science, Wenzhou Medical UniversityWenzhouChina
- National Engineering Research Center of Ophthalmology and Optometry, Wenzhou Medical UniversityWenzhouChina
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5
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Leinonen H, Fu Z, Bull E. Neural and Müller glial adaptation of the retina to photoreceptor degeneration. Neural Regen Res 2023; 18:701-707. [DOI: 10.4103/1673-5374.354511] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022] Open
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6
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Caravaca-Rodriguez D, Gaytan SP, Suaning GJ, Barriga-Rivera A. Implications of Neural Plasticity in Retinal Prosthesis. Invest Ophthalmol Vis Sci 2022; 63:11. [PMID: 36251317 DOI: 10.1167/iovs.63.11.11] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Retinal degenerative diseases such as retinitis pigmentosa cause a progressive loss of photoreceptors that eventually prevents the affected person from perceiving visual sensations. The absence of a visual input produces a neural rewiring cascade that propagates along the visual system. This remodeling occurs first within the retina. Then, subsequent neuroplastic changes take place at higher visual centers in the brain, produced by either the abnormal neural encoding of the visual inputs delivered by the diseased retina or as the result of an adaptation to visual deprivation. While retinal implants can activate the surviving retinal neurons by delivering electric current, the unselective activation patterns of the different neural populations that exist in the retinal layers differ substantially from those in physiologic vision. Therefore, artificially induced neural patterns are being delivered to a brain that has already undergone important neural reconnections. Whether or not the modulation of this neural rewiring can improve the performance for retinal prostheses remains a critical question whose answer may be the enabler of improved functional artificial vision and more personalized neurorehabilitation strategies.
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Affiliation(s)
- Daniel Caravaca-Rodriguez
- Department of Applied Physics III, Technical School of Engineering, Universidad de Sevilla, Sevilla, Spain
| | - Susana P Gaytan
- Department of Physiology, Universidad de Sevilla, Sevilla, Spain
| | - Gregg J Suaning
- School of Biomedical Engineering, University of Sydney, Sydney, Australia
| | - Alejandro Barriga-Rivera
- Department of Applied Physics III, Technical School of Engineering, Universidad de Sevilla, Sevilla, Spain.,School of Biomedical Engineering, University of Sydney, Sydney, Australia
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7
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Chen X, Hall K, Bobier WR, Thompson B, Chakraborty A. Transcranial random noise stimulation and exercise do not modulate ocular dominance plasticity in adults with normal vision. J Vis 2022; 22:14. [PMID: 36107124 PMCID: PMC9483237 DOI: 10.1167/jov.22.10.14] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Affiliation(s)
- Xiaoxin Chen
- School of Optometry & Vision Science, University of Waterloo, Waterloo, ON, Canada
| | - Kennedy Hall
- Chicago College of Optometry, Midwestern University, Downers Grove, IL, USA
| | - William R. Bobier
- School of Optometry & Vision Science, University of Waterloo, Waterloo, ON, Canada
| | - Benjamin Thompson
- School of Optometry & Vision Science, University of Waterloo, Waterloo, ON, Canada
- Centre for Eye and Vision Research, 17W Science Park, Hong Kong
- Liggins Institute, University of Auckland, Auckland, New Zealand
| | - Arijit Chakraborty
- School of Optometry & Vision Science, University of Waterloo, Waterloo, ON, Canada
- Chicago College of Optometry, Midwestern University, Downers Grove, IL, USA
- College of Health Sciences, Rush University, Chicago, IL, USA
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8
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Chen Y, Mao Y, Zhou J, He Z, Hess RF. The shift in sensory eye dominance from short-term monocular deprivation exhibits no dependence on test spatial frequency. EYE AND VISION 2022; 9:32. [PMID: 36045414 PMCID: PMC9434876 DOI: 10.1186/s40662-022-00303-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/09/2022] [Accepted: 08/08/2022] [Indexed: 12/02/2022]
Abstract
Background Studies have shown that short-term monocular deprivation induces a shift in sensory eye dominance in favor of the deprived eye. Yet, how short-term monocular deprivation modulates sensory eye dominance across spatial frequency is not clear. To address this issue, we conducted a study to investigate the dependence of short-term monocular deprivation effect on test spatial frequency. Methods Ten healthy young adults (age: 24.7 ± 1.7 years, four males) with normal vision participated. We deprived their dominant eye with a translucent patch for 2.5 h. The interocular contrast ratio (dominant eye/non-dominant eye, i.e., the balance point [BP]), which indicates the contribution that the two eyes make to binocular combination, was measured using a binocular orientation combination task. We assessed if BPs at 0.5, 4 or 6 cycles/degree (c/d) change as a result of monocular deprivation. Different test spatial frequency conditions were conducted on three separate days in a random fashion. Results We compared the BPs at 0.5, 4 and 6 c/d before and after monocular deprivation. The BPs were found to be significantly affected by deprivation, where sensory eye dominance shift to the deprived eye (F1.86, 16.76 = 33.09, P < 0.001). The changes of BP were consistent at 0.5, 4, and 6 c/d spatial frequencies (F2,18 = 0.15, P = 0.57). Conclusion The sensory eye dominance plasticity induced by short-term deprivation is not dependent on test spatial frequency, suggesting it could provide a practical solution for amblyopic therapy that was concerned with the binocular outcome. Supplementary Information The online version contains supplementary material available at 10.1186/s40662-022-00303-4.
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9
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Menicucci D, Lunghi C, Zaccaro A, Morrone MC, Gemignani A. Mutual interaction between visual homeostatic plasticity and sleep in adult humans. eLife 2022; 11:70633. [PMID: 35972073 PMCID: PMC9417418 DOI: 10.7554/elife.70633] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2021] [Accepted: 08/15/2022] [Indexed: 11/13/2022] Open
Abstract
Sleep and plasticity are highly interrelated, as sleep slow oscillations and sleep spindles are associated with consolidation of Hebbian-based processes. However, in adult humans, visual cortical plasticity is mainly sustained by homeostatic mechanisms, for which the role of sleep is still largely unknown. Here, we demonstrate that non-REM sleep stabilizes homeostatic plasticity of ocular dominance induced in adult humans by short-term monocular deprivation: the counterintuitive and otherwise transient boost of the deprived eye was preserved at the morning awakening (>6 hr after deprivation). Subjects exhibiting a stronger boost of the deprived eye after sleep had increased sleep spindle density in frontopolar electrodes, suggesting the involvement of distributed processes. Crucially, the individual susceptibility to visual homeostatic plasticity soon after deprivation correlated with the changes in sleep slow oscillations and spindle power in occipital sites, consistent with a modulation in early occipital visual cortex.
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Affiliation(s)
- Danilo Menicucci
- Department of Surgical, Medical and Molecular Pathology and Critical Care Medicine, University of Pisa, Pisa, Italy
| | - Claudia Lunghi
- Département d'études Cognitives, École Normale Supérieure, UMR 8248 CNRS, Paris, France
| | - Andrea Zaccaro
- Department of Surgical, Medical and Molecular Pathology and Critical Care Medicine, University of Pisa, Pisa, Italy
| | - Maria Concetta Morrone
- Department of Translational Research and New Technologies in Medicine and Surgery, University of Pisa, Pisa, Italy
| | - Angelo Gemignani
- Department of Surgical, Medical and Molecular and Critical Area Pathology, University of Pisa, Pisa, Italy
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10
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Bhattacharyya A. The detrimental effects of progression of retinal degeneration in the visual cortex. Front Cell Neurosci 2022; 16:904175. [PMID: 35966197 PMCID: PMC9372284 DOI: 10.3389/fncel.2022.904175] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2022] [Accepted: 07/04/2022] [Indexed: 11/13/2022] Open
Abstract
The leading cause of blindness in inherited and age-related retinal degeneration (RD) is the death of retinal photoreceptors such as rods and cones. The most prevalent form of RD is age-related macular degeneration (AMD) which affects the macula resulting in an irreversible loss of vision. The other is a heterogenous group of inherited disorders known as Retinitis Pigmentosa (RP) caused by the progressive loss of photoreceptors. Several approaches have been developed in recent years to artificially stimulate the remaining retinal neurons using optogenetics, retinal prostheses, and chemical photoswitches. However, the outcome of these strategies has been limited. The success of these treatments relies on the morphology, physiology, and proper functioning of the remaining intact structures in the downstream visual pathway. It is not completely understood what all alterations occur in the visual cortex during RD. In this review, I will discuss the known information in the literature about morphological and functional changes that occur in the visual cortex in rodents and humans during RD. The aim is to highlight the changes in the visual cortex that will be helpful for developing tools and strategies directed toward the restoration of high-resolution vision in patients with visual impairment.
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11
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Francia S, Shmal D, Di Marco S, Chiaravalli G, Maya-Vetencourt JF, Mantero G, Michetti C, Cupini S, Manfredi G, DiFrancesco ML, Rocchi A, Perotto S, Attanasio M, Sacco R, Bisti S, Mete M, Pertile G, Lanzani G, Colombo E, Benfenati F. Light-induced charge generation in polymeric nanoparticles restores vision in advanced-stage retinitis pigmentosa rats. Nat Commun 2022; 13:3677. [PMID: 35760799 PMCID: PMC9237035 DOI: 10.1038/s41467-022-31368-3] [Citation(s) in RCA: 23] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2021] [Accepted: 06/14/2022] [Indexed: 12/16/2022] Open
Abstract
Retinal dystrophies such as Retinitis pigmentosa are among the most prevalent causes of inherited legal blindness, for which treatments are in demand. Retinal prostheses have been developed to stimulate the inner retinal network that, initially spared by degeneration, deteriorates in the late stages of the disease. We recently reported that conjugated polymer nanoparticles persistently rescue visual activities after a single subretinal injection in the Royal College of Surgeons rat model of Retinitis pigmentosa. Here we demonstrate that conjugated polymer nanoparticles can reinstate physiological signals at the cortical level and visually driven activities when microinjected in 10-months-old Royal College of Surgeons rats bearing fully light-insensitive retinas. The extent of visual restoration positively correlates with the nanoparticle density and hybrid contacts with second-order retinal neurons. The results establish the functional role of organic photovoltaic nanoparticles in restoring visual activities in fully degenerate retinas with intense inner retina rewiring, a stage of the disease in which patients are subjected to prosthetic interventions. Retinal dystrophies such as Retinitis pigmentosa are among the most prevalent causes of inherited incurable legal blindness. Here the authors demonstrate that conjugated polymer nanoparticles reinstate visual functions in aged rats with fully degenerated and rewired retinas.
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Affiliation(s)
- S Francia
- Center for Synaptic Neuroscience and Technology, Istituto Italiano di Tecnologia, Genova, Italy.,IRCCS Ospedale Policlinico San Martino, Genova, Italy
| | - D Shmal
- Center for Synaptic Neuroscience and Technology, Istituto Italiano di Tecnologia, Genova, Italy.,Department of Experimental Medicine, University of Genova, Genova, Italy
| | - S Di Marco
- Center for Synaptic Neuroscience and Technology, Istituto Italiano di Tecnologia, Genova, Italy.,IRCCS Ospedale Policlinico San Martino, Genova, Italy
| | - G Chiaravalli
- Center for Nanoscience and Technology, Istituto Italiano di Tecnologia, Milano, Italy
| | - J F Maya-Vetencourt
- Center for Synaptic Neuroscience and Technology, Istituto Italiano di Tecnologia, Genova, Italy.,Department of Biology, University of Pisa, Pisa, Italy
| | - G Mantero
- Center for Synaptic Neuroscience and Technology, Istituto Italiano di Tecnologia, Genova, Italy.,Department of Experimental Medicine, University of Genova, Genova, Italy
| | - C Michetti
- Center for Synaptic Neuroscience and Technology, Istituto Italiano di Tecnologia, Genova, Italy.,Department of Experimental Medicine, University of Genova, Genova, Italy
| | - S Cupini
- Center for Synaptic Neuroscience and Technology, Istituto Italiano di Tecnologia, Genova, Italy.,Department of Experimental Medicine, University of Genova, Genova, Italy
| | - G Manfredi
- Center for Nanoscience and Technology, Istituto Italiano di Tecnologia, Milano, Italy.,Novavido s.r.l., Bologna, Italy
| | - M L DiFrancesco
- Center for Synaptic Neuroscience and Technology, Istituto Italiano di Tecnologia, Genova, Italy.,IRCCS Ospedale Policlinico San Martino, Genova, Italy
| | - A Rocchi
- Center for Synaptic Neuroscience and Technology, Istituto Italiano di Tecnologia, Genova, Italy
| | - S Perotto
- Center for Nanoscience and Technology, Istituto Italiano di Tecnologia, Milano, Italy
| | - M Attanasio
- Department of Ophthalmology, IRCCS Sacrocuore Don Calabria Hospital, Negrar, Verona, Italy
| | - R Sacco
- Department of Mathematics, Politecnico di Milano, Milano, Italy
| | - S Bisti
- Center for Synaptic Neuroscience and Technology, Istituto Italiano di Tecnologia, Genova, Italy
| | - M Mete
- Department of Ophthalmology, IRCCS Sacrocuore Don Calabria Hospital, Negrar, Verona, Italy
| | - G Pertile
- Department of Ophthalmology, IRCCS Sacrocuore Don Calabria Hospital, Negrar, Verona, Italy
| | - G Lanzani
- Center for Nanoscience and Technology, Istituto Italiano di Tecnologia, Milano, Italy. .,Department of Physics, Politecnico di Milano, Milan, Italy.
| | - E Colombo
- Center for Synaptic Neuroscience and Technology, Istituto Italiano di Tecnologia, Genova, Italy.,IRCCS Ospedale Policlinico San Martino, Genova, Italy
| | - F Benfenati
- Center for Synaptic Neuroscience and Technology, Istituto Italiano di Tecnologia, Genova, Italy. .,IRCCS Ospedale Policlinico San Martino, Genova, Italy.
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12
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Koo B, Weiland JD. Progressive Retinal Degeneration Increases Cortical Response Latency of Light Stimulation but Not of Electric Stimulation. Transl Vis Sci Technol 2022; 11:19. [PMID: 35446408 PMCID: PMC9034728 DOI: 10.1167/tvst.11.4.19] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2021] [Accepted: 03/31/2022] [Indexed: 12/02/2022] Open
Abstract
Purpose The brain is known to change functionally and structurally in response to blindness, but less is known about the effects of restoration of cortical input on brain function. Here, we present a preliminary study to observe alterations in visual and electrical evoked cortical potentials as a function of age in a clinically relevant animal model of retinitis pigmentosa. Methods We recorded brain potentials elicited by light (visual evoked potentials [VEPs]) or corneal electrical stimulation (electrical evoked response [EER]) in retinal degenerate animal model LE-P23H-1. We used a linear mixed model to examine the effects of age on latency and amplitude of VEP and EER age groups P120, P180, and P360. Results VEP N1, P1, and N2 latency and amplitude were analyzed across animal age. For 1 Hz VEP, N1 latency increased significantly with animal age (slope = 0.053 ± 0.020 ms/day, P < 0.01). For 10 Hz VEP, N1, P1, and N2 latency increased significantly with animal age (slope = 0.104 ± 0.011, 0.135 ± 0.011, 0.087 ± 0.023 ms/day, and P < 0.001 for all VEP peaks). Conversely, EER latency did not change with age. Signal amplitude of VEP or EER did not change with age. Conclusions Cortical potentials evoked by electrical stimulation of the retina do not diminish in spite of continued retinal degeneration in P23H rats. Translational Relevance These findings suggest that retinal bioelectronic treatments of retinitis pigmentosa will activate cortex consistently despite variations in outer retinal degeneration. Clinical studies of retinal stimulation should consider varying retinitis pigmentosa genotypes as part of the experimental design.
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Affiliation(s)
- Beomseo Koo
- Department of Biomedical Engineering, University of Michigan, Ann Arbor, MI, USA
- Biointerfaces Institute, University of Michigan, Ann Arbor, MI, USA
| | - James D. Weiland
- Department of Biomedical Engineering, University of Michigan, Ann Arbor, MI, USA
- Biointerfaces Institute, University of Michigan, Ann Arbor, MI, USA
- Department of Ophthalmology and Visual Sciences, University of Michigan, Ann Arbor, MI, USA
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13
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Pietra G, Bonifacino T, Talamonti D, Bonanno G, Sale A, Galli L, Baroncelli L. Visual Cortex Engagement in Retinitis Pigmentosa. Int J Mol Sci 2021; 22:ijms22179412. [PMID: 34502320 PMCID: PMC8431500 DOI: 10.3390/ijms22179412] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2021] [Revised: 08/20/2021] [Accepted: 08/26/2021] [Indexed: 11/24/2022] Open
Abstract
Retinitis pigmentosa (RP) is a family of inherited disorders caused by the progressive degeneration of retinal photoreceptors. There is no cure for RP, but recent research advances have provided promising results from many clinical trials. All these therapeutic strategies are focused on preserving existing photoreceptors or substituting light-responsive elements. Vision recovery, however, strongly relies on the anatomical and functional integrity of the visual system beyond photoreceptors. Although the retinal structure and optic pathway are substantially preserved at least in early stages of RP, studies describing the visual cortex status are missing. Using a well-established mouse model of RP, we analyzed the response of visual cortical circuits to the progressive degeneration of photoreceptors. We demonstrated that the visual cortex goes through a transient and previously undescribed alteration in the local excitation/inhibition balance, with a net shift towards increased intracortical inhibition leading to improved filtering and decoding of corrupted visual inputs. These results suggest a compensatory action of the visual cortex that increases the range of residual visual sensitivity in RP.
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Affiliation(s)
- Gianluca Pietra
- Neuroscience Institute, National Research Council (CNR), I-56124 Pisa, Italy; (G.P.); (D.T.); (A.S.); (L.G.)
| | - Tiziana Bonifacino
- Section of Pharmacology and Toxicology Unit, Department of Pharmacy, University of Genova, I-16148 Genova, Italy; (T.B.); (G.B.)
| | - Davide Talamonti
- Neuroscience Institute, National Research Council (CNR), I-56124 Pisa, Italy; (G.P.); (D.T.); (A.S.); (L.G.)
- Department of Life Science, University of Trieste, I-34128 Trieste, Italy
| | - Giambattista Bonanno
- Section of Pharmacology and Toxicology Unit, Department of Pharmacy, University of Genova, I-16148 Genova, Italy; (T.B.); (G.B.)
- IRCCS Ospedale Policlinico San Martino, I-16132 Genova, Italy
| | - Alessandro Sale
- Neuroscience Institute, National Research Council (CNR), I-56124 Pisa, Italy; (G.P.); (D.T.); (A.S.); (L.G.)
| | - Lucia Galli
- Neuroscience Institute, National Research Council (CNR), I-56124 Pisa, Italy; (G.P.); (D.T.); (A.S.); (L.G.)
| | - Laura Baroncelli
- Neuroscience Institute, National Research Council (CNR), I-56124 Pisa, Italy; (G.P.); (D.T.); (A.S.); (L.G.)
- Department of Developmental Neuroscience, IRCCS Stella Maris Foundation, I-56128 Pisa, Italy
- Correspondence: ; Tel.: +39-503-153199; Fax: +39-503-153220
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14
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Min SH, Gong L, Baldwin AS, Reynaud A, He Z, Zhou J, Hess RF. Some psychophysical tasks measure ocular dominance plasticity more reliably than others. J Vis 2021; 21:20. [PMID: 34410308 PMCID: PMC8383899 DOI: 10.1167/jov.21.8.20] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
In the recent decade, studies have shown that short-term monocular deprivation strengthens the deprived eye's contribution to binocular vision. However, the magnitude of the change in eye dominance after monocular deprivation (i.e., the patching effect) has been found to be different between different methods and within the same method. There are three possible explanations for the discrepancy. First, the mechanisms underlying the patching effect that are probed by different measurement tasks might exist at different neural sites. Second, the test–retest variability of the same test can produce inconsistent results. Third, the magnitude of the patching effect itself within the same observer can vary across separate days or experimental sessions. To explore these possibilities, we assessed the test–retest reliability of the three most commonly used tasks (binocular rivalry, binocular combination, and dichoptic masking) and the repeatability of the shift in eye dominance after short-term monocular deprivation for each of the task. Two variations for binocular phase combination were used, at one and many contrasts of the stimuli. Also, two variations for dichoptic masking were employed; the orientation of the mask grating was either horizontal or vertical. Thus, five different tasks were evaluated. We hoped to resolve some of the inconsistencies reported in the literature concerning this form of visual plasticity. In this study, we also aimed to recommend a measurement method that would allow us to better understand its physiological basis and the underpinning of visual disorders.
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Affiliation(s)
- Seung Hyun Min
- McGill Vision Research, Department of Ophthalmology and Visual Sciences, McGill University, Montreal, Canada.,
| | - Ling Gong
- School of Ophthalmology & Optometry and Eye Hospital, and State Key Laboratory of Ophthalmology, Optometry and Vision Science, Wenzhou Medical University.,
| | - Alex S Baldwin
- McGill Vision Research, Department of Ophthalmology and Visual Sciences, McGill University, Montreal, Canada.,
| | - Alexandre Reynaud
- McGill Vision Research, Department of Ophthalmology and Visual Sciences, McGill University, Montreal, Canada.,
| | - Zhifen He
- School of Ophthalmology & Optometry and Eye Hospital, and State Key Laboratory of Ophthalmology, Optometry and Vision Science, Wenzhou Medical University.,
| | - Jiawei Zhou
- School of Ophthalmology & Optometry and Eye Hospital, and State Key Laboratory of Ophthalmology, Optometry and Vision Science, Wenzhou Medical University.,
| | - Robert F Hess
- McGill Vision Research, Department of Ophthalmology and Visual Sciences, McGill University, Montreal, Canada.,
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15
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Sun L, Jiang Z, Li S, Liu J, Su M, Lu Y, Li Z, Ding X. What Is Left After Resolution of Neonatal Retinal Hemorrhage: The Longitudinal Long-term Outcome in Foveal Structure and Visual Function. Am J Ophthalmol 2021; 226:182-190. [PMID: 33556380 DOI: 10.1016/j.ajo.2021.01.028] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2020] [Revised: 01/27/2021] [Accepted: 01/28/2021] [Indexed: 10/22/2022]
Abstract
PURPOSE Neonatal retinal hemorrhage (NRH) is one of the most common neonatal fundus conditions. Hemorrhage resolves spontaneously; however, its long-term outcome is unknown yet. The current study explores the long-term role of NRH in foveal structure and visual function. DESIGN Cohort study (a prospective longitudinal study, in which the participants were followed up for 4-6 years). METHODS A total of 125 healthy newborns during 2013-2015, including 50 newborns with NRH and 75 newborns without NRH, were enrolled. The eyes with NRH were further categorized into the foveal hemorrhage (FH) group and non-FH group. A comprehensive ophthalmic examination including best-corrected visual acuity (BCVA) measurement, slit-lamp examination, refractive error measurement, scanning laser ophthalmoscopy, and spectral-domain OCT was performed. Total retinal thickness (TRT) and the inner and outer retinal layers in the fovea were measured and compared. RESULTS The NRH was absorbed within 2.1 ± 0.98 weeks (median: 3 weeks). No difference was noted in the demographic characteristics between the groups; there was no significant difference in the logMAR BCVA (P = .83) or in the TRT. Subgroup analysis showed that TRT at the fovea in the FH group was significantly thicker (P = .005). Segmentation analysis showed a significantly thicker foveal outer nuclear layer (ONL) in the FH group (P = .017). CONCLUSIONS Birth-related retinal hemorrhage, even FH, might not lead to obvious visual abnormalities at the age of 4 years, at least according to this study with relatively small sample size. However, a thicker fovea, mainly attributed to a wider ONL and a shallower foveal pit, is noted in our study.
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16
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Begenisic T, Mazziotti R, Sagona G, Lupori L, Sale A, Galli L, Baroncelli L. Preservation of Visual Cortex Plasticity in Retinitis Pigmentosa. Neuroscience 2020; 424:205-210. [PMID: 31901258 DOI: 10.1016/j.neuroscience.2019.10.045] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2019] [Revised: 10/07/2019] [Accepted: 10/27/2019] [Indexed: 02/07/2023]
Abstract
Retinitis Pigmentosa (RP) is a class of inherited disorders caused by the progressive death of photoreceptors in the retina. RP is still orphan of an effective treatment, with increasing optimism deriving from research aimed at arresting neurodegeneration or replacing light-responsive elements. All these therapeutic strategies rely on the functional integrity of the visual system downstream of photoreceptors. Whereas the inner retinal structure and optic radiation are known to be considerably preserved at least in early stages of RP, very little is known about the visual cortex. Remarkably, it remains completely unclear whether visual cortex plasticity is still present in RP. Using a well-established murine model of RP, the rd10 mouse, we report that visual cortical circuits retain high levels of plasticity, preserving their capability of input-dependent remodelling even at a late stage of retinal degeneration.
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Affiliation(s)
- Tatjana Begenisic
- Institute of Neuroscience, National Research Council (CNR), I-56124 Pisa, Italy
| | - Raffaele Mazziotti
- Institute of Neuroscience, National Research Council (CNR), I-56124 Pisa, Italy; Department of Neuroscience, Psychology, Drug Research and Child Health NEUROFARBA, University of Florence, I-50135 Florence, Italy
| | - Giulia Sagona
- Department of Neuroscience, Psychology, Drug Research and Child Health NEUROFARBA, University of Florence, I-50135 Florence, Italy; Department of Developmental Neuroscience, IRCCS Stella Maris Foundation, I-56128 Pisa, Italy
| | - Leonardo Lupori
- BIO@SNS lab, Scuola Normale Superiore di Pisa, I-56125 Pisa, Italy
| | - Alessandro Sale
- Institute of Neuroscience, National Research Council (CNR), I-56124 Pisa, Italy
| | - Lucia Galli
- Institute of Neuroscience, National Research Council (CNR), I-56124 Pisa, Italy
| | - Laura Baroncelli
- Institute of Neuroscience, National Research Council (CNR), I-56124 Pisa, Italy; Department of Developmental Neuroscience, IRCCS Stella Maris Foundation, I-56128 Pisa, Italy.
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17
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Baroncelli L, Lunghi C. Neuroplasticity of the visual cortex: in sickness and in health. Exp Neurol 2020; 335:113515. [PMID: 33132181 DOI: 10.1016/j.expneurol.2020.113515] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2020] [Revised: 10/14/2020] [Accepted: 10/21/2020] [Indexed: 01/18/2023]
Abstract
Brain plasticity refers to the ability of synaptic connections to adapt their function and structure in response to experience, including environmental changes, sensory deprivation and injuries. Plasticity is a distinctive, but not exclusive, property of the developing nervous system. This review introduces the concept of neuroplasticity and describes classic paradigms to illustrate cellular and molecular mechanisms underlying synapse modifiability. Then, we summarize a growing number of studies showing that the adult cerebral cortex retains a significant degree of plasticity highlighting how the identification of strategies to enhance the plastic potential of the adult brain could pave the way for the development of novel therapeutic approaches aimed at treating amblyopia and other neurodevelopmental disorders. Finally, we analyze how the visual system adjusts to neurodegenerative conditions leading to blindness and we discuss the crucial role of spared plasticity in the visual system for sight recovery.
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Affiliation(s)
- Laura Baroncelli
- Institute of Neuroscience, National Research Council (CNR), I-56124 Pisa, Italy; Department of Developmental Neuroscience, IRCCS Stella Maris Foundation, I-56128 Pisa, Italy.
| | - Claudia Lunghi
- Laboratoire des systèmes perceptifs, Département d'études cognitives, École normale supérieure, PSL University, CNRS, 75005 Paris, France
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18
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Chen K, Hou B, Zhao Y, Yuan P, Yao D, Chan LLH. Residual contrast response in primary visual cortex of rats with inherited retinal degeneration. Vision Res 2020; 177:6-11. [PMID: 32932127 DOI: 10.1016/j.visres.2020.08.007] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2020] [Revised: 08/15/2020] [Accepted: 08/21/2020] [Indexed: 12/22/2022]
Abstract
Rhodopsin S334ter-3 retinal degeneration rats have been widely used to investigate degenerative diseases of the retina. In this model, morphological and electrophysiological changes have been observed in the retina, superior colliculus and primary visual cortex (V1). However, no study so far has examined rhodopsin S334ter-3 rats with regards to their contrast response in V1 - a fundamental property of visual information processing. In this study, experimental rats (S334ter-3) carried one copy of the mutant transgene. We compared responses to spatio-temporal variations in luminance contrast in the primary visual cortex of these rats with those in Long-Evans (LE) rats to elucidate the degeneration-specific activity changes in this part of the visual pathway. We measured extracellular responses to different stimulus contrasts at the preferred parameters of each recorded cell under classical receptive field (CRF) stimulation. Our results show that V1 cells in the S334ter-3 group exhibit stronger spontaneous activity but weaker stimulus-evoked responses at medium and high contrasts. By fitting responses to a sigmoid function, we found that the S334ter-3 group had a lower Rmax but a larger exponent N than the LE group. However, we did not find a significant difference in C50 value. These results indicate the decrease in discriminating the stimuli contrast and loss in responses and lower signal to noise ratio after retinal degeneration. Our study supports the notion that a considerable degree of plasticity is found in cortex after retinal degeneration, indicating that visual restoration therapies would succeed if the retina could send useful signals to the brain.
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Affiliation(s)
- Ke Chen
- The Clinical Hospital of Chengdu Brain Science Institute, MOE Key Lab for NeuroInformation, University of Electronic Science and Technology of China, Chengdu 610054, People's Republic of China
| | - Bojun Hou
- The Clinical Hospital of Chengdu Brain Science Institute, MOE Key Lab for NeuroInformation, University of Electronic Science and Technology of China, Chengdu 610054, People's Republic of China
| | - Yilei Zhao
- The Clinical Hospital of Chengdu Brain Science Institute, MOE Key Lab for NeuroInformation, University of Electronic Science and Technology of China, Chengdu 610054, People's Republic of China
| | - Peimin Yuan
- The Clinical Hospital of Chengdu Brain Science Institute, MOE Key Lab for NeuroInformation, University of Electronic Science and Technology of China, Chengdu 610054, People's Republic of China
| | - Dezhong Yao
- The Clinical Hospital of Chengdu Brain Science Institute, MOE Key Lab for NeuroInformation, University of Electronic Science and Technology of China, Chengdu 610054, People's Republic of China
| | - Leanne Lai Hang Chan
- Department of Electrical Engineering, City University of Hong Kong, Tat Chee Avenue, Hong Kong SAR, China; Centre for Biosystems, Neuroscience, and Nanotechnology, City University of Hong Kong, Tat Chee Avenue, Hong Kong SAR, China.
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Visual Cortex Rewiring in Retinitis Pigmentosa: Plasticity is Preserved. Neuroscience 2020; 424:203-204. [DOI: 10.1016/j.neuroscience.2019.10.053] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2019] [Accepted: 10/30/2019] [Indexed: 11/22/2022]
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20
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Castaldi E, Cicchini GM, Falsini B, Binda P, Morrone MC. Residual Visual Responses in Patients With Retinitis Pigmentosa Revealed by Functional Magnetic Resonance Imaging. Transl Vis Sci Technol 2019; 8:44. [PMID: 31867144 PMCID: PMC6922275 DOI: 10.1167/tvst.8.6.44] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2019] [Accepted: 09/24/2019] [Indexed: 01/20/2023] Open
Abstract
PURPOSE We evaluated the potential of magnetic resonance imaging in identifying signs of cortical visual processing with greater sensitivity than standard ophthalmological measures in patients with retinitis pigmentosa (RP) at advanced stages. METHODS Eight patients affected with RP with only bare light perception and weak or absent visual evoked potential (VEP) or electroretinogram (ERG) responses to flashes of light were tested. Visual impairment was evaluated by means of psychophysical testing, where patients were asked to discriminate the drifting direction of a contrast modulated grating. Patients underwent magnetic resonance imaging scanning, and the behavioral performance was correlated with both blood oxygenation level-dependent (BOLD) signal elicited by flashes of lights and cortical thickness measured in primary visual area. RESULTS Contrast sensitivity to drifting gratings of very low spatial and temporal frequency was greatly impaired, yet measurable in all patients. Weak luminance flashes elicited significant BOLD responses in the striate and extrastriate cortex, despite that the stimuli were not perceived during scanning. Importantly, patients with less severe impairment of contrast sensitivity showed stronger V1 BOLD responses. Striate cortical thickness did not correlate with visual sensitivity. CONCLUSIONS BOLD responses provide a sensitive and reliable index of visual sparing more than VEPs or ERGs, which are often absent in RP patients. The minimal residual vision can be assessed by optimal visual stimulation in two alternative forced choice discrimination tasks and by BOLD responses. Imaging techniques provide useful information to monitor progressive vision loss. TRANSLATIONAL RELEVANCE Functional magnetic resonance imaging might be a practical tool for assessing visual sparing, as it is more feasible and sensitive than psychophysical or ophthalmological testing.
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Affiliation(s)
- Elisa Castaldi
- Department of Neuroscience, Psychology, Pharmacology and Child Health, University of Florence, Florence, Italy
| | | | - Benedetto Falsini
- Department of Ophthalmology, Policlinico Gemelli, Università Cattolica del Sacro Cuore, Rome, Italy
| | - Paola Binda
- Institute of Neuroscience CNR, Pisa, Italy
- Department of Translational Research and New technologies in Medicine and Surgery, University of Pisa, Pisa, Italy
| | - Maria Concetta Morrone
- Department of Translational Research and New technologies in Medicine and Surgery, University of Pisa, Pisa, Italy
- IRCCS Stella Maris, Calambrone, Pisa, Italy
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