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Elul D, Levin N. The Role of Population Receptive Field Sizes in Higher-Order Visual Dysfunction. Curr Neurol Neurosci Rep 2024:10.1007/s11910-024-01375-6. [PMID: 39266871 DOI: 10.1007/s11910-024-01375-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/31/2024] [Indexed: 09/14/2024]
Abstract
PURPOSE OF REVIEW Population receptive field (pRF) modeling is an fMRI technique used to retinotopically map visual cortex, with pRF size characterizing the degree of spatial integration. In clinical populations, most pRF mapping research has focused on damage to visual system inputs. Herein, we highlight recent work using pRF modeling to study high-level visual dysfunctions. RECENT FINDINGS Larger pRF sizes, indicating coarser spatial processing, were observed in homonymous visual field deficits, aging, and autism spectrum disorder. Smaller pRF sizes, indicating finer processing, were observed in Alzheimer's disease and schizophrenia. In posterior cortical atrophy, a unique pattern was found in which pRF size changes depended on eccentricity. Changes to pRF properties were observed in clinical populations, even in high-order impairments, explaining visual behavior. These pRF changes likely stem from altered interactions between brain regions. Furthermore, some studies suggested that pRF sizes change as part of cortical reorganization, and they can point towards future prognosis.
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Affiliation(s)
- Deena Elul
- fMRI Unit, Neurology Department Hadassah Medical Organization, Faculty of Medicine, The Hebrew University of Jerusalem, POB 12000, Jerusalem, 91120, Israel
- Edmond and Lily Safra Center for Brain Sciences (ELSC), The Hebrew University of Jerusalem, Jerusalem, Israel
| | - Netta Levin
- fMRI Unit, Neurology Department Hadassah Medical Organization, Faculty of Medicine, The Hebrew University of Jerusalem, POB 12000, Jerusalem, 91120, Israel.
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Ashtari M, Bennett J, Leopold DA. Central visual pathways affected by degenerative retinal disease before and after gene therapy. Brain 2024; 147:3234-3246. [PMID: 38538211 PMCID: PMC11370797 DOI: 10.1093/brain/awae096] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2023] [Revised: 02/09/2024] [Accepted: 02/20/2024] [Indexed: 09/04/2024] Open
Abstract
Genetic diseases affecting the retina can result in partial or complete loss of visual function. Leber's congenital amaurosis (LCA) is a rare blinding disease, usually inherited in an autosomally recessive manner, with no cure. Retinal gene therapy has been shown to improve vision in LCA patients caused by mutations in the RPE65 gene (LCA2). However, little is known about how activity in central visual pathways is affected by the disease or by subsequent gene therapy. Functional MRI (fMRI) was used to assess retinal signal transmission in cortical and subcortical visual structures before and 1 year after retinal intervention. The fMRI paradigm consisted of 15-s blocks of flickering (8 Hz) black and white checkerboards interleaved with 15 s of blank (black) screen. Visual activation in the brain was assessed using the general linear model, with multiple comparisons corrected using the false discovery rate method. Response to visual stimulation through untreated eyes of LCA2 patients showed heightened fMRI responses in the superior colliculus and diminished activities in the lateral geniculate nucleus (LGN) compared to controls, indicating a shift in the patients' visual processing towards the retinotectal pathway. Following gene therapy, stimuli presented to the treated eye elicited significantly stronger fMRI responses in the LGN and primary visual cortex, indicating some re-engagement of the geniculostriate pathway (GS) pathway. Across patients, the post-treatment LGN fMRI responses correlated significantly with performance on a clinical test measuring light sensitivity. Our results demonstrate that the low vision observed in LCA2 patients involves a shift in visual processing toward the retinotectal pathway, and that gene therapy partially reinstates visual transmission through the GS pathway. This selective boosting of retinal output through the GS pathway and its correlation to improved visual performance, following several years of degenerative retinal disease, is striking. However, while retinal gene therapy and other ocular interventions have given hope to RPE65 patients, it may take years before development of therapies tailored to treat the diseases in other low vision patients are available. Our demonstration of a shift toward the retinotectal pathway in these patients may spur the development of new tools and rehabilitation strategies to help maximize the use of residual visual abilities and augment experience-dependent plasticity.
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Affiliation(s)
- Manzar Ashtari
- Center for Advanced Retinal and Ocular Therapeutics (CAROT), University of Pennsylvania, Philadelphia, PA 19104, USA
- Department of Ophthalmology, University of Pennsylvania, Philadelphia, PA 19104, USA
- Department of Radiology, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Jean Bennett
- Center for Advanced Retinal and Ocular Therapeutics (CAROT), University of Pennsylvania, Philadelphia, PA 19104, USA
- Department of Ophthalmology, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - David A Leopold
- Laboratory of Neuropsychology, National Institute of Mental Health, National Institutes of Health, Bethesda, MD 20892, USA
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Molz B, Herbik A, Baseler HA, de Best P, Raz N, Gouws A, Ahmadi K, Lowndes R, McLean RJ, Gottlob I, Kohl S, Choritz L, Maguire J, Kanowski M, Käsmann-Kellner B, Wieland I, Banin E, Levin N, Morland AB, Hoffmann MB. Achromatopsia-Visual Cortex Stability and Plasticity in the Absence of Functional Cones. Invest Ophthalmol Vis Sci 2023; 64:23. [PMID: 37847226 PMCID: PMC10584018 DOI: 10.1167/iovs.64.13.23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2023] [Accepted: 08/07/2023] [Indexed: 10/18/2023] Open
Abstract
Purpose Achromatopsia is a rare inherited disorder rendering retinal cone photoreceptors nonfunctional. As a consequence, the sizable foveal representation in the visual cortex is congenitally deprived of visual input, which prompts a fundamental question: is the cortical representation of the central visual field in patients with achromatopsia remapped to take up processing of paracentral inputs? Such remapping might interfere with gene therapeutic treatments aimed at restoring cone function. Methods We conducted a multicenter study to explore the nature and plasticity of vision in the absence of functional cones in a cohort of 17 individuals affected by autosomal recessive achromatopsia and confirmed biallelic disease-causing CNGA3 or CNGB3 mutations. Specifically, we tested the hypothesis of foveal remapping in human achromatopsia. For this purpose, we applied two independent functional magnetic resonance imaging (fMRI)-based mapping approaches, i.e. conventional phase-encoded eccentricity and population receptive field mapping, to separate data sets. Results Both fMRI approaches produced the same result in the group comparison of achromatopsia versus healthy controls: sizable remapping of the representation of the central visual field in the primary visual cortex was not apparent. Conclusions Remapping of the cortical representation of the central visual field is not a general feature in achromatopsia. It is concluded that plasticity of the human primary visual cortex is less pronounced than previously assumed. A pretherapeutic imaging workup is proposed to optimize interventions.
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Affiliation(s)
- Barbara Molz
- Department of Psychology, University of York, Heslington, York, United Kingdom
- Department of Ophthalmology, University Hospital, Otto-von-Guericke University, Magdeburg, Germany
- Language & Genetics Department, Max Planck Institute for Psycholinguistics, Nijmegen, the Netherlands
| | - Anne Herbik
- Department of Ophthalmology, University Hospital, Otto-von-Guericke University, Magdeburg, Germany
| | - Heidi A. Baseler
- Department of Psychology, University of York, Heslington, York, United Kingdom
- Hull York Medical School, University of York, Heslington, York, United Kingdom
- York Biomedical Research Institute, University of York, Heslington, York, United Kingdom
| | - Peter de Best
- fMRI Unit, Department of Neurology, Hadassah Medical Center, Jerusalem, Israel
| | - Noa Raz
- fMRI Unit, Department of Neurology, Hadassah Medical Center, Jerusalem, Israel
| | - Andre Gouws
- Department of Psychology, University of York, Heslington, York, United Kingdom
- York Neuroimaging Centre, Department of Psychology, University of York, York, United Kingdom
| | - Khazar Ahmadi
- Department of Ophthalmology, University Hospital, Otto-von-Guericke University, Magdeburg, Germany
| | - Rebecca Lowndes
- York Neuroimaging Centre, Department of Psychology, University of York, York, United Kingdom
| | - Rebecca J. McLean
- University of Leicester Ulverscroft Eye Unit, University of Leicester, Leicester Royal Infirmary, Leicester, United Kingdom
| | - Irene Gottlob
- University of Leicester Ulverscroft Eye Unit, University of Leicester, Leicester Royal Infirmary, Leicester, United Kingdom
| | - Susanne Kohl
- Molecular Genetics Laboratory, Institute for Ophthalmic Research, Centre for Ophthalmology, University Clinics Tübingen, Tübingen, Germany
| | - Lars Choritz
- Department of Ophthalmology, University Hospital, Otto-von-Guericke University, Magdeburg, Germany
| | - John Maguire
- School of Optometry and Vision Sciences, University of Bradford, Bradford, United Kingdom
- Department of Neurophysiology, Children's Health Ireland (CHI) at Crumlin, Dublin, Ireland
| | - Martin Kanowski
- Department of Neurology, University Hospital, Otto-von-Guericke University, Magdeburg, Germany
| | - Barbara Käsmann-Kellner
- Department of Ophthalmology, Saarland University Hospital and Medical Faculty of the Saarland University Hospital, Homburg, Germany
| | - Ilse Wieland
- Department for Molecular Genetics, Institute for Human Genetics, University Hospital, Otto-von-Guericke University, Magdeburg, Germany
| | - Eyal Banin
- Center for Retinal and Macular Degenerations, Department of Ophthalmology, Hadassah-Hebrew University Medical Center, Jerusalem, Israel
| | - Netta Levin
- fMRI Unit, Department of Neurology, Hadassah Medical Center, Jerusalem, Israel
| | - Antony B. Morland
- Department of Psychology, University of York, Heslington, York, United Kingdom
- York Biomedical Research Institute, University of York, Heslington, York, United Kingdom
- York Neuroimaging Centre, Department of Psychology, University of York, York, United Kingdom
| | - Michael B. Hoffmann
- Department of Ophthalmology, University Hospital, Otto-von-Guericke University, Magdeburg, Germany
- Center for Behavioral Brain Sciences, Magdeburg, Germany
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Silson EH, Baker CI, Aleman TS, Maguire AM, Bennett J, Ashtari M. Motion-selective areas V5/MT and MST appear resistant to deterioration in choroideremia. Neuroimage Clin 2023; 38:103384. [PMID: 37023490 PMCID: PMC10119684 DOI: 10.1016/j.nicl.2023.103384] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2022] [Revised: 03/07/2023] [Accepted: 03/20/2023] [Indexed: 04/08/2023]
Abstract
Choroideremia (CHM) is an X-linked recessive form of hereditary retinal degeneration, which preserves only small islands of central retinal tissue. Previously, we demonstrated the relationship between central vision and structure and population receptive fields (pRF) using functional magnetic resonance imaging (fMRI) in untreated CHM subjects. Here, we replicate and extend this work, providing a more in-depth analysis of the visual responses in a cohort of CHM subjects who participated in a retinal gene therapy clinical trial. fMRI was conducted in six CHM subjects and six age-matched healthy controls (HC's) while they viewed drifting contrast pattern stimuli monocularly. A single ∼3-minute fMRI run was collected for each eye. Participants also underwent ophthalmic evaluations of visual acuity and static automatic perimetry (SAP). Consistent with our previous report, a single ∼ 3 min fMRI run accurately characterized ophthalmic evaluations of visual function in most CHM subjects. In-depth analyses of the cortical distribution of pRF responses revealed that the motion-selective regions V5/MT and MST appear resistant to progressive retinal degenerations in CHM subjects. This effect was restricted to V5/MT and MST and was not present in either primary visual cortex (V1), motion-selective V3A or regions within the ventral visual pathway. Motion-selective areas V5/MT and MST appear to be resistant to the continuous detrimental impact of CHM. Such resilience appears selective to these areas and may be mediated by independent retina-V5/MT anatomical connections that bypass V1. We did not observe any significant impact of gene therapy.
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Affiliation(s)
- Edward H Silson
- Section on Learning and Plasticity, Laboratory of Brain and Cognition, National Institute of Mental Health, National Institutes of Health, Bethesda, MD, United States
| | - Chris I Baker
- Section on Learning and Plasticity, Laboratory of Brain and Cognition, National Institute of Mental Health, National Institutes of Health, Bethesda, MD, United States
| | - Tomas S Aleman
- Center for Advanced Retinal and Ocular Therapeutics (CAROT), University of Pennsylvania, Philadelphia, PA, United States; F.M. Kirby Center for Molecular Ophthalmology, Scheie Eye Institute, University of Pennsylvania, Philadelphia, PA, United States
| | - Albert M Maguire
- Center for Advanced Retinal and Ocular Therapeutics (CAROT), University of Pennsylvania, Philadelphia, PA, United States; F.M. Kirby Center for Molecular Ophthalmology, Scheie Eye Institute, University of Pennsylvania, Philadelphia, PA, United States
| | - Jean Bennett
- Center for Advanced Retinal and Ocular Therapeutics (CAROT), University of Pennsylvania, Philadelphia, PA, United States; F.M. Kirby Center for Molecular Ophthalmology, Scheie Eye Institute, University of Pennsylvania, Philadelphia, PA, United States
| | - Manzar Ashtari
- Center for Advanced Retinal and Ocular Therapeutics (CAROT), University of Pennsylvania, Philadelphia, PA, United States; F.M. Kirby Center for Molecular Ophthalmology, Scheie Eye Institute, University of Pennsylvania, Philadelphia, PA, United States; Department of Radiology, University of Pennsylvania, Philadelphia, PA, United States.
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Pawloff M, Linhardt D, Woletz M, Hummer A, Sacu S, Vasileiadi M, Garikoitz LU, Holder G, Schmidt-Erfurth UM, Windischberger C, Ritter M. Comparison of Stimulus Types for Retinotopic Cortical Mapping of Macular Disease. Transl Vis Sci Technol 2023; 12:6. [PMID: 36912591 PMCID: PMC10020948 DOI: 10.1167/tvst.12.3.6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2022] [Accepted: 01/19/2023] [Indexed: 03/14/2023] Open
Abstract
Purpose Retinotopic maps acquired using functional magnetic resonance imaging (fMRI) provide a valuable adjunct in the assessment of macular function at the level of the visual cortex. The present study quantitatively assessed the performance of different visual stimulation approaches for mapping visual field coverage. Methods Twelve patients with geographic atrophy (GA) secondary to age-related macular degeneration (AMD) were examined using high-resolution ultra-high field fMRI (Siemens Magnetom 7T) and microperimetry (MP; Nidek MP-3). The population receptive field (pRF)-based coverage maps obtained with two different stimulus techniques (moving bars, and rotating wedges and expanding rings) were compared with the results of MP. Correspondence between MP and pRF mapping was quantified by calculating the simple matching coefficient (SMC). Results Stimulus choice is shown to bias the spatial distribution of pRF centers and eccentricity values with pRF sizes obtained from wedge/ring or bar stimulation showing systematic differences. Wedge/ring stimulation results show a higher number of pRF centers in foveal areas and strongly reduced pRF sizes compared to bar stimulation runs. A statistical comparison shows significantly higher pRF center numbers in the foveal 2.5 degrees region of the visual field for wedge/ring compared to bar stimuli. However, these differences do not significantly influence SMC values when compared to MP (bar <2.5 degrees: 0.88 ± 0.13; bar >2.5 degrees: 0.88 ± 0.11; wedge/ring <2.5 degrees: 0.89 ± 0.12 wedge/ring; >2.5 degrees: 0.86 ± 0.10) for the peripheral visual field. Conclusions Both visual stimulation designs examined can be applied successfully in patients with GA. Although the two designs show systematic differences in the distribution of pRF center locations, this variability has minimal impact on the SMC when compared to the MP outcome.
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Affiliation(s)
- Maximilian Pawloff
- Department of Ophthalmology, Medical University of Vienna, Vienna, Austria
| | - David Linhardt
- MR Center of Excellence, Center for Medical Physics and Biomedical Engineering, Medical University of Vienna, Vienna, Austria
| | - Michael Woletz
- MR Center of Excellence, Center for Medical Physics and Biomedical Engineering, Medical University of Vienna, Vienna, Austria
| | - Allan Hummer
- MR Center of Excellence, Center for Medical Physics and Biomedical Engineering, Medical University of Vienna, Vienna, Austria
| | - Stefan Sacu
- Department of Ophthalmology, Medical University of Vienna, Vienna, Austria
| | - Maria Vasileiadi
- MR Center of Excellence, Center for Medical Physics and Biomedical Engineering, Medical University of Vienna, Vienna, Austria
| | - Lerma Usabiaga Garikoitz
- BCBL Basque Center on Cognition, Brain and Language Donostia, San Sebastian, Gipuzkoa, Spain
- IKERBASQUE Basque Foundation for Science, Bilbao, Spain
| | - Graham Holder
- Department of Ophthalmology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore
- UCL Institute of Ophthalmology, London, UK
| | | | - Christian Windischberger
- MR Center of Excellence, Center for Medical Physics and Biomedical Engineering, Medical University of Vienna, Vienna, Austria
| | - Markus Ritter
- Department of Ophthalmology, Medical University of Vienna, Vienna, Austria
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Linhardt D, Pawloff M, Woletz M, Hummer A, Tik M, Vasileiadi M, Ritter M, Lerma-Usabiaga G, Schmidt-Erfurth U, Windischberger C. Intrasession and Intersession Reproducibility of Artificial Scotoma pRF Mapping Results at Ultra-High Fields. eNeuro 2022; 9:ENEURO.0087-22.2022. [PMID: 36635900 PMCID: PMC9512620 DOI: 10.1523/eneuro.0087-22.2022] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2022] [Revised: 06/29/2022] [Accepted: 08/23/2022] [Indexed: 02/02/2023] Open
Abstract
Functional magnetic resonance imaging (fMRI) combined with population receptive field (pRF) mapping allows for associating positions on the visual cortex to areas on the visual field. Apart from applications in healthy subjects, this method can also be used to examine dysfunctions in patients suffering from partial visual field losses. While such objective measurement of visual deficits (scotoma) is of great importance for, e.g., longitudinal studies addressing treatment effects, it requires a thorough assessment of accuracy and reproducibility of the results obtained. In this study, we quantified the reproducibility of pRF mapping results within and across sessions in case of central visual field loss in a group of 15 human subjects. We simulated scotoma by masking a central area of 2° radius from stimulation to establish ground-truth conditions. This study was performed on a 7T ultra-high field MRI scanner for increased sensitivity. We found excellent intrasession and intersession reproducibility for the pRF center position (Spearman correlation coefficients for x, y: >0.95; eccentricity: >0.87; polar angle: >0.98), but only modest reproducibility for pRF size (Spearman correlation coefficients around 0.4). We further examined the scotoma detection performance using an automated method based on a reference dataset acquired with full-field stimulation. For the 2° artificial scotoma, the group-averaged scotoma sizes were estimated at between 1.92° and 2.19° for different sessions. We conclude that pRF mapping of visual field losses yields robust, reproducible measures of retinal function and suggest the use of pRF mapping as an objective method for monitoring visual deficits during therapeutic interventions or disease progression.
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Affiliation(s)
- David Linhardt
- High Field MR Center, Center for Medical Physics and Biomedical Engineering, Medical University of Vienna, 1090 Vienna, Austria
| | - Maximilian Pawloff
- Department of Ophthalmology, Medical University of Vienna, 1090 Vienna, Austria
| | - Michael Woletz
- High Field MR Center, Center for Medical Physics and Biomedical Engineering, Medical University of Vienna, 1090 Vienna, Austria
| | - Allan Hummer
- High Field MR Center, Center for Medical Physics and Biomedical Engineering, Medical University of Vienna, 1090 Vienna, Austria
| | - Martin Tik
- High Field MR Center, Center for Medical Physics and Biomedical Engineering, Medical University of Vienna, 1090 Vienna, Austria
| | - Maria Vasileiadi
- High Field MR Center, Center for Medical Physics and Biomedical Engineering, Medical University of Vienna, 1090 Vienna, Austria
| | - Markus Ritter
- Department of Ophthalmology, Medical University of Vienna, 1090 Vienna, Austria
| | - Garikoitz Lerma-Usabiaga
- BCBL, Basque Center on Cognition, Brain and Language, 20009 Donostia-San Sebastián, Gipuzkoa, Spain
| | | | - Christian Windischberger
- High Field MR Center, Center for Medical Physics and Biomedical Engineering, Medical University of Vienna, 1090 Vienna, Austria
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Urale PWB, Puckett AM, York A, Arnold D, Schwarzkopf DS. Highly accurate retinotopic maps of the physiological blind spot in human visual cortex. Hum Brain Mapp 2022; 43:5111-5125. [PMID: 35796159 PMCID: PMC9812231 DOI: 10.1002/hbm.25996] [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: 01/19/2022] [Revised: 05/18/2022] [Accepted: 06/15/2022] [Indexed: 01/15/2023] Open
Abstract
The physiological blind spot is a naturally occurring scotoma corresponding with the optic disc in the retina of each eye. Even during monocular viewing, observers are usually oblivious to the scotoma, in part because the visual system extrapolates information from the surrounding area. Unfortunately, studying this visual field region with neuroimaging has proven difficult, as it occupies only a small part of retinotopic cortex. Here, we used functional magnetic resonance imaging and a novel data-driven method for mapping the retinotopic organization in and around the blind spot representation in V1. Our approach allowed for highly accurate reconstructions of the extent of an observer's blind spot, and out-performed conventional model-based analyses. This method opens exciting opportunities to study the plasticity of receptive fields after visual field loss, and our data add to evidence suggesting that the neural circuitry responsible for impressions of perceptual completion across the physiological blind spot most likely involves regions of extrastriate cortex-beyond V1.
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Affiliation(s)
- Poutasi W. B. Urale
- School of Optometry & Vision ScienceUniversity of AucklandAucklandNew Zealand
| | - Alexander M. Puckett
- School of PsychologyUniversity of QueenslandBrisbaneQueenslandAustralia
- Queensland Brain InstituteUniversity of QueenslandBrisbaneQueenslandAustralia
| | - Ashley York
- School of PsychologyUniversity of QueenslandBrisbaneQueenslandAustralia
- Queensland Brain InstituteUniversity of QueenslandBrisbaneQueenslandAustralia
| | - Derek Arnold
- School of PsychologyUniversity of QueenslandBrisbaneQueenslandAustralia
- Queensland Brain InstituteUniversity of QueenslandBrisbaneQueenslandAustralia
| | - D. Samuel Schwarzkopf
- School of Optometry & Vision ScienceUniversity of AucklandAucklandNew Zealand
- Experimental PsychologyUniversity College LondonLondonUnited Kingdom
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Groen IIA, Dekker TM, Knapen T, Silson EH. Visuospatial coding as ubiquitous scaffolding for human cognition. Trends Cogn Sci 2021; 26:81-96. [PMID: 34799253 DOI: 10.1016/j.tics.2021.10.011] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2021] [Revised: 10/19/2021] [Accepted: 10/19/2021] [Indexed: 01/28/2023]
Abstract
For more than 100 years we have known that the visual field is mapped onto the surface of visual cortex, imposing an inherently spatial reference frame on visual information processing. Recent studies highlight visuospatial coding not only throughout visual cortex, but also brain areas not typically considered visual. Such widespread access to visuospatial coding raises important questions about its role in wider cognitive functioning. Here, we synthesise these recent developments and propose that visuospatial coding scaffolds human cognition by providing a reference frame through which neural computations interface with environmental statistics and task demands via perception-action loops.
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Affiliation(s)
- Iris I A Groen
- Institute for Informatics, University of Amsterdam, Amsterdam, The Netherlands
| | - Tessa M Dekker
- Institute of Ophthalmology, University College London, London, UK
| | - Tomas Knapen
- Behavioral and Movement Sciences, Vrije Universiteit Amsterdam, Amsterdam, The Netherlands; Spinoza Centre for NeuroImaging, Royal Dutch Academy of Sciences, Amsterdam, The Netherlands
| | - Edward H Silson
- Department of Psychology, School of Philosophy, Psychology & Language Sciences, University of Edinburgh, Edinburgh, UK.
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Prabhakaran GT, Al-Nosairy KO, Tempelmann C, Thieme H, Hoffmann MB. Mapping Visual Field Defects With fMRI - Impact of Approach and Experimental Conditions. Front Neurosci 2021; 15:745886. [PMID: 34566575 PMCID: PMC8455880 DOI: 10.3389/fnins.2021.745886] [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] [Received: 07/22/2021] [Accepted: 08/19/2021] [Indexed: 11/13/2022] Open
Abstract
Current initiatives to restore vision emphasize the need for objective assessments of visual field (VF) defects as pursued with functional magnetic resonance imaging (fMRI) approaches. Here, we compared population receptive field (pRF) mapping-based VF reconstructions to an fMRI method that uses more robust visual stimulation (on-off block design) in combination with individualized anatomy-driven retinotopic atlas-information (atlas-based VF). We investigated participants with sizable peripheral VF-deficits due to advanced glaucoma (n = 4) or retinitis pigmentosa (RP; n = 2) and controls (n = 6) with simulated scotoma. We obtained (1) standard automated perimetry (SAP) data as reference VFs and 3T fMRI data for (2) pRF-mapping [8-direction bar stimulus, fixation color change task] and (3) block-design full-field stimulation [8-direction drifting contrast patterns during (a) passive viewing (PV) and (b) one-back-task (OBT; reporting successions of identical motion directions) to probe the impact of previously reported task-related unspecific visual cortex activations]. Correspondence measures between the SAP and fMRI-based VFs were accuracy, assisted by sensitivity and specificity. We found an accuracy of pRF-based VF from V1 in patients [median: 0.62] that was similar to previous reports and increased by adding V2 and V3 to the analysis [0.74]. In comparison to the pRF-based VF, equivalent accuracies were obtained for the atlas-based VF for both PV [0.67] and, unexpectedly, the OBT [0.59], where, however, unspecific cortical activations were reflected by a reduction in sensitivity [0.71 (PV) and 0.35 (OBT)]. In conclusion, in patients with peripheral VF-defects, we demonstrate that previous fMRI procedures to obtain VF-estimates might be enhanced by: (1) pooling V1-V3 to enhance accuracy; (2) reporting sensitivity and specificity measures to increase transparency of the VF-reconstruction metric; (3) applying atlas-based procedures, if pRF-based VFs are not available or difficult to obtain; and (4) giving, counter-intuitively, preference to PV. These findings are expected to provide guidance to overcome current limitations of translating fMRI-based methods to a clinical work-up.
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Affiliation(s)
| | | | - Claus Tempelmann
- Department of Neurology, Otto von Guericke University, Magdeburg, Germany
| | - Hagen Thieme
- Department of Ophthalmology, Otto von Guericke University, Magdeburg, Germany
| | - Michael B Hoffmann
- Department of Ophthalmology, Otto von Guericke University, Magdeburg, Germany.,Center for Behavioral Brain Sciences, Magdeburg, Germany
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10
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Halbertsma HN, Bridge H, Carvalho J, Cornelissen FW, Ajina S. Visual Field Reconstruction in Hemianopia Using fMRI Based Mapping Techniques. Front Hum Neurosci 2021; 15:713114. [PMID: 34447301 PMCID: PMC8382851 DOI: 10.3389/fnhum.2021.713114] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2021] [Accepted: 07/21/2021] [Indexed: 11/21/2022] Open
Abstract
PURPOSE A stroke that includes the primary visual cortex unilaterally leads to a loss of visual field (VF) representation in the hemifield contralateral to the damage. While behavioral procedures for measuring the VF, such as perimetry, may indicate that a patient cannot see in a particular area, detailed psychophysical testing often detects the ability to perform detection or discrimination of visual stimuli ("blindsight"). The aim of this study was to determine whether functional magnetic resonance imaging (fMRI) could be used to determine whether perimetrically blind regions of the VF were still represented in VF maps reconstructed on the basis of visually evoked neural activity. METHODS Thirteen patients with hemianopia and nine control participants were scanned using 3T MRI while presented with visual stimulation. Two runs of a dynamic "wedge and ring" mapping stimulus, totaling approximately 10 min, were performed while participants fixated centrally. Two different analysis approaches were taken: the conventional population receptive field (pRF) analysis and micro-probing (MP). The latter is a variant of the former that makes fewer assumptions when modeling the visually evoked neural activity. Both methods were used to reconstruct the VF by projecting modeled activity back onto the VF. Following a normalization step, these "coverage maps" can be compared to the VF sensitivity plots obtained using perimetry. RESULTS While both fMRI-based approaches revealed regions of neural activity within the perimetrically "blind" sections of the VF, the MP approach uncovered more voxels in the lesioned hemisphere in which a modest degree of visual sensitivity was retained. Furthermore, MP-based analysis indicated that both early (V1/V2) and extrastriate visual areas contributed equally to the retained sensitivity in both patients and controls. CONCLUSION In hemianopic patients, fMRI-based approaches for reconstructing the VF can pick up activity in perimetrically blind regions of the VF. Such regions of the VF may be particularly amenable for rehabilitation to regain visual function. Compared to conventional pRF modeling, MP reveals more voxels with retained visual sensitivity, suggesting it is a more sensitive approach for VF reconstruction.
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Affiliation(s)
- Hinke N. Halbertsma
- Laboratory for Experimental Ophthalmology, University of Groningen, University Medical Center Groningen, Groningen, Netherlands
| | - Holly Bridge
- Wellcome Centre for Integrative Neuroimaging, Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford, United Kingdom
| | - Joana Carvalho
- Champalimaud Centre for the Unknown, Champalimaud Foundation, Lisbon, Portugal
| | - Frans W. Cornelissen
- Laboratory for Experimental Ophthalmology, University of Groningen, University Medical Center Groningen, Groningen, Netherlands
| | - Sara Ajina
- Wellcome Centre for Integrative Neuroimaging, Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford, United Kingdom
- Department of Neurorehabilitation, National Hospital for Neurology and Neurosurgery, London, United Kingdom
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Linhardt D, Pawloff M, Hummer A, Woletz M, Tik M, Ritter M, Schmidt-Erfurth U, Windischberger C. Combining stimulus types for improved coverage in population receptive field mapping. Neuroimage 2021; 238:118240. [PMID: 34116157 DOI: 10.1016/j.neuroimage.2021.118240] [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: 05/12/2021] [Accepted: 06/04/2021] [Indexed: 10/21/2022] Open
Abstract
Retinotopy experiments using population receptive field (pRF) mapping are ideal for assigning regions in the visual field to cortical brain areas. While various designs for visual stimulation were suggested in the literature, all have specific shortcomings regarding visual field coverage. Here we acquired high-resolution 7 Tesla fMRI data to compare pRF-based coverage maps obtained with the two most commonly used stimulus variants: moving bars; rotating wedges and expanding rings. We find that stimulus selection biases the spatial distribution of pRF centres. In addition, eccentricity values and pRF sizes obtained from wedge/ring or bar stimulation runs show systematic differences. Wedge/ring stimulation results show lower eccentricity values and strongly reduced pRF sizes compared to bar stimulation runs. Statistical comparison shows significantly higher pRF centre numbers in the foveal 2° region of the visual field for wedge/ring compared to bar stimuli. We suggest and evaluate approaches for combining pRF data from different visual stimulus patterns to obtain improved mapping results.
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Affiliation(s)
- David Linhardt
- High Field MR Center, Center for Medical Physics and Biomedical Engineering, Medical University of Vienna, Vienna, Austria
| | - Maximilian Pawloff
- Department of Ophthalmology, Medical University of Vienna, Vienna, Austria
| | - Allan Hummer
- High Field MR Center, Center for Medical Physics and Biomedical Engineering, Medical University of Vienna, Vienna, Austria
| | - Michael Woletz
- High Field MR Center, Center for Medical Physics and Biomedical Engineering, Medical University of Vienna, Vienna, Austria
| | - Martin Tik
- High Field MR Center, Center for Medical Physics and Biomedical Engineering, Medical University of Vienna, Vienna, Austria
| | - Markus Ritter
- Department of Ophthalmology, Medical University of Vienna, Vienna, Austria
| | | | - Christian Windischberger
- High Field MR Center, Center for Medical Physics and Biomedical Engineering, Medical University of Vienna, Vienna, Austria.
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12
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Elshout JA, Bergsma DP, van den Berg AV, Haak KV. Functional MRI of visual cortex predicts training-induced recovery in stroke patients with homonymous visual field defects. NEUROIMAGE-CLINICAL 2021; 31:102703. [PMID: 34062384 PMCID: PMC8173295 DOI: 10.1016/j.nicl.2021.102703] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/27/2020] [Revised: 05/17/2021] [Accepted: 05/18/2021] [Indexed: 12/28/2022]
Abstract
Damage to the visual brain typically leads to vision loss. Vision loss may be partially recovered with visual restitution training (VRT) Cortical responses to visual stimulation do not always lead to visual awareness. A mismatch between Humphrey and neural perimetry predicts training outcome. This finding has important implications for better rehabilitation strategies.
Post-chiasmatic damage to the visual system leads to homonymous visual field defects (HVDs), which can severely interfere with daily life activities. Visual Restitution Training (VRT) can recover parts of the affected visual field in patients with chronic HVDs, but training outcome is variable. An untested hypothesis suggests that training potential may be largest in regions with ‘neural reserve’, where cortical responses to visual stimulation do not lead to visual awareness as assessed by Humphrey perimetry—a standard behavioural visual field test. Here, we tested this hypothesis in a sample of twenty-seven hemianopic stroke patients, who participated in an assiduous 80-hour VRT program. For each patient, we collected Humphrey perimetry and wide-field fMRI-based retinotopic mapping data prior to training. In addition, we used Goal Attainment Scaling to assess whether personal activities in daily living improved. After training, we assessed with a second Humphrey perimetry measurement whether the visual field was improved and evaluated which personal goals were attained. Confirming the hypothesis, we found significantly larger improvements of visual sensitivity at field locations with neural reserve. These visual field improvements implicated both regions in primary visual cortex and higher order visual areas. In addition, improvement in daily life activities correlated with the extent of visual field enlargement. Our findings are an important step toward understanding the mechanisms of visual restitution as well as predicting training efficacy in stroke patients with chronic hemianopia.
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Affiliation(s)
- J A Elshout
- Donders Institute for Brain, Cognition and Behaviour, Radboud University Medical Centre, Nijmegen, The Netherlands
| | - D P Bergsma
- Donders Institute for Brain, Cognition and Behaviour, Radboud University Medical Centre, Nijmegen, The Netherlands
| | - A V van den Berg
- Donders Institute for Brain, Cognition and Behaviour, Radboud University Medical Centre, Nijmegen, The Netherlands
| | - K V Haak
- Donders Institute for Brain, Cognition and Behaviour, Radboud University Medical Centre, Nijmegen, The Netherlands.
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13
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Carvalho J, Invernizzi A, Martins J, Jansonius NM, Renken RJ, Cornelissen FW. Visual Field Reconstruction Using fMRI-Based Techniques. Transl Vis Sci Technol 2021; 10:25. [PMID: 33520421 PMCID: PMC7814355 DOI: 10.1167/tvst.10.1.25] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2020] [Accepted: 11/18/2020] [Indexed: 11/24/2022] Open
Abstract
Purpose To evaluate the accuracy and reliability of functional magnetic resonance imaging (fMRI)-based techniques to assess the integrity of the visual field (VF). Methods We combined 3T fMRI and neurocomputational models, that is, conventional population receptive field (pRF) mapping and a new advanced pRF framework "microprobing" (MP), to reconstruct the VF representations of different cortical areas. To demonstrate their scope, both approaches were applied in healthy participants with simulated scotomas and participants with glaucoma. For the latter group we compared the VFs obtained with standard automated perimetry (SAP) and via fMRI. Results Using SS, we found that the fMRI-based techniques can detect absolute defects in VFs that are larger than 3°, in single participants, based on 12 minutes of fMRI scan time. Moreover, we found that the MP approach results in a less biased estimation of the preserved VF. In participants with glaucoma, we found that fMRI-based VF reconstruction detected VF defects with a correspondence to SAP that was decent, reflected by the positive correlation between fMRI-based sampling density and SAP-based contrast sensitivity loss (SAP) r2 = 0.44, P = 0.0002. This correlation was higher for MP compared to that for the conventional pRF analysis. Conclusions The fMRI-based reconstruction of the VF enables the evaluation of vision loss and provides useful details on the properties of the visual cortex. Translational Relevance The fMRI-based VF reconstruction provides an objective alternative to detect VF defects. It may either complement SAP or could provide VF information in patients unable to perform SAP.
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Affiliation(s)
- Joana Carvalho
- Laboratory of Experimental Ophthalmology, University Medical Center Groningen, University of Groningen, The Netherlands
| | - Azzurra Invernizzi
- Laboratory of Experimental Ophthalmology, University Medical Center Groningen, University of Groningen, The Netherlands
| | - Joana Martins
- Laboratory of Experimental Ophthalmology, University Medical Center Groningen, University of Groningen, The Netherlands
| | - Nomdo M. Jansonius
- Laboratory of Experimental Ophthalmology, University Medical Center Groningen, University of Groningen, The Netherlands
| | - Remco J. Renken
- Laboratory of Experimental Ophthalmology, University Medical Center Groningen, University of Groningen, The Netherlands
- Cognitive Neuroscience Center, University Medical Center Groningen, University of Groningen, The Netherlands
| | - Frans W. Cornelissen
- Laboratory of Experimental Ophthalmology, University Medical Center Groningen, University of Groningen, The Netherlands
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A low-cost telescope for enhanced stimulus visual field coverage in functional MRI. J Neurosci Methods 2020; 350:109023. [PMID: 33316315 DOI: 10.1016/j.jneumeth.2020.109023] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2020] [Revised: 10/29/2020] [Accepted: 12/03/2020] [Indexed: 11/23/2022]
Abstract
BACKGROUND A common limitation of typical projection systems used for visual fMRI is the limited field of view that can be presented to the observer within the scanner. A wide field of view over which stimuli can be presented is critical when investigating peripheral visual function, in particular visual disorders or diseases that lead to the loss of peripheral vision. NEW METHOD We present a relatively low-cost Galilean telescopic device that can be used in most MRI scanners to double the effective visual field being presented. The system described is non-ferromagnetic, and compatible with most standard methods of visual presentation in MRI environments. The increase in area of visual cortex activation was quantified by comparing the extent of visual activity evoked by observing flickering checkerboards with and without the telescope in place. RESULTS In all three observers that reported image fusion from the telescope, the extent of cortical activation was greater with the telescope, while in the fourth observer there was no difference between the two methods due to a lack of fusion. CONCLUSION The telescope is a low cost, easy to implement solution in situations where changes to the existing equipment or setup are not feasible.
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Studying Cortical Plasticity in Ophthalmic and Neurological Disorders: From Stimulus-Driven to Cortical Circuitry Modeling Approaches. Neural Plast 2019; 2019:2724101. [PMID: 31814821 PMCID: PMC6877932 DOI: 10.1155/2019/2724101] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2019] [Accepted: 08/05/2019] [Indexed: 12/30/2022] Open
Abstract
Unsolved questions in computational visual neuroscience research are whether and how neurons and their connecting cortical networks can adapt when normal vision is compromised by a neurodevelopmental disorder or damage to the visual system. This question on neuroplasticity is particularly relevant in the context of rehabilitation therapies that attempt to overcome limitations or damage, through either perceptual training or retinal and cortical implants. Studies on cortical neuroplasticity have generally made the assumption that neuronal population properties and the resulting visual field maps are stable in healthy observers. Consequently, differences in the estimates of these properties between patients and healthy observers have been taken as a straightforward indication for neuroplasticity. However, recent studies imply that the modeled neuronal properties and the cortical visual maps vary substantially within healthy participants, e.g., in response to specific stimuli or under the influence of cognitive factors such as attention. Although notable advances have been made to improve the reliability of stimulus-driven approaches, the reliance on the visual input remains a challenge for the interpretability of the obtained results. Therefore, we argue that there is an important role in the study of cortical neuroplasticity for approaches that assess intracortical signal processing and circuitry models that can link visual cortex anatomy, function, and dynamics.
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