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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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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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Molz B, Herbik A, Baseler HA, de Best PB, Vernon RW, Raz N, Gouws AD, 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, Hoffmann MB, Morland AB. Structural changes to primary visual cortex in the congenital absence of cone input in achromatopsia. Neuroimage Clin 2022; 33:102925. [PMID: 34959047 PMCID: PMC8718719 DOI: 10.1016/j.nicl.2021.102925] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2021] [Revised: 12/20/2021] [Accepted: 12/21/2021] [Indexed: 11/30/2022]
Abstract
Anatomy of primary visual cortex (V1) assessed with surface-based morphmetry in those with congenital achromatopsia (ACHM). Reduction in cortical surface area in foveal, parafoveal and paracentral representations of V1 in those with ACHM. In ACHM a localized thickening in the area of V1 that represents the region of retina occupied solely by cones. V1 changes in ACHM may limit its ability to take on normal properties if retinal function were to be restored. Early intervention, before the development plastic period is over, may offer better restoration of vision in ACHM.
Autosomal recessive Achromatopsia (ACHM) is a rare inherited disorder associated with dysfunctional cone photoreceptors resulting in a congenital absence of cone input to visual cortex. This might lead to distinct changes in cortical architecture with a negative impact on the success of gene augmentation therapies. To investigate the status of the visual cortex in these patients, we performed a multi-centre study focusing on the cortical structure of regions that normally receive predominantly cone input. Using high-resolution T1-weighted MRI scans and surface-based morphometry, we compared cortical thickness, surface area and grey matter volume in foveal, parafoveal and paracentral representations of primary visual cortex in 15 individuals with ACHM and 42 normally sighted, healthy controls (HC). In ACHM, surface area was reduced in all tested representations, while thickening of the cortex was found highly localized to the most central representation. These results were comparable to more widespread changes in brain structure reported in congenitally blind individuals, suggesting similar developmental processes, i.e., irrespective of the underlying cause and extent of vision loss. The cortical differences we report here could limit the success of treatment of ACHM in adulthood. Interventions earlier in life when cortical structure is not different from normal would likely offer better visual outcomes for those with ACHM.
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Affiliation(s)
- Barbara Molz
- Department of Psychology, University of York, Heslington, YO10 5DD York, United Kingdom; Language and Genetics Department, Max Planck Institute for Psycholinguistics, 6525 XD Nijmegen, Netherlands
| | - Anne Herbik
- Department of Ophthalmology, University Hospital, Otto-von-Guericke University, 39120 Magdeburg, Germany
| | - Heidi A Baseler
- Department of Psychology, University of York, Heslington, YO10 5DD York, United Kingdom; Hull York Medical School, University of York, Heslington, YO10 5DD York, United Kingdom; York Biomedical Research Institute, University of York, Heslington, YO10 5DD York, United Kingdom
| | - Pieter B de Best
- MRI Unit, Department of Neurology, Hadassah Medical Center, 91120 Jerusalem, Israel
| | - Richard W Vernon
- Department of Psychology, University of York, Heslington, YO10 5DD York, United Kingdom
| | - Noa Raz
- MRI Unit, Department of Neurology, Hadassah Medical Center, 91120 Jerusalem, Israel
| | - Andre D Gouws
- York Neuroimaging Centre, Department of Psychology, University of York, YO10 5NY York, United Kingdom
| | - Khazar Ahmadi
- Department of Ophthalmology, University Hospital, Otto-von-Guericke University, 39120 Magdeburg, Germany
| | - Rebecca Lowndes
- York Neuroimaging Centre, Department of Psychology, University of York, YO10 5NY York, United Kingdom
| | - Rebecca J McLean
- University of Leicester Ulverscroft Eye Unit, University of Leicester, Leicester Royal Infirmary, LE2 7LX Leicester, United Kingdom
| | - Irene Gottlob
- University of Leicester Ulverscroft Eye Unit, University of Leicester, Leicester Royal Infirmary, LE2 7LX Leicester, United Kingdom
| | - Susanne Kohl
- Molecular Genetics Laboratory, Institute for Ophthalmic Research, Centre for Ophthalmology, University Clinics Tübingen, 72076 Tübingen, Germany
| | - Lars Choritz
- Department of Ophthalmology, University Hospital, Otto-von-Guericke University, 39120 Magdeburg, Germany
| | - John Maguire
- School of Optometry and Vision Sciences, University of Bradford, BD7 1DP Bradford, United Kingdom
| | - Martin Kanowski
- Department of Neurology, University Hospital, Otto-von-Guericke University, 39120 Magdeburg, Germany
| | - Barbara Käsmann-Kellner
- Department of Ophthalmology, Saarland University Hospital and Medical Faculty of the Saarland University, 66421 Homburg, Germany
| | - Ilse Wieland
- Department for Molecular Genetics, Institute for Human Genetics, University Hospital, Otto-von-Guericke University, 39120 Magdeburg, Germany
| | - Eyal Banin
- Degenerative Diseases of the Retina Unit, Department of Ophthalmology, Hadassah Medical Center, 91120 Jerusalem, Israel
| | - Netta Levin
- MRI Unit, Department of Neurology, Hadassah Medical Center, 91120 Jerusalem, Israel
| | - Michael B Hoffmann
- Department of Ophthalmology, University Hospital, Otto-von-Guericke University, 39120 Magdeburg, Germany; Center for Behavioral Brain Sciences, 39106 Magdeburg, Germany
| | - Antony B Morland
- Department of Psychology, University of York, Heslington, YO10 5DD York, United Kingdom; York Biomedical Research Institute, University of York, Heslington, YO10 5DD York, United Kingdom; York Neuroimaging Centre, Department of Psychology, University of York, YO10 5NY York, United Kingdom.
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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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Gaze direction influences grasping actions towards unseen, haptically explored, objects. Sci Rep 2020; 10:15774. [PMID: 32978418 PMCID: PMC7519081 DOI: 10.1038/s41598-020-72554-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2020] [Accepted: 08/04/2020] [Indexed: 11/25/2022] Open
Abstract
Haptic exploration produces mental object representations that can be memorized for subsequent object-directed behaviour. Storage of haptically-acquired object images (HOIs), engages, besides canonical somatosensory areas, the early visual cortex (EVC). Clear evidence for a causal contribution of EVC to HOI representation is still lacking. The use of visual information by the grasping system undergoes necessarily a frame of reference shift by integrating eye-position. We hypothesize that if the motor system uses HOIs stored in a retinotopic coding in the visual cortex, then its use is likely to depend at least in part on eye position. We measured the kinematics of 4 fingers in the right hand of 15 healthy participants during the task of grasping different unseen objects behind an opaque panel, that had been previously explored haptically. The participants never saw the object and operated exclusively based on haptic information. The position of the object was fixed, in front of the participant, but the subject’s gaze varied from trial to trial between 3 possible positions, towards the unseen object or away from it, on either side. Results showed that the middle and little fingers’ kinematics during reaching for the unseen object changed significantly according to gaze position. In a control experiment we showed that intransitive hand movements were not modulated by gaze direction. Manipulating eye-position produces small but significant configuration errors, (behavioural errors due to shifts in frame of reference) possibly related to an eye-centered frame of reference, despite the absence of visual information, indicating sharing of resources between the haptic and the visual/oculomotor system to delayed haptic grasping.
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Castaldi E, Lunghi C, Morrone MC. Neuroplasticity in adult human visual cortex. Neurosci Biobehav Rev 2020; 112:542-552. [DOI: 10.1016/j.neubiorev.2020.02.028] [Citation(s) in RCA: 52] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2019] [Revised: 12/30/2019] [Accepted: 02/20/2020] [Indexed: 12/27/2022]
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Abstract
Background Several neuroimaging studies demonstrated that visual deprivation led to significant cross-modal plasticity in the brain’s functional and anatomical architecture. Purpose To investigate the pattern of the interhemispheric functional connectivity in individuals with late blindness using the voxel-mirrored homotopic connectivity (VMHC) and seed-based functional connectivity (FC) methods. Material and Methods Forty-four individuals with late blindness (22 men, 22 women; mean age = 39.88 ± 12.84 years) and 55 sighted control individuals (35 men, 20 women; mean age = 43.13 ± 13.98 years)—closely matched for age, sex, and education—underwent resting-state magnetic resonance imaging scans. The VMHC and seed-based FC methods were applied to assess interhemispheric coordination in a voxel-wise manner. Results Compared with the sighted control groups, the late blindness groups showed decreased VMHC values in the bilateral cuneus/calcarine/lingual gyrus (CUN/CAL/LING) (BA 17/18/19) (voxel level: P < 0.001, Gaussian random field [GRF] correction, cluster level: P < 0.005). Meanwhile, for seed-based FC analysis, compared with the sighted control group, the late blindness group showed a decreased FC between the right lower VMHC regions and the bilateral CUN/LING/CAL/precuneus (PreCUN)/left middle occipital gyrus (MOG) (BA 18/19/30/31) and left precentral gyrus (PreCG) and postcentral gyrus (PostCG) (BA 2/3/4/6). The late blindness group showed a decreased FC between the left lower VMHC regions and the bilateral CUN/LING/CAL/PreCUN (BA 18/19/31) and left PreCG and PostCG (BA 2/3/4/6) relative to the sighted control group (voxel level: P < 0.001, GRF correction, cluster level: P < 0.005). Moreover, a negative correlation was observed between the duration of blindness and VMHC values in the bilateral CUN/CAL/LING (r = −0.393, P = 0.008) in individuals with late blindness. Conclusion Our results indicated that late blindness induced substantial impairment of interhemispheric coordination in the visual cortex. This might reflect impaired visual fusion, visual recognition function, and top-down modulations in individuals with late blindness.
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Affiliation(s)
- Xin Huang
- Eye Center, Renmin Hospital of Wuhan University, Wuhan, PR China
| | - Fu-Qing Zhou
- Department of Radiology, The First Affiliated Hospital of Nanchang University, Jiangxi Province Medical Imaging Research Institute, Nanchang, PR China
| | - Han-Dong Dan
- Eye Center, Renmin Hospital of Wuhan University, Wuhan, PR China
| | - Yin Shen
- Eye Center, Renmin Hospital of Wuhan University, Wuhan, PR 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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Lunghi C, Galli-Resta L, Binda P, Cicchini GM, Placidi G, Falsini B, Morrone MC. Visual Cortical Plasticity in Retinitis Pigmentosa. Invest Ophthalmol Vis Sci 2019; 60:2753-2763. [PMID: 31247082 PMCID: PMC6746622 DOI: 10.1167/iovs.18-25750] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
Abstract
Purpose Retinitis pigmentosa is a family of genetic diseases inducing progressive photoreceptor degeneration. There is no cure for retinitis pigmentosa, but prospective therapeutic strategies are aimed at restoring or substituting retinal input. Yet, it is unclear whether the visual cortex of retinitis pigmentosa patients retains plasticity to react to the restored visual input. Methods To investigate short-term visual cortical plasticity in retinitis pigmentosa, we tested the effect of short-term (2 hours) monocular deprivation on sensory ocular dominance (measured with binocular rivalry) in a group of 14 patients diagnosed with retinitis pigmentosa with a central visual field sparing greater than 20° in diameter. Results After deprivation most patients showed a perceptual shift in ocular dominance in favor of the deprived eye (P < 0.001), as did control subjects, indicating a level of visual cortical plasticity in the normal range. The deprivation effect correlated negatively with visual acuity (r = −0.63, P = 0.015), and with the amplitude of the central 18° focal electroretinogram (r = −0.68, P = 0.015) of the deprived eye, revealing that in retinitis pigmentosa stronger visual impairment is associated with higher plasticity. Conclusions Our results provide a new tool to assess the ability of retinitis pigmentosa patients to adapt to altered visual inputs, and suggest that in retinitis pigmentosa the adult brain has sufficient short-term plasticity to benefit from prospective therapies.
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Affiliation(s)
- Claudia Lunghi
- Laboratoire des systèmes perceptifs, Département d'études Cognitives, École Normale Supérieure, PSL University, CNRS, Paris, France.,Department of Translational Research and New Technologies in Medicine and Surgery, University of Pisa, Pisa, Italy
| | | | - Paola Binda
- Department of Translational Research and New Technologies in Medicine and Surgery, University of Pisa, Pisa, Italy.,Institute of Neuroscience CNR, Pisa, Italy
| | | | - Giorgio Placidi
- Department of Ophthalmology, Policlinico Gemelli, Università Cattolica del Sacro Cuore, Rome, Italy
| | - Benedetto Falsini
- Department of Ophthalmology, Policlinico Gemelli, Università Cattolica del Sacro Cuore, Rome, 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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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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Dan H, Shen Y, Huang X, Zhou F, Xing Y. Arterial Spin Labeling Perfusion Magnetic Resonance Imaging Reveals Resting Cerebral Blood Flow Alterations Specific to Retinitis Pigmentosa Patients. Curr Eye Res 2019; 44:1353-1359. [PMID: 31352839 DOI: 10.1080/02713683.2019.1649702] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
Purpose: This study aimed to assess resting cerebral blood flow (CBF) changes in retinitis pigmentosa (RP) patients using a pseudo-continuous arterial spin labeling (pCASL) perfusion method.Methods: Forty-nine RP patients and 51 healthy controls (HCs) underwent T1-weighted structural and pCASL sequence magnetic resonance imaging (MRI) scans at rest. Two-sample t-tests were performed to compare CBF differences between groups. Pearson correlation was used to analyze relationships between CBF values and clinical variables in the RP group.Results: Compared with HCs, RP patients had significantly lower CBF values in the bilateral cuneus/lingual gyrus/precuneus/posterior cingulate/middle occipital gyrus. In the RP group, CBF values in the left middle occipital and inferior occipital gyrus were positively correlated with mean retinal nerve fiber layer thickness; furthermore, CBF values in several regions were correlated with duration of disease and age of onset.Conclusions: Our results highlighted that RP patients exhibited decreased CBF values in the visual cortices and vision-related cortices. The results suggest that altered CBF might contribute to trans-synaptic retrograde degeneration of the visual pathway in RP patients.
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Affiliation(s)
- Handong Dan
- Eye Center, Renmin Hospital of Wuhan University, Wuhan, Hubei, China
| | - Yin Shen
- Eye Center, Renmin Hospital of Wuhan University, Wuhan, Hubei, China
| | - Xin Huang
- Eye Center, Renmin Hospital of Wuhan University, Wuhan, Hubei, China
| | - Fuqing Zhou
- Eye Center, Renmin Hospital of Wuhan University, Wuhan, Hubei, China.,Department of Radiology, The First Affiliated Hospital of Nanchang University, Jiangxi Province Medical Imaging Research Institute, Nanchang, Jiangxi, China
| | - Yiqiao Xing
- Eye Center, Renmin Hospital of Wuhan University, Wuhan, Hubei, China
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12
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Abnormal intrinsic brain activity in individuals with peripheral vision loss because of retinitis pigmentosa using amplitude of low-frequency fluctuations. Neuroreport 2019; 29:1323-1332. [PMID: 30113921 DOI: 10.1097/wnr.0000000000001116] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
The study aimed to determine alterations in intrinsic brain activity in retinitis pigmentosa (RP) individuals using the amplitude of low-frequency fluctuation (ALFF)/fractional amplitude of low-frequency fluctuation (fALFF) method. Sixteen RP individuals (10 men and six women) and 14 healthy controls (HCs) (six men and eight women) closely matched in age, sex, and education were enrolled in the study. The ALFF/fALFF method was applied to compare different intrinsic brain activities between the RP group and the HC group. The relationship between the mean ALFF/fALFF signal values of different brain regions and the visual measurements in RP group was analyzed by Pearson correlation. Compared with HCs, RP individuals had significantly lower ALFF values in the bilateral lingual gyrus (LIGG)/cerebellum posterior lobe [Brodmann area (BA) 17,18], but lower fALFF values in the bilateral LIGG/cerebellum anterior lobe (BA 17,18). Meanwhile, RP individuals had significantly higher ALFF in the bilateral precuneus cortex/middle cingulate cortex (BA 7,31), as well as higher fALFF values in the left superior/middle frontal gyrus (BA 9,10) and bilateral supplementary motor area (BA 6,8) (voxel-level P<0.01, cluster-level P<0.05). Moreover, the fALFF values of the bilateral LIGG/cerebellum anterior lobe showed positive relationships with the best-corrected visual acuity (BCVA)-oculus dexter (r=0.574, P=0.020) and BCVA-oculus sinister (r=0.570, P=0.021) in RP individuals; our results provide evidence that RP individuals may have impaired intrinsic brain activity in the primary visual area and the visuomotor coordination area that correlates with BCVA. Moreover, our findings indicate that reorganization of the dorsal visual stream and the parietoprefrontal pathway occurs in RP individuals.
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Dan HD, Zhou FQ, Huang X, Xing YQ, Shen Y. Altered intra- and inter-regional functional connectivity of the visual cortex in individuals with peripheral vision loss due to retinitis pigmentosa. Vision Res 2019; 159:68-75. [PMID: 30904614 DOI: 10.1016/j.visres.2019.02.013] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2018] [Revised: 02/04/2019] [Accepted: 02/27/2019] [Indexed: 01/05/2023]
Abstract
This study investigated changes in intra- and inter-regional functional connectivity (FC) in individuals with retinitis pigmentosa (RP) by using regional homogeneity (ReHo) and FC methods. Sixteen RP individuals and 14 healthy controls (HCs) underwent resting-state functional magnetic resonance imaging scans (fMRI). A combined ReHo and FC method was conducted to evaluate synchronization of brain activity. Compared with HCs, RP individuals had significantly lower ReHo values in the bilateral lingual gyrus/cerebellum posterior lobe (LGG/CPL). In FC analysis, the RP group showed decreased positive FC relative to the HC group, from bilateral LGG/CPL to bilateral LGG/cuneus (CUN) and to left postcentral gyrus (PosCG). In contrast, the RP group showed increased negative FC relative to the HC group, from bilateral LGG/CPL to bilateral thalamus, and decreased negative FC from bilateral LGG/CPL to right middle frontal gyrus (MFG), and to left inferior parietal lobule (IPL). Moreover, ReHo values of the bilateral LGG/CPL showed negative correlations with the duration of RP. FC values of the bilateral LGG/CPL-left IPL showed negative correlations with best-corrected visual acuity (BCVA) of the right eye and left eye in RP individuals. Our results reveal reduced synchronicity of neural activity changes in the primary visual area in RP individuals. Moreover, RP individuals showed intrinsic visual network disconnection and reorganization of the retino-thalamocortical pathway and dorsal visual stream, suggesting impaired visuospatial and stereoscopic vision.
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Affiliation(s)
- Han-Dong Dan
- Eye Center, Renmin Hospital of Wuhan University, Wuhan 430060, Hubei, China
| | - Fu-Qing Zhou
- Department of Radiology, The First Affiliated Hospital of Nanchang University, Jiangxi Province Medical Imaging Research Institute, Nanchang 330006, Jiangxi, China
| | - Xin Huang
- Eye Center, Renmin Hospital of Wuhan University, Wuhan 430060, Hubei, China
| | - Yi-Qiao Xing
- Eye Center, Renmin Hospital of Wuhan University, Wuhan 430060, Hubei, China
| | - Yin Shen
- Eye Center, Renmin Hospital of Wuhan University, Wuhan 430060, Hubei, China.
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14
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Abstract
Recent advances in neuroscience and devices are ushering in a new generation of medical treatments. Engineered biodevices are demonstrating the potential to create long-term changes in neural circuits, termed neuroplasticity. Thus, the approach of engineering neuroplasticity is rapidly expanding, building on recent demonstrations of improved quality of life for people with movement disorders, epilepsy, and spinal cord injury. In addition, discovering the fundamental mechanisms of engineered neuroplasticity by leveraging anatomically well-documented systems like the spinal cord is likely to provide powerful insights into solutions for other neurotraumas, such as stroke and traumatic brain injury, as well as neurodegenerative disorders, such as Alzheimer's, Parkinson disease, and multiple sclerosis. Now is the time for advancing both the experimental neuroscience, device development, and pioneering human trials to reap the benefits of engineered neuroplasticity as a therapeutic approach for improving quality of life after spinal cord injury.
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Affiliation(s)
- Chet T Moritz
- Division of Physical Therapy, Department of Rehabilitation Medicine, University of Washington, Seattle, WA, USA.
- Department of Physiology & Biophysics, University of Washington, Seattle, WA, USA.
- Graduate Program in Neuroscience, University of Washington, Seattle, WA, USA.
- UW Institute of Neuroengineering (UWIN), University of Washington, Seattle, WA, USA.
- Washington Spinal Cord Injury Consortium, University of Washington, Seattle, WA, USA.
- Center for Sensorimotor Neural Engineering, Seattle, WA, USA.
- Department of Electrical Engineering, University of Washington , Box 356490, Seattle, WA, 98195, USA.
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15
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Wang H, Chen T, Ye L, Yang QC, Wei R, Zhang Y, Jiang N, Shao Y. Network centrality in patients with acute unilateral open globe injury: A voxel‑wise degree centrality study. Mol Med Rep 2017; 16:8295-8300. [PMID: 28983610 DOI: 10.3892/mmr.2017.7635] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2017] [Accepted: 08/01/2017] [Indexed: 11/06/2022] Open
Abstract
The present study aimed to investigate functional networks underlying brain‑activity alterations in patients with acute unilateral open globe injury (OGI) and associations with their clinical features using the voxel‑wise degree centrality (DC) method. In total, 18 patients with acute OGI (16 males and 2 females), and 18 healthy subjects (16 males and 2 females), closely matched in age, sex and education, participated in the present study. Each subject underwent a resting‑state functional magnetic resonance imaging scan. The DC method was used to assess local features of spontaneous brain activity. Receiver operating characteristic curve analysis was used to distinguish OGIs from healthy controls (HCs). Correlation analysis was used to examine the association between the observed mean DC values of different brain areas and behavioral performance. Compared with HCs, patients with acute unilateral OGI had significantly increased DC values in the bilateral primary visual cortex (V1/V2) and left precuneus (PCUN), and significantly decreased DC values in the right insula, left insula, right inferior parietal lobule (IPL)/supramarginal gyrus (SMG), IPL/SMG, right supplementary motor area and right postcentral gyrus. Additionally, in the acute OGI group, it was observed that the duration of OGI was negatively correlated with the DC signal value of the bilateral V1/V2 (r=‑0.581; P=0.011) and left PCUN (r=‑0.508; P=0.031). Acute OGI led to brain functional network dysfunction in a number of brain regions, which may indicate impairment of the visual cortex and other vision‑associated brain regions in OGI.
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Affiliation(s)
- Hua Wang
- Department of Ophthalmology, Xiangya Hospital, Central South University, Changsha, Hunan 410008, P.R. China
| | - Ting Chen
- Department of Ophthalmology, Xiangya Hospital, Central South University, Changsha, Hunan 410008, P.R. China
| | - Lei Ye
- Department of Ophthalmology, The First Affiliated Hospital of Nanchang University, Jiangxi Province Clinical Ophthalmology Institute and Oculopathy Research Centre, Nanchang, Jiangxi 330006, P.R. China
| | - Qi-Chen Yang
- Eye Institute of Xiamen University, Fujian Provincial Key Laboratory of Ophthalmology and Visual Science, Xiamen, Fujian 361102, P.R. China
| | - Rong Wei
- Department of Ophthalmology, The First Affiliated Hospital of Nanchang University, Jiangxi Province Clinical Ophthalmology Institute and Oculopathy Research Centre, Nanchang, Jiangxi 330006, P.R. China
| | - Ying Zhang
- Department of Ophthalmology, The First Affiliated Hospital of Nanchang University, Jiangxi Province Clinical Ophthalmology Institute and Oculopathy Research Centre, Nanchang, Jiangxi 330006, P.R. China
| | - Nan Jiang
- Department of Ophthalmology, The First Affiliated Hospital of Nanchang University, Jiangxi Province Clinical Ophthalmology Institute and Oculopathy Research Centre, Nanchang, Jiangxi 330006, P.R. China
| | - Yi Shao
- Department of Ophthalmology, Xiangya Hospital, Central South University, Changsha, Hunan 410008, P.R. China
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16
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Aguirre GK, Butt OH, Datta R, Roman AJ, Sumaroka A, Schwartz SB, Cideciyan AV, Jacobson SG. Postretinal Structure and Function in Severe Congenital Photoreceptor Blindness Caused by Mutations in the GUCY2D Gene. Invest Ophthalmol Vis Sci 2017; 58:959-973. [PMID: 28403437 PMCID: PMC5308769 DOI: 10.1167/iovs.16-20413] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Purpose To examine how severe congenital blindness resulting from mutations of the GUCY2D gene alters brain structure and function, and to relate these findings to the notable preservation of retinal architecture in this form of Leber congenital amaurosis (LCA). Methods Six GUCY2D-LCA patients (ages 20–46) were studied with optical coherence tomography of the retina and multimodal magnetic resonance imaging (MRI) of the brain. Measurements from this group were compared to those obtained from populations of normally sighted controls and people with congenital blindness of a variety of causes. Results Patients with GUCY2D-LCA had preservation of the photoreceptors, ganglion cells, and nerve fiber layer. Despite this, visual function in these patients ranged from 20/160 acuity to no light perception, and functional MRI responses to light stimulation were attenuated and restricted. This severe visual impairment was reflected in substantial thickening of the gray matter layer of area V1, accompanied by an alteration of resting-state correlations within the occipital lobe, similar to a comparison group of congenitally blind people with structural damage to the retina. In contrast to the comparison blind population, however, the GUCY2D-LCA group had preservation of the size of the optic chiasm, and the fractional anisotropy of the optic radiations as measured with diffusion tensor imaging was also normal. Conclusions These results identify dissociable effects of blindness upon the visual pathway. Further, the relatively intact postgeniculate white matter pathway in GUCY2D-LCA is encouraging for the prospect of recovery of visual function with gene augmentation therapy.
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Affiliation(s)
- Geoffrey K Aguirre
- Department of Neurology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, United States
| | - Omar H Butt
- Department of Neurology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, United States
| | - Ritobrato Datta
- Department of Neurology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, United States
| | - Alejandro J Roman
- Department of Ophthalmology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, United States
| | - Alexander Sumaroka
- Department of Ophthalmology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, United States
| | - Sharon B Schwartz
- Department of Ophthalmology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, United States
| | - Artur V Cideciyan
- Department of Ophthalmology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, United States
| | - Samuel G Jacobson
- Department of Ophthalmology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, United States
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17
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Sabbah N, Sanda N, Authié CN, Mohand-Saïd S, Sahel JA, Habas C, Amedi A, Safran AB. Reorganization of early visual cortex functional connectivity following selective peripheral and central visual loss. Sci Rep 2017; 7:43223. [PMID: 28233790 PMCID: PMC5324137 DOI: 10.1038/srep43223] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2016] [Accepted: 01/20/2017] [Indexed: 12/27/2022] Open
Abstract
Behavioral alterations emerging after central or peripheral vision loss suggest that cerebral reorganization occurs for both the afferented and deafferented early visual cortex (EVC). We explored the functional reorganization of the central and peripheral EVC following visual field defects specifically affecting central or peripheral vision. Compared to normally sighted, afferented central and peripheral EVC enhance their functional connectivity with areas involved in visual processing, whereas deafferented central and peripheral EVC increase their functional connectivity with more remote regions. The connectivity pattern of afferented EVC suggests adaptive changes that might enhance the visual processing capacity whereas the connectivity pattern of deafferented EVC may reflect the involvement of these regions in high-order mechanisms. Characterizing and understanding the plastic changes induced by these visual defects is essential for any attempt to develop efficient rehabilitation strategies.
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Affiliation(s)
- Norman Sabbah
- Sorbonne Universités, UPMC Université Paris 06, UMR S968, Institut de la Vision, Paris, F-75012, France.,INSERM, U968, Institut de la Vision, Paris, F-75012, France.,CNRS, UMR 7210, Institut de la Vision, Paris, F-75012, France.,Centre d'investigation clinique, Centre Hospitalier National d'Ophtalmologie des Quinze-Vingts, INSERM-DGOS CIC 1423, Paris, F-75012, France
| | - Nicolae Sanda
- Sorbonne Universités, UPMC Université Paris 06, UMR S968, Institut de la Vision, Paris, F-75012, France.,INSERM, U968, Institut de la Vision, Paris, F-75012, France.,CNRS, UMR 7210, Institut de la Vision, Paris, F-75012, France.,Centre d'investigation clinique, Centre Hospitalier National d'Ophtalmologie des Quinze-Vingts, INSERM-DGOS CIC 1423, Paris, F-75012, France.,Service de neurologie, Hôpital Foch, Suresnes, France
| | - Colas N Authié
- Sorbonne Universités, UPMC Université Paris 06, UMR S968, Institut de la Vision, Paris, F-75012, France.,INSERM, U968, Institut de la Vision, Paris, F-75012, France.,CNRS, UMR 7210, Institut de la Vision, Paris, F-75012, France.,Centre d'investigation clinique, Centre Hospitalier National d'Ophtalmologie des Quinze-Vingts, INSERM-DGOS CIC 1423, Paris, F-75012, France
| | - Saddek Mohand-Saïd
- Sorbonne Universités, UPMC Université Paris 06, UMR S968, Institut de la Vision, Paris, F-75012, France.,INSERM, U968, Institut de la Vision, Paris, F-75012, France.,CNRS, UMR 7210, Institut de la Vision, Paris, F-75012, France.,Centre d'investigation clinique, Centre Hospitalier National d'Ophtalmologie des Quinze-Vingts, INSERM-DGOS CIC 1423, Paris, F-75012, France
| | - José-Alain Sahel
- Sorbonne Universités, UPMC Université Paris 06, UMR S968, Institut de la Vision, Paris, F-75012, France.,INSERM, U968, Institut de la Vision, Paris, F-75012, France.,CNRS, UMR 7210, Institut de la Vision, Paris, F-75012, France.,Centre d'investigation clinique, Centre Hospitalier National d'Ophtalmologie des Quinze-Vingts, INSERM-DGOS CIC 1423, Paris, F-75012, France.,Institute of Ophthalmology, University College of London, United Kingdom.,Fondation Ophtalmologique Adolphe de Rothschild, Paris, France.,Department of Ophthalmology, The University of Pittsburgh School of Medicine, Pittsburgh, PA 15213, US
| | - Christophe Habas
- Sorbonne Universités, UPMC Université Paris 06, UMR S968, Institut de la Vision, Paris, F-75012, France.,INSERM, U968, Institut de la Vision, Paris, F-75012, France.,CNRS, UMR 7210, Institut de la Vision, Paris, F-75012, France.,Centre de neuroimagerie, Centre Hospitalier National d'Ophtalmologie des Quinze-Vingts, Paris, F-75012, France
| | - Amir Amedi
- Sorbonne Universités, UPMC Université Paris 06, UMR S968, Institut de la Vision, Paris, F-75012, France.,INSERM, U968, Institut de la Vision, Paris, F-75012, France.,CNRS, UMR 7210, Institut de la Vision, Paris, F-75012, France.,Department of Medical Neurobiology, The Institute for Medical Research Israel-Canada, Faculty of Medicine, The Hebrew University of Jerusalem, Jerusalem 91220, Israel.,The Edmond and Lily Safra Center for Brain Sciences (ELSC), The Hebrew University of Jerusalem, Jerusalem 91220, Israel.,The Cognitive Science Program, The Hebrew University of Jerusalem, Jerusalem 91220, Israel
| | - Avinoam B Safran
- Sorbonne Universités, UPMC Université Paris 06, UMR S968, Institut de la Vision, Paris, F-75012, France.,INSERM, U968, Institut de la Vision, Paris, F-75012, France.,CNRS, UMR 7210, Institut de la Vision, Paris, F-75012, France.,Centre d'investigation clinique, Centre Hospitalier National d'Ophtalmologie des Quinze-Vingts, INSERM-DGOS CIC 1423, Paris, F-75012, France.,Department of Clinical Neurosciences, Geneva University School of Medicine, Geneva, Switzerland
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18
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Aguirre GK, Datta R, Benson NC, Prasad S, Jacobson SG, Cideciyan AV, Bridge H, Watkins KE, Butt OH, Dain AS, Brandes L, Gennatas ED. Patterns of Individual Variation in Visual Pathway Structure and Function in the Sighted and Blind. PLoS One 2016; 11:e0164677. [PMID: 27812129 PMCID: PMC5094697 DOI: 10.1371/journal.pone.0164677] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2016] [Accepted: 09/28/2016] [Indexed: 11/18/2022] Open
Abstract
Many structural and functional brain alterations accompany blindness, with substantial individual variation in these effects. In normally sighted people, there is correlated individual variation in some visual pathway structures. Here we examined if the changes in brain anatomy produced by blindness alter the patterns of anatomical variation found in the sighted. We derived eight measures of central visual pathway anatomy from a structural image of the brain from 59 sighted and 53 blind people. These measures showed highly significant differences in mean size between the sighted and blind cohorts. When we examined the measurements across individuals within each group we found three clusters of correlated variation, with V1 surface area and pericalcarine volume linked, and independent of the thickness of V1 cortex. These two clusters were in turn relatively independent of the volumes of the optic chiasm and lateral geniculate nucleus. This same pattern of variation in visual pathway anatomy was found in the sighted and the blind. Anatomical changes within these clusters were graded by the timing of onset of blindness, with those subjects with a post-natal onset of blindness having alterations in brain anatomy that were intermediate to those seen in the sighted and congenitally blind. Many of the blind and sighted subjects also contributed functional MRI measures of cross-modal responses within visual cortex, and a diffusion tensor imaging measure of fractional anisotropy within the optic radiations and the splenium of the corpus callosum. We again found group differences between the blind and sighted in these measures. The previously identified clusters of anatomical variation were also found to be differentially related to these additional measures: across subjects, V1 cortical thickness was related to cross-modal activation, and the volume of the optic chiasm and lateral geniculate was related to fractional anisotropy in the visual pathway. Our findings show that several of the structural and functional effects of blindness may be reduced to a smaller set of dimensions. It also seems that the changes in the brain that accompany blindness are on a continuum with normal variation found in the sighted.
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Affiliation(s)
- Geoffrey K. Aguirre
- Department of Neurology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, United States of America
- * E-mail:
| | - Ritobrato Datta
- Department of Neurology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, United States of America
| | - Noah C. Benson
- Department of Neurology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, United States of America
| | - Sashank Prasad
- Department of Neurology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, United States of America
| | - Samuel G. Jacobson
- Department of Ophthalmology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, United States of America
| | - Artur V. Cideciyan
- Department of Ophthalmology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, United States of America
| | - Holly Bridge
- FMRIB Centre, Clinical Neurosciences, University of Oxford, Oxford OX3 9DU, United Kingdom
| | - Kate E. Watkins
- Department of Experimental Psychology, University of Oxford, Oxford, OX1 3UD, United Kingdom
| | - Omar H. Butt
- Department of Neurology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, United States of America
| | - Aleksandra S. Dain
- Department of Neurology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, United States of America
| | - Lauren Brandes
- Department of Neurology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, United States of America
| | - Efstathios D. Gennatas
- Department of Neurology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, United States of America
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19
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Castaldi E, Cicchini GM, Cinelli L, Biagi L, Rizzo S, Morrone MC. Visual BOLD Response in Late Blind Subjects with Argus II Retinal Prosthesis. PLoS Biol 2016; 14:e1002569. [PMID: 27780207 PMCID: PMC5079588 DOI: 10.1371/journal.pbio.1002569] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2016] [Accepted: 09/19/2016] [Indexed: 11/19/2022] Open
Abstract
Retinal prosthesis technologies require that the visual system downstream of the retinal circuitry be capable of transmitting and elaborating visual signals. We studied the capability of plastic remodeling in late blind subjects implanted with the Argus II Retinal Prosthesis with psychophysics and functional MRI (fMRI). After surgery, six out of seven retinitis pigmentosa (RP) blind subjects were able to detect high-contrast stimuli using the prosthetic implant. However, direction discrimination to contrast modulated stimuli remained at chance level in all of them. No subject showed any improvement of contrast sensitivity in either eye when not using the Argus II. Before the implant, the Blood Oxygenation Level Dependent (BOLD) activity in V1 and the lateral geniculate nucleus (LGN) was very weak or absent. Surprisingly, after prolonged use of Argus II, BOLD responses to visual input were enhanced. This is, to our knowledge, the first study tracking the neural changes of visual areas in patients after retinal implant, revealing a capacity to respond to restored visual input even after years of deprivation.
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Affiliation(s)
- E. Castaldi
- Department of Translational Research on New Technologies in Medicine and Surgery, University of Pisa, Pisa, Italy
| | | | - L. Cinelli
- Azienda Ospedaliero-Universitaria Careggi, SOD Oculistica, Florence, Italy
| | - L. Biagi
- Stella Maris Scientific Institute, Pisa, Italy
| | - S. Rizzo
- Azienda Ospedaliero-Universitaria Careggi, SOD Oculistica, Florence, Italy
| | - M. C. Morrone
- Department of Translational Research on New Technologies in Medicine and Surgery, University of Pisa, Pisa, Italy
- Stella Maris Scientific Institute, Pisa, Italy
- * E-mail:
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20
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Sabbah N, Authié CN, Sanda N, Mohand-Saïd S, Sahel JA, Safran AB, Habas C, Amedi A. Increased functional connectivity between language and visually deprived areas in late and partial blindness. Neuroimage 2016; 136:162-73. [DOI: 10.1016/j.neuroimage.2016.04.056] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2015] [Revised: 04/12/2016] [Accepted: 04/22/2016] [Indexed: 01/09/2023] Open
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21
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Abstract
Low vision is any type of visual impairment that affects activities of daily living. In the context of low vision, we define plasticity as changes in brain or perceptual behavior that follow the onset of visual impairment and that are not directly due to the underlying pathology. An important goal of low-vision research is to determine how plasticity affects visual performance of everyday activities. In this review, we consider the levels of the visual system at which plasticity occurs, the impact of age and visual experience on plasticity, and whether plastic changes are spontaneous or require explicit training. We also discuss how plasticity may affect low-vision rehabilitation. Developments in retinal imaging, noninvasive brain imaging, and eye tracking have supplemented traditional clinical and psychophysical methods for assessing how the visual system adapts to visual impairment. Findings from contemporary research are providing tools to guide people with low vision in adopting appropriate rehabilitation strategies.
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Affiliation(s)
- Gordon E Legge
- Department of Psychology, University of Minnesota, Minneapolis, Minnesota 55455;
| | - Susana T L Chung
- School of Optometry, University of California, Berkeley, California 94720;
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22
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Cunningham SI, Shi Y, Weiland JD, Falabella P, Olmos de Koo LC, Zacks DN, Tjan BS. Feasibility of Structural and Functional MRI Acquisition with Unpowered Implants in Argus II Retinal Prosthesis Patients: A Case Study. Transl Vis Sci Technol 2015; 4:6. [PMID: 26693097 DOI: 10.1167/tvst.4.6.6] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2015] [Accepted: 09/27/2015] [Indexed: 11/24/2022] Open
Abstract
PURPOSE Magnetic resonance imaging (MRI) can measure the effects of vision loss and recovery on brain function and structure. In this case study, we sought to determine the feasibility of acquiring anatomical and functional MRI data in recipients of the Argus II epiretinal prosthesis system. METHODS Following successful implantation with the Argus II device, two retinitis pigmentosa (RP) patients completed MRI scans with their implant unpowered to measure primary visual cortex (V1) functional responses to a tactile task, whole-brain morphometry, V1 cortical thickness, and diffusion properties of the optic tract and optic radiation. Measurements in the subjects with the Argus II implant were compared to measurements obtained previously from RP patients and sighted individuals. RESULTS The presence of the Argus II implant resulted in artifacts that were localized around the patient's implanted eye and did not extend into cortical regions or white matter tracts associated with the visual system. Structural data on V1 cortical thickness and the retinofugal tract obtained from the two Argus II subjects fell within the ranges of sighted and RP groups. When compared to the RP and sighted subjects, Argus II patients' tactile-evoked cross-modal functional MRI (fMRI) blood oxygen level-dependent (BOLD) responses in V1 also fell within the range of either sighted or RP groups, apparently depending on time since implantation. CONCLUSIONS This study demonstrates that successful acquisition and quantification of structural and functional MR images are feasible in the presence of the inactive implant and provides preliminary information on functional changes in the brain that may follow sight restoration treatments. TRANSITIONAL RELEVANCE Successful MRI and fMRI acquisition in Argus II recipients demonstrates feasibility of using MRI to study the effect of retinal prosthesis use on brain structure and function.
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Affiliation(s)
- Samantha I Cunningham
- Department of Biomedical Engineering, University of Southern California, Los Angeles, CA, USA
| | - Yonggang Shi
- Laboratory of Neuro Imaging, USC Stevens Neuroimaging and Informatics Institute, Keck School of Medicine, University of Southern California, Los Angeles, CA, USA
| | - James D Weiland
- USC Eye Institute, University of Southern California, Los Angeles, CA, USA
| | - Paulo Falabella
- USC Eye Institute, University of Southern California, Los Angeles, CA, USA ; Department of Ophthalmology and Visual Sciences, Federal University of São Paulo, São Paulo, Brazil
| | | | - David N Zacks
- Kellogg Eye Center, University of Michigan, Ann Arbor, MI, USA
| | - Bosco S Tjan
- Neuroscience Graduate Program, University of Southern California, Los Angeles, CA, USA ; Department of Psychology, University of Southern California, Los Angeles, CA, USA
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