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Martinez JD, Donnelly MJ, Popke DS, Torres D, Wilson LG, Brancaleone WP, Sheskey S, Lin CM, Clawson BC, Jiang S, Aton SJ. Enriched binocular experience followed by sleep optimally restores binocular visual cortical responses in a mouse model of amblyopia. Commun Biol 2023; 6:408. [PMID: 37055505 PMCID: PMC10102075 DOI: 10.1038/s42003-023-04798-y] [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: 10/10/2022] [Accepted: 04/03/2023] [Indexed: 04/15/2023] Open
Abstract
Studies of primary visual cortex have furthered our understanding of amblyopia, long-lasting visual impairment caused by imbalanced input from the two eyes during childhood, which is commonly treated by patching the dominant eye. However, the relative impacts of monocular vs. binocular visual experiences on recovery from amblyopia are unclear. Moreover, while sleep promotes visual cortex plasticity following loss of input from one eye, its role in recovering binocular visual function is unknown. Using monocular deprivation in juvenile male mice to model amblyopia, we compared recovery of cortical neurons' visual responses after identical-duration, identical-quality binocular or monocular visual experiences. We demonstrate that binocular experience is quantitatively superior in restoring binocular responses in visual cortex neurons. However, this recovery was seen only in freely-sleeping mice; post-experience sleep deprivation prevented functional recovery. Thus, both binocular visual experience and subsequent sleep help to optimally renormalize bV1 responses in a mouse model of amblyopia.
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Affiliation(s)
- Jessy D Martinez
- Department of Molecular, Cellular, and Developmental Biology, University of Michigan, Ann Arbor, MI, USA
| | - Marcus J Donnelly
- Undergraduate Program in Neuroscience, University of Michigan, Ann Arbor, MI, USA
| | - Donald S Popke
- Undergraduate Program in Neuroscience, University of Michigan, Ann Arbor, MI, USA
| | - Daniel Torres
- Department of Molecular, Cellular, and Developmental Biology, University of Michigan, Ann Arbor, MI, USA
| | - Lydia G Wilson
- Department of Molecular, Cellular, and Developmental Biology, University of Michigan, Ann Arbor, MI, USA
| | | | - Sarah Sheskey
- Department of Ophthalmology and Visual Sciences, University of Michigan Medical School, Ann Arbor, MI, USA
| | - Cheng-Mao Lin
- Department of Ophthalmology and Visual Sciences, University of Michigan Medical School, Ann Arbor, MI, USA
| | - Brittany C Clawson
- Department of Molecular, Cellular, and Developmental Biology, University of Michigan, Ann Arbor, MI, USA
| | - Sha Jiang
- Department of Molecular, Cellular, and Developmental Biology, University of Michigan, Ann Arbor, MI, USA
| | - Sara J Aton
- Department of Molecular, Cellular, and Developmental Biology, University of Michigan, Ann Arbor, MI, USA.
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Fong MF, Duffy KR, Leet MP, Candler CT, Bear MF. Correction of amblyopia in cats and mice after the critical period. eLife 2021; 10:70023. [PMID: 34464258 PMCID: PMC8456712 DOI: 10.7554/elife.70023] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2021] [Accepted: 08/20/2021] [Indexed: 11/25/2022] Open
Abstract
Monocular deprivation early in development causes amblyopia, a severe visual impairment. Prognosis is poor if therapy is initiated after an early critical period. However, clinical observations have shown that recovery from amblyopia can occur later in life when the non-deprived (fellow) eye is removed. The traditional interpretation of this finding is that vision is improved simply by the elimination of interocular suppression in primary visual cortex, revealing responses to previously subthreshold input. However, an alternative explanation is that silencing activity in the fellow eye establishes conditions in visual cortex that enable the weak connections from the amblyopic eye to gain strength, in which case the recovery would persist even if vision is restored in the fellow eye. Consistent with this idea, we show here in cats and mice that temporary inactivation of the fellow eye is sufficient to promote a full and enduring recovery from amblyopia at ages when conventional treatments fail. Thus, connections serving the amblyopic eye are capable of substantial plasticity beyond the critical period, and this potential is unleashed by reversibly silencing the fellow eye.
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Affiliation(s)
- Ming-Fai Fong
- The Picower Institute for Learning and Memory, Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology, Cambridge, United States
| | - Kevin R Duffy
- Department of Psychology and Neuroscience, Dalhousie University, Halifax, Canada
| | - Madison P Leet
- The Picower Institute for Learning and Memory, Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology, Cambridge, United States
| | - Christian T Candler
- The Picower Institute for Learning and Memory, Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology, Cambridge, United States
| | - Mark F Bear
- The Picower Institute for Learning and Memory, Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology, Cambridge, United States
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Classification of Visual Cortex Plasticity Phenotypes following Treatment for Amblyopia. Neural Plast 2019; 2019:2564018. [PMID: 31565045 PMCID: PMC6746165 DOI: 10.1155/2019/2564018] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2018] [Revised: 04/04/2019] [Accepted: 05/13/2019] [Indexed: 12/25/2022] Open
Abstract
Monocular deprivation (MD) during the critical period (CP) has enduring effects on visual acuity and the functioning of the visual cortex (V1). This experience-dependent plasticity has become a model for studying the mechanisms, especially glutamatergic and GABAergic receptors, that regulate amblyopia. Less is known, however, about treatment-induced changes to those receptors and if those changes differentiate treatments that support the recovery of acuity versus persistent acuity deficits. Here, we use an animal model to explore the effects of 3 visual treatments started during the CP (n = 24, 10 male and 14 female): binocular vision (BV) that promotes good acuity versus reverse occlusion (RO) and binocular deprivation (BD) that causes persistent acuity deficits. We measured the recovery of a collection of glutamatergic and GABAergic receptor subunits in the V1 and modeled recovery of kinetics for NMDAR and GABAAR. There was a complex pattern of protein changes that prompted us to develop an unbiased data-driven approach for these high-dimensional data analyses to identify plasticity features and construct plasticity phenotypes. Cluster analysis of the plasticity phenotypes suggests that BV supports adaptive plasticity while RO and BD promote a maladaptive pattern. The RO plasticity phenotype appeared more similar to adults with a high expression of GluA2, and the BD phenotypes were dominated by GABAA α1, highlighting that multiple plasticity phenotypes can underlie persistent poor acuity. After 2-4 days of BV, the plasticity phenotypes resembled normals, but only one feature, the GluN2A:GluA2 balance, returned to normal levels. Perhaps, balancing Hebbian (GluN2A) and homeostatic (GluA2) mechanisms is necessary for the recovery of vision.
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Effects of digesting chondroitin sulfate proteoglycans on plasticity in cat primary visual cortex. J Neurosci 2013; 33:234-43. [PMID: 23283337 DOI: 10.1523/jneurosci.2283-12.2013] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Monocular deprivation (MD) during a critical period of postnatal development produces significant changes in the anatomy and physiology of the visual cortex, and the deprived eye becomes amblyopic. Extracellular matrix molecules have a major role in restricting plasticity such that the ability to recover from MD decreases with age. Chondroitin sulfate proteoglycans (CSPGs) act as barriers to cell migration and axon growth. Previous studies showing that degradation of CSPGs by the bacterial enzyme chondroitinase can restore plasticity in the adult rat visual cortex suggest a potential treatment for amblyopia. Here MD was imposed in cats from the start of the critical period until 3.5 months of age. The deprived eye was reopened, the functional architecture of the visual cortex was assessed by optical imaging of intrinsic signals, and chondroitinase was injected into one hemisphere. Imaging was repeated 1 and 2 weeks postinjection, and visually evoked potentials (VEPs) and single-cell activity were recorded. Immunohistochemistry showed that digestion of CSPGs had been successful. After 2 weeks of binocular exposure, some recovery of deprived-eye responses occurred when chondroitinase had been injected into the hemisphere contralateral to that eye; when injected into the ipsilateral hemisphere, no recovery was seen. Deprived-eye VEPs were no larger in the injected hemisphere than in the opposite hemisphere. The small number of neurons dominated by the deprived eye exhibited poor tuning characteristics. These results suggest that despite structural effects of chondroitinase in adult cat V1, plasticity was not sufficiently restored to enable significant functional recovery of the deprived eye.
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Abstract
Human amblyopia has been modeled in a number of mammalian species in physiological, anatomical and behavioral terms for nearly 50 years, and insights from these studies have both offered explanations of observations made in humans and resulted in improved prevention and refined treatment. In recent years, animal models of part-time daily monocular deprivation have made an important contribution to the occlusion therapy of amblyopia in children.
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Mitchell DE, Sengpiel F. Neural mechanisms of recovery following early visual deprivation. Philos Trans R Soc Lond B Biol Sci 2009; 364:383-98. [PMID: 18977734 PMCID: PMC2674472 DOI: 10.1098/rstb.2008.0192] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Natural patterned early visual input is essential for the normal development of the central visual pathways and the visual capacities they sustain. Without visual input, the functional development of the visual system stalls not far from the state at birth, and if input is distorted or biased the visual system develops in an abnormal fashion resulting in specific visual deficits. Monocular deprivation, an extreme form of biased exposure, results in large anatomical and physiological changes in terms of territory innervated by the two eyes in primary visual cortex (V1) and to a loss of vision in the deprived eye reminiscent of that in human deprivation amblyopia. We review work that points to a special role for binocular visual input in the development of V1 and vision. Our unique approach has been to provide animals with mixed visual input each day, which consists of episodes of normal and biased (monocular) exposures. Short periods of concordant binocular input, if continuous, can offset much longer episodes of monocular deprivation to allow normal development of V1 and prevent amblyopia. Studies of animal models of patching therapy for amblyopia reveal that the benefits are both heightened and prolonged by daily episodes of binocular exposure.
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Affiliation(s)
- Donald E Mitchell
- Psychology Department, Dalhousie University, Halifax, Nova Scotia, Canada.
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Iny K, Heynen AJ, Sklar E, Bear MF. Bidirectional modifications of visual acuity induced by monocular deprivation in juvenile and adult rats. J Neurosci 2006; 26:7368-74. [PMID: 16837583 PMCID: PMC6674195 DOI: 10.1523/jneurosci.0124-06.2006] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Recent electrophysiological studies of rodent visual cortex suggest that, in addition to deprived-eye depression, monocular deprivation (MD) also shifts ocular dominance by potentiation of open-eye responses. We used computer-based, two-choice discrimination tasks to assess the behavioral significance of these findings in rats. As expected, prolonged MD, from postnatal day 21 until adulthood (>150 d) markedly decreased visual acuity through the deprived eye. However, we also found that the acuity through the nondeprived eye was significantly enhanced compared with normally reared controls. Interestingly, when the deprived eye was opened in adults, there was a gradual but incomplete recovery of acuity in the deprived eye preceded by a loss of the enhanced acuity in the nondeprived eye. These changes were reversed by again reclosing the eye. These findings suggest that the bidirectional changes in visually evoked responses after MD are behaviorally meaningful and that significant plasticity is exhibited well into adulthood.
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Faulkner SD, Vorobyov V, Sengpiel F. Visual cortical recovery from reverse occlusion depends on concordant binocular experience. J Neurophysiol 2005; 95:1718-26. [PMID: 16354732 DOI: 10.1152/jn.00912.2005] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The effects of early monocular deprivation on visual acuity and visual cortical responses can be reversed quickly if vision is restored to the deprived eye and the other eye is deprived instead, a procedure known as reverse occlusion. However, recovery of vision through the originally deprived eye (ODE) is not stable. Following re-opening of the recently deprived (originally nondeprived) eye (ONDE), vision in the ODE typically deteriorates rapidly, possibly because of competitive interactions, whereas vision in the ONDE also remains compromised, resulting in bilateral amblyopia, the reasons for which are unknown. Here we monitor the physiological changes in the visual cortex during recovery from reverse occlusion in a longitudinal study, using optical imaging of intrinsic signals and single-cell recording in anesthetized cats. We show that a brief period of just 4 days of concordant binocular vision intercalated between the two periods of monocular experience allows close to equal responses to develop through both eyes, both in terms of cortical territory and orientation selectivity. In contrast, with no binocular vision or discordant binocular experience, cortical territory dominated by the ONDE is significantly reduced, and orientation tuning of cells dominated by the ODE is wider than that of cells dominated by the ONDE. These results support the notion that a brief period of binocular vision is sufficient to prevent bilateral acuity loss caused by reverse occlusion.
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Mitchell DE, MacKinnon S. The present and potential impact of research on animal models for clinical treatment of stimulus deprivation amblyopia. Clin Exp Optom 2002; 85:5-18. [PMID: 11952391 DOI: 10.1111/j.1444-0938.2002.tb03067.x] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/07/2002] [Indexed: 11/29/2022] Open
Abstract
OBJECTIVE With the benefit of hindsight based on an additional 20 years of research, we review a question posed originally by Marg of whether animal models for stimulus deprivation amblyopia in children are valid or useful for clinical application. METHOD Following a review of relevant research on animal models, the human clinical literature on treatment of stimulus deprivation amblyopia has been reviewed with respect to past and current impact of animal research on clinical treatment. In addition, we speculate on the potential future clinical impact of animal work on developmental plasticity in the visual cortex that is directed towards an understanding of its underlying molecular basis. CONCLUSIONS Animal research that has begun to define the timing, nature and sites of critical periods in the central visual pathways with greater precision than was known 20 years ago has had a demonstrable impact on clinical practice. In turn, these changes in clinical practice have produced far better outcomes than prior to 1980, for both the acuity of the amblyopic eye and for binocular functions such as stereopsis.
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Affiliation(s)
- Donald E Mitchell
- Psychology Department, Dalhousie University, Halifax, NS, B3H 4J1, Canada.
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