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Casciano F, Zauli E, Celeghini C, Caruso L, Gonelli A, Zauli G, Pignatelli A. Retinal Alterations Predict Early Prodromal Signs of Neurodegenerative Disease. Int J Mol Sci 2024; 25:1689. [PMID: 38338966 PMCID: PMC10855697 DOI: 10.3390/ijms25031689] [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: 12/21/2023] [Revised: 01/25/2024] [Accepted: 01/27/2024] [Indexed: 02/12/2024] Open
Abstract
Neurodegenerative diseases are an increasingly common group of diseases that occur late in life with a significant impact on personal, family, and economic life. Among these, Alzheimer's disease (AD) and Parkinson's disease (PD) are the major disorders that lead to mild to severe cognitive and physical impairment and dementia. Interestingly, those diseases may show onset of prodromal symptoms early after middle age. Commonly, the evaluation of these neurodegenerative diseases is based on the detection of biomarkers, where functional and structural magnetic resonance imaging (MRI) have shown a central role in revealing early or prodromal phases, although it can be expensive, time-consuming, and not always available. The aforementioned diseases have a common impact on the visual system due to the pathophysiological mechanisms shared between the eye and the brain. In Parkinson's disease, α-synuclein deposition in the retinal cells, as well as in dopaminergic neurons of the substantia nigra, alters the visual cortex and retinal function, resulting in modifications to the visual field. Similarly, the visual cortex is modified by the neurofibrillary tangles and neuritic amyloid β plaques typically seen in the Alzheimer's disease brain, and this may reflect the accumulation of these biomarkers in the retina during the early stages of the disease, as seen in postmortem retinas of AD patients. In this light, the ophthalmic evaluation of retinal neurodegeneration could become a cost-effective method for the early diagnosis of those diseases, overcoming the limitations of functional and structural imaging of the deep brain. This analysis is commonly used in ophthalmic practice, and interest in it has risen in recent years. This review will discuss the relationship between Alzheimer's disease and Parkinson's disease with retinal degeneration, highlighting how retinal analysis may represent a noninvasive and straightforward method for the early diagnosis of these neurodegenerative diseases.
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Affiliation(s)
- Fabio Casciano
- Department of Translational Medicine and LTTA Centre, University of Ferrara, 44121 Ferrara, Italy
| | - Enrico Zauli
- Department of Translational Medicine, University of Ferrara, 44121 Ferrara, Italy
| | - Claudio Celeghini
- Department of Translational Medicine, University of Ferrara, 44121 Ferrara, Italy
| | - Lorenzo Caruso
- Department of Environment and Prevention Sciences, University of Ferrara, 44121 Ferrara, Italy
| | - Arianna Gonelli
- Department of Translational Medicine, University of Ferrara, 44121 Ferrara, Italy
| | - Giorgio Zauli
- Research Department, King Khaled Eye Specialistic Hospital, Riyadh 12329, Saudi Arabia
| | - Angela Pignatelli
- Department of Neuroscience and Rehabilitation, University of Ferrara, 44124 Ferrara, Italy
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2
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Constable PA, Lim JKH, Thompson DA. Retinal electrophysiology in central nervous system disorders. A review of human and mouse studies. Front Neurosci 2023; 17:1215097. [PMID: 37600004 PMCID: PMC10433210 DOI: 10.3389/fnins.2023.1215097] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2023] [Accepted: 07/17/2023] [Indexed: 08/22/2023] Open
Abstract
The retina and brain share similar neurochemistry and neurodevelopmental origins, with the retina, often viewed as a "window to the brain." With retinal measures of structure and function becoming easier to obtain in clinical populations there is a growing interest in using retinal findings as potential biomarkers for disorders affecting the central nervous system. Functional retinal biomarkers, such as the electroretinogram, show promise in neurological disorders, despite having limitations imposed by the existence of overlapping genetic markers, clinical traits or the effects of medications that may reduce their specificity in some conditions. This narrative review summarizes the principal functional retinal findings in central nervous system disorders and related mouse models and provides a background to the main excitatory and inhibitory retinal neurotransmitters that have been implicated to explain the visual electrophysiological findings. These changes in retinal neurochemistry may contribute to our understanding of these conditions based on the findings of retinal electrophysiological tests such as the flash, pattern, multifocal electroretinograms, and electro-oculogram. It is likely that future applications of signal analysis and machine learning algorithms will offer new insights into the pathophysiology, classification, and progression of these clinical disorders including autism, attention deficit/hyperactivity disorder, bipolar disorder, schizophrenia, depression, Parkinson's, and Alzheimer's disease. New clinical applications of visual electrophysiology to this field may lead to earlier, more accurate diagnoses and better targeted therapeutic interventions benefiting individual patients and clinicians managing these individuals and their families.
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Affiliation(s)
- Paul A. Constable
- College of Nursing and Health Sciences, Caring Futures Institute, Flinders University, Adelaide, SA, Australia
| | - Jeremiah K. H. Lim
- Discipline of Optometry, School of Allied Health, University of Western Australia, Perth, WA, Australia
| | - Dorothy A. Thompson
- The Tony Kriss Visual Electrophysiology Unit, Clinical and Academic Department of Ophthalmology, Great Ormond Street Hospital for Children NHS Trust, London, United Kingdom
- UCL Great Ormond Street Institute of Child Health, University College London, London, United Kingdom
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3
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Alswailmi FK. A Cross Talk between the Endocannabinoid System and Different Systems Involved in the Pathogenesis of Hypertensive Retinopathy. Pharmaceuticals (Basel) 2023; 16:ph16030345. [PMID: 36986445 PMCID: PMC10058254 DOI: 10.3390/ph16030345] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2022] [Revised: 02/14/2023] [Accepted: 02/16/2023] [Indexed: 02/26/2023] Open
Abstract
The prognosis of hypertension leads to organ damage by causing nephropathy, stroke, retinopathy, and cardiomegaly. Retinopathy and blood pressure have been extensively discussed in relation to catecholamines of the autonomic nervous system (ANS) and angiotensin II of the renin–angiotensin aldosterone system (RAAS) but very little research has been conducted on the role of the ECS in the regulation of retinopathy and blood pressure. The endocannabinoid system (ECS) is a unique system in the body that can be considered as a master regulator of body functions. It encompasses the endogenous production of its cannabinoids, its degrading enzymes, and functional receptors which innervate and perform various functions in different organs of the body. Hypertensive retinopathy pathologies arise normally due to oxidative stress, ischemia, endothelium dysfunction, inflammation, and an activated renin–angiotensin system (RAS) and catecholamine which are vasoconstrictors in their biological nature. The question arises of which system or agent counterbalances the vasoconstrictors effect of noradrenaline and angiotensin II (Ang II) in normal individuals? In this review article, we discuss the role of the ECS and its contribution to the pathogenesis of hypertensive retinopathy. This review article will also examine the involvement of the RAS and the ANS in the pathogenesis of hypertensive retinopathy and the crosstalk between these three systems in hypertensive retinopathy. This review will also explain that the ECS, which is a vasodilator in its action, either independently counteracts the effect produced with the vasoconstriction of the ANS and Ang II or blocks some of the common pathways shared by the ECS, ANS, and Ang II in the regulation of eye functions and blood pressure. This article concludes that persistent control of blood pressure and normal functions of the eye are maintained either by decreasing systemic catecholamine, ang II, or by upregulation of the ECS which results in the regression of retinopathy induced by hypertension.
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Affiliation(s)
- Farhan Khashim Alswailmi
- Department of Pharmacy Practice, College of Pharmacy, University of Hafr Al Batin, Hafr Al Batin 39524, Saudi Arabia
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4
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Alves JN, Westner BU, Højlund A, Weil RS, Dalal SS. Structural and functional changes in the retina in Parkinson's disease. J Neurol Neurosurg Psychiatry 2023; 94:448-456. [PMID: 36806480 PMCID: PMC7614544 DOI: 10.1136/jnnp-2022-329342] [Citation(s) in RCA: 14] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/31/2022] [Accepted: 01/05/2023] [Indexed: 02/19/2023]
Abstract
Parkinson's disease is caused by degeneration of dopaminergic neurons, originating in the substantia nigra pars compacta and characterised by bradykinesia, rest tremor and rigidity. In addition, visual disorders and retinal abnormalities are often present and can be identified by decreased visual acuity, abnormal spatial contrast sensitivity or even difficulty in complex visual task completion. Because of their early onset in patients with de novo Parkinson's disease, the anatomical retinal changes and electrophysiological modification could be valuable markers even at early stages of the disease. However, due to the concomitant occurrence of normal ageing, the relevance and specificity of these predictive values can be difficult to interpret. This review examines retinal dysfunction arising in Parkinson's disease. We highlight the electrophysiological delays and decreased amplitude in the electroretinography recorded in patients and animal models. We relate this to coexisting anatomical changes such as retinal nerve fibre layer and macular thinning, measured using optical coherence tomography, and show that functional measures are more consistent overall than optical coherence-measured structural changes. We review the underlying chemical changes seen with loss of retinal dopaminergic neurons and the effect of levodopa treatment on the retina in Parkinson's disease. Finally, we consider whether retinal abnormalities in Parkinson's disease could have a role as potential markers of poorer outcomes and help stratify patients at early stages of the disease. We emphasise that retinal measures can be valuable, accessible and cost-effective methods in the early evaluation of Parkinson's disease pathogenesis with potential for patient stratification.
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Affiliation(s)
- Jordan N Alves
- Center of Functionally Integrative Neuroscience, Aarhus University, Aarhus, Denmark
| | - Britta U Westner
- Radboud University, Donders Institute for Brain, Cognition and Behaviours, Nijmegen, The Netherlands
| | - Andreas Højlund
- Department of Linguistics, Cognitive Science & Semiotics, Aarhus University, Aarhus, Denmark
| | - Rimona Sharon Weil
- Dementia Research Centre, University College London, London, UK.,Movement Disorders Consortium, University College London, London, UK.,Wellcome Centre for Human Neuroimaging, University College London, London, UK
| | - Sarang S Dalal
- Center of Functionally Integrative Neuroscience, Aarhus University, Aarhus, Denmark
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Mello LGM, Paraguay IBB, Andrade TDS, Rocha AADN, Barbosa ER, Oyamada MK, Monteiro MLR. Electroretinography reveals retinal dysfunction in Parkinson's disease despite normal high-resolution optical coherence tomography findings. Parkinsonism Relat Disord 2022; 101:90-95. [PMID: 35810523 DOI: 10.1016/j.parkreldis.2022.06.018] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/01/2022] [Revised: 06/19/2022] [Accepted: 06/20/2022] [Indexed: 10/17/2022]
Abstract
INTRODUCTION Parkinson's disease (PD)-associated inner retinal abnormalities, particularly the retinal ganglion cells (RGC) layer, on optical coherence tomography (OCT) have recently gained importance as a biomarker of non-motor involvement of the disease but functional RGC evaluation using photopic negative response (PhNR) has not yet been determined. This study aims to compare structural and functional findings of the retina and optic nerve in PD with healthy controls (CT) including PhNR and OCT. METHODS Forty-one eyes of 21 PD patients and 38 eyes of 19 CT underwent ophthalmic examination including visual contrast sensitivity test (CS), OCT, light-adapted full-field electroretinography (ffERG), and PhNR. OCT was used to measure the peripapillary retinal nerve fiber layer, the segmented macular layers, and the choroid. For functional parameters, CS, ffERG (oscillatory potentials, photopic response, 30 Hz-flicker), and PhNR waves were used. Measurements were compared using generalized estimating equation and significance was set at P ≤ 0.05. RESULTS The PD group presented a significantly lower mono- and binocular CS, oscillatory potentials amplitude, b-wave amplitude on ffERG (152.3[45.4] vs 187.1[32.7]μV; P = 0.002), and PhNR amplitude (135.0[35.0] vs 156.3[34.1]μV; P = 0.025). There was no statistically significant difference in OCT measurements between groups. No correlation was found between statistically significant measurements and clinical data. CONCLUSIONS Functional abnormalities on CS, ffERG, and PhNR can be detected in PD even when structural damages are not observed on OCT. PhNR represents a new potential biomarker in PD. Our findings indicate dysfunction of bipolar, amacrine, and retinal ganglion cells in PD, probably with a cellular dysfunction overcoming morphological damage.
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Affiliation(s)
- Luiz Guilherme Marchesi Mello
- Division of Ophthalmology, Faculdade de Medicina FMUSP, Universidade de São Paulo, São Paulo, Brazil; Department of Specialized Medicine, Centro de Ciências da Saúde (CCS), Universidade Federal do Espírito Santo, Vitória, Brazil.
| | | | - Thais de Souza Andrade
- Division of Ophthalmology, Faculdade de Medicina FMUSP, Universidade de São Paulo, São Paulo, Brazil
| | | | - Egberto Reis Barbosa
- Division of Neurology, Faculdade de Medicina FMUSP, Universidade de São Paulo, São Paulo, Brazil
| | - Maria Kiyoko Oyamada
- Division of Ophthalmology, Faculdade de Medicina FMUSP, Universidade de São Paulo, São Paulo, Brazil
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6
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Tyler CW, Likova LT. Brain trauma impacts retinal processing: photoreceptor pathway interactions in traumatic light sensitivity. Doc Ophthalmol 2022; 144:179-190. [PMID: 35445376 PMCID: PMC9192363 DOI: 10.1007/s10633-022-09871-1] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2021] [Accepted: 03/12/2022] [Indexed: 11/21/2022]
Abstract
BACKGROUND Concussion-induced light sensitivity, or traumatic photalgia, is a lifelong debilitating problem for upwards of 50% of mild traumatic brain injury (mTBI) cases, though of unknown etiology. We employed spectral analysis of electroretinographic (ERG) responses to assess retinal changes in mTBI as a function of the degree of photalgia. METHODS The design was a case-control study of the changes in the ERG waveform as a function of level of light sensitivity in individuals who had suffered incidents of mild traumatic brain injury. The mTBI participants were categorized into non-, mild-, and severe-photalgic groups based on their spectral nociophysical settings. Light-adapted ERG responses were recorded from each eye for 200 ms on-off stimulation of three spectral colors (R:red, G:green, and B:blue) and their sum (W:white) at the highest pain-free intensity level for each participant. The requirement of controls for testing hypersensitive individuals at lower light levels was addressed by recording a full light intensity series in the control group. RESULTS Both the b-wave and the photopic negative response (PhNR) were significantly reduced in the non-photalgic mTBI group relative to controls. In the photalgic groups, the main b-wave peak shifted to the timing of the rod b-wave, with reduced amplitude at the timing of the cone response. CONCLUSION These results suggest the interpretation that the primary etiology of the painful light sensitivity in mTBI is release of the rod pathway from cone-mediated inhibition at high light levels, causing overactivation of the rod pathway.
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Affiliation(s)
- Christopher W Tyler
- Smith-Kettlewell Eye Research Institute, 2318 Fillmore Street, San Francisco, 94115, USA.
- Division of Optometry and Vision Science, School of Health Sciences, City University of London, London, UK.
| | - Lora T Likova
- Smith-Kettlewell Eye Research Institute, 2318 Fillmore Street, San Francisco, 94115, USA
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7
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Veys L, Devroye J, Lefevere E, Cools L, Vandenabeele M, De Groef L. Characterizing the Retinal Phenotype of the Thy1-h[A30P]α-syn Mouse Model of Parkinson's Disease. Front Neurosci 2021; 15:726476. [PMID: 34557068 PMCID: PMC8452874 DOI: 10.3389/fnins.2021.726476] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2021] [Accepted: 08/19/2021] [Indexed: 12/30/2022] Open
Abstract
Despite decades of research, disease-modifying treatments of Parkinson’s disease (PD), the second most common neurodegenerative disease worldwide, remain out of reach. One of the reasons for this treatment gap is the incomplete understanding of how misfolded alpha-synuclein (α-syn) contributes to PD pathology. The retina, as an integral part of the central nervous system, recapitulates the PD disease processes that are typically seen in the brain, and retinal manifestations have emerged as prodromal symptoms of the disease. The timeline of PD manifestations in the visual system, however, is not fully elucidated and the underlying mechanisms are obscure. This highlights the need for new studies investigating retinal pathology, in order to propel its use as PD biomarker, and to develop validated research models to investigate PD pathogenesis. The present study pioneers in characterizing the retina of the Thy1-h[A30P]α-syn PD transgenic mouse model. We demonstrate widespread α-syn accumulation in the inner retina of these mice, of which a proportion is phosphorylated yet not aggregated. This α-syn expression coincides with inner retinal atrophy due to postsynaptic degeneration. We also reveal abnormal retinal electrophysiological responses. Absence of selective loss of melanopsin retinal ganglion cells or dopaminergic amacrine cells and inflammation indicates that the retinal manifestations in these transgenic mice diverge from their brain phenotype, and questions the specific cellular or molecular alterations that underlie retinal pathology in this PD mouse model. Nevertheless, the observed α-syn accumulation, synapse loss and functional deficits suggest that the Thy1-h[A30P]α-syn retina mimics some of the features of prodromal PD, and thus may provide a window to monitor and study the preclinical/prodromal stages of PD, PD-associated retinal disease processes, as well as aid in retinal biomarker discovery and validation.
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Affiliation(s)
- Lien Veys
- Research Group of Neural Circuit Development and Regeneration, Department of Biology, KU Leuven, Leuven, Belgium.,Department of Biomedical Sciences, Leuven Brain Institute, Leuven, Belgium
| | - Joyce Devroye
- Research Group of Neural Circuit Development and Regeneration, Department of Biology, KU Leuven, Leuven, Belgium.,Department of Biomedical Sciences, Leuven Brain Institute, Leuven, Belgium
| | - Evy Lefevere
- Research Group of Neural Circuit Development and Regeneration, Department of Biology, KU Leuven, Leuven, Belgium.,Department of Biomedical Sciences, Leuven Brain Institute, Leuven, Belgium
| | - Lien Cools
- Research Group of Neural Circuit Development and Regeneration, Department of Biology, KU Leuven, Leuven, Belgium.,Department of Biomedical Sciences, Leuven Brain Institute, Leuven, Belgium
| | - Marjan Vandenabeele
- Research Group of Neural Circuit Development and Regeneration, Department of Biology, KU Leuven, Leuven, Belgium.,Department of Biomedical Sciences, Leuven Brain Institute, Leuven, Belgium
| | - Lies De Groef
- Research Group of Neural Circuit Development and Regeneration, Department of Biology, KU Leuven, Leuven, Belgium.,Department of Biomedical Sciences, Leuven Brain Institute, Leuven, Belgium
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8
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Amorim-de-Sousa A, Schilling T, Fernandes P, Seshadri Y, Bahmani H, González-Méijome JM. Blue light blind-spot stimulation upregulates b-wave and pattern ERG activity in myopes. Sci Rep 2021; 11:9273. [PMID: 33927248 PMCID: PMC8085027 DOI: 10.1038/s41598-021-88459-2] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2020] [Accepted: 04/05/2021] [Indexed: 01/03/2023] Open
Abstract
Upregulation of retinal dopaminergic activity may be a target treatment for myopia progression. This study aimed to explore the viability of inducing changes in retinal electrical activity with short-wavelength light targeting melanopsin-expressing retinal ganglion cells (ipRGCs) passing through the optic nerve head. Fifteen healthy non-myopic or myopic young adults were recruited and underwent stimulation with blue light using a virtual reality headset device. Amplitudes and implicit times from photopic 3.0 b-wave and pattern electroretinogram (PERG) were measured at baseline and 10 and 20 min after stimulation. Relative changes were compared between non-myopes and myopes. The ERG b-wave amplitude was significantly larger 20 min after blind-spot stimulation compared to baseline (p < 0.001) and 10 min (p < 0.001) post-stimulation. PERG amplitude P50-N95 also showed a significant main effect for ‘Time after stimulation’ (p < 0.050). Implicit times showed no differences following blind-spot stimulation. PERG and b-wave changes after blind-spot stimulation were stronger in myopes than non-myopes. It is possible to induce significant changes in retinal electrical activity by stimulating ipRGCs axons at the optic nerve head with blue light. The results suggest that the changes in retinal electrical activity are located at the inner plexiform layer and are likely to involve the dopaminergic system.
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Affiliation(s)
- Ana Amorim-de-Sousa
- Clinical & Experimental Optometry Research Lab (CEORLab), Center of Physics (Optometry), School of Sciences, University of Minho, Gualtar, 4710-057, Braga, Portugal
| | | | - Paulo Fernandes
- Clinical & Experimental Optometry Research Lab (CEORLab), Center of Physics (Optometry), School of Sciences, University of Minho, Gualtar, 4710-057, Braga, Portugal
| | | | - Hamed Bahmani
- Dopavision GmbH, Berlin, Germany.,Department of Physiology of Cognitive Processes, Max Planck Institute for Biological Cybernetics, Tübingen, Germany.,Bernstein Center for Computational Neuroscience, Tübingen, Germany
| | - José Manuel González-Méijome
- Clinical & Experimental Optometry Research Lab (CEORLab), Center of Physics (Optometry), School of Sciences, University of Minho, Gualtar, 4710-057, Braga, Portugal.
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9
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Korshunov KS, Blakemore LJ, Trombley PQ. Illuminating and Sniffing Out the Neuromodulatory Roles of Dopamine in the Retina and Olfactory Bulb. Front Cell Neurosci 2020; 14:275. [PMID: 33110404 PMCID: PMC7488387 DOI: 10.3389/fncel.2020.00275] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2020] [Accepted: 08/04/2020] [Indexed: 01/28/2023] Open
Abstract
In the central nervous system, dopamine is well-known as the neuromodulator that is involved with regulating reward, addiction, motivation, and fine motor control. Yet, decades of findings are revealing another crucial function of dopamine: modulating sensory systems. Dopamine is endogenous to subsets of neurons in the retina and olfactory bulb (OB), where it sharpens sensory processing of visual and olfactory information. For example, dopamine modulation allows the neural circuity in the retina to transition from processing dim light to daylight and the neural circuity in the OB to regulate odor discrimination and detection. Dopamine accomplishes these tasks through numerous, complex mechanisms in both neural structures. In this review, we provide an overview of the established and emerging research on these mechanisms and describe similarities and differences in dopamine expression and modulation of synaptic transmission in the retinas and OBs of various vertebrate organisms. This includes discussion of dopamine neurons’ morphologies, potential identities, and biophysical properties along with their contributions to circadian rhythms and stimulus-driven synthesis, activation, and release of dopamine. As dysregulation of some of these mechanisms may occur in patients with Parkinson’s disease, these symptoms are also discussed. The exploration and comparison of these two separate dopamine populations shows just how remarkably similar the retina and OB are, even though they are functionally distinct. It also shows that the modulatory properties of dopamine neurons are just as important to vision and olfaction as they are to motor coordination and neuropsychiatric/neurodegenerative conditions, thus, we hope this review encourages further research to elucidate these mechanisms.
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Affiliation(s)
- Kirill S Korshunov
- Department of Biological Science, Florida State University, Tallahassee, FL, United States.,Program in Neuroscience, Florida State University, Tallahassee, FL, United States
| | - Laura J Blakemore
- Department of Biological Science, Florida State University, Tallahassee, FL, United States.,Program in Neuroscience, Florida State University, Tallahassee, FL, United States
| | - Paul Q Trombley
- Department of Biological Science, Florida State University, Tallahassee, FL, United States.,Program in Neuroscience, Florida State University, Tallahassee, FL, United States
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10
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Silverstein SM, Demmin DL, Schallek JB, Fradkin SI. Measures of Retinal Structure and Function as Biomarkers in Neurology and Psychiatry. Biomark Neuropsychiatry 2020. [DOI: 10.1016/j.bionps.2020.100018] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
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11
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Belluscio V, Bergamini E, Tramontano M, Orejel Bustos A, Allevi G, Formisano R, Vannozzi G, Buzzi MG. Gait Quality Assessment in Survivors from Severe Traumatic Brain Injury: An Instrumented Approach Based on Inertial Sensors. SENSORS 2019; 19:s19235315. [PMID: 31816843 PMCID: PMC6928771 DOI: 10.3390/s19235315] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/06/2019] [Revised: 11/15/2019] [Accepted: 11/28/2019] [Indexed: 12/21/2022]
Abstract
Despite existing evidence that gait disorders are a common consequence of severe traumatic brain injury (sTBI), the literature describing gait instability in sTBI survivors is scant. Thus, the present study aims at quantifying gait patterns in sTBI through wearable inertial sensors and investigating the association of sensor-based gait quality indices with the scores of commonly administered clinical scales. Twenty healthy adults (control group, CG) and 20 people who suffered from a sTBI were recruited. The Berg balance scale, community balance and mobility scale, and dynamic gait index (DGI) were administered to sTBI participants, who were further divided into two subgroups, severe and very severe, according to their score in the DGI. Participants performed the 10 m walk, the Figure-of-8 walk, and the Fukuda stepping tests, while wearing five inertial sensors. Significant differences were found among the three groups, discriminating not only between CG and sTBI, but also for walking ability levels. Several indices displayed a significant correlation with clinical scales scores, especially in the 10 m walking and Figure-of-8 walk tests. Results show that the use of wearable sensors allows the obtainment of quantitative information about a patient’s gait disorders and discrimination between different levels of walking abilities, supporting the rehabilitative staff in designing tailored therapeutic interventions.
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Affiliation(s)
- Valeria Belluscio
- Department of Movement, Human and Health Sciences, University of Rome “Foro Italico”, Interuniversity Centre of Bioengineering of the Human Neuromusculoskeletal System, P.zza Lauro de Bosis 15, 00135 Roma, Italy; (V.B.); (E.B.); (M.T.); (A.O.B.)
- IRCSS Fondazione Santa Lucia, Via Ardeatina 306, 00179 Roma, Italy; (G.A.); (R.F.); (M.G.B.)
| | - Elena Bergamini
- Department of Movement, Human and Health Sciences, University of Rome “Foro Italico”, Interuniversity Centre of Bioengineering of the Human Neuromusculoskeletal System, P.zza Lauro de Bosis 15, 00135 Roma, Italy; (V.B.); (E.B.); (M.T.); (A.O.B.)
| | - Marco Tramontano
- Department of Movement, Human and Health Sciences, University of Rome “Foro Italico”, Interuniversity Centre of Bioengineering of the Human Neuromusculoskeletal System, P.zza Lauro de Bosis 15, 00135 Roma, Italy; (V.B.); (E.B.); (M.T.); (A.O.B.)
- IRCSS Fondazione Santa Lucia, Via Ardeatina 306, 00179 Roma, Italy; (G.A.); (R.F.); (M.G.B.)
| | - Amaranta Orejel Bustos
- Department of Movement, Human and Health Sciences, University of Rome “Foro Italico”, Interuniversity Centre of Bioengineering of the Human Neuromusculoskeletal System, P.zza Lauro de Bosis 15, 00135 Roma, Italy; (V.B.); (E.B.); (M.T.); (A.O.B.)
| | - Giulia Allevi
- IRCSS Fondazione Santa Lucia, Via Ardeatina 306, 00179 Roma, Italy; (G.A.); (R.F.); (M.G.B.)
| | - Rita Formisano
- IRCSS Fondazione Santa Lucia, Via Ardeatina 306, 00179 Roma, Italy; (G.A.); (R.F.); (M.G.B.)
| | - Giuseppe Vannozzi
- Department of Movement, Human and Health Sciences, University of Rome “Foro Italico”, Interuniversity Centre of Bioengineering of the Human Neuromusculoskeletal System, P.zza Lauro de Bosis 15, 00135 Roma, Italy; (V.B.); (E.B.); (M.T.); (A.O.B.)
- Correspondence: ; Tel.: +39-063673-3522
| | - Maria Gabriella Buzzi
- IRCSS Fondazione Santa Lucia, Via Ardeatina 306, 00179 Roma, Italy; (G.A.); (R.F.); (M.G.B.)
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12
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Veys L, Vandenabeele M, Ortuño-Lizarán I, Baekelandt V, Cuenca N, Moons L, De Groef L. Retinal α-synuclein deposits in Parkinson's disease patients and animal models. Acta Neuropathol 2019; 137:379-395. [PMID: 30721408 DOI: 10.1007/s00401-018-01956-z] [Citation(s) in RCA: 71] [Impact Index Per Article: 14.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2018] [Revised: 12/22/2018] [Accepted: 12/22/2018] [Indexed: 12/21/2022]
Abstract
Despite decades of research, accurate diagnosis of Parkinson's disease remains a challenge, and disease-modifying treatments are still lacking. Research into the early (presymptomatic) stages of Parkinson's disease and the discovery of novel biomarkers is of utmost importance to reduce this burden and to come to a more accurate diagnosis at the very onset of the disease. Many have speculated that non-motor symptoms could provide a breakthrough in the quest for early biomarkers of Parkinson's disease, including the visual disturbances and retinal abnormalities that are seen in the majority of Parkinson's disease patients. An expanding number of clinical studies have investigated the use of in vivo assessments of retinal structure, electrophysiological function, and vision-driven tasks as novel means for identifying patients at risk that need further neurological examination and for longitudinal follow-up of disease progression in Parkinson's disease patients. Often, the results of these studies have been interpreted in relation to α-synuclein deposits and dopamine deficiency in the retina, mirroring the defining pathological features of Parkinson's disease in the brain. To better understand the visual defects seen in Parkinson's disease patients and to propel the use of retinal changes as biomarkers for Parkinson's disease, however, more conclusive neuropathological evidence for the presence of retinal α-synuclein aggregates, and its relation to the cerebral α-synuclein burden, is urgently needed. This review provides a comprehensive and critical overview of the research conducted to unveil α-synuclein aggregates in the retina of Parkinson's disease patients and animal models, and thereby aims to aid the ongoing discussion about the potential use of the retinal changes and/or visual symptoms as biomarkers for Parkinson's disease.
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Guo L, Normando EM, Shah PA, De Groef L, Cordeiro MF. Oculo-visual abnormalities in Parkinson's disease: Possible value as biomarkers. Mov Disord 2018; 33:1390-1406. [DOI: 10.1002/mds.27454] [Citation(s) in RCA: 41] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2017] [Revised: 05/16/2018] [Accepted: 05/18/2018] [Indexed: 12/16/2022] Open
Affiliation(s)
- Li Guo
- Glaucoma and Retinal Degenerative Disease Research Group, Institute of Ophthalmology; University College London; London UK
| | - Eduardo M. Normando
- Glaucoma and Retinal Degenerative Disease Research Group, Institute of Ophthalmology; University College London; London UK
- Western Eye Hospital, Imperial College Healthcare National Health Service Trust; London UK
- Imperial College Ophthalmology Research Group, Department of Surgery and Cancer, Imperial College London; London UK
| | - Parth Arvind Shah
- Glaucoma and Retinal Degenerative Disease Research Group, Institute of Ophthalmology; University College London; London UK
| | - Lies De Groef
- Glaucoma and Retinal Degenerative Disease Research Group, Institute of Ophthalmology; University College London; London UK
- Neural Circuit Development and Regeneration Research Group, Department of Biology; University of Leuven; Leuven Belgium
| | - M. Francesca Cordeiro
- Glaucoma and Retinal Degenerative Disease Research Group, Institute of Ophthalmology; University College London; London UK
- Western Eye Hospital, Imperial College Healthcare National Health Service Trust; London UK
- Imperial College Ophthalmology Research Group, Department of Surgery and Cancer, Imperial College London; London UK
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Schwitzer T, Schwan R, Angioi-Duprez K, Giersch A, Lalanne L, Albuisson E, Laprevote V. Delayed bipolar and ganglion cells neuroretinal processing in regular cannabis users: The retina as a relevant site to investigate brain synaptic transmission dysfunctions. J Psychiatr Res 2018; 103:75-82. [PMID: 29783078 DOI: 10.1016/j.jpsychires.2018.04.021] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/16/2017] [Revised: 04/25/2018] [Accepted: 04/30/2018] [Indexed: 12/23/2022]
Abstract
Cannabis use is widespread worldwide, but the impact of smoking cannabis regularly on brain synaptic transmission has only been partially elucidated. The retina is considered as an easy means of determining dysfunction in brain synaptic transmission. The endocannabinoid system is involved in regulating retinal synaptic transmission, which might also be affected by tobacco. Previous preliminary results have shown impairments in retinal ganglion cell response in cannabis users. Here, we test the extent to which earlier retinal levels-bipolar cells and photoreceptors-are affected in cannabis users, i.e. by the association of tobacco and cannabis. We recorded pattern (PERG) and flash (fERG) ERG in 53 regular cannabis users and 29 healthy controls. Amplitude and peak time of P50 and N95 (PERG) and of a- and b-waves (fERG) were evaluated. Cannabis users showed a significant increase in PERG N95 peak time and in fERG light-adapted 3.0 b-wave peak time, compared with controls (p = 0.0001 and p = 0.002, respectively; Mann-Whitney U test). No significant difference was found between the groups in terms of wave amplitude (p = 0.525 and p = 0.767 for the N95 and light-adapted 3.0 b-wave amplitude respectively; Mann-Whitney U test). The results demonstrated delayed ganglion and bipolar cell responses in cannabis users. These results reflect a delay in the transmission of visual information from the retina to the brain. This retinal dysfunction may be explained by an effect of cannabis use on retinal synaptic transmission. Main limitations of these results concern tobacco and alcohol use that differed between groups. The consequences of these anomalies on visual perception along with the molecular mechanisms underlying this retinal dysfunction should be explored in future human and animal studies.
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Affiliation(s)
- Thomas Schwitzer
- Pôle Hospitalo-Universitaire de Psychiatrie d'Adultes du Grand Nancy, Centre Psychothérapique de Nancy, Laxou, France; EA7298, INGRES, Université de Lorraine, Vandœuvre-lès-Nancy, France; INSERM U1114, Fédération de Médecine Translationnelle de Strasbourg, Pôle de Psychiatrie, Centre Hospitalier Régional Universitaire de Strasbourg, Strasbourg, France.
| | - Raymund Schwan
- Pôle Hospitalo-Universitaire de Psychiatrie d'Adultes du Grand Nancy, Centre Psychothérapique de Nancy, Laxou, France; INSERM U1114, Fédération de Médecine Translationnelle de Strasbourg, Pôle de Psychiatrie, Centre Hospitalier Régional Universitaire de Strasbourg, Strasbourg, France; Maison des Addictions, CHRU Nancy, Nancy, France
| | | | - Anne Giersch
- INSERM U1114, Fédération de Médecine Translationnelle de Strasbourg, Pôle de Psychiatrie, Centre Hospitalier Régional Universitaire de Strasbourg, Strasbourg, France
| | - Laurence Lalanne
- INSERM U1114, Fédération de Médecine Translationnelle de Strasbourg, Pôle de Psychiatrie, Centre Hospitalier Régional Universitaire de Strasbourg, Strasbourg, France; Pôle de Psychiatrie et d'addictologie, Fédération de Médecine Translationnelle de Strasbourg, Centre Hospitalier Régional Universitaire de Strasbourg, Strasbourg, France
| | - Eliane Albuisson
- Pôle S(2)R, PARC, BIOBASE, CHRU Nancy, Vandoeuvre lès Nancy, France; Université de Lorraine, Faculté de Médecine, InSciDens, Vandoeuvre lès Nancy, France; Université de Lorraine, CNRS, IECL, Nancy, France
| | - Vincent Laprevote
- Pôle Hospitalo-Universitaire de Psychiatrie d'Adultes du Grand Nancy, Centre Psychothérapique de Nancy, Laxou, France; EA7298, INGRES, Université de Lorraine, Vandœuvre-lès-Nancy, France; INSERM U1114, Fédération de Médecine Translationnelle de Strasbourg, Pôle de Psychiatrie, Centre Hospitalier Régional Universitaire de Strasbourg, Strasbourg, France; Maison des Addictions, CHRU Nancy, Nancy, France
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He SB, Liu CY, Chen LD, Ye ZN, Zhang YP, Tang WG, Wang BD, Gao X. Meta-Analysis of Visual Evoked Potential and Parkinson's Disease. PARKINSON'S DISEASE 2018; 2018:3201308. [PMID: 30123489 PMCID: PMC6079328 DOI: 10.1155/2018/3201308] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/21/2018] [Revised: 05/20/2018] [Accepted: 06/03/2018] [Indexed: 11/18/2022]
Abstract
BACKGROUND Previous studies suggested that visual evoked potential (VEP) was impaired in patients with Parkinson's disease (PD), but the results were inconsistent. METHODS We conducted a systematic review and meta-analysis to explore whether the VEP was significantly different between PD patients and healthy controls. Case-control studies of PD were selected through an electronic search of the databases PubMed, Embase, and the Cochrane Central Register of Controlled Trials. We calculated the pooled weighted mean differences (WMDs) and 95% confidence intervals (CIs) between individuals with PD and controls using the random-effects model. RESULTS Twenty case-control studies which met our inclusion criteria were included in the final meta-analysis. We found that the P100 latency in PD was significantly higher compared with healthy controls (pooled WMD = 6.04, 95% CI: 2.73 to 9.35, P=0.0003, n=20). However, the difference in the mean amplitude of P100 was not significant between the two groups (pooled WMD = 0.64, 95% CI: -0.06 to 1.33, P=0.07) based on 10 studies with the P100 amplitude values available. CONCLUSIONS The higher P100 latency of VEP was observed in PD patients, relative to healthy controls. Our findings suggest that electrophysiological changes and functional defect in the visual pathway of PD patients are important to our understanding of the pathophysiology of visual involvement in PD.
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Affiliation(s)
- Song-bin He
- Department of Neurology, Zhoushan Hospital, Wenzhou Medical University, Zhoushan 316021, China
| | - Chun-yan Liu
- Department of Critical Care Medicine, Huzhou Central Hospital, Huzhou 313000, China
| | - Lin-di Chen
- Department of Neurology, Zhoushan Hospital, Wenzhou Medical University, Zhoushan 316021, China
| | - Zhi-nan Ye
- Department of Neurology, Taizhou Municipal Hospital, Taizhou 318000, China
| | - Ya-ping Zhang
- Department of Neurology, Taizhou Municipal Hospital, Taizhou 318000, China
| | - Wei-guo Tang
- Department of Neurology, Zhoushan Hospital, Wenzhou Medical University, Zhoushan 316021, China
| | - Bin-da Wang
- Department of Neurology, Zhoushan Hospital, Wenzhou Medical University, Zhoushan 316021, China
| | - Xiang Gao
- Department of Nutritional Sciences, The Pennsylvania State University, USA
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16
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Bandini F. On the role of visual electrophysiology in Parkinson’s disease. Parkinsonism Relat Disord 2017; 45:97. [DOI: 10.1016/j.parkreldis.2017.09.005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/26/2017] [Accepted: 09/03/2017] [Indexed: 10/18/2022]
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17
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Measurement of spontaneous blinks in patients with Parkinson's disease using a new high-speed blink analysis system. J Neurol Sci 2017; 380:200-204. [DOI: 10.1016/j.jns.2017.07.035] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2016] [Revised: 07/19/2017] [Accepted: 07/24/2017] [Indexed: 11/23/2022]
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18
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Schwitzer T, Schwan R, Bubl E, Lalanne L, Angioi-Duprez K, Laprevote V. Looking into the brain through the retinal ganglion cells in psychiatric disorders: A review of evidences. Prog Neuropsychopharmacol Biol Psychiatry 2017; 76:155-162. [PMID: 28336492 DOI: 10.1016/j.pnpbp.2017.03.008] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/05/2017] [Revised: 03/06/2017] [Accepted: 03/19/2017] [Indexed: 01/11/2023]
Abstract
Psychiatry and neuroscience research need novel approaches to indirectly investigate brain function. As the retina is an anatomical and developmental extension of the central nervous system (CNS), changes in retinal function may reflect neurological dysfunctions in psychiatric disorders. The last and most integrated retinal relay before visual information transfer to the brain is the ganglion cell layer. Here, based on collected arguments, we argue that these cells offer a crucial site for indirectly investigating brain function. We describe the anatomical and physiological properties of these cells together with measurements of their functional properties named pattern electroretinogram (PERG). Based on ganglion cell dysfunctions measured with PERG in neurological disorders, we argue for the relevance of studying ganglion cell function in psychiatric research. We review studies that have evaluated ganglion cell function in psychiatric and addictive disorders and discuss how changes in PERG measurements could be functional markers of pathophysiological mechanisms of psychiatric disorders.
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Affiliation(s)
- Thomas Schwitzer
- Pôle Hospitalo-Universitaire de Psychiatrie d'Adulte du Grand Nancy, Centre Psychothérapique de Nancy, Laxou, France; EA7298, INGRES, Université de Lorraine, Vandœuvre-lès-Nancy, France; INSERM U1114, Fédération de Médecine Translationnelle de Strasbourg, Département de Psychiatrie, Centre Hospitalier Régional Universitaire de Strasbourg, Strasbourg, France.
| | - Raymund Schwan
- Pôle Hospitalo-Universitaire de Psychiatrie d'Adulte du Grand Nancy, Centre Psychothérapique de Nancy, Laxou, France; EA7298, INGRES, Université de Lorraine, Vandœuvre-lès-Nancy, France; Maison des Addictions, CHRU Nancy, Nancy, France
| | - Emanuel Bubl
- Saarland University Medical Center, Department for Psychiatry and Psychotherapy, Homburg, Germany
| | - Laurence Lalanne
- INSERM U1114, Fédération de Médecine Translationnelle de Strasbourg, Département de Psychiatrie, Centre Hospitalier Régional Universitaire de Strasbourg, Strasbourg, France
| | | | - Vincent Laprevote
- Pôle Hospitalo-Universitaire de Psychiatrie d'Adulte du Grand Nancy, Centre Psychothérapique de Nancy, Laxou, France; EA7298, INGRES, Université de Lorraine, Vandœuvre-lès-Nancy, France; Maison des Addictions, CHRU Nancy, Nancy, France
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19
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Nguyen CTO, Hui F, Charng J, Velaedan S, van Koeverden AK, Lim JKH, He Z, Wong VHY, Vingrys AJ, Bui BV, Ivarsson M. Retinal biomarkers provide "insight" into cortical pharmacology and disease. Pharmacol Ther 2017; 175:151-177. [PMID: 28174096 DOI: 10.1016/j.pharmthera.2017.02.009] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
The retina is an easily accessible out-pouching of the central nervous system (CNS) and thus lends itself to being a biomarker of the brain. More specifically, the presence of neuronal, vascular and blood-neural barrier parallels in the eye and brain coupled with fast and inexpensive methods to quantify retinal changes make ocular biomarkers an attractive option. This includes its utility as a biomarker for a number of cerebrovascular diseases as well as a drug pharmacology and safety biomarker for the CNS. It is a rapidly emerging field, with some areas well established, such as stroke risk and multiple sclerosis, whereas others are still in development (Alzheimer's, Parkinson's, psychological disease and cortical diabetic dysfunction). The current applications and future potential of retinal biomarkers, including potential ways to improve their sensitivity and specificity are discussed. This review summarises the existing literature and provides a perspective on the strength of current retinal biomarkers and their future potential.
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Affiliation(s)
- Christine T O Nguyen
- Department of Optometry and Vision Sciences, University of Melbourne, Parkville, 3010, Victoria, Australia.
| | - Flora Hui
- Department of Optometry and Vision Sciences, University of Melbourne, Parkville, 3010, Victoria, Australia
| | - Jason Charng
- Department of Optometry and Vision Sciences, University of Melbourne, Parkville, 3010, Victoria, Australia
| | - Shajan Velaedan
- Department of Optometry and Vision Sciences, University of Melbourne, Parkville, 3010, Victoria, Australia
| | - Anna K van Koeverden
- Department of Optometry and Vision Sciences, University of Melbourne, Parkville, 3010, Victoria, Australia
| | - Jeremiah K H Lim
- Department of Optometry and Vision Sciences, University of Melbourne, Parkville, 3010, Victoria, Australia
| | - Zheng He
- Department of Optometry and Vision Sciences, University of Melbourne, Parkville, 3010, Victoria, Australia
| | - Vickie H Y Wong
- Department of Optometry and Vision Sciences, University of Melbourne, Parkville, 3010, Victoria, Australia
| | - Algis J Vingrys
- Department of Optometry and Vision Sciences, University of Melbourne, Parkville, 3010, Victoria, Australia
| | - Bang V Bui
- Department of Optometry and Vision Sciences, University of Melbourne, Parkville, 3010, Victoria, Australia
| | - Magnus Ivarsson
- Department of Optometry and Vision Sciences, University of Melbourne, Parkville, 3010, Victoria, Australia
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The Endocannabinoid System in the Retina: From Physiology to Practical and Therapeutic Applications. Neural Plast 2016; 2016:2916732. [PMID: 26881099 PMCID: PMC4736597 DOI: 10.1155/2016/2916732] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2015] [Accepted: 11/23/2015] [Indexed: 01/11/2023] Open
Abstract
Cannabis is one of the most prevalent drugs used in industrialized countries. The main effects of Cannabis are mediated by two major exogenous cannabinoids: ∆9-tetrahydroxycannabinol and cannabidiol. They act on specific endocannabinoid receptors, especially types 1 and 2. Mammals are endowed with a functional cannabinoid system including cannabinoid receptors, ligands, and enzymes. This endocannabinoid signaling pathway is involved in both physiological and pathophysiological conditions with a main role in the biology of the central nervous system. As the retina is a part of the central nervous system due to its embryonic origin, we aim at providing the relevance of studying the endocannabinoid system in the retina. Here, we review the distribution of the cannabinoid receptors, ligands, and enzymes in the retina and focus on the role of the cannabinoid system in retinal neurobiology. This review describes the presence of the cannabinoid system in critical stages of retinal processing and its broad involvement in retinal neurotransmission, neuroplasticity, and neuroprotection. Accordingly, we support the use of synthetic cannabinoids as new neuroprotective drugs to prevent and treat retinal diseases. Finally, we argue for the relevance of functional retinal measures in cannabis users to evaluate the impact of cannabis use on human retinal processing.
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21
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The emerging field of retinal electrophysiological measurements in psychiatric research: A review of the findings and the perspectives in major depressive disorder. J Psychiatr Res 2015; 70:113-20. [PMID: 26424430 DOI: 10.1016/j.jpsychires.2015.09.003] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/06/2015] [Revised: 08/15/2015] [Accepted: 09/08/2015] [Indexed: 02/08/2023]
Abstract
Major depressive disorder (MDD) is a severe mental illness leading to long-term disabilities. One of the current challenges in psychiatric research is to develop new approaches to investigate the pathophysiology of MDD and monitor drug response in order to provide better therapeutic strategies to the patients. Since the retina is considered as part of the central nervous system, it was suggested that it constitutes an appropriate site to investigate mental illnesses. In the past years, several teams assessed the retinal function of patients with mood disorders and many relevant abnormalities have been reported. Investigation of the retinal electrophysiological abnormalities in MDD remains a young emerging field, but we believe that the current findings are very promising and we argue that objective retinal electrophysiological measurements may eventually become relevant tools to investigate the pathophysiology of MDD. Here, we review the retinal abnormalities detected with objective electrophysiological measurements such as the flash electroretinogram (fERG), the pattern electroretinogram (PERG) and the electrooculogram (EOG) in patients with MDD. We discuss how these changes might reflect the pathophysiology of MDD in both clinical and scientific points of view, according especially to the monoamine neurotransmission deficiency hypothesis. We also discuss the technical details that must be taken into consideration for a potential use of the objective retinal electrophysiological measurements as tools to investigate the pathophysiology of MDD.
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22
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Nowacka B, Lubiński W, Honczarenko K, Potemkowski A, Safranow K. Bioelectrical function and structural assessment of the retina in patients with early stages of Parkinson's disease (PD). Doc Ophthalmol 2015; 131:95-104. [PMID: 25972299 PMCID: PMC4567588 DOI: 10.1007/s10633-015-9503-0] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2014] [Accepted: 05/07/2015] [Indexed: 11/09/2022]
Abstract
Purpose
To determine bioelectrical function and structural changes of the retina in patients with early stages of Parkinson’s disease (PD). Materials and methods Thirty-eight eyes of 20 patients with early idiopathic PD and 38 eyes of 20 healthy age- and sex-matched controls were ophthalmologically examined, including assessment of distance best-corrected visual acuity (DBCVA), slit lamp examination of the anterior and posterior segment of the eye, evaluation of the eye structures: paramacular retinal thickness (RT) and retinal nerve fiber layer (RNFL) thickness with the aid of OCT, and the bioelectrical function by full-field electroretinogram (ERG). Additionally, PD patients were interviewed as to the presence of dopamine-dependent visual functions abnormalities. Results In patients with early PD, statistically significant changes in comparison with the control group were observed in ERG. They contained a reduction in mean amplitudes of the scotopic a-wave (rod–cone response), the scotopic oscillatory potentials (OPs)—OP2 and OP3, the photopic b-wave, and a reduction in the overall index (OP1 + OP2 + OP3) and a prolongation of mean peak times of the scotopic OP1, OP2, OP3, OP4 (p < 0.05). A questionnaire concerning abnormalities of dopamine-dependent visual functions revealed that PD patients with abnormal peak times of OP1, OP2, and OP3 reported non-specific visual disturbances more frequently in comparison with PD patients with normal peak times of OPs. Other analyzed parameters of ERG, DBCVA, RT, and RNFL did not significantly differ between patients with PD and the control group. Conclusion In patients with early PD, bioelectrical dysfunction of the retina was observed in the ERG test, probably as a result of dopamine deficiency in the retina. The results of our study indicate that ERG may also be a useful tool for understanding the reason for non-specific visual disturbances occurring in PD patients.
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Affiliation(s)
- Barbara Nowacka
- Department of Ophthalmology, Pomeranian Medical University, Powstancow Wlkp. 72, 70-111, Szczecin, Poland.
| | - Wojciech Lubiński
- Department of Ophthalmology, Pomeranian Medical University, Powstancow Wlkp. 72, 70-111, Szczecin, Poland
| | | | | | - Krzysztof Safranow
- Department of Biochemistry and Medical Chemistry, Pomeranian Medical University, Szczecin, Poland
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23
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Müller AK, Blasberg C, Südmeyer M, Aktas O, Albrecht P. Photoreceptor layer thinning in parkinsonian syndromes. Mov Disord 2014; 29:1222-3. [PMID: 24925731 DOI: 10.1002/mds.25939] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2013] [Revised: 02/10/2014] [Accepted: 05/07/2014] [Indexed: 11/06/2022] Open
Affiliation(s)
- Ann-Kristin Müller
- Department of Neurology, Medical Faculty, Heinrich-Heine University Düsseldorf, Germany
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24
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Péran P, Catani S, Falletta Caravasso C, Nemmi F, Sabatini U, Formisano R. Supplementary Motor Area Activation Is Impaired in Severe Traumatic Brain Injury Parkinsonism. J Neurotrauma 2014; 31:642-8. [DOI: 10.1089/neu.2013.3103] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Affiliation(s)
- Patrice Péran
- INSERM, Imagerie Cérébrale et Handicaps Neurologiques, Centre Hospitalier Universitaire de Toulouse, Toulouse, France
- Université de Toulouse III, UPS, Imagerie Cérébrale et Handicaps Neurologiques, Centre Hospitalier Universitaire de Toulouse, Toulouse, France
| | | | | | - Federico Nemmi
- INSERM, Imagerie Cérébrale et Handicaps Neurologiques, Centre Hospitalier Universitaire de Toulouse, Toulouse, France
- Université de Toulouse III, UPS, Imagerie Cérébrale et Handicaps Neurologiques, Centre Hospitalier Universitaire de Toulouse, Toulouse, France
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25
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Hyett M, Parker G. Loss of light in the eyes: A window to melancholia. Med Hypotheses 2013; 81:186-91. [DOI: 10.1016/j.mehy.2013.05.008] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2013] [Accepted: 05/15/2013] [Indexed: 12/15/2022]
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26
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Foveal vision is impaired in Parkinson's disease. Parkinsonism Relat Disord 2013; 19:1-14. [DOI: 10.1016/j.parkreldis.2012.07.012] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/06/2010] [Revised: 07/16/2012] [Accepted: 07/21/2012] [Indexed: 11/23/2022]
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27
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Remodeling of the fovea in Parkinson disease. J Neural Transm (Vienna) 2012; 120:745-53. [DOI: 10.1007/s00702-012-0909-5] [Citation(s) in RCA: 50] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2012] [Accepted: 10/19/2012] [Indexed: 01/24/2023]
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28
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Alexander GE. Biology of Parkinson's disease: pathogenesis and pathophysiology of a multisystem neurodegenerative disorder. DIALOGUES IN CLINICAL NEUROSCIENCE 2012. [PMID: 22033559 PMCID: PMC3181806 DOI: 10.31887/dcns.2004.6.3/galexander] [Citation(s) in RCA: 276] [Impact Index Per Article: 23.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Parkinson's disease (PD) is the second most common movement disorder. The characteristic motor impairments - bradykinesia, rigidity, and resting tremor - result from degenerative loss of midbrain dopamine (DA) neurons in the substantia nigra, and are responsive to symptomatic treatment with dopaminergic medications and functional neurosurgery. PD is also the second most common neurodegenerative disorder. Viewed from this perspective, PD is a disorder of multiple functional systems, not simply the motor system, and of multiple neurotransmitter systems, not merely that of DA. The characteristic pathology - intraneuronal Lewy body inclusions and reduced numbers of surviving neurons - is similar in each of the targeted neuron groups, suggesting a common neurodegenerative process. Pathological and experimental studies indicate that oxidative stress, proteolytic stress, and inflammation figure prominently in the pathogenesis of PD. Yet, whether any of these mechanisms plays a causal role in human PD is unknown, because to date we have no proven neuroprotective therapies that slow or reverse disease progression in patients with PD. We are beginning to understand the pathophysiology of motor dysfunction in PD, but its etiopathogenesis as a neurodegenerative disorder remains poorly understood.
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Affiliation(s)
- Garrett E Alexander
- Department of Neurology, Emory University School of Medicine, Atlanta, Ga, USA
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29
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Interocular asymmetry of foveal thickness in Parkinson disease. J Ophthalmol 2012; 2012:728457. [PMID: 22900149 PMCID: PMC3415246 DOI: 10.1155/2012/728457] [Citation(s) in RCA: 50] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2012] [Revised: 06/03/2012] [Accepted: 06/03/2012] [Indexed: 01/19/2023] Open
Abstract
Purpose. To quantify interocular asymmetry (IA) of foveal thickness in Parkinson disease (PD) versus that of controls. Design. Prospective case-control series. Methods. In vivo assessment of foveal thickness of 46 eyes of 23 PD patients and 36 eyes of 18 control subjects was studied using spectral domain optical coherence tomography (SD-OCT). Inner versus outer layer retinal segmentation and macular volumes were quantified using the manufacturer's software, while foveal thickness was measured using the raw data from each eye in a grid covering a 6 by 6 mm area centered on the foveola in 0.25 mm steps. Thickness data were entered into MATLAB software. Results. Macular volumes differed significantly at the largest (Zone 3) diameter centered on the foveola (ETDRS protocol). By segmenting inner from outer layers, we found that the IA in PD is mostly due to changes on the slope of the foveal pit at the radial distances of 0.5 and 0.75 mm (1.5 mm and 1 mm diameter). Conclusions. About half of the PD patients had IA of the slope of the foveal pit. IA is a potentially useful marker of PD and is expected to be comparable across different SD-OCT equipment. Data of larger groups may be developed in future multicenter studies.
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Esteve-Rudd J, Fernández-Sánchez L, Lax P, De Juan E, Martín-Nieto J, Cuenca N. Rotenone induces degeneration of photoreceptors and impairs the dopaminergic system in the rat retina. Neurobiol Dis 2011; 44:102-15. [DOI: 10.1016/j.nbd.2011.06.009] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2011] [Revised: 05/24/2011] [Accepted: 06/16/2011] [Indexed: 12/21/2022] Open
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Fox DA, Hamilton WR, Johnson JE, Xiao W, Chaney S, Mukherjee S, Miller DB, O'Callaghan JP. Gestational lead exposure selectively decreases retinal dopamine amacrine cells and dopamine content in adult mice. Toxicol Appl Pharmacol 2011; 256:258-67. [PMID: 21703292 DOI: 10.1016/j.taap.2011.05.021] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2011] [Revised: 05/30/2011] [Accepted: 05/31/2011] [Indexed: 10/18/2022]
Abstract
Gestational lead exposure (GLE) produces supernormal scotopic electroretinograms (ERG) in children, monkeys and rats, and a novel retinal phenotype characterized by an increased number of rod photoreceptors and bipolar cells in adult mice and rats. Since the loss of dopaminergic amacrine cells (DA ACs) in GLE monkeys and rats contributes to supernormal ERGs, the retinal DA system was analyzed in mice following GLE. C57BL/6 female mice were exposed to low (27 ppm), moderate (55 ppm) or high (109 ppm) lead throughout gestation and until postnatal day 10 (PN10). Blood [Pb] in control, low-, moderate- and high-dose GLE was ≤ 1, ≤ 10, ~25 and ~40 μg/dL, respectively, on PN10 and by PN30 all were ≤ 1 μg/dL. At PN60, confocal-stereology studies used vertical sections and wholemounts to characterize tyrosine hydroxylase (TH) expression and the number of DA and other ACs. GLE dose-dependently and selectively decreased the number of TH-immunoreactive (IR) DA ACs and their synaptic plexus without affecting GABAergic, glycinergic or cholinergic ACs. Immunoblots and confocal revealed dose-dependent decreases in retinal TH protein expression and content, although monoamine oxidase-A protein and gene expression were unchanged. High-pressure liquid chromatography showed that GLE dose-dependently decreased retinal DA content, its metabolites and DA utilization/release. The mechanism of DA selective vulnerability is unknown. However, a GLE-induced loss/dysfunction of DA ACs during development could increase the number of rods and bipolar cells since DA helps regulate neuronal proliferation, whereas during adulthood it could produce ERG supernormality as well as altered circadian rhythms, dark/light adaptation and spatial contrast sensitivity.
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Affiliation(s)
- Donald A Fox
- College of Optometry, University of Houston, Houston, TX 77204-2020, USA.
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Gagné AM, Hébert M. Atypical pattern of rod electroretinogram modulation by recent light history: a possible biomarker of seasonal affective disorder. Psychiatry Res 2011; 187:370-4. [PMID: 20832867 DOI: 10.1016/j.psychres.2010.08.010] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/07/2009] [Revised: 08/09/2010] [Accepted: 08/12/2010] [Indexed: 10/19/2022]
Abstract
Our goal was to challenge both normal controls and patients with seasonal affective disorders (SAD) to various light histories and then measure their retinal response modulation using the electroretinogram (ERG) in both winter and summer. In winter and summer, 11 normal controls and 12 SAD patients were exposed to three different light conditions for 1 h (10,000, 100 and 5 lux) followed by an ERG. Groups showed similar ERG amplitudes in the 100 lux condition. Compared with the 100-lux condition, in controls, the ERG response was significantly increased in the 5-lux condition; in SAD, it was significantly decreased in the 10,000-lux condition. This pattern was present in both seasons. This is the first time a retinal response modulation anomaly has been observed in SAD patients in both the depressed and euthymic states. Retinal response modulation may represent an interesting biomarker of the disease for future research.
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Affiliation(s)
- Anne-Marie Gagné
- Research Center University Laval Robert-Giffard, Québec, QC, Canada
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Setting the pace for retinal development: environmental enrichment acts through insulin-like growth factor 1 and brain-derived neurotrophic factor. J Neurosci 2009; 29:10809-19. [PMID: 19726638 DOI: 10.1523/jneurosci.1857-09.2009] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Environmental enrichment strongly affects visual system maturation both at retinal and cortical levels. Which molecular pathways are activated by an enriched environment (EE) to regulate visual system development has not been clarified. Here, we show that early [postnatal day 1 (P1) to P7] insulin-like growth factor 1 (IGF-1) injections in the eyes of non-EE rat pups mimic EE effects both in increasing BDNF levels in the retinal ganglion cell layer at P10 and in determining a more adult-like retinal acuity, assessed with pattern electroretinogram at P25. Blocking IGF-1 action in EE animals during the same early postnatal time window by injecting the IGF-1 receptor antagonist JB1 prevents EE effects both on BDNF expression and on retinal acuity maturation. Reducing BDNF expression in the retina of IGF-1-treated rats prevents IGF-1 effects on retinal acuity development. Finally, we show that tyrosine hydroxylase (TH) expression is increased in the retina of P10 EE and IGF-1-treated rats and that blocking TH expression in EE animals prevents EE from affecting retinal acuity development. Thus, early levels of IGF-1 play a key role in mediating EE effects on retinal development through an action that requires BDNF and involves dopaminergic amacrine cell network.
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Retinopathy in Parkinson disease. J Neural Transm (Vienna) 2009; 116:1493-501. [DOI: 10.1007/s00702-009-0292-z] [Citation(s) in RCA: 92] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2009] [Accepted: 08/02/2009] [Indexed: 10/20/2022]
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Abstract
As a more complete picture of the clinical phenotype of Parkinson's disease emerges, non-motor symptoms have become increasingly studied. Prominent among these non-motor phenomena are mood disturbance, cognitive decline and dementia, sleep disorders, hyposmia and autonomic failure. In addition, visual symptoms are common, ranging from complaints of dry eyes and reading difficulties, through to perceptual disturbances (feelings of presence and passage) and complex visual hallucinations. Such visual symptoms are a considerable cause of morbidity in Parkinson's disease and, with respect to visual hallucinations, are an important predictor of cognitive decline as well as institutional care and mortality. Evidence exists of visual dysfunction at several levels of the visual pathway in Parkinson's disease. This includes psychophysical, electrophysiological and morphological evidence of disruption of retinal structure and function, in addition to disorders of 'higher' (cortical) visual processing. In this review, we will draw together work from animal and human studies in an attempt to provide an insight into how Parkinson's disease affects the retina and how these changes might contribute to the visual symptoms experienced by patients.
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Affiliation(s)
- Neil K Archibald
- Clinical Research Fellow, Clinical Ageing Research Unit, Newcastle University, Campus for Ageing and Vitality, Newcastle upon Tyne, NE4 5PL, UK.
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Correlation between retinal morphological and functional findings and clinical severity in Parkinson’s disease. Doc Ophthalmol 2007; 116:137-46. [DOI: 10.1007/s10633-007-9091-8] [Citation(s) in RCA: 152] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2007] [Accepted: 10/11/2007] [Indexed: 02/05/2023]
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Brandies R, Yehuda S. The possible role of retinal dopaminergic system in visual performance. Neurosci Biobehav Rev 2007; 32:611-56. [PMID: 18061262 DOI: 10.1016/j.neubiorev.2007.09.004] [Citation(s) in RCA: 72] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2007] [Revised: 09/23/2007] [Accepted: 09/28/2007] [Indexed: 10/22/2022]
Abstract
It is a well-known fact that the retina is one of the tissues in the body, which is richest in dopamine (DA), yet the role of this system in various visual functions remains unclear. We have identified 13 types of DA retinal pathologies, and 15 visual functions. The pathologies were arranged in this review on a net grid, where one axis was "age" (i.e., from infancy to old age) and the other axis the level of retinal DA (i.e., from DA deficiency to DA excess, from Parkinson disorder to Schizophrenia). The available data on visual dysfunction(s) is critically presented for each of the DA pathologies. Special effort was made to evaluate whether the site of DA malfunction in the different DA pathologies and visual function is at retinal level or in higher brain centers. The mapping of DA and visual pathologies demonstrate the pivot role of retinal DA in mediating visual functions and also indicate the "missing links" in our understanding of the mechanisms underlying these relationships.
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Affiliation(s)
- R Brandies
- Department of Pharmacology, Israel Institute for Biological Research, P.O. Box 19, Ness Ziona 74100, Israel
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Palmowski-Wolfe AM, Perez MT, Behnke S, Fuss G, Martziniak M, Ruprecht KW. Influence of Dopamine Deficiency in Early Parkinson’s Disease on the Slow Stimulation Multifocal-ERG. Doc Ophthalmol 2006; 112:209-15. [PMID: 16791744 DOI: 10.1007/s10633-006-0008-8] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/08/2006] [Indexed: 10/24/2022]
Abstract
PURPOSE In animal studies intravitreal injection of tetrodotoxin (TTX) results in mfERG waveform changes similar to those observed in glaucoma. As TTX blocks amacrine as well as ganglion cells, there is still a question regarding the underlying cell population responsible for these changes in waveform. In an attempt to assess the contribution of the amacrine cells to these changes, a mfERG was obtained from patients with Parkinson's disease as some amacrine cells are mediated by dopamine, a substance lacking in Parkinson's. METHODS Eight patients with early Parkinson's disease underwent ophthalmologic examination, testing of contrast sensitivity and electrophysiological examination according to ISCEV standard at least 12 h following their last medication with Dopamine. A slow stimulation mfERG was obtained with a stimulus base interval of 53.3 ms and with a stimulus base interval of 106.6 ms. During MF-ERG recordings 103 hexagons stimulated the central 50 deg of the retina simultaneously and independently (m-sequence 2(13), L(max): 200 cd/m(2), approximately 100% contrast). RESULTS Contrast sensitivity and ISCEV standard electrophysiological testing was unremarkable. When the mfERG was analyzed, only four patients had an adequate signal-to-noise ratio to allow further data analysis - one of whom was diagnosed with a multi system atrophy in retrospect. The first order response component was analyzed at a filter setting of 10-300 Hz and at 100-300 Hz (OPs) and compared to mfERGs of a control group. On average, in patients, the amplitude of N1P1 was slightly lower in the central and nasal response averages. When the three OPs at a latency of 72-89 ms were analyzed in the 53.3 ms base interval recording, the most marked difference in amplitude was observed in the superior nasal response average of the first OP. Here a mean amplitude of 1.3 nV/deg(2) in patients compared to a mean amplitude of 1.9 nV/deg(2) in the control group (P: 0.08). DISCUSSION In contrast to our previous findings in NTG, there was a consistent presence of three OPs. Under the stimulus conditions applied, we did not find an influence of dopaminergic amacrine cells on the mfERG in our patients with moderate stages of Parkinsion's. The difficulties in obtaining an adequate signal-to noise ratio due to e.g. muscle artifacts even in Parkinson patients of moderate disease stages render a success of mfERG recording in patients with more advanced stages unlikely. The question of the influence of dopaminergic amacrine cells on the mfERG could possibly be addressed using MPDT in animal research.
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Tobimatsu S, Celesia GG. Studies of human visual pathophysiology with visual evoked potentials. Clin Neurophysiol 2006; 117:1414-33. [PMID: 16516551 DOI: 10.1016/j.clinph.2006.01.004] [Citation(s) in RCA: 110] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2005] [Revised: 12/28/2005] [Accepted: 01/11/2006] [Indexed: 11/19/2022]
Abstract
Visual evoked potentials (VEPs) offer reproducible and quantitative data on the function of the visual pathways and the visual cortex. Pattern reversal VEPs to full-field stimulation are best suited to evaluate anterior visual pathways while hemi-field stimulation is most effective in the assessment of post-chiasmal function. However, visual information is processed simultaneously via multiple parallel channels and each channel constitutes a set of sequential processes. We outline the major parallel pathways of the visual system from the retina to the primary visual cortex and higher visual areas via lateral geniculate nucleus that receive visual input. There is no best method of stimulus selection, rather visual stimuli and VEPs' recording should be tailored to answer specific clinical and/or research questions. Newly developed techniques that can assess the functions of extrastriate as well as striate cortices are discussed. Finally, an algorithm of sequential steps to evaluate the various levels of visual processing is proposed and its clinical use revisited.
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Affiliation(s)
- Shozo Tobimatsu
- Department of Clinical Neurophysiology, Neurological Institute, Graduate School of Medical Sciences, Kyushu University, 3-1-1 Maidashi, Higashi-Ku, Fukuoka 812-8582, Japan.
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Abstract
Amblyopia has a 1.6-3.6% prevalence, higher in the medically underserved. It is more complex than simply visual acuity loss and the better eye has sub-clinical deficits. Functional limitations appear more extensive and loss of vision in the better eye of amblyopes more prevalent than previously thought. Amblyopia screening and treatment are efficacious, but cost-effectiveness concerns remain. Refractive correction alone may successfully treat anisometropic amblyopia and it, minimal occlusion, and/or catecholamine treatment can provide initial vision improvement that may improve compliance with subsequent long-duration treatment. Atropine penalization appears as effective as occlusion for moderate amblyopia, with limited-day penalization as effective as full-time. Cytidin-5'-diphosphocholine may hold promise as a medical treatment. Interpretation of much of the amblyopia literature is made difficult by: inaccurate visual acuity measurement at initial visit, lack of adequate refractive correction prior to and during treatment, and lack of long-term follow-up results. Successful treatment can be achieved in at most 63-83% of patients. Treatment outcome is a function of initial visual acuity and type of amblyopia, and a reciprocal product of treatment efficacy, duration, and compliance. Age at treatment onset is not predictive of outcome in many studies but detection under versus over 2-3 years of age may be. Multiple screenings prior to that age, and prompt treatment, reduce prevalence. Would a single early cycloplegic photoscreening be as, or more, successful at detection or prediction than the multiple screenings, and more cost-effective? Penalization and occlusion have minimal incidence of reverse amblyopia and/or side-effects, no significant influence on emmetropization, and no consistent effect on sign or size of post-treatment changes in strabismic deviation. There may be a physiologic basis for better age-indifferent outcome than tapped by current treatment methodologies. Infant refractive correction substantially reduces accommodative esotropia and amblyopia incidence without interference with emmetropization. Compensatory prism, alone or post-operatively, and/or minus lens treatment, and/or wide-field fusional amplitude training, may reduce risk of early onset esotropia. Multivariate screening using continuous-scale measurements may be more effective than traditional single-test dichotomous pass/fail measures. Pigmentation may be one parameter because Caucasians are at higher risk for esotropia than non-whites.
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Affiliation(s)
- Kurt Simons
- Pediatric Vision Laboratory, Krieger Children's Eye Center, Wilmer Institute, Johns Hopkins University School of Medicine, Baltimore, Maryland 21287-9028, USA
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Di Russo F, Incoccia C, Formisano R, Sabatini U, Zoccolotti P. Abnormal Motor Preparation in Severe Traumatic Brain Injury with Good Recovery. J Neurotrauma 2005; 22:297-312. [PMID: 15716635 DOI: 10.1089/neu.2005.22.297] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Movement-related cortical potentials (MRCPs) were examined in seven patients with severe traumatic brain injury (TBI) and 12 matched control subjects. All patients had clinically established good recovery by the time of testing. Flexion movements of the index finger of the left or right hand were recorded in two (alternating and repetitive) self-paced conditions and in one externally triggered condition. In control subjects, the bereitschaftspotential (BP) component of MRCP was detected approximately 2000 msec prior to movement onset in the self-paced conditions and was larger and earlier in the alternating compared to the repetitive condition. The BP component was absent in the externally triggered condition. In TBI patients, the BP was greatly reduced and no difference between the alternating-repetitive conditions was detected; in contrast, only small differences were present in the controls for the negative slope (NS) and MP components and no difference for the reafferent positivity (RAP) component. A dipole analysis indicated the supplementary motor area and the premotor area as the likely generators of BP and NS' components, respectively. Gradientrecalled echo magnetic resonance imaging allowed the detection of a number of small hypointense lesions primarily located in the frontal lobes, as in diffuse axonal injury. This pattern of results indicates a selective deficit in motor preparation and a relatively spared pattern of activation during and following movement in these patients. Imaging data appear generally consistent with the pattern of MRCPs observed in the patient group. Implications of these results for the problem of slowness in TBI patients are discussed.
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Affiliation(s)
- F Di Russo
- IRCCS, Fondazione Santa Lucia, Rome, Italy., Istituto Universitario di Scienze Motorie (IUSM), Rome, Italy.
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Wylie SA, Stout JC, Bashore TR. Activation of conflicting responses in Parkinson's disease: evidence for degrading and facilitating effects on response time. Neuropsychologia 2005; 43:1033-43. [PMID: 15769489 DOI: 10.1016/j.neuropsychologia.2004.10.008] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2004] [Revised: 10/14/2004] [Accepted: 10/21/2004] [Indexed: 11/29/2022]
Abstract
Response selection often occurs in a context of competition among conflicting responses. According to recent models, the basal ganglia may play an integral role in resolving this competition by focusing the selection and inhibition of responses. We hypothesized that basal ganglia dysfunction produced by Parkinson's disease (PD) disrupts selection among conflicting responses. Using a version of the Eriksen flanker task, we tested the specific prediction that individuals with PD would experience greater response interference when distractors in the visual field activate a response that conflicts with the target response. In addition, we investigated whether greater response interference induced by these distractors could actually reduce normal response time costs in PD when the task required production of the response opposite the target. Compared to 16 healthy controls (HC), 16 individuals with PD showed an exacerbated slowing when target and distracting stimuli corresponded to conflicting responses. No group differences occurred when targets and distractors corresponded to the same response. Furthermore, the slowing induced by the distractors was reduced in both groups, but more so in PD, when execution of a response opposite the target response (i.e. incompatible response) was required. Moreover, among individuals with PD, the magnitude of the interference produced by the distractors was related to clinical ratings of bradykinesia. These findings are consistent with the hypothesis that basal ganglia dysfunction due to Parkinson's disease disrupts processes that resolve response conflict.
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Affiliation(s)
- Scott A Wylie
- Department of Neurology, University of Virginia, Charlottesville, VA, USA
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Chapter 25 Visual dysfunction in disorders with altered dopaminergic neurotransmission. ACTA ACUST UNITED AC 2005. [DOI: 10.1016/s1567-4231(09)70222-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register]
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Bandini F, Pierantozzi M, Bodis-Wollner I. Parkinson's disease changes the balance of onset and offset visual responses: an evoked potential study. Clin Neurophysiol 2001; 112:976-83. [PMID: 11377254 DOI: 10.1016/s1388-2457(01)00531-4] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
OBJECTIVES We investigated whether the transient pattern onset and offset visual evoked potential (VEP) can distinguish between patients with Parkinson's disease (PD) and normal subjects. METHODS Two horizontal sinusoidal gratings differing in spatial frequency, i.e. 1 and 4 cycles per degree, were presented to 17 patients with PD and 16 age-matched control subjects. We analyzed the responses in the time-domain and measured the latencies and amplitudes of N1 and P1 to the onset and the offset of the stimulus; we also derived the measures of offset N1 and P1 amplitude responses 'normalized' to onset N1 and P1 amplitude values, respectively (amplitude ratios). RESULTS Absolute and normalized offset P1 amplitude is a distinguishing feature of PD patients from controls. Offset P1 amplitude was significantly larger in PD patients than in controls, particularly to the lower spatial frequency stimulus (P<0.01 for absolute and P<0.001 for normalized values, respectively). CONCLUSIONS We conclude that the pattern onset/offset VEP amplitude provides a simple measure to evaluate visual processing deficits in PD and could contribute to an understanding of the pathophysiology of these changes.
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Affiliation(s)
- F Bandini
- Department of Neurological and Visual Sciences, University of Genoa, Genoa, Italy
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Stanzione P, Bodis-Wollner I, Pierantozzi M, Semprini R, Tagliati M, Peppe A, Bernardi G. A mixed D1 and D2 antagonist does not replay pattern electroretinogram alterations observed with a selective D2 antagonist in normal humans: relationship with Parkinson's disease pattern electroretinogram alterations. Clin Neurophysiol 1999; 110:82-5. [PMID: 10348324 DOI: 10.1016/s0168-5597(98)00047-1] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
Abstract
The human retina produces a tuned response to stimuli of increasing spatial frequency reversed at a steady state. The peak amplitude response, at medium spatial frequencies, is decreased in Parkinson's disease and in normal subjects (n = 18) treated with a D2 dopaminergic antagonist (l-sulpiride). Here, we report that a mixed D1-D2 receptor antagonist (haloperidol) in normal subjects (n = 18) does not produce an amplitude decrease of medium spatial frequencies (SFs) responses but it decreases low-frequency response. It could argued that the increased dopamine release produced by the presynaptic D2 antagonistic action of haloperidol is subsequently counteracted at postsynaptic level by its D1 antagonistic effect, producing a net counterbalance at medium SFs. These data suggest that the two dopamine receptors may play different roles in the retinal function and in the origin of visual alterations in Parkinson's disease.
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